Learning from Mitch Payton on Jetting a Two Stroke Dirt Bike

Two stroke dirt bike jetting experts, Mitch Payton and Schnike from Pro Circuit Racing, jetted the 1999 KX250 Splitfire Build. There are no two better people in the entire planet to do so. I stopped by the Pro Circuit race shop in Corona, Ca with the Whiskey Throttle Media crew to get my bike dialed in for the test ride planned with them. This is what we learned and how it went down.
If you are experienced with jetting a two stroke, leave your jetting tips and tricks below, it is greatly appreciated!
If you are enjoying the two stroke bike build content, consider showing your support of the channel for free! Any tools or parts that you need for your bike, please shop through the Rocky Mountain ATV/MC link below. When you do this, you are directly supporting me and this channel. Thank you 🙌🏼 It keeps me motivated to produce more insane build videos for you.
🔥Rocky Mountain ATV/MC: www.rockymountainatvmc.com/?r...
🔥EMAIL [e-mail] with any questions or inquiries
🔥Maxima Grease: www.rockymountainatvmc.com/pa...
🔥Scissor Stand: www.rockymountainatvmc.com/pa...
🔥Frame Grip Tape: www.prymemx.com/collections/f...
🔥Grip Safety Wire Kit: www.rockymountainatvmc.com/pa...
🔥Dunlop MX34 Tires: www.rockymountainatvmc.com/ti...
🔥STAPLE GUN: amzn.to/3sdw0T0
🔥CERAKOTE TRIM COAT: amzn.to/3xVToqd
🔥Primary Drive Sprockets: www.rockymountainatvmc.com/pa...
🔥MOTION PRO STEERING RACE DRIVER: amzn.to/3BF8wKt
🔥 / billet_dreams
🔥Chain Breakerwww.rockymountainatvmc.com/pa...
🔥JIS SCREWDRIVERS: www.prymemx.com/collections/t...
DISCOUNT CODES:
🔥 Save 20% at GUTS Racing - Use Code GH20
🔥 Save 20% at ARMA Sport armasport.com/discount/GH20 - Use Code GH20
🔥 Save 10% at Phat Head Racing phatheadracing.com/ - Use Code GREG10
How To Install Seat Cover: • What It's Actually Lik...
Engine Tear Down Part 1 Video: • See How Easy It Is To ...
Engine Tear Down Part 2 Video: • 92-04 Kawasaki KX250 E... E
1999 KX250 Splitfire Rebuild Series - Part 1: • New Two Stroke Project...
1999 KX250 Splitfire Rebuild Series - Part 2: • SOS I Need Your Help |...
OEM vs PC Kit Suspension: • The Shocking Truth: Pr...
🔥Vapor Blasting and Zinc Plating Services: / moto_resurgence
[e-mail]
🔥RMATV/MC OEM Parts: www.rockymountainatvmc.com/oe...
🔥MOTION PRO TORQUE WRENCH ADAPTER: www.rockymountainatvmc.com/pa...
🔥MAXIMA 80W MTL TRANSMISSION OIL: www.rockymountainatvmc.com/pa...
🔥MAXIMA COOLANOL: www.rockymountainatvmc.com/pa...
🔥MAXIMA QUICK MIX CUP: www.rockymountainatvmc.com/pa...
****TOOLS****
🔥DEWALT IMPACT GUN: amzn.to/3wQgTl8
🔥DIGITAL CALIPER MEASURING TOOL: www.rockymountainatvmc.com/pa...
MUSIC: EPIDEMIC SOUND www.epidemicsound.com/referra... This video is NOT sponsored.
Some product links are affiliate links which means if you buy something I'll receive a small commission.
Thank you for supporting the channel!

[@mikebrown41182]

He is an artist and there not many in the world that knows how to like him. So pumped for you budd, such a nice experience. Also happy that i was a miniscule part of it.

[@GregHitchko]

It's a true art that is for sure! Very much appreciated my dude 🙌🏼💨💨

[@danarussell4246]

Mitch is an awesome guy and I love his passion for the sport of off-road motorcycles. Great guy for the industry.

