2017 KTM 300 XC - top end rebuild

Hey guys, we are going to take care of our 2 stroke dirt bike 2017 KTM 300 XC top end rebuild today. This KTM 300 has over 250 hours on stock piston and everything else, we are curious to see how the top end, piston and engine in general looks after this many hours. We have new Vertex piston, RKtech head and Cometic gaskets to take care of this top end rebuild. Let me know your thoughts, cheers!
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ktm 300 top end rebuild

[@ironwolph]

THIS GUY HAS BEEN PUTTING IN WORK!!! Started watching this guy a while ago when he had the same bike as me a WR450F. Love to see he is still after his passion!!! More people should be subscribed..

[@dirtniron]

thanks a lot Tom, very encouraging! You have been for quite some time, appreciate it 👍

[@robh3267]

Kelsey at RK Tek has done a couple of heads for me, he's a cool guy, I think his head work is the best in the industry, I didn't think my 300 could get any better at low end torque but the work he did on my head proved to me that it can. Over 200psi with over 250 hrs and the excellent condition of that cylinder is about as good as it gets, it's also proof that proper maintenance and care of your bike is well worth the time and effort.

[@dirtniron]

yea, good products for sure. So happy bike was taken care of well. A lot of life left in it

[@rauliniesta9118]

I love seeing how you work, I wish I could take my Ktm with you, lots of encouragement and thanks for the videos 👍

[@dirtniron]

thanks Raul, glad you get little motovation here ;)

[@dorianrodriguez7591]

These two have become such good friends man it’s nice to see that

[@dirtniron]

thanks Dorian, we are really good friends, glad you guys can see it thru the videos

[@haitzyice]

@@dirtniron - I will have to say and catch up for a ride next time I’m in Temecula

[@brendanmingo3486]

Really enjoy your channel! Fun to watch your projects and fun to watch your riding adventures.

[@dirtniron]

Glad you enjoy it! Thanks Brendan!

[@jakefalk6350]

This is great to see as many 2023 tbi bikes seem to be blowing up with much lower hours

[@husaislander4838]

Just finished my top end last night. 257hrs on my TE 300 looked great as well

[@dirtniron]

right on man! great bikes!

[@Danman1972]

Also, You should probably check the kick start idler gear bolt. They were put it short and have a tendency to break the cases from what I've hear for that year. Not that you will use the kick start, but the PO may have already done that. You google around and you will likely see what I'm talking about. You can tap the hole deeper and install a longer bolt. I remember reading that on a forum a while back and it happened to a lot of folks. Pretty simple as the bolt sits under the clutch basket so you don't have to remove the cover... just the clutch. My buddy did one on his 250xc.

[@dirtniron]

thanks Danny, I have to look into it.. appreciate it

[@mud-monkeez2655]

for ktm and husky piston clips i always use a inner tube valve core tool to install. works a treat

[@dirtniron]

Great idea, thanks for sharing

[@mud-monkeez2655]

@@dirtniron not a problem. Your videos are cool keep it up . 🤙

[@louis1997louis]

@@mud-monkeez2655 do you have a link I have problems installing my c clips on my 300 ktm...

[@post_historic]

Always good to pre-scuff the new piston!

[@dirtniron]

yea..

[@matthewblank214]

My 1997 yz125 manual noted to lap the new piston with 600-1000 grit before ever riding the bike when new

[@woidviatlalausbua8699]

Amazes me how good the condition is after 250 hrs.. On a two stroke!

[@dirtniron]

yes, we were surprised too, good maintenance and trail riding are a great combination for a long lasting performance

[@tudorcotoi7011]

2 strokes can run for surprisingly long times between service intervals. Give them extra oil in the mix and run them rich, and you have a happy 2 stroke.

[@jasonlonon4198]

Just did a top end on my 2003 RM 250 2 days ago....AT LEAST 100 hrs...maybe 130 on a vertex piston....old piston looked amazing....still had the machining marks on the skirt...yep, new Vertex piston went right back in...quality pistons.

[@greg6162]

So how much more difficult/labor intensive is it to rebuild a 4-stroke?

[@ByIntros]

@@greg6162 ticking time bombs lol

[@zardportugal]

Almost done. Congrats.

[@dirtniron]

thanks brother, almost! ;)

[@Montana_Motorized]

I also like to use the Slavens/old KTM style ez circlips. Makes life a lot easier.

