How Powerful is a 2023 YZ500 2 Stroke?

The time has come to put the YZilla 500 on the dyno to find out how much power it has. In this video we show you how we turned our standard looking bike into the work of art it is today and also the processes we've gone through in the dyno room to make it one of the bike dirt bikes on the planet!
Ebay Link to the Wulfsport Yzilla Limited edition T-Shirt on the Wulfsport store:
www.ebay.co.uk/itm/1856332167...

[@999lazer]

Please watch out for replies to your comments offering prizes (using our profile photo but a slightly different name ). These are scams and not us. the only real replies will be from "999lazer" and we wont offer prizes via comments . Be Careful guys.

[@gerdastimmel2968]

^wow... what money can do... can any other with money too.. a big win with u at the humans+1 ..

[@peterjohn3180]

Can you do a test in them Chinese 2 stroke endure bikes? Yamaha wr250 /yz250 clones They look ok once bolts are swapped along with other bits,. Like frame, ..... engine.....wheels.... sorry I jest but can you? They are cheap..... I've only seen them on KZbin so can't recall name.

[@bigbird-xm]

I have 63.8hp Dyno build on are 510cc 1985 YZ490. 42mm carb, Custom pipe, and months of testing porting, Motor is balanced by Crank Works, Cryogenic all the parts. More testing on Cycle Parts Dyno in Eugene Oregon with a 4 speed gear box. It's not the same motor and the power is so fun to race. Love your video and I know how much time it takes to build awesome power. Have a good day!

[@rocksteady5603]

I have loosely watched your channel for years, never have I been so glued to it as I have for this project

[@999lazer]

Thanks Matt, appreciate you watching. We have got some pretty cool stuff coming up over the next few weeks too.

[@murraykidd840]

Awesome video , been waiting for a brc 500 comparison to a modern 450, one thing I’ve learnt is horsepower is not so important, a lot claim massive horsepower but torque and track ridability is far more important as nev stated, you have done a fantastic job of bringing this to us when others didn’t have the balls , well done

[@999lazer]

Thanks Murray

[@belvedere98]

Totally forgot to compliment you all on this amazing build in my previous reaction. Completely addicted to your content, as a former professional 2-stroke tuner I'm a real scavenger for everything related to 'sucking' and 'blowing' (mechanically that is) ;-)

[@999lazer]

Thank you

[@MDY-hjy845]

I would love to see how this YZ500 compares to Kaplan America's CR500. He uses Built motors, he uses this power plant in the Kawasaki KX and in the Suzuki RM. But he's doing something special with the with CR'S, because he gets more power out of them. He has them for sale. I would love to see a head-to-head comparisons on the track, not just on the dyno. 👍

[@levisylvester]

55hp isnt bad, but when it hits 70hp it will be a real weapon! Cant wait for the next one! The episode we all are waiting for!

[@999lazer]

Haha thanks. There will be a few surprises in the next episode too - one of the most fun shoots we've ever had. I can't wait to share it with you :)

[@christavandeweyer4468]

@@999lazerAre those bh power?

[@motomallen]

Bloody awesome! Well done Max, this makes fantastic viewing, you're really smashing it.

[@999lazer]

Thanks Martin, I really appreciate your comment :)

[@dazmos_65]

Excellent Max! Really enjoying seeing the progress and development of YZilla. Thanks for the awesome content.

[@999lazer]

Thanks Darren, Glad you're enjoying it.

[@shanekuntz8906]

This build really has my interest! I think this kit bridges the gap between modern 450's and the smokers! I'm impatiently waiting your test on the '23 300SX and how well it stacks up against this monster!

[@larsborgman3443]

300sx probably pretty much the same power but cheaper, more reliable and easier to get spares for

[@JM-nt5fm]

Lars is spot on. The 300sx is the smart way to go....of course BRC makes a upgrade for the 300sx 😎

[@kevinmee3501]

Max I loved this video from beginning to end, bloody great. I'm not sure who loves that bike more you or Roland. Keep the top quality videos rolling in Max.

[@999lazer]

Thanks Kevin. I think Roland need to have a proper ride on it :)

[@TheSkullthumper]

I owned an 81 IT490 bored 30 over and that thing was nasty , a modern version like this is a work of art

[@marktrad65]

Really special project, substantial changes to the test bench. I would like that monster in my garage !!!

