KTM 390 125 200 250 Duke Rear Sprocket Upgraded to 50 Teeth

[@gnagsaar_]

Also i just realised that putting the chain lock on the inside of the sprocket would be like 100 times better :p then we would not have one black link on the «show side» of the bike :p

[@MotoMirius]

When I have the use of both hands I’m going to refit that link because the only way I could get it on was to put the plate on backwards. But I think you are right anyway if you are using a coloured chain so I will give that a go 👍

[@gnagsaar_]

Moto Mirius yeah I gotta flip mine too 😂 I was in a rush tho :p My gf was for real standing behind me waiting to ride 😂 u can see in the vid when she just leavs without me 😂

[@MotoMirius]

@@gnagsaar_ I did see, it made me laugh - builds always take too long :D

[@gnagsaar_]

Moto Mirius It was only like 1-1,5 hrs :p But I said it would be less tho 😂 I tough the calipter adapter was a spacer, not a new slider. So I had to split the caliper. And the MF C-clip on the front sprocket didn't have bloody holes in it 😂 So those two things was prob half the job 😂 Or felt like it alteast :p I'ts not like anyone uses a week to swap the wheels,sprockets and chain 😏😏

[@robheg382]

Best motorcycle channel, thanks so much. The techno music is hard to take, but it's a small price to pay for the great content.

[@MotoMirius]

Thanks. Music will never make everyone happy sadly.

[@robheg382]

@@MotoMirius True. Might be fingernails on a chalkboard to me, but I'm sure many just love it. I think Gypsy Kings would make awesome background music. 😁

[@iPritamHD]

Good job there,old man!

[@MotoMirius]

Ha! Cheers. Much appreciated Pritam. Skäl. David

[@C.A.MARSUPIAL]

Excellent video. Thanks. I'm getting a orange chain and sprocket soon so to see the chain on helps me.

[@MotoMirius]

Glad it helped and thanks

[@sumatrajohnny]

Another great video David. Very orange!!

[@MotoMirius]

Cheers John. Makes a change from black! Wonder how fast it is now 🤔. Hope to see you around soon. Skäl. David

[@woodybuddyjack]

I was wondering once you fit a new chain should you clean it (with chain cleaner) and then lube it out of the box? Or just spray chain lube on it or nothing at all? I just got a new chain and sprockets and dont know what to do.

[@MotoMirius]

New chain comes prelubed. You could clean it all off, but it would be an odd choice.

[@woodybuddyjack]

@@MotoMirius thanks for the reply. Much appreciated :)

[@sairohith6794]

I'm planning to put a duke 390 sprocket(front - 14, rear - 46 teeth) in my duke 250(front - 15, rear - 45 teeth stock). 1. What changes will I experience, top speed + mileage or more acceleration? 2. Do I need a replacement chain? 3. A video uploaded from motorcyclist magazine say a software calibration is required so the rpm's are displayed correctly, is it required for ktm duke 250? (I noticed you didn't make any calibrations) Enjoying your content very informative!

[@MotoMirius]

1. 390 has a 15 front, 45 rear sprocket. I don't have a 250 - effects will depend on what power the 250 makes. With a small bike you cannot use the online charts which show the theoretical changes which assume unlimited power and torque. Since I'm not clear what changes you intend to make, it's hard to comment. But I will say that swapping between the two ratios above will have only a small effect since the changes at front and back reverse each other. 2. It depends on what change you intend to make, as above I'm not clear, but unless your current chain is quite new and in good condition then a new chain is always a good idea. 3. Many magazine articles and videos are written by people who have copy/pasted from the internet and they have limited understanding of how things actually work, so I would treat magazine articles as entertainment - which is what they are intended to be, not as a source of information. Modern bikes read rpm directly from the engine as part of the engine management software. If you mean recalibrate the speedo, then the Duke reads speed from the front wheel - even if it read speed from the rear wheel it would not need recalibrating - that is only necessary if speed were read from the gearbox which I doubt any modern bike with abs does.

[@sairohith6794]

​@@MotoMirius Duke 250 puts out 30 PS @ 9000 rpm & 24 Nm @ 7500 rpm. My usage is city riding, where I need instant acceleration around 4000-6000rpm, which duke 250 clearly lacks unlike a duke 200 or 390. 250 doesn't provide the kick you feel in acceleration in lower rpms(unless I rev the engine). I also travel occasional rides on weekends, where I should be able to cruise around 100-120 km/h. However, city use is my main priority. 1. What changes do you recommend for the above use? Thank you for your suggestions..

[@nizarrazzouk9385]

What is the top speed now? I'm sure it's less.. But how much?

[@MotoMirius]

Drops top speed by about 10 - 15 mph. I’m going to have a new video up soon where I’m modifying the gearing again and talking about the effects in real life rather than what you see on a chart. Skäl. David

[@jakenelson66]

Hey got a question for you, is the stock chain long enough to run the 50 tooth?

[@MotoMirius]

Nope. But it will allow you to go one tooth down at the front which is the equivalent of a 48 tooth. Skäl. David

[@jakenelson66]

Moto Mirius alright thank you I appreciate it!