[@dirtniron]

thanks for the tip man!

[@avidsledder]

Great video and ur tunes are killer

[@umadbroyolo8413]

Just a little tip, apply grease to your gaskets before installing them. It's a lot easier to remove them when you need to do maintenance, hardly any scraping if any needed.

[@jpmorgen5726]

Deburr outer edge of snap ring grooves before removing pin, then you shouldn't have to hammer it out.

[@flashbang243]

Can’t wait to see the next video 👍

[@dirtniron]

thanks, should be pretty good!

[@sidecarbod1441]

I'm surprised that you did not check the ring gaps, I fitted a Vertex B piston into my KTM 300 the other day, the ring gaps were on the tight side, too tight without the ring ends being dressed.

[@WildStyleWorks]

i am currently rebuilding my RM250 from 1997, i dont know how much hours she had, but the piston had 0,25mm or 0,01 inch of clearance wich is a bit much. suzuki says 0,045-0,075mm or 0,0017-0,003 inches would be ok. she had only 70 psi of compression, but still was runinng. lot of power loss, but for me as a beginner it was ok. now i put in a D piston with 0,055mm or 0,0019 inches of clearance and i have to say, i am a bit scared of how strong she will be, but i guess i have to take it as is 🙂 i may make a video on the installation of the piston and her first run after that, if she even ever runs again. we will see. thanks for the great content, it helps a lot for people like me doing this the first time.

[@gethexe]

I've been waiting for this one :)

[@dirtniron]

hope you like it ;)

[@brycebutterfield9236]

Great vid !

[@dirtniron]

thanks Bryce!

[@dragoslavpetrovic3616]

I enjoy Top end rebuilds.

[@dirtniron]

bike like them too, he should run real good

[@Catman1987]

yeah try doing a top end on a four stroke .

[@louis1997louis]

Did you regap the ring? Just in the process of changing my 300piston. Greeting from holland

[@robm3357]

What oil was being used in this bike ? Was it pre mix and at what ratio or was it run on the oil injection

[@jeffwendorf170]

Curious if you did cylinder and piston measurments

[@anthonyfox5337]

Do you normally deck the head or measure the piston clearance at TDC and add or subtract base gasket thickness to suit the specified tolerance ? I didn`t see you do that with this rebuild and its a critical step.

[@bersisaburdick4498]

Good looking bike.

[@dirtniron]

thanks a lot, she should look decent once all done

[@c3r3bralm.f]

The scratches on the piston scare me.

[@dirtniron]

it'll be fine..

[@caseyjoe4827]

Haha big dummy aluminum is super soft won’t be a problem at all plus the plating in the cylinder is super hard

[@tomnekuda3818]

Rado, another excellent upload......wonder how many times over my 74 years I "rebuilt" a two-stroke like you guys are doing? Not only do I love the content of your uploads but I would give anything to know where the background music that you use comes from.....Do you think you could add that info in your "Show More" section of the upload? Please? Keep the faith, Tom.

[@dirtniron]

hi Tom, I bet you did more than I will ever do ;) here is the artist - kzbin.info/door/DwI_82Yzy5pvIBVWnkZrTw

[@rebornoffroaddude7292]

Thought your not suppose to hone a nikesil cylinder ?

[@edimihaip]

what oil did that bike eat? that CYLINDER LOOKS GREAT!

[@dirtniron]

probably motorex.. not 100% sure

[@Danman1972]

Slavens racing sells an older husky part he rebrands as "easy clips". that are way easier to install. Worth the extra.

[@nickdawson9881]

I use them every time I do a top end

[@dirtniron]

I will look into it, thanks for the tip.. wasnt aware of it

[@thewangster123]

Good stuff guys. What was the compression with the new piston installed?

[@dirtniron]

thanks man, we did not test.. I also have different head so we wont be comparing the same setup

[@michele1342000]

Man can you tell us what 2t premix oil you are using? Because i am havin a hard time choosing it. After trying the motul 710, the ipone samourai and the bardahl i think i prefer the 710.

[@dirtniron]

klotz r50

[@UnChavitoBien]

have to do this on my 450x 05 is there a chance of a video doing it?

[@dirtniron]

if I get a chance I would do it for sure.

[@craigster1952]

Why don’t you give us more information on the piston tool?

[@jenmarkandion26]

Watching from philipines sir ..