[@jasonacool]

Thank you for doing this series. I've been salivating over these kits since before the first KTM kits shipped. So excited they did the YZ kit. Please do the back to back test, I really want to know the difference in how they ride. The Hyygge sounded amazing, it started that fizzing feeling. I raced 500s from 85-87 and the sound makes me feel like an addict needing a fix.

[@999lazer]

Thanks for watching Jason. Glad you are enjoying the series. We will do the back to back test very soon. Cheers Max

[@jasonacool]

@@999lazer By the way, how is it you kids are so worried about starting a 500? I would get it if it was a left leg kick, but on the right they were OK. You just had to pay attention. I don't think I ever had a problem with my Cagiva 500 back then (it ate CR 500s as a snack). Maybe do one of those MXA Raw type videos of the bike going through it's paces going BRRAAAAAA and no talking. Sort of like a compilation of the interesting parts that can be found on one of those websites that have "Special Interest" videos, as Clarkson might call them.

[@aussiehardwood6196]

Keep on keeping on this is a fantastic series. Great job!

[@999lazer]

I've got some cool videos coming up that'll keep you happy. Thanks for watching :)

[@James-we2gx]

Wish you well Max, I appreciate the video’s and suggestion’s and idea’s. I THAT CONE PIPE NICE.

[@James-we2gx]

LIKE, spelling correction 🙂

[@jmendo2546]

That HYGGE pipe is awesome showing gains in hp. Can't wait for the video of side /side comparasion should wheely coming out of coners with a hard punch like dinosaur 500's did back in the day

[@Mickbono06]

More awesome content max, definitely do the test on track with different riders and the stock cone and after market cone. Love to see that 💯🤙🏻🔥

[@999lazer]

Thanks Michael, will do :)

[@Extremegaz25]

Top bikes and great tuning guys.

[@hosac99]

It is trully strong as it name says ! Bring out the beast!!!!! Let the Yzila devour the tracks!!!! You can find on kaplancycles video of specially tuned cr 500 and a gas gas 500 on dyno so you can compare. Regards

[@harm97]

U did everything right on this bike(except ugly muffler) ..this is a real dreambike 👌🏼👌🏼

[@999lazer]

Thank you Harm

[@TrollJosh]

Max, you are a madman, (in a good way of course)!

[@999lazer]

haha , Thanks

[@officialmysteriousrider130]

Great video max definitely could see that it was more lively just changing that pipe

[@999lazer]

Thank you. In the next video you'll see drag racing with the hygge pipe on :)

[@ronald8673]

good content ! keep up the good work

[@999lazer]

Thanks, will do!

[@Thor555555]

awesome as always

[@999lazer]

Thank you! Cheers!

[@speckledjim5150]

Description as of March 3rd: "...to make it one of the bike dirt bikes on the planet!" *best

[@dennismillus4581]

55hp is impressive. But, my 2010 Service Honda CR500AF with worn ri gs with excessive ring gaps. Produced 54.4hp. On the dyno

[@AgapeWarrior]

wow yea I was pretty close I would call that close to 60 lol,,, sure sounds like it will be soon hehe,,,, yea considering the thing was a beast b4 I am thinkin u r gettin close to the sweet spot right there,,, Awesome job !!! good on ya mate !!

[@999lazer]

Thanks for watching :)

[@warrenkrywko3704]

Big numbers seem sexy, but as a vet 500 rider (I won the Alberta 500 evo championship this year) a smooth power delivery that can lug low in the corners for minimal gyroscopic effect is much more important. I ride a Husky 500 twin shocker usually, with a totally stock motor other than a 38mm PWK carb and v-fierce reeds, but won the championship with a husky 430 in a 1984 chassis. Everyone who rode that bike loved it, and thought it was like cheating it is so easy to ride. Big numbers should not be the goal. Remember many of these bikes are used for snow bikes in Canada, which have a ton of parasitic loss, and are tuned for higher horsepower and lower gearing to make up for that. A setup like that would be u rideable on a MX track.

[@warrenkrywko3704]

It is a beautiful bike, and a great build. If I had the cash, I’d consider one myself, but probably a KTM version. I have 8 open bikes, 9 if a 300 counts as open, both 4 stroke and 2 stroke. What I have learned is tune then to have as smooth of a power delivery as you can, and use the minimum flywheel weight you can get away with, so the suckers turn. If you need more flywheel to smooth it out, you are working at cross purposes.

