All 2st Jetting Chat - Need Help? Post Your Questions Here

I bought a 38 lectron. Bolted it on and am in love. Bike feels more tame but still revs good. Needs a bit of enrichment, but the low to mid rpm and idle to 3/4 throttle is infinitely better.

Now the top end is slightly less but i havent dialed it in yet. Still rips.

All the hype is true guys. Worth every penmy.

In warmer weather my experience has been needing to go at least 2-3 sizes on the pilot jet a carb is delivered with. Probably go one position leaner on the needle too.

Cant find any jetting specs on the new and improved database for - 2011 WR300 - TMXX38 & JD kit.

Riding 0 - 2000 feet but regularly between 1 & 2000 feet low humidity.

Stock internals C piston, FMF Gnarly with stock silencer, running 40:1 Motul 800 ester blend

Where do I start?

SLIDE:
NEEDLE:
PRIMARY:
MAIN:
AIR SCREW:

Lets hear your ideas or update the Jetting Data base and help us out.

Cheers

Stu

Start air screw get that right two turns either way or more and your looking at a different pilot.
Pilots right, good now do needle jet boging? Raise the needle a clip hanging throttle lower it one, still cant get it right change the needle jet smaller = leaner bigger = richer.
Got that right? Done if not you may need a slide but imo unless its worn out you wont.

What's the trick to getting the nozzle in?

Can't get the new or old nozzle back in. Has anyone done this before and if so, how did you do it without damaging it?

And which way is it supposed to go in?

I am no expert but I did find that the newer Mikuni's don't have a replaceable nozzle jet.

Should go back in the reverse of getting it out some are peenied over(spellings suspect) de bur the edge and try again, my old mkrappy carb im sure unscrewed.
How did you get it out stu?

Got it back in. Stupid me didn't take notice of which way it came out and was trying to put it in the wrong way.

Stu

Chill 'saul good man

I've got an 11 wr300 and I run a JD kit with a 30 pilot, 420 main, red needle @ position 4 (from the top) and a 6.0 slide. Stock pipe and silencer. 40:1 oil ratio. I ride faster two track stuff in the desert. Mine seized with the stock crap. This has worked for me for 100 hours now.

What would change if you went to an aftermarket pipe?

Bank balance. Lol depends what the pipes tuned for could make it lean could blubber at idle and be perfect uptop or vise versa..

I always have to lean out jetting with FMF pipes.

can anyone tell me if they would reccomend running 110 race gas in a 03 CR250 or not, i just picked this up last month and plan on riding tomorrow. I used to use that in my race bikes a few years ago and they loved it but a friend that rides a KTM 2 smoke said his ran like crap when he tried running hi octane before so 97 works best for him. Any thoughts??

No problems with race gas the good stuff you can advance ignition and you cant get it to detonate, good times.
Try it.

I highly recommend VP110. It's got a longer shelf life (approximately 3 years) without having to use additives and has the octane to insure against detonation due to poor fuel. FYI don't leave it in a clear fuel jug in the sun, if you do the sunlight can separate the lead from the fuel.

Sweet thanks there's a oil co. down the street that sell VP110...Thanks

I have been running straight 110 octane race gas since 2005. I had a a KX250 which had really high compression stock. When I got my WR250 I never switched back to anything else. The benefits of race gas:
1) You can run higher compression, I had the head on my WR250 modified for more.
2) You can advance your timing
3) You can jet your bike really crisp and never have any detonation.
4) It smells good.
The only negative is that you may need much different jetting than if you were running something like 92 pump.

Great thank you for the info... I raced a 98 RM250 in non-current and a YZ426F for years and they both ran like a Swiss clock on it. I'll just watch my plug and jetting real close..thanks again