[@dirtniron]

cool, thanks man!

[@christos8861]

nice video

[@dirtniron]

thanks Christos!

[@leondeblaauw2082]

hey just wondering how did he get this many ours like how does he ride what kind of maintanance

[@dirtniron]

he did some GNCC racing, not high revving but more low to mid range and he kept really good maintenance

[@acefreely3556]

8:19 you hacked that piston up bra! 8:47 now I know why. SNIPS!

[@dirtniron]

yea there is a little scratch..

[@joshuakimble2229]

Why go to a B size piston when you had no scoring on the cylinder walls, or piston, and you had excellent compression before the tear down?

[@dirtniron]

too many hours on stock top end, 250.. time for lil bigger piston

[@MAXlMUS]

@@dirtniron Would you install a standard size piston if there were two pistons for that time?

[@horsepowerhorsepower3657]

I have a ktm 530 EXC how long do you think I can drive with te piston 300 hours

[@dirtniron]

I would not go that far.. depends how you ride and maintain your bike.. I would not go over 150-200H

[@lukejones8161]

What was the psi with the new piston?

[@dirtniron]

we did not test.. I also have different head so we wont be comparing the same setup. would be good idea to check tho..

[@mark4079]

Lots of advise in the comments so just thought I’d throw in my two cents. It’s Christmas tree cake season, always take a few snack breaks.

[@SwormCycles]

I have always read and have been told to NOT hone a plated cylinder but you mentioned it a few times in the vid. Can you elaborate on how that was done?? Also no mention of setting the Z dimension or cylinder base nut torque. I'm also not sure if I would have done a top end with 200psi. I have the same year bike but mine is only showing 165psi and with about 75 less hours. I'm positive you guys know what you are doing and just shot a quick vid, but really, a lot of good info was left out.

[@rcf3773]

@swormcycles The reason you're told not to use a hone is because it leaves material behind And if you don't clean the cylinder really well after it will cause premature wear of the rings. I usually hit them with scotch bright First to see if I can remove the glaze that way And use a ball or brush hone If I can't get the cross hatch to come back. If you hone it you have to disassemble the powerball and clean it also So if you're not confident in doing so stick to scotch bright. The z dimension Is your power valve height Which can we set with A caliper or There's a cheap tool you can buy to do it And it could also be used to set the x dimensions which is The cylinder height. Slavin's website has some good videos on doing this and also Disassembling and assembling the power valve. And as far as the base bolt go I've never Torque them I just use a small wrench in a cross pattern and tighten them. Your head bolts absolutely need to be torqued

[@SwormCycles]

@@rcf3773 Thanks! Good info. I just completed my top end kit from Slaven's, pulled out and vapor honed the power valve, set all dimensions and went with a bit smaller of a base gasket instead of a machined head and it runs like new. My bike had much lower hours (like 175) but only showed 165 psi. Yours having near 200 psi at 250 hours is freakin unreal......

[@freddunbar]

Do you have a link to that 2ride(SP??) piston holding tool? I'm not finding it when Googling it.

[@dirtniron]

its tworide www.tworide.net/product-page/top-hand-3rd-hand-for-top-end-work

[@craigster1952]

Ditto

[@poorwhiteboy6521]

Is the vertex piston heavier than the stock piston ?

[@dirtniron]

vertex is stock on KTM

[@danilomilosavljevic8476]

why do you have 2 head gaskets i didnt understand?

[@dirtniron]

for port timing change, the cylinder sits higher

[@senor7857]

OK, I'm not the only one who scratches the new piston 🤣🤣

[@dirtniron]

lol, yea..

[@listomoto]

Why did he put two base gaskets. Will it reduce vacuum compression from doing it?

[@aleksilaukka2302]

You can adjust the squish by adding more or less base gaskets😁

[@listomoto]

@@aleksilaukka2302 why did he want less compression

[@aleksilaukka2302]

@@listomoto He said he chanched the sylinder head to some other brands head so he had to adjust the squish.

[@listomoto]

@@aleksilaukka2302 that will effect the vacuum pressure pulling the air and fuel mix from the carb

[@dirtniron]

the compression is the same, thick gasket changes the port timing and that ads power in mid to top range. Head was done to compensate for that and maintain the same compression

[@robertwoods2505]

Where did you find that piston holder?