[@Lumalee-]

can you do a follow up video on how the upgrade affected the bike.

[@MotoMirius]

I will see what I can do. I’m thinking of a video it might fit into. Skäl. David

[@steveroberts2533]

Yeah you make it look easy 👍

[@MotoMirius]

And you can do it easily too!

[@PhantomRides]

Nice job there

[@MotoMirius]

Thanks Phantom. Much appreciated 👍 Skäl. David

[@stangoodvibes]

awesome video(s). So... the 120 link chain fits the 50 teeth rear sprocket exactly?

[@MotoMirius]

There was no editing of that in this video - as you saw it did require repositioning of the wheel. So long as a chain isn't too short, too long is easy to deal with by removing links. Skäl David

[@stangoodvibes]

@@MotoMirius Thanks for the reply. I wasn't sure. These videos are really helpful btw - great work!

[@hereandnow424]

wow. great job and video!

[@MotoMirius]

Thank you very much! Skäl David

[@matthewweaver6967]

Great vid man. Where’d you get that chain I’ve been looking for one like that for ages

[@MotoMirius]

Thanks, from memory it's an RK - so a random chain example chainsandsprockets.co.uk/products/rk-orange-hd-rx-ring-motorcycle-bike-chain-520-xso-120-links-with-rivet-link

[@matthewweaver6967]

@@MotoMirius thank you bro, your vids have always helped me. I’ve saved so much money from watching your videos. Easily saved over £500 on labour charges 😂

[@dujeklanac1639]

Hey can i do 48 in the rear and stock in the front whit stock chain or whitch chain do i need, and will pigyback make my bike go faster, and shod i upgrade air filter when ading pigyback

[@MotoMirius]

No. You will need a longer chain. Typically the next longer chain and shorten to length - probably 114 to 116 from memory. You can upgrade the air filter yes, might as well while you are at it.

[@dujeklanac1639]

@@MotoMirius thanks a lot didnt think you woud respond, and is pigyback worth it will i gain some speed, i know whit 48 sprocket it will go a bit faster so will pigyback boost it

[@MotoMirius]

Piggyback tends not to boost unless you are getting a map professionally built to do that. 48 sprocket may make it faster but it will also mean gear changes more quickly @@dujeklanac1639

[@dujeklanac1639]

@@MotoMirius damn gear changing is kiling me bought new duke a month ago, i think i wont invest more money in it except exhaust, will sell it in a year and buy biger bike only problem is i am 16 and i can go for less than 35kw at 18, but yea... Thanks a lot

[@MotoMirius]

Don't assume a big bike will solve all your u issues. 125 are just a starter but there is a reason why I mostly ride a 390 and don't ride the bigger bikes - roads are too busy, too many cameras, speed limits are reducing - big bikes are incredibly frustrating as you just can't ride more than a fraction of their power and abilities. Great for impressing your friends but that is about it@@dujeklanac1639

[@Gaming_live_10]

Hello i have duke 250 can i change 14 teeth to 13 teeth front sprocket bcoz im ride my bike 2 gear low rpm so my bike front sprocket knowing ??

[@MotoMirius]

I'm not a big fan of fitting the 13. Yes you can do it, but you need to be very careful and check regularly to make sure that the chain does not damage the swinging arm.

[@damienhowell3727]

Quality video welldone, may I ask where did u ordered the 50 sprocket from? I have an orange one for my rc supposed to match but the 6 attachment holes on the sprocket seem further apart then the standard 45 already attached, is there an size adjuster that could be brought to make it fit hmm?

[@MotoMirius]

Thanks, much appreciated. This was a sprocket being supplied by Bagoros Performance at the time. The stock 45 tooth - part number 90510051045 was fitted to both Duke and RC from 2014 to 2021. In 2022 they fitted 95810051045 (the sprocket from the Adventure) to both Duke and RC as well as the Adventure, and appear to still be fitting it. I claim no expertise on the RC, but I would be a little dubious about the sprocket you have purchased. Edit - I see the later RC 125 was using the same sprocket as the Dukes - some other special RC models appear to have different sprockets which are only used on the RC.

[@pflolssa]

What was that white pasty stuff you put on the two sides of the chain under where you put the master link on?? Where you connect the two points of the new orange chain. It wasn't some type of glue I imagine so I can't figure out what it could have been 😳

[@MotoMirius]

It would be a lithium based grease - came with the chain for that purpose, so I can't confirm exactly what it is, but typically lithium.

[@pflolssa]

@@MotoMirius mine must have been Missing that! Good to know

[@arunam716]

Hii.. it is possible to install duke 250's chain sprocket in duke 200... wot are the benefits and drawbacks?? Plzz reply to my question... it is possible to ride in off road terrains?

[@MotoMirius]

I think no, the gearbox output shaft I think is a different size. Benefits and drawbacks is that it changes the gearing - but whether its a benefit or a drawback will depend on what you are trying to do. Too small a front sprocket can cause wear on the swinging arm. It's possible to ride off road - but you are limited by the suspension and close fit of the front mudguard - many people ride these off road, some have modified them, but maybe you should consider the Adventure?