[@ragnarironspear1791]

Bike looks fantastic guys

[@999lazer]

Thanks Ragnar

[@MonkeyButtRides]

Such an awesome project.

[@999lazer]

Glad you think so! , Thanks for watching

[@fullnoyz7670]

Man I’m a 125 guy because I think they sound the best but I’m sooo in love with yzilla I think I’m converted

[@Jacare1973]

Now that you have tested this bike with a couple different pipes, etc. Get a Stic kit & add it to the carb. Then dyno it. Great vids btw.

[@make2strokesgreatagain512]

Bbbbbrrrrraaaaaapmungus The pipe looks well slick 🔊

[@teamgonzo9289]

Love this project, I would have rather seen it in yellow black and white, bumblebee scheme. Or serious red and white bumblebee scheme. Had an sc500 before they had Yz's. Bringing it on all fresh, really let's this bike morph. I still want to see a drag race between the Yzilla, and the megalodon. Drag racing, a little desert racing, and some Motocross laps. Don't let the megalodon lose its luster. I should have watched the end of the video before I printed that. Can't wait brother, can't wait to see.

[@999lazer]

Did you see the teaser at the end :) If you didn't you need to take a look - You might get a nice surprise about the drag race. Cheers Max

[@andreawhalen4142]

Right inline with the kx and cr500's, wish yamaha had made it, it would have been straight up holeshot with the best. The power curve looks cr like with that big jump in the curve so it's likely a beast to hold on to. I had the chance to ride a cr500 that had been worked over and dynoed at 74hp, to be honest with you it wasn't very pleasant to ride, more like a dragster than a motocross bike, i never rode it again and in fact the owner was killed on that very same bike.

[@alecboswell5527]

Great job. I’m excited to see more! Things to consider for more tuning. There was a lot of chatter in the back tire as it was turning the drum of the dyno. Any slip will give lower readings. Sit on the bike. Also a tail pipe sniffer would help with jetting. I’m an unsure what you elevation is there but a 1999 yz250 had a stock main jet of a 172. Just things to think about. LOVE THAT BIKE!

[@999lazer]

Thanks for the tips Alec

[@alecboswell5527]

@@999lazer no problem man! That thing should realistically put down 60ish to the back tire at the max give or take a few. That’s what CR500s will do when set properly. It’s the tq you are looking for. 20ish percent more torque than a modern 4 stroke 450. Rip your house off the foundation! Once again stunning machine in the vintage white and red of the 80s!

[@chargernk7748]

you seem to think 172 is too lean for this setup. Well youre wrong. a big bore kit will pull more vaccum through the carb thats why you need to lean it out. im pretty sure jetting is close to perfect on this bike

[@alecboswell5527]

@@chargernk7748 never said that. I simply stated that checking the fueling would be a good idea. FOR SCIENCE! Lol. I should have been more clear with my statement. To be honest a 172 may be too much gas. For example. Take the stock 250 and pipe it along with a squish adjustment and a mild port job, 172 was wayyy too much gas. Blubbery. Now drop that down to a 168 and all better. Usually when doubling the displacement it needs like a 2ish percent drop in the main anyway. But then the pipe and other factors start to effect it all in a multitude of ways. Thus the need for the tail pipe sniffer to make sure the fuel to air mix is proper across the rev range. I have see large gains, up to 8 hp, by using proper jetting on engines like this. Every build is slightly different and custom fueling is very important for maximum usability and performance.

[@chargernk7748]

@Alistair Balistair well you’re right in a sense but it isn’t “impossible” it’s more designed for very fine tuning since you’ll have unburnt mixture only when it’s far too rich. But on a smaller scale with closer number to 14:1 it does work

[@jasperracingmotorsports7232]

Soon to have 2 check out what it looks like on my channel waiting on kits

[@Capt.K72]

Only got as far as the title, but would guess..... VERY 😅💪🏼. Love the work u put in an the uploads, keep it up my man. Would love to scare the sh#t out of myself with a razz on that beast 😅

[@999lazer]

Thanks so much for the awesome comment. Really appreciate it :)

[@malccolliver4721]

Yeah of course bring it on

[@carlosmiguelalisaje3933]

For next project could you make a 1000cc 2stroke?