[@GregHitchko]

Mitch has had such a positive influence on the sport. Massive to think about it. So grateful to have him 🙌🏼

[@fredm4197]

Mitch is an ICON for the sport!

[@joshmx28]

Wow I feel like I can hear a change in the exhaust note between the fuels. The C12 seems a little throatier. Throat goat.

[@GregHitchko]

Right?! It's crazy how it cleaned it right up.

[@CJRSBK]

That kx 250 right there is the best looking dirt bike I've seen in my life.

[@GregHitchko]

Haha thanks my man!

[@nvclxud]

Greg, I agree with the T4 recommendation. Personally, I prefer C12 with Castor 927. You lose the oxygenation, so you don't have to worry about that jetting issue, but you also get leaded and it has a bit higher octane. For me, I like that I can run OEM spec on the carb with C12.

[@Spencer758]

The one thing I will share with those new to jetting, is that it is often easier to feel the dead spots that it is to hear them. Sometimes going down the street in third gear, and doing a weighted pull through the RPM range with a load, can be more helpful than just revving a static bike - it all depends on your sensitivity and what may work best for you. Once you've done this enough, you may be able to get it closer, just by listening - similar to the way Mitch is figuring things here. Cool video, Greg!

[@wesleysharpston4906]

Good Saturday morning when the man uploads!

[@GregHitchko]

Haha thanks Wesley! Perfect timing for SX updates too🙌🏼. Thanks for watching man

[@johnallard9876]

Dude worker bee that’s spectacular 😂😂😂😂 so true and prolly one of the best selling two strokes moves of all time!!!! Lol

[@alexwyatt7800]

The front and rear fender look so good on them late 90’s bikes

[@GregHitchko]

Big fan! No thanks to the restyle kits 💨💨

[@joshalger6059]

Thank you so much for this video! It helped me dial in some jetting issues I was having with my 98 that it desperately needed! I would be so hyped to be at the PC shop and Mitch revving my bike like that! 😂 what an awesome experience. My only issue is I am running on 93 ethanol free pump gas which is runs great as it is but I would like to find some good race fuel for it which I have zero experience running.

[@HairryTurttleneck]

holy!! awesome vid! love the bike too, I'm a zuke nuker myself, but beautiful kawi dude!

[@GregHitchko]

Haha thanks dude! It's been a fun build and experience 💨💨

[@patrickfarrell7598]

Dope bike!!

[@GregHitchko]

Thanks dude 💨

[@jeremyrude6883]

That's one bad ass bike

[@GregHitchko]

Thanks Jeremy! 💨💨

[@mattfillman1182]

Here to hear the bike. Sweet vid. My neighbors are about to hate me.

[@GregHitchko]

Haha let it rip my man! Who knows, they may love it 😂

[@cbh148]

Man, Mitch is my favorite person and I’ve never even met the guy or seen him in the flesh, just going off of his Whiskey Throttle interviews and occasional calls on Pulp. I consider it an honor to do something so involved with him like this. Also, bike looked bitchin’ in Bham last week in the pits.

[@GregHitchko]

He is such a cool dude in person! Hopefully you'll get to meet him someday. Too bad he wasn't at Birmingham, I'm assuming he'll be at Nashville though! Maybe see you there too?! Thanks dude💨

[@cbh148]

@@GregHitchko Absolutely going to Nashville! I live halfway between there and Bham up in Huntsville so it’s too close to miss.

[@GregHitchko]

@@cbh148 right on! Huntsville is actually where I bought the KX lol. Cool area. Yeah definitely way too close not to go 🙌🏼💨

[@benjaminemerald8027]

I got Vp 108 octane from the pump for 14$ a gallon I had to drive 50 mile round trip but it was nice rural backroads w 65° weather w the top down in my Honda S2000 was a fun ride and good deal I think 😊

[@augieh6146]

I knew a guy that went by ear. Best running little 80 ever

[@GregHitchko]

It's wild how they can do it and be so precise. Super cool

[@darronmiller9126]

I had the 98 version that was bakers bike. Beautiful neon frame and plastics. Wish I could find it again bought it in 99 through dryer Motorsports.