[@tinks43]

Nice bit of added bling & kool tunes. Still no closer to getting back in the saddle?

[@MotoMirius]

I’ve had the first quick ride now but just 100 yards up the road. Not officially approved by the doctor yet 🤔. But no videos for a while now as I’ve run out of light jobs to do ☹️. Skäl. David

[@gameforce2003]

The orginal chain is so bad, after 10k km I needed to change both sporckets and chain, got the same chain, but the powerpart rear sprocket :)

[@MotoMirius]

It’s really important to keep the chain well lubricated otherwise it’s life is reduced and a worn chain will take out the sprockets. 👍. Skäl. David

[@gameforce2003]

@@MotoMirius Jupp :) I was a little to lazy about that, but now i do its so much often

[@Kuper133]

Ответь пожалуйста на мой вопрос. У меня Duke 250 я когда открутил крышку передней звезды из одного из отверстий вытекло не много масла. Отверстие которое посередине. Чтобы это могло быть? Не опасно ли это? Масло машинное.

[@MotoMirius]

Это нормально. Один из болтов проходит через кожух двигателя. Это проблема только в том случае, если вы управляете велосипедом без болта.

[@Kuper133]

@@MotoMirius Thank you very much for your reply! And I was already starting to worry. I was wondering where the oil might come from. You have a very useful channel. I signed up and watched a lot of videos.

[@prithamcharlesvardhanapu5870]

Does this effects the speedometer readings compared to stock sprocket ?

[@MotoMirius]

No. Speedo reads from ABS sensor on front wheel so is not affected by engine or transmission.

[@panchochilli11]

Hey David, love your videos. Just wondering if you have ever lubed a Cush Drive during your rear tire changes?

[@MotoMirius]

Thanks. I have, but I'm unconvinced that it helps.

[@ezioauditore2376]

Love your series! Would be very interesting to know how this upgrade affected performance.

[@MotoMirius]

Hi Elia. It’s a difficult question to answer. 15 mph off top speed, faster off the line but you need to change gear more often so it’s not something I’d recommend as a performance upgrade. Skäl. David

[@ezioauditore2376]

@@MotoMirius thanks very much for your answer! If I may ask your opinon, problably losing one tooth on the front sprocket would be a cheaper and more reasonable mod?

[@DerSchweiz3r]

This 50T is not aviable to buy? Please help, i need one!

[@MotoMirius]

They are out there. This appears to be the same one. 1fngr.com/products/1fngr-rear-sprocket?_pos=2&_sid=4adf7f659&_ss=r Skäl. David

[@ulby3731]

You have a new speed test from 0-100 km/h (after replacement )?

[@MotoMirius]

Good question. Not at the moment. Would need some practice to confirm. Faster acceleration is balanced by more gear changes if you are looking at the 0 to 60mph range. That measure doesn’t take into account normal riding such as pulling away from lights or roll on acceleration say for over taking which is where the faster acceleration becomes more important. Skäl. David

[@ulby3731]

@@MotoMirius Thanks, but Sprocket upgrade must improve acceleration, because have bigger radius than stock

[@MotoMirius]

Yes. That’s what I said. But trying to compare it by looking at 0 to 100 is not necessarily a good test of how much better the bike accelerates in normal riding. Compared to a stock setup you will need an extra gear change to get to 100.

[@MotoMirius]

One thing I can offer you is that a Honda NC750 had a very hard time getting away from me and only did it once we hit the motorway and he could use a faster top speed.

[@ulby3731]

@@MotoMiriusgreat, thanks !

[@stubbenrr6622]

The speedo measures nearly perfect speed. Because you changed the sprocket, does the speed sensor read the speed wrong? Would like to know before I do this on my own bike

[@MotoMirius]

I"m led to believe that the speed is read from the ABS sensor - as such it measures the speed of the wheels and so gearing has no impact - but changing tyre size would impact it. Skäl David

[@stubbenrr6622]

@@MotoMirius okay thanks

[@fredstah714]

Hi. What size for from and back I can go for this duke? I want taller and wider tire for this bike. Thanks

[@MotoMirius]

You can have taller or wider, you can't really have both. The problem with the Duke is that KTM chose an odd rim size - the only tyres that fit were intended for the smaller Japanese superbikes. If you are serious about this then I'd suggest you get a pair of spoke wheels from a Huskvana 401 and have different rims laced on. I believe that the biggest tyre that could fit on the back rim is a 170/70 - but it might not actually fit into the space and you would need a matching profile front tyre otherwise the bike handling would be seriously compromised. Good luck!

[@fredstah714]

Moto Mirius I just read from forums that 120/60-17 front and 160/60-17 rear fits. What do you think?

[@KTM.SPINXY]

hi mate got 125 also don't do long journeys can I change my front sprocket to get a bit more lower end speed is it worth doing and what sprocket should I buy .thanks 😉

[@MotoMirius]

With a 125 I don't recommend going down on the front as you can create wear on the swinging arm. Try something like a 48 on the back. Now whether its worth it is really subjective, some love it, some hate it.