[@bananabrooks3836]

So the exhaust port diaphragm is actuated by the pressure differential between the exploded charge being higher than the pressure in the pipe, controlled by the spring in compression. Later in the cycle the scavenging/resonance effect of the expansion chamber, prevents the fresh incoming charge being wasted down the pipe as the piston returns to the top. The spring rate must be of importance not to interfere with the advantageous physical resonance, yet be able to perform its primary function. What I'm trying to say is that a mechanical valve (which the Jap factories decided on) does not have to be 'sprung' so their relative complexity is a worthwhile trade off for efficiency, but a lighter spring might help the diaphragm system balance the pressures.

[@robertwoods2505]

I'd love to see the back to back results on the track. Cheers.

[@Lee-mx5li]

Great job on video, Thanks👍👍👍 And let "Mr 500" test both pipe set ups on the track and let us see!! ASAP!!!

[@999lazer]

thanks lee, we'll make that happen for sure

[@AndrewJohnClive]

Sounds like a MotoGP bike!❤

[@siraff4461]

🤤I want this. Infact I want a twin made from two of these.

[@listenupfools731]

Def wanna see the back to back track attack

[@Luftbubblan]

Looked a bit disappointing at first but if you can hit that 70hp mark it starts looking interesting again :D Still a cool build no matter the numbers.

[@jpslaym0936]

These are rear wheel hp numbers so you have to add 15% to dyno numbers to get comparable manufacturer at the crank values. But even then your right these numbers arent great since you can get 60+ RW hp out CR500 motors

[@teakvinson5889]

Quick unbelievable story… even with an all time bad rap I’ve owned 2 1984 YZ490’s… been riding for 42 years, as well as my brothers… my younger brother had a meant 2017 KTM450… on a straight run from standing start my old dinosaur would out accelerate and top out faster than the KTM… even when we swapped bikes. Yes… the old YZ will not keep up on a track… but on a straight head on drag race… it held its own… I was highly impressed considering the technology difference

[@Duken4evr29]

I believe it. I had a '92 WR 500 that had it's ports matched, no changes to them other than arching the exhaust a bit, just matching the iron liner to the aluminum casting, and the head reshaped for wider squish band. Doing this and swapping out the reeds allowed me to drop 3 main jet sizes and clean up the way it ran - it was crisp and fast. No idea what it would have dyno'd at, but it had more power than I knew what to do with. It also ran an FMF pipe and the stock cannon length silencer, which smoothed the hit compared to the shorty FMF unit. One thing that can't be smoothed away on the old 500s is the engine vibration - at sustained high revs it would make my hands go numb. Raced D37 desert on it, geared 15/42 gave it more top speed for the desert and stretched out the close ratio MX gearbox, helping it to cover lots of ground instead of lighting up the tire and running out of breath and vibrating me to death. 1st was tall in the tighter stuff, but the torque was stupid and the clutch apparently was quite good. Third gear tire spinning wheelies on pavement were easy - it was violent if ya got happy with the revs and throttle opening! That was all a long time ago. Still riding these days at age 62 on a 300 XC with an air fork spring fork conversion kit on it. The 300 is so awesome it practically rides itself. As we age we need all the help we can get. I'd happily take a spin on a 500 but have no interest in owning one again as I know exactly what they are 😆

[@eduardominasi4069]

isso e um sonho!!!! parabens!!!!😄

[@Funder4]

Let’s go!

[@belvedere98]

Please do some porting and a A/F reading. Seems like there are some huge gains in hp waiting to be unleased

[@Hanky_Bannist8r]

70hp on a machine that weighs less than 300lbs has got to be a rocket ! The 55+ it has now is probably perfect.

[@999lazer]

Thanks Hanky, Nev Bradsahw thought it was the perfect 2 stroke when he rode it (and that was with the standard pipe) so you're spot on.

[@Coyotethumper5]

Well crap get Nev on the track with the two different pipes🤘🤘🤘🤘🔥🔥🔥🔥🔥

[@999lazer]

we will do that for sure :)

[@isaiesquivel1759]

you could immediately hear the difference when he adjusted the power valve.