[@GregHitchko]

I heard people liked the 98 way better than the 99. Here's to hoping you come across that bike too! 💨

[@brainstain22]

I think people over look the needle profile far too often. That is what makes jd jetting look so good...lol. They do know their sh/t. Loving the build.

[@GregHitchko]

I'd like to do some different needle testing too! Maybe even go a hair richer with it. Especially if I decide to stick with the oxygenated fuel. Thanks dude!

[@insanetaco98]

Yeah on my 4 stroke I'm running a needle hardly anybody knows about with a shaved down slide and it's wildly different from how the FCR carbs perform stock. I've also added shit like the boyesen qs3 and a deeper sump cause why not. Crisp consistent power

[@07motoman]

I was a test rider in the 90's and we did a lot of testing with porting, reeds, exhaust, jetting specs, oils, timing specs, etc. There is one thing you can try, I saw your running 927 there are a couple of things you should know besides being hands-down the best smelling 2 stroke oil ever made , first off 927 is a great lubricant but it is super dirty and builds up carbon in the exhaust which makes the power valve get sticky, the other thing is it makes the bikes jetting very finicky especially with elevation changes. Bottom line if your gonna run it plan on servicing your power valve more often and get used to the weird traits your motor will have, If your not real witty with jetting I would run Motul or Motorex. Ive been racing shifter karts for a long time and we run Motul because the motors are always at high rpm and we have never had a engine failure, by the way we run at 24.1. If your doing MX run 32.1 you can't go wrong. Good luck!

[@michaelcasale884]

Greg, all you had to do was just ask. That year(99) used an odd ball jetting spec, not that the later years KX250 were any better, but that 99 was a little different the rest.

[@jimmy_dirtbike]

Harbor freight is the only place I get bike stands! Thanks for keeping it real!😅

[@GregHitchko]

I really want a PC stand but I can't bring myself to spend the money 😂. The harbor freight stands are legit. Is four too many to have? Haha

[@jimmy_dirtbike]

@@GregHitchko I have 3 so no! 😅

[@coloradodirtbike5930]

You didnt leak down test the motor after rebuilding it??

[@brandonbladen4691]

I’m currently building a 2003 KX250 and I’m about to jet the carb for southern Utah where I live. I too hate jetting carbs and have no idea what I’m doing so I ordered a JD jet kit. I’ll let you know how that goes but I’m sure you’ve used them before.

[@GregHitchko]

Right on Brandon! I'm a big fan of the JD jetting kits. They are very informative and direct you what to use based on your elevation and temperature. Let me know how it works out for you. I miss being in Utah to ride in St. George, etc

[@sleepeasywithwhitenoise3860]

My dad was a genius with jetting bikes and building carbs not many masters left

[@GregHitchko]

Respect. Definitely not a skill that's highly needed in the sport anymore, but great to have 🙌🏼

[@olliechristopher467]

Hi there Greg, I normally would use the good old C12 and just leave it alone. It's so much more forgiving and less fussing with jetting. However, what you are doing is perfectly fine. I'm sure Mitch made you aware of the shortcomings and reliability issues you can face when running the T4. Your jetting has to be spot on for the elevations and temps.

[@nvclxud]

What about T2? I am finishing up a rebuild at the moment and want to stick with a solid fuel that will treat my bike well. Is there anything specific I should know about running T2? Is there a better alternative?

[@GregHitchko]

That's for sure! They couldn't stress enough about how consistent and reliable C12 is across the board. That's why they trust it so much. Looking forward to doing some more fuel testing. Thanks for the response dude!

[@GregHitchko]

I'm actually not familiar enough with T2 to comment on it. I want to make an educated guess that you'd have to run a richer setting because of the oxygen content in T2. I'd love to ask Mitch or Schnike the next time I see them about their thoughts on it. Thanks man!