[@KTM.SPINXY]

@@MotoMirius thanks mate appreciate advice I leave it be

[@KTM.SPINXY]

Just wondering why would it wear the swing arm ?

[@MotoMirius]

@@KTM.SPINXY because when the rear wheel drops down, the chain can against the top of the swinging arm. It's why there is a rubber buffer there - but it wears through and if it does the chain cuts into the swinging arm. A smaller front sprocket puts the chain closer to the swinging arm.

[@KTM.SPINXY]

Moto sorry to bug u .I'm quite a novice as u can tell lol I have this pipe on bike that was on ut when I got it from superbike factory and don't know wot pipe it is .also I had a 2016 rc from them both bikes randomly cut out when clutched in have u ever came across this problem .my duke cut out twice on me today 😒. Can't upload pic of pipe sorry

[@u.s.e.r.x.]

Hey man..I am having a bike pulsar 150 here in India..i want to upgrade from 15t to 13t would it be too much..?? Ratio 2.93:1 to 3.46:1 keeping the same chain..

[@MotoMirius]

Too much for what? You haven't told me what you want to happen.

[@u.s.e.r.x.]

@@MotoMirius i want increased acceleration..

[@MotoMirius]

@@u.s.e.r.x. You will get increased acceleration but bear in mind you will need to change gears more often so you may in the end be slower to accelerate - depending on how good you are at changing gear.

[@u.s.e.r.x.]

@@MotoMirius it's not that expensive though..so i think it's worth I'll try both 14t and 13t its about 10 dollars eacj

[@MotoMirius]

@@u.s.e.r.x. If you watch my video on changing the front sprocket you will see that I recommend it for that very reason.

[@sandorturanszky2401]

On my 2021 Duke 125, I noticed that the chain slack is uneven. When I adjust the tension at its tightest point, the chain hits the guard when I go slowly over bumps with the clutch fully engaged. It feels like the rear sprocket isn’t 100% centered, and since there are no guides for the sprocket, I imagine it could be off by about 1mm to one side. Do you have any idea how this can be fixed?

[@MotoMirius]

This is caused by wear on the chain. Now you have seen this you will understand why I do not take part in arguments about exactly how to measure the chain - because it is only valid with a new chain - and most bikes have worn chains. You may need to consider whether you need a new chain.

[@sandorturanszky2401]

@@MotoMirius I bought it with 1,400 miles on the clock, but the chain was very rusty. The previous owner had kept it outside and hadn’t used it since February this year. I’ve just finished the restoration work, and the previous owner had it since new. After cleaning the chain, I noticed the issues mentioned above while adjusting the tension. Visually, the chain appears to be in great condition, and the O-rings all seem intact. Neither the front nor rear sprocket shows any signs of wear. I’m wondering if the rust caused enough wear on the chain for these problems to happen.

[@MotoMirius]

@@sandorturanszky2401 What normally kills chains is not mileage, it is indeed rust. And for this O-rings do not help. O-rings seal the gap between the end of the pin and the side plate. But chain wear mostly happens from water leaking down the inside of the plate and the roller - where there is no seal. If the sprockets are good then you might just be OK with a new chain.

[@sandorturanszky2401]

@@MotoMirius will replace the chain then. Thanks!

[@jeremylalruatzela9387]

4:06 you put grece in that rod, that rod will never get inside the bearing

[@MotoMirius]

It's more about avoiding corrosion that will make it hard to take apart again.

[@elmo3575]

@@MotoMirius What kind of grease did you use?

[@mrtopbreak333]

have you ever done a video on replacing the tappet shims ?

[@MotoMirius]

No. It is on my list of videos to make, but the video will be high level - this is not something for people who are not confident in mechanics because getting it wrong is very, very expensive.

[@mrtopbreak333]

@@MotoMirius No problem there for me.

[@paulmcmanus8018]

Hi there I'm trying to buy the same chain and 50 tooth sprocket that you have fitted to your ktm duke in this video please could you help me find and buy the same one thanks

[@MotoMirius]

These were bought from Bagoros Performance - I think they only do a 48 tooth now - and a bigger stunt sprocket.

[@vrk1131]

I have a duke 125. I am not interested in going top speed. But if I'm going for a long trip I want to go smooth on atleast 80 to 85kmph. Should I upgrade to this ? please reply.

[@MotoMirius]

The 125 is fitted with the same chainset as the 125, which hinders its acceleration and top speed. I suggest watching this video kzbin.info/www/bejne/nKa7hamvmc11o8U as it shows the improvement of fitting a similar sprocket to a stock 125. As I don't have a 125 I can't comment on the smoothness at 80 kph.