[@paulpaul5606]

I think you might need to sit on that I think you are getting wheelspin. But what do I know

[@oliverscorsim]

With this being a big bore motor with massive port area I'd love to see a top end pipe with a bigger reed and opened up airbox.

[@jhmonthetube6339]

Would be nice to see a dyno chart to know where it is making its power. 55 top end reading doesn’t mean much. To beat the current 4 strokes it has to be easy to ride like they are. Thanks for the video. Two strokes forever !

[@morley3810]

I'm never one to judge a bike by dyno numbers, as I know they really only tell part of the story, but to be honest I'm a bit disappointed. All the new 450's (other than the RMZ perhaps) make better power. I love 2 strokes and I've been riding YZ's for a long time, but if a 500 2 stroke can't soundly stomp a 450 4 stroke, then what's really the point?

[@straighttimestirrups]

I’m sure the Torque numbers on the 4-Pukes is way under this BRC Engine. That’s what it’s truly all about. I’m not sure why they are fixated on the HP numbers to be honest.

[@999lazer]

Its an interesting point as every dyno is different which is why we did the test on the stock YZ 250 first . The bike is unbelievable to ride and we know there is more to come, but I can tell you 55 -60 in a two stroke feels more than enough. I guess there becomes a point when there is more power than most can handle . I think you'll like the next episode where we put it against our 700 :) Thanks for watching and really appreciate your comment/

[@straighttimestirrups]

Different dyno but in Dirt Rider’s Dyno Test on a CRF450R only had 34.1 ft/lbs of torque compared to this bikes 44.X ft/lbs of torque.

[@scootypuffjr.]

Big fat torque curve on 500

[@morley3810]

@@999lazer I guess I overlooked the torque and rpm where the power is. The bike is beautiful, what a monster.

[@kymbrice]

I love the idea of big bore kits. Although this kit it isn't cost effective when ya consider it's equivalent to the price of another new yz250 over again.

[@999lazer]

Hi Kym, its more than a big bore kit, as the kit comes with new cases, crank, bottom end, pipe as well as the barrel, piston and head,etc. All you use from the original bikes engine is the clutch and transmission so its kind of easy to see where the cost comes from. Over here CR 500 's are going for crazy prices (in some cases more than it would cost to build one of these)and some parts are becoming very difficult to get hold of on the CR500's so the decision was easy for us. To have a brand new 500 that we could get parts for, handles like a modern bike and has none of the typical vibrations an old school 500 has was a no brainer. Thanks for watching and really appreciate taking the time to comment. Cheers Max

[@satan657]

Isnt the main jet maybe still to big? When i went with the esr bigbore 325 kit i was informed to got smaller mains as the piston pulls more fuel, im sitting at around 52hp but on the ceo kit with racefuel Im on a 165 main at 5000 above sea level, have gone till 160 but the 165 seemed to be the sweet spot

[@cosmicsurfer5911]

Getting to Motard level madness requirement. That would be some fun in road legal form. 💯👀🙈🤣🤣🤣🤣

[@999lazer]

it sure would. Thanks for watching:)

[@maksimlang2299]

You should do it 1000 CC 2 stroke build

[@maksimlang2299]

@@Thor555555 ok

[@Thor555555]

@@maksimlang2299 added a facebooklink photo and got erased. EML Jumbo engines also were Sidecarcross engines in the 80´s. a little wide for a solo bike but would be interesting to see if it´s posible.

[@maksimlang2299]

@@Thor555555 wow, you really know your stuff

[@Thor555555]

@@maksimlang2299 sidecarcross scene isn´t that big and there are only a few engines used over the years so it´s more like common knowlege. before the 80 there were mainly 4 strokes like the XS 650 tuned up to 800ccm, some norton... then in the 80´s it began to switch to two stroke with this eml engine but it was nearly not to handle even in a sidecar bike so by the time they went down to 750ccm. when the CR500 came to market within a few years nearly everyone in GP used that engine, also some Maico 500 which later was the basis for the 620, 685 and 700 ccm Zabel engines on which the GP was won for over 15 times till today. later came the mega 700 engines (today 750) singles which are build by Rübig an austrian engine builder who mainly builds engines for carts and paragliderpropellers based on KTM engines. by the time 4 strokes came back like al kind of modern 450s as ktm 525´s, LC 620´s or 650 Husabergs. i got 2 sidecars, one 97´er EML with 700 Zabel and a 2013 VMC with the 650 Husaberg. as said, common knowlege if you ride a sidecar.