[@nivek_nz]

Any reason why the preference to mix C12 with an oil additive over already premixed 40:1 VP T2 fuel?

[@GregHitchko]

I like running 32:1. I've heard T2 is great fuel but don't have much experience with it

[@safeerhuseyin1180]

Can i use c9 on yz250 2 stroke? its unleaded will it be fine pump gas are extremely bad in my country . I can get c9 from dealer any suggestion?

[@chestertownelectric6290]

With race fuel, you have to verify if it’s compatible with 2-stroke oil. Some VP fuel was reformulated a year ago and is no longer compatible. The oil will separate and you will seize. VP C-12 is a very good 2-stroke fuel for all but pros, where rules don’t allow lead. Some race gas has components that make the bike run great, but will evaporate overnight.

[@GregHitchko]

Thanks for adding the knowledge about the race fuels man! Very interesting to note. I'll have to call and get the scoop on that. Much appreciated

[@panic-revv85]

Shell in Spanish fork has VP110 at the pump.

[@GregHitchko]

Too bad I'm not in Utah anymore 😭

[@wernerxldata]

The first thing that came to my mind about rejetting to oxygenated fuel is can't you calculate it. The amount of oxygen is a known fact in percentage. Not sure if that would work but I would assume you will get pretty close. The other option is to put it on a dyno and use a wideband O2 sensor to figure out the afr and compensate. In the end the laps at the track are telling the only true story I guess. I think everyone here is pretty jealous you were there, with Mitch Payton, working on your bike. Awesome experience man !

[@GregHitchko]

That would be interesting to throw it on a dyno and figure out that calculation. I've got a shop near me who could potentially do it for me. Keep you posted if I do! Thank you 🙌🏼💨💨

[@wernerxldata]

@@GregHitchko If you have that opportunity that would be really interesting. Cool stuff !! Of course it can never beat having Mitch working on your bike 😇

[@GregHitchko]

@@wernerxldata he's the two stroke master! They know what they're talking about there that's for sure 💨

[@mxracer5407]

I like messing with the needle. My 03 has basically the same motor and people say the Suzuki needle is good but I think I have the ktm250sx needle in there now and I really like it. It’s the closest to the Suzuki but has a different taper. Theres threads about it on ThumperTalk. You can lean out the middle and different areas with the needle and make the bike feel different, I think.

[@GregHitchko]

I'm definitely going to have to look into this! I've heard other people say the Suzuki needle as well. Thanks for sharing dude!

[@stevemccurley1707]

It's hard to compare fuel and jetting when we live in Australia 🇦🇺 My preference in pipe is FMF FATTY...seem to get better overall performance

[@GregHitchko]

I'd love to do some pipe testing down the road! I've got a JSV cone pipe, and I'll have to pick up an FMF to compare as well. Good stuff dude 💨

[@eyalcr500]

Mr. Greg, here's a suggestion : take your beautiful KX , come with it to Israel ! here there is only one kind of fuel, unleaded, clean without alcohol, put 1:32 pre mix of your favorite oil - no more worries with which fuel to use , and RIDE TILL YOU CAN'T HOLD ANYMORE 😉

[@GregHitchko]

Haha you don't have to invite me twice!

[@kylewaters7409]

not a jetting expert im a lectron expert lol because its dummy proof and i love it

[@GregHitchko]

Haha that's fair enough! I've used them in the past as well 💨

[@Thenorthforknwelder]

Ran c16 in my 125 n 32:1 on the oil jetted the carb ran like a animal fired first kick every time

[@corvette_jake7225]

Is it possible to sell one of these bikes you've built for the amount of money you put into them? Or would you take a loss if you tried to sell them? Do factory bike builds like this hold any value other than sentimental?

[@OGLD]

Are you running a higher comp head/dome?