[@billmillar8148]

hi i was thinking about trying a 16/45 sprocket set to lower revs on motorway ,would the 390 lose much punch low down ,have you ever tried the set up

[@MotoMirius]

16/45 or 15/43 is a popular choice but the latter can require a chain change. I've not tried the setup as I rarely use this bike on the motorway, but if I did I would be tempted to do so. I've covered this in more depth in this video - kzbin.info/www/bejne/qJC4oplngN1jp9E

[@springy-2112]

A good idea to up the sprocket size as you have other high speed bikes.. you got me thinking now as i rarely use overdrive on mine..👍🏻☮❤

[@MotoMirius]

Cheers Springy. Better acceleration but with the price of changing gear more often. I’m interested to see how this works out. Skäl. David

[@peterpanimg]

Can a sprocket change reduce gear changes required? I mean a setting, where the bike can hold lower speeds in higher gears. That would be fantastic for traffic congested roads. Any help appreciated

[@MotoMirius]

A larger rear sprocket or smaller front sprocket means your bike will be moving more slowly at any given rpm/gear combination. If you do a lot of slow riding this can be a good thing which is one reason stunt riders do this. Once you start to accelerate you will need to change gear more often to hit the same speed as you would on stock gearing. Skäl. David

[@eliseovazquez6546]

Le pusiste piñón 16 y corona 52 . Eso que t daría??? Un pokito de salida y mayo velocidad final o como seria??

[@MotoMirius]

La relación lo es todo. La parte trasera 52 reduce la velocidad de la bicicleta y le da más aceleración. 16 revierte esto, reduce el impacto. Skäl David

[@Kuper133]

Мириус, я недавно на своем Дьюк 250 натянул цепь и проехав 60-70 км заметил что ее опять нужнр натянуть. Это не проблема цепи что ее нужно менять? Мотцикл не новый 2016 год. Звезды в хорошем состоянии. Она же не могла ослабнуть? Я хорошо затянул все болты.

[@MotoMirius]

Цепь не тянется на такое расстояние. Есть две возможности, которые наиболее вероятны. Старая цепь будет иметь затянутые и ослабленные точки. Необходимо проверить натяжение в самой натянутой точке цепи. Если вы проверили натяжение в ослабленном месте, то цепь будет повреждена в натянутом месте, что приведет к значительному ослаблению всей цепи. Или вы сейчас измеряете неплотную точку, и она, конечно, не соответствует спецификации.

[@Kuper133]

@@MotoMirius Я понял. Спасибо большое за ответ. Вы очень помогаете мне.

[@Kuper133]

@@MotoMirius Скажите, а у Вас есть видео как регулировать задний амортизатор? Я искал и не нашел.

[@premkamavaram3596]

Will it avoid chain sound or any other idea to avoid chain sound??. Please do reply.

[@MotoMirius]

It depends why you have chain sound. If your chain is stretched or damaged, if the sprockets are worn then the chain and sprockets need to be replaced. If the noise is because the chain needs adjustment or is not aligned then correct that first. Skäl. David

[@pannodramavisuals2667]

If we install Duke 390 sprocket in Duke 200. Will it increases the acceleration of the bike or? Please do reply ;)

[@MotoMirius]

Yes so long as there are more teeth but you will need a longer chain. I suggest going one tooth smaller on the front instead. Skäl. David

[@adamzelorubungen6301]

What is the top speed of 56tooth sprocket in the ktm duke 390?

[@MotoMirius]

Simple maths suggests a 20% reduction in top speed. Most people fitting this are not interested in impact on top speed. Skäl. David

[@adamzelorubungen6301]

@@MotoMirius salamat.👍👍👍

[@ghazalehostovar3913]

it's impossible to take the rear sprocket off, the bolts are too dam tight. you did it so easy🤦🏻‍♀️

[@MotoMirius]

Normally the bolts have loctite - it's all about the right leverage, normally I have the wheel upright so you are pushing down. You may need heat.

[@markmitchell8448]

Hi I'm thinking of getting the rok bagoros 48 tooth rear sprocket for my 125 & keeping it once I get through my A licence for the 390 how good are these sprockets do they wear out quickly

[@MotoMirius]

I don’t have the current version but so long as you keep up with the chain piling and adjustment then wear shouldn’t be much of an issue.

[@dujeklanac1639]

Hey did you get the 48 tooth sprocket and did you leave the front sprocket and the chain stock or? And did you notoce any change

[@varunthakur45]

Did you change the sprocket on duke 125 or 390? Also what was the stock number of teeth?

[@MotoMirius]

Hi Varun. 390 Duke. Stock teeth is 45. Skäl. David

[@MotoMirius]

Was that a question?

[@rogermacaranas3299]

Great idea powerful acceleration

[@MotoMirius]

Thanks. Skäl. David

[@foodfirst499]

Can the same be done for 390? Does it require engine tuning ?

[@MotoMirius]

It is a 390. You can change the sprocket ratios to suit your riding style on all the small Dukes. It doesn't require engine tuning. You may find this useful kzbin.info/www/bejne/qJC4oplngN1jp9E Skäl David

[@jonstiles3003]

What’s the torque spec for the Front and rear sprocket

[@MotoMirius]

Front sprocket carrier 12Nm Rear 27Nm

[@futuregadgetgo2921]

I like to know the torque you set for tightening for sprocket and rear axle rod re-tightening?

[@MotoMirius]

Sprocket 27 Nm. Rear axle nut 98 Nm. Skäl. David

[@yourajbadgujar7837]

after modification mileage increase or decrease?

[@MotoMirius]

The bike runs slower in any gear and accelerates faster so mileage decreases. But I’ve not measured just what the difference is. Skäl. David

[@-R-.]