[@maksimlang2299]

@@Thor555555 yeah, I ride dirt bikes so I don't really know that much about side cars

[@miikasparf2613]

Awesome test 👍 A YZF450 Dyno chart would have been nice to see also, and maybe a CR500 if available for testing 😎

[@999lazer]

Next time!, thanks for watching

[@miikasparf2613]

@@999lazer amd thanks for the awesome content 😎

[@BigEightiesNewWave]

Need porting and head mods too. My CR500 MADE OVER 70 BACK IN THE DAY.

[@EmperorNerox]

Acerbis plastics were complete shit when I used to race...back in 87 88 89.

[@ruarifoley1554]

In Australia we call it a howger (hauger) pipe

[@brownydwbrown7485]

500cc 2 strokes are soooo much fun to ride....

[@nimrodus658]

No doubt that engines full capabilities are being limited by the restrictions on the pipe your able to run on it. My quadzilla makes 68hp on stock porting...but you can fit a big volume pipe on the quad!

[@scotmiller1678]

I didn't hear you talk about the most important part of the transformation, the cylinder. Where did it come from? Also, what is the bore and stroke? Are the porting specs based on the YZ490?

[@graemedoolan4107]

Midrange is where ya ride them

[@peteodonnell4494]

thats the dogs bollox well played boys !!

[@999lazer]

Thanks Pete :)

[@leonrawls892]

I feel the X transmission would work nice for the 500.

[@henrikk7658]

impressive tried yzf 250f longer svingarm ?

[@john63397]

Hi Max, being a 2 stroke boffin I love these videos so thanks for making them. I was wondering if you have a programmable cdi to put on the YZM500, I think it would deliver some good gains with programming on the dyno.

[@999lazer]

Yes we have a HPI which Roland is setting up and doing some tests on. We've only ridden it on track with the stock cdi at the moment but when the tests with the HPI are finished we expect to see some good gains all round.

[@john63397]

@@999lazer I look forward to seeing the results. I make digital programmable ignitions in the u.k on a small scale. If you and Rolland should run in any problems on the ignition side of things please get in touch I would be more that happy to help out on a project as awesome as this. In the mean time keep up good work, loving it.

[@LeeTillbury]

Love how that looks. I thought the YZM 500 had chrome/ silver rims not gold though?

[@999lazer]

I think your right Luke, but I've always wanted a set of gold rims and thought its the perfect bike to put them on. Thanks for watching

[@joenobody2580]

@@999lazer I love the gold rims

[@scottyd2262]

@@999lazer Gold rims set it off. I've always loved gold rims on the white & red YZ's..

[@andrewhall841]

Its all about torque, Hp = how fast you hit the wall. Torque = how far you move it. Build a big fat torque curve and enjoy the ride

[@999lazer]

Thanks for watching Andrew. The brand new YZ 250 had 26 ft lbs of torque on Rolands dyno befoer we fitted the kit and the Yzilla is 45 Ft lbs which is probably why is pulls so well in any gear on track. Its such an awesome bike to ride. Cheers Max

[@andrewhall841]

@@999lazer cheers for the reply, Loving the 2 stroke content and looking forward to the next instalment👍

[@slimsady87]

55HP - there…I saved everybody!

[@Boorer_555]

Hey max love the yzilla build I'm interested to see what numbers a 23 yz450 or a Cr500 runs on your dyno so we can see how much more the yzilla actually has

[@999lazer]

Roland's run a cr500 before and got mid 40's but we will try and make that happen as it would be a great comparison

[@Boorer_555]

@@999lazerthanks man that is awesome I have a 94 Cr500 looking forward to see what you do next

[@dr.hugog.hackenbush9443]

My CR500 is mostly stock if you want to do a comparison. The only thing is a different silencer..

[@kingkong81icloud]

My YZ was white an red like that , I think a YZ should be white, looks better than blue

[@patrickkillilea5225]

I want a "Dyno".

[@dominicwebb8000]

A decent standard Honda CR250 from the mid 90’s will put out 50hp plus, so maybe it more about delivery than absolute power?