[@GregHitchko]

I have an oem dome that was cut for C12 by pro circuit, to raise the compression. But I'm actually running a Phathead cylinder here with a stock dome. Mitch and Schnike said it was still fine to run the C12 with the stock compression dome

[@danpoxon2425]

Proper killing it Greg 👍🏽that bike is so so sexy

[@GregHitchko]

Thank you Dan! Really appreciate it my man 💨

[@beycengales2030]

Can anybody tell what I can run in my 2003 cr250r 2srtoke what fuel

[@GregHitchko]

Do you have any engine work done? High compression or is it stock?

[@ravanderveur]

Why in the world are you opposed to running leaded fuel? Two strokes love lead !!!!!! It is a lubricant , anti scuff agent . octane improver and the fuel is stabil for long lay ups. Oxygenated fuels are also corrosive so you really need to clear the fuel system after each use. And VP-2T IS Oxygenated. I found out when it corroded the needle in my perfectly jetted 2 stroke. It began to run all Fed up down low and I found the needle had been pitted on the straight section. New needle and Back to C-12 for me after that.

[@manny.9273]

Yeah i would stick to c12 or vp110 thats all i run in my cr, no pinging and no lean problems just 40:1 927 and runs like a dream

[@GregHitchko]

It's really hard to beat C12 in these bikes. It just runs so consistent and clean 🙌🏼

[@beycengales2030]

Is the C12 nonethonal fuel

[@GregHitchko]

Yes C12 is ethanol free!

[@Thepianobird]

my. only question is, will the engine behave differently with a load on it? Like should it maybe be in the dyno?

[@GregHitchko]

I feel like they always perform differently when you ride it than what the dyno says, right? Lol. If only I had. Dyno near me to run some testing

[@davidmcnerney3048]

She sounds crispy.

[@user-ep6wd7ip7v]

How’s those fox boots still holding up

[@GregHitchko]

Still like new since I've only used them like 4 times 😂. Don't get out as much as I used to lol

[@amfk8079]

really really cool video man!

[@GregHitchko]

Thanks man! It was a rad time 💨💨

[@manofknowledge1000]

Here in England Britain and Ireland it is impossible to get fuel as low grade as 88 octane. Lowest you can get at the pump is 95. Super unleaded at the pump is 99 octane sum places. I always always use super in my bikes. If I put even 95 in my R1 or gsxr superbike a I noticed it . Can’t imagine putting 88 innit lol

[@GregHitchko]

That is incredible to have that high octane at the pump!! I'm jealous haha. I'm assuming no ethanol either? Wish I could run that out of the pump 🙌🏼💨

[@manofknowledge1000]

@@GregHitchko £1.45 per litre here though so costs a fair bit more though. Maybe where you are race fuel is cheaper lol

[@Steve-pp9ig]

pump gas in the UK is rated differently than in the US. The UK uses research octane number. This is a higher octane number.The US test uses motor octane number. This is a lower octane number.At a US pump the octane number is called the pump octane number. To get PON you add RON plus MON and divide by two. Basically 95 octane at a UK pump is equal to 91 octane at a US pump.

[@michellatour150]

UK and Europe does not use the same measuring method for octane, your UK gasoline is advertised in 'RON' (research octane number), in north america the AKI (anti-knock index) or R+M/2 (average of RON and MON) are used. Your 95 RON pump premium is equal to 91 AKI. Our low grade 87 octane is equal to your 91 RON.

[@dylangarsed7254]

​@michellatour150 what about Australia? Here our premium is 95 and we have 98 octane super premium. Our standard fuel is 91

[@jeremyeubanks2387]

sure go with whatever fuel you think will work... what does pro circuit know...not like they do alot of testing..

[@GregHitchko]

The audacity 😂

[@denniswilder3014]

C12 is a much better fuel for a motor that has some work.if its stock then t-4 is more than you need.you only need enough to stop detonation.just before detonation is your best power

[@GregHitchko]

For sure! Im looking forward to testing out C9 which is the 96.8 octane too

[@denniswilder3014]

@@GregHitchko have not tried that fuel yet. But when i was racing motocross with a stock motor just a pipe. I found the best set up was 87 octane for 3 gallons and 2 gallons of c12. I would notice better throttle response and no occasional lean pop when in deep sand. When i grass dragged stock snowmobiles the best runs where with garbage fuel

[@GregHitchko]

@@denniswilder3014 that is super interesting about the snowmobile grass drags with crap fuel. I wonder why lol?!