What is the torque on the sproket bolt?

[@MotoMirius]

27 Nm. Skäl. David

[@-R-.]

@@MotoMirius thank you for your video and quick reply!

[@pogingbagsikmagno4976]

Were did you get your new chain and rear sprocket

[@MotoMirius]

Chain and sprocket are from Bagoros Performance

[@pogingbagsikmagno4976]

@@MotoMirius thanks mates

[@plazek84]

Hello, what parts do I need?! From 125 to 390

[@MotoMirius]

To convert a 125 to 390?

[@plazek84]

@MotoMirius yes please 👏

[@MotoMirius]

@@plazek84 Basically everything. Don't mix generations - gear position sensors changed, etc. So complete engine unit, all electronics, airbox (or just modify for intake runner) and wiring. From 2017 390 is ride by wire, so throttle body and twist grip with wiring. Fuel pump is different and I'm not sure if it fits the 125 tank - but people seem to get by with the 125 fuel pump. You should consider swapping out the suspension too given the increased power. As you can see this is an expensive option to take, so you only do it if the 125 is the only bike you have - much cheaper to pass any tests etc and buy the 390 - since the price difference between 125 and 390 is very small.

[@plazek84]

Thank You

[@franciscorivera5979]

Can u pass a link on a front + rear sprocket + chain kit that u would recommend? Salute from 🇵🇷

[@MotoMirius]

Rear sprocket and chain links are in the description - not that Bagaros Performance now have a 48 tooth rear sprocket if you are heading in that direction. Driven - in the US - do front sprockets. What ratio will depend on which bike you have and what sort of riding you do. Skäl David

[@franciscorivera5979]

Moto Mirius I got a 2019 duke 390. I was thinking going -1 teeth (44 teeth) on the rear and stock (16 teeth) on front. What u think of that combination?

[@franciscorivera5979]

Moto Mirius because I do a lot of highway im trying to lower my rpm’s on high speed

[@ChronicTHCBlaze]

Hi David you're from England, can u review England's own Triumph Bonneville bobber or speed master??

[@MotoMirius]

Not in the scope of my channel. I would recommend The Missenden Flyer. Not sure if he has reviewed those bikes. Skäl. David

[@ChronicTHCBlaze]

@@MotoMirius it's fine and nevermind, these technical videos of yours are very useful since I own a 390 duke myself, goodnight I'm a subscriber!!

[@nuclear_angelx1111]

bro what do u think of going 52teeth for rc390..? (I'm going to install soon)

[@MotoMirius]

Depends what you want to get from it. Stunting, drifting, low speed riding then sure. If you want faster bike then maybe not. Skäl. David

[@nuclear_angelx1111]

@@MotoMirius for stunts and mad acceleration bro.. what do u think?

[@MotoMirius]

Works. But as far as acceleration goes it’s not as simple as people assume. You will lose time changing gear and that slows you down.

[@nuclear_angelx1111]

@@MotoMirius thanks dude

[@pedroplatzerdamotta]

Does the 50t provides a faster 0 - 60?

[@MotoMirius]

Only if you are very good at gear changes. It will get you off the line faster but you will squeeze the power band into a smaller MPH range, so you will change gear at least once more than if you were on stock gearing. Skäl David

[@moderbicker525]

If the top speed was 120km how many km it goes now?

[@MotoMirius]

I would say it lost about 15mph. I wouldn't recommend if you need to ask about top speed.

[@Rwhatify]

Why didn’t you change the front sprocket to the 520 pitch?

[@MotoMirius]

Front sprocket is stock OEM. Skäl. David

[@Rwhatify]

The factory KTM front sprocket is not 520 pitch to match the 520 chain and 520 rear sprocket.

[@MotoMirius]

It is in the UK

[@Rwhatify]

Moto Mirius Sorry, I didn’t realize the factory is 520.

[@MotoMirius]

No problem. I try not to make assumptions that the bikes are the same in all the markets 👍

[@sreenatht8845]

What is the difference in acceleration of rc125

[@MotoMirius]

125 is very different from 390, so best demonstrated on a 125 kzbin.info/www/bejne/nKa7hamvmc11o8U

[@tamilguys393]

How to increase 125 top speed tell me sir😭😭

[@MotoMirius]

Watch this video kzbin.info/www/bejne/nKa7hamvmc11o8U

[@bboy2932]

Hi David, i want to fix this 50 teeth sprocket & chain on my 390. can you help me with the link to buy it. i am from india...

[@MotoMirius]

Hi. You can buy it from Rok Bagoros Parts - they ship to India. I will put a link in the description of the video as well. Skäl. David

[@Unni_verse]

Sir the link is not working... And I am not able to find the part in Website.. they have a 56t part which seems like too much..

[@MotoMirius]

Hi, the link text indicates that the 50 tooth is now not available. I know people who use the 56 tooth but it is not right for me. I suggest that you consider a front sprocket with one less tooth instead. Skäl. David

[@lalaraj8765]

चाइनीस पॉकेट का प्राइस कितना है

[@elmo3575]

What kind of grease did you use?