[@dirtniron]

email Jay Clark, he will send you the info. Wasnt it in the video tho?

[@GhostHammerX]

Why not use those ez circlips from Slavens?

[@dirtniron]

have to check them out, thanks

[@GhostHammerX]

@@dirtniron they are 100x easier.

[@bryanslittlegarage5724]

❤️❤️❤️

[@Montana_Motorized]

Be sure to do the kicker fix. Lots of people have broke the cases.

[@dirtniron]

thanks Glenn, I will look into it. Do you happen to have a link ?

[@Montana_Motorized]

@@dirtniron kzbin.info/www/bejne/boHEd4WBZcRpbdk

[@DS-to7kx]

What are peoples opinion on single ring piston vs double ring?

[@dirtniron]

I like 2 rings :) but dont tell my wife, she is fine with one

[@DS-to7kx]

Haha

[@DS-to7kx]

Ive heard about the bottom ring not getting enough lubrication and damaging the cylinder

[@supacat1298]

Sweet......sounds a little on the lean side

[@dirtniron]

yep, good ear man! she sound good now ;)

[@supacat1298]

Ok good, nice to hear

[@kepler240]

So you don't remove the circlips when removing the pin? You just pound the wrist pin out by force? Wow. Never seen it done that way.

[@Marcus-fj4fu]

Nice work👍what's the Name of the song "let it shine"?

[@dirtniron]

Shine by Casey Parnell, glad you like it

[@Marcus-fj4fu]

@@dirtniron thx👍👍👍

[@acn-6264]

Maybe you already said it during the video. But why did you put to gaskets in the cilinder?

[@willjenner7108]

It will adjust the height of the cylinder, so when you do a top end on these bikes you need to be within a specific measurement. So if you put two gaskets opposed to one the cylinder will be higher, and the piston at top dead center will be farther away from the head

[@acn-6264]

@@willjenner7108 The thing i didn't understand was why the cylinder had to be higher. Its because he dosen't want as much compression because he is already putting the rk head?

[@willjenner7108]

@@acn-6264 You can use multiple size base gaskets to vary the height of the cylinder, but sometimes when you measure your X-Dimension - which is just checking the relationship between the top of the cylinder and the top of the piston You realize you may need two base gaskets to meet a certain cylinder height And regarding why the cylinder height you can adjust base gaskets to either get you higher compression-by lowering the distance between the head and the top of the piston, you are going to get more bottom end grunt Or you do the opposite and go with a thicker base gasket or even two and increase the distance from the top of the piston and the head and get more top end power Really the main thing you want to focus on when doing this is do not let the piston come up to far and contact the head

[@dirtniron]

the thick gasket in my case doesn't change the compression at all, the head is cut to compensate for the thickness of the gasket. It will however change the port timing as the ports (openings in the cylinder) are now higher than before and will make the bike run better in mid and top range.

[@acn-6264]

@@dirtniron I never thought that option during a build. Thank you both for answering.

[@bushbasher69]

thats so clean, my bike with 80 hours looks 10 times worse 😂

[@dirtniron]

you ride hard ;)

[@Recedinghairline180]

Holy blow-by batman. seat those rings with a full dose of send it

[@dirtniron]

haha, they will be seated soon ;)

[@degerlitaslar375]

yes one 😁

[@TWDStroke]

I wish i had a Jay Clark to help work on my bikes😂😂

[@NirHason]

I hate the C clips on the KTM 300 - they are really difficult to install!

[@dirtniron]

yea, they are

[@thesom187]

ask the name of the song?

[@dirtniron]

Shine - here is the artist - kzbin.info/door/DwI_82Yzy5pvIBVWnkZrTw

[@waynekerr8003]

It's only just run in

[@letsdroneit7060]

Omg 250 hours,, here in sweden we get rid of bikes When Close to 100 hours .. this bike must be ready for the dumpster 😅

[@edwardclark3980]

Would of been nice to have done another compression test.

[@dirtniron]

yea, I agree 100%..

[@fredmitchel1236]

You folks seem to be butchers....what up with the scratches on the new piston?

[@terryfonz4603]

Put it back together and run it 200psi you shitting me???

[@dirtniron]

its way better now ;)

[@senor7857]

250h is nothing to a cylinder (enduro guy)

[@dirtniron]

thats right ;)

[@agee8322]

Honing a nikasil bore??? No!!