[@denniswilder3014]

@@GregHitchko a motor only needs just enough octane to not detonate. The most power you will get is just before deto.

[@denniswilder3014]

@@GregHitchko its all about burn speed. The higher the octane the slower it burns. There is alot more of course but it boils down to burn speed. Advance the timing to get it to fire a tic faster when piston is closer to tdc it detonates. So you raise octane so it burns a little slower and it will burn slower and not detonate. You will get guys saying no way blah blah blah. But remember things happen at a millisecond. So a small change goes far.

[@markgaudreau8053]

didn't Mike Brown rip that bike?

[@bmxdestroy]

Pro circuit runs c12, its designed to run c12, it runs better with c12. Just run c12. Leave t4 for your lawnmower

[@GregHitchko]

What if I have a two stroke lawn mower 😂😂

[@user-bl6to5eq8m]

​@@GregHitchkoplease build a yz125 lawnmower.

[@minibikemadman]

c16 or nothing hahaha that's what I'm doing in a 380cc big bore built on a trx 250r.

[@zachklamfoth7583]

Sounds a tad lean on the needle

[@GregHitchko]

I'd like to explore richer needles here in the future 💨

[@jeremyeubanks2387]

you went through all the recomended seetings and decided not to go with the recomended fuel..thats crazy. if you can ship the bike then you could have gotten the correct fuel...

[@GregHitchko]

If I can ship the bike I can do anything right? 😂😂😂

[@revvinkevin85]

Moral of the story if someone has done the research and tell you what works dont listen to VP. They dont tune and build motors they sell fuel…

[@curtg5654]

Just stick with the c12

[@GregHitchko]

Hard to beat that's for sure

[@jonathanmoulton9251]

Had a 07 kx 250, when I bought my PC pipe and silencer they gave me all the info for my jetting. I believe it was from James Stewart’s bike. Bike rode fine on 91 octane. Also use iridium plugs big difference, stay away from that race gas you’ll blow a motor.

[@GregHitchko]

That's really cool! I wish there was something higher than 88 non ethanol out of the pump around me. Higher compression engines definitely take a away from the reliability of a stock engine just a little bit

[@jameswilliamson6532]

Tighten your chain

[@GregHitchko]

It's about time someone noticed 😂

[@Workerbee-zy5nx]

Yall are allowed to have bikes there now..hell I thought yall voted liberal and got rid of fun stuff?😳😳😳😳🤣🤣🤣

[@GregHitchko]

Someone's always got to bring politics into play 😂.

[@Workerbee-zy5nx]

@@GregHitchko Just noticing the oddness from the strange Left coast. 😉🇺🇸🏴󠁧󠁢󠁳󠁣󠁴󠁿🤠👍🤷‍♂️

[@GregHitchko]

@@Workerbee-zy5nx so true, I try not to think about it. Luckily in terms of that I don't live there 😂 lol

[@Workerbee-zy5nx]

@@GregHitchko Glory be, I hears y'all, yes I own a 89 cr250 with the pro circuit pipe and muffler, and I did a little local motocross on my long gone 84 Cr500r..Trump 2024, keep petrol power 4ever.🤠🇺🇸👍🍻

[@SoCalMisfit712]

Best things about California. We make twice as much as other states, our houses are worth twice as much, and we can still ride any dirt bike we want since we sell out of state OHV stickers. Only thing that costs more here is the gas, which is right at 5$. Bikes, cars, and food cost the same as other states 😂. Oh yeah and pro circuit and alot of the big name motocross companies reside here.

[@223hpyhooker]

Fantastic build as usual Greg. Hey by chance have you tried the pc high compression head that you opted not to use with the c12? I would think it would be a noticeable power increase and work with their porting unless the phathead had a hc insert in it already