[@MotoMirius]

For what part?

[@elmo3575]

04:05 for the rod. And which grease would you generally recommend I use for the moveable parts of the bike?

[@MotoMirius]

@@elmo3575 well that is a minefield of opinions. I use general purpose grease for the rod - it isn't so much to lubricate it as it is to prevent the metal from corroding which makes the rod hard to remove. General purpose grease or lithium grease is generally OK - which is not the same as white lithium grease. There are other greases out there such as moly but general purpose car type grease is a good starting point.

[@elmo3575]

@@MotoMirius Thank you very much.

[@anumandhanmadhu4252]

This chain sprocket is fit for ns 200

[@bunnyhopes8165]

Yes it does

[@brayanpulgarin3532]

The chain is 420 ? 520 ?

[@MotoMirius]

520. Some people use 410 to save weight when racing but wear will be accelerated

[@gnagsaar_]

IT seems like alot faster job here on YT Then your IG :p

[@MotoMirius]

I can’t imagine why you’d think that 😂😂. Skäl. David

[@gnagsaar_]

Moto Mirius 😂

[@chandanagamage3339]

Mr David , is possible to upgrade tire size 160 to kTM 125 duke

[@MotoMirius]

I have heard of people trying it but since the rim size remains the same, this can lead to a narrower tyre profile.

[@chandanagamage3339]

Moto Mirius thank you sir

[@fertilesanglyne9335]

Hello sir can i get this sprocket from India

[@MotoMirius]

They deliver worldwide. Check their website.

[@stangoodvibes]

You know I watch these videos and it all seems so easy and then I try it on my bike... and. In this instance at about 1:48 when you remove the chain guard I assume you just take the little sticky-uppy bit off the rearset and the long bolt that holds the front of the chain guard just slides out easily after undoing. On *my* bike however - there rearset is one piece, and the long bolt won't slide all the way out before it hits the inside of the rearset. So I have to take the rearset off before I can get the chainguard off :-| *sigh*

[@stangoodvibes]

p.s. I have gone for a Tyga aluminium 42T. I find that my Duke is very jerky with the stock gearing - possibly to the IXIL exhaust, K&N filter, and the ECB mapping. It's considerably lighter as well being the earlier 2015 model + antigravity battery + a few other ligher parts (and no rear seat or pillion pegs and handles) etc. I read the KTM Duke 390 forums and quite a few posters said that the longer gearing from less rear teeth really helped smooth out the ride. So I would be interested to know how you found having the bigger rear sprocket. it seems ideal for BangBros to do his stunts on, but for everyday riding? (I'm assuming you aren't popping wheelies and stoppies and slides everywhere LOL)

[@stangoodvibes]

addendum: I didn't need to remove the chain guard to remove the back wheel (doh!). However I think your nice chain and my DID chain would look better without the chain guard (I've seen photos of it removed online). Is the chain guard really necessary? My bike came with an aftermarket aluminium chain guard, but i don't really like it that much TBH.

[@MotoMirius]

Ah, it's always looks easy when someone else does it doesn't it? It's one reason I try to make my videos long enough to include all the detail - which some people moan about, but I suspect the key issue is that the gen 1 bike is superficially the same, but as you've found, small but important differences do change between models.

[@MotoMirius]

Doesn't everyone wheelie off junctions and slide round the corners? Rok uses a 56 tooth on his stunt bikes I believe. Seriously though optimal gearing is much to do about where you ride, and yes, a lot of people seem to like the longer gearing. My commuting has changed so I'm playing with the gearing again now so I'm currently back close to stock. I don't have any issues with rough running because I don't ride in that rev range, for me this is a specialist bike I use for a certain type of riding. The bigger sprocket was perfect as it puts the bike at higher revs in every gear to achieve the same speed which takes you out of the rough range and puts you further into the peak acceleration range. This is bad for high speed riding, but when you spend your time filtering around and through stationary traffic it's much better because the last thing you want to do is to stall it when you are at full lock in trials riding mode in front of someone bonnet as you change lanes to access a bigger gap on that side. The additional acceleration also helps when you get to the front of the queue because the car drivers have spent ages getting there and are impatient to put their foot down when the lights change so it's just rude to get in their way. This guy lives just down the road from me. kzbin.info

[@MotoMirius]

Chain guards are important and are fitted for two reasons - it stops the chain oil slinging off onto the tyre and you, but more importantly when the chain snaps it can take a chunk out of your calf muscle - I know a couple of riders who have a nasty scar there. Which isn't to say you can't modify it, just leave enough protection to catch the end of the chain before it whips into your leg - just a short stretch is all need.

[@arinelliluca4611]

a cosa serve fare quello che hai fatto , sono ignorante in maniera

[@MotoMirius]

Cambia il rapporto della bici. Maggiore controllo a bassa velocità, qualche perdita di velocità massima - a volte.