[@EmperorNerox]

1985 cr500 put down 60hp outta the box. This thing should be putting out 70 to the wheels like the other guy was getting

[@coryjohn4057]

I wonder how a little less flywheel would do on hp. Anytime your hitting 50 hp some times lug can be replaced with Rev.

[@mikebrown41182]

What programmable ignition box did you use? Absolutely stunning piece of machine, good work!

[@999lazer]

Thanks & it was the HPI iginition

[@stevegrimeszz]

how does the clutch not slip? try rekluse clutch pack???

[@colinwhitehead9661]

My old Kx 500 had good spread of power , my Cr 500 was mid to top, Just a feeling. The Yz sounds flat . Please match up all the old oil burners on track. Top 3 2T 500's 👍

[@999lazer]

Thanks Colin, that shoot out is coming up soon :)

[@scottm7341]

A much bigger gain over the 250 than I guessed, since the carb and reeds are the same. Is it hard to start? Does it have some kind of compression release?

[@999lazer]

It has a decompressor button on the head so its easy to start

[@ryonreginato6242]

Horsepower is cool but so is torque. Can you please post the torque curve so we can see at what rpm the torque is coming on and where it peaks? Thank you

[@MajorTendonitis]

Awesome bike,but I really liked the blue 😢

[@marcschulze3813]

I think all this modification/ conversion to a 500 engine need more time to setup up right. The max power isn't important, but I see some week points in the power curve. The exhaustvalve controlling by pressure is not a good idea. Give the bike a ignitech unit, nice ignitioncurve and full adjustable exhaustvalve control by an Servo.

[@eamh2002]

I wonder when someone actually tries to get the most HP out of a 500cc then trims it down to rideable power curve flatness AND gears it so it uses the powerband (eliminating the "no low end") In engine power, if 35hp 125cc and 55-60hp 250cc then 500cc should be able to get 70-80hp easily. The exhaust gas mass and flow dynamics are pretty hard to keep on high RPM in bigger cc 2-strokes because the efficiency is at a higher rpm in smaller cc cylinders (less mixture mass=needs faster resonance=shorter pipe=higher rpm) On 4-strokes you just increase the flow area over the cylinder and make a wide piston so you can combust more at the same rpm as a smaller engine. Thats why 450cc 4-strokes can make 60hp (more than a stock 500 2-smoke) and 250cc 4 makes 35-40hp but a 125cc 4-stroke would do around 20hp when a 125 2-stroke almost doubles it Some guys have gotten over 70hp from a cr250 engine by ignoring the common bolt on limitations and doing their own things to get the timings for HP :)

[@texasphi801]

I was way off on my guess. My YZ 125 did close to 30 on a dyno so I was expecting this to do around 90.

[@joelatkinson2080]

Do the comparison!!!

[@davidlowe9780]

I'm pretty sure the Yamaha YZ 490 aircooled of the mid to late 80s was around 55hp from factory so theres not much improving over the old

[@garagecedric]

Check out zinzin the french guy on KZbin, he recently put a KTM 500 on his dyno, and also compared to a cr500(the ktm crushed the ol CR). Interesting to see how they compare. I guess the port design is reasonably similar since the cylinder on the yz500 is from the same place.

[@garagecedric]

He get about 55.8hp something at the rear wheel, and roughly similar shape to the power curve with the bump midway.

[@bilboswaggens2975]

All of this to be slightly more powerful than my ported stock bore yz250. 😅

[@bougie2k]

Is it 55 hp at the rear wheel

[@dirtbikedave]

Hahahaha. 'No thanks. Not interested.'..said no one, ever!

[@geraldkoth654]

1971 Husky 400 Cross has 52 HP at the rear wheel. And what is with all that clutching? Never used the clutch on the Husky, toe only needed. As well it was 232 pounds soaking wet. The angle of the frame to the ground (front wheel lift) was exactly equal to the position of the 1/4 turn throttle. Get over the bars and get your nose close enough to the front knobs to feel the air coming off them. I cannot for the life of me understand the sit down riding position. Malcolm Smith cleared the Widowmaker on his first pass on the 400 Cross. Also rode it for the front wheel never touching the ground for who knows how many miles. I surely made a lot of close tree passes by lifting the front wheel and putting the bars at 45 degrees for a narrower profile. What is the top speed of that heavy beast?