[@afteroffice_yt]

👍

[@MotoMirius]

👍 Skäl. David

[@jaycar5979]

it would of helped instead of playing music to tell us what the steps you were doing. most youtube motorbikes don't understand we all don't have your knowledge so we come here for it. so learn us not just show with music. for example do we all know what a sprocket is, how the teeth ratio makes us go slower faster at higher speeds, how/where you got the chain and sprocket and why you picked them

[@MotoMirius]

Thanks for the feedback James, always appreciated to get constructive feedback. What you are asking would be a very different video, so maybe I will consider that. This is just an installation video, so limited to that because otherwise there is too much information and the video would be very long and not very useful for someone who just wanted to install a sprocket. Purchase links are in the description. I have a different video giving an overview of the gearing choices for this bike and why you might choose them. But even that doesn't cover everything on that subject. For example, teeth ratio does not always make you go faster or slower in the way you might expect or the way that the online charts predict - it works with big powerful bikes, but with smaller bikes the change can produce the opposite effect to what you expect. Skäl David

[@winswilson5040]

Top speed plzz

[@MotoMirius]

Top speed depends on many things especially including rider weight and if you are lying flat on the tank - try this video for a similar sprocket - kzbin.info/www/bejne/nKa7hamvmc11o8U

[@hanzakihasashi3033]

Its written 125 not 390?

[@MotoMirius]

Yes that is correct. It’s a 390 with 125 decals. You can buy them at any KTM dealer. Skäl. David

[@hanzakihasashi3033]

Ohh I now I got it I was confused cos their was written 125🙆

[@janhorber5681]

Oh oke now I got it. I was confused too because of the orange rims and the the orange front framepart.

[@SammyL0k]

Not a one off, these oem chains were a joke

[@akhilraj5861]

Price

[@MotoMirius]

You’ll find it on the Bagoros Performance website

[@akhilraj5861]

@@MotoMirius tnku

[@akhilraj5861]

How mach

[@MotoMirius]

bagorosperformance.com/product/sprocket-48t-ktm-duke-125-200-250-390/

[@frankusujan3233]

can you suggest me number of teeth for duke 200 for front and rare sprocket...

[@MotoMirius]

What are you trying to achieve? Skäl. David

[@frankusujan3233]

Better acceleration..

[@MotoMirius]

I would suggest going one tooth smaller on the front sprocket and leave the rear sprocket. You can check how that works for you. You should be able to use your current chain for the test but unless chain and sprockets are new, best to change both if you like the change. Skäl. David

[@jithinsankar787]

He could just remove the clip in chain instead of grinding it..

[@MotoMirius]

The stock chain supplied on a UK market 390 doesn’t have a clip. But if you have one then of course it’s the obvious choice. Skäl. David

[@johnybrokeit]

Moto Mirius I was wondering why the grinding was happening. Cuz I’m about to change my chain n sprocket set myself at home for the first time on my 390. Ive done it on a smaller Yamaha 2 stroke 135cc bike but nothing like the ktm. I need to go downstairs and check if it has this clip in the chain u speak of. I so hope it does, cuz I don’t have or want to use a grinder anywhere close to my bike hahaha. I’m a novice not like u experienced gentlemen. So far, all that’s missing in my tool kit for the change is grease.

[@MotoMirius]

Grinding is OK if you cover the bike. Or since you are replacing the sprocket, just hacksaw the chain while it's on the rear sprocket. Shouldn't be an issue at all for you, just a bit more elbow grease! Good luck Skäl David

[@johnybrokeit]

Moto Mirius thank you for your advice, David.

[@tomg6284]

Stock chains on ktm's are junk. 400 miles on my bike and junk. Lube a chain the correct way. Good grease mix with gas, soak chain. Air dry, grease inside and out. Job done. Screw o-rings. Do it, chain will last years.

[@MotoMirius]

With chains you always get what you pay for. You can come up with your own systems and they may work for you. Plenty of bikes ran for years without O rings.

[@Bazza.baz224]

So why does it say Duke 125 on the tank?

[@MotoMirius]

Hey Bazza. Because I had to replace the tank plastics. So it was more fun to rebadge it at the same time. Skäl. David

[@rahulraveendran6911]

Check the meter and the head light

[@MotoMirius]

UK Market 125's have the TFT screen and LED front light, just like the 390. Not sure why different in different parts of the world!

[@BADBOYWITHGOODSOUL]

Moto Mirius It is to Cut down the Price which inturn helps to compete with the likes of domestic companies and also attracts more customers.

[@MotoMirius]

Thanks Rahul. Yes that makes sense. LED headlights and TFT must be expensive. 👍. Skäl. David

[@theadda3526]

How can I purchase it I can't find it?

[@MotoMirius]

A 50 tooth sprocket is linked in the description. Let me know if the link isn’t working. Skäl. David

[@Firby1988]

It won’t pull 70mph on the flat lol

[@MotoMirius]

You might want to redo your maths - top speed is about 90mph and since you are in the peak torque range at 70 it will pull at it's max. But it's not gearing for speed and never intended to be.

[@Firby1988]

Moto Mirius I haven’t had much more than 72mph from my 2019 duke 125 it seems like it’s holding back all the time

[@PD-dj7cu]

@@Firby1988 It's a Duke 390. The decal says 125 but it's a 390 underneath. Even I was confused initially.