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

Check for air leaks. I am much leaner than you at sea level. Mine has never overheated.

+1 on that, my dealer (Bill at BMP) installed reed block gaskets on both sides of the reeds because so many of the 250-300 WRs had problems with leakage. Its a cheap fix and I think a Honda uses the same gaskets so they are easy to get if you don't have a nearby Husky dealer.

Oh the joys of living in a small town. The nearest Husky dealer is 200+ miles away but don't seem to stock many of the Husky parts. I called the 2 Honda dealers in the area and no luck. I'm assuming I can test it for leaks by spraying some carb cleaner around the boot when it's running?

That should work but I would get the gaskets and do it anyway for cheap insurance. If it leaked in the future it could cost you a top end.

I'll have to do that. I put a 50 pilot in it today and it felt like a different bike. Last week I was really struggling going up some hills where you couldn't get much momentum at the bottom. Today they were fairly easy for me, I'm still a squid, though. I let a guy who races an older Yamaha WR250 2 stroke, take it for a ride and he came back with a big grin. He told me the jetting seemed perfect and that he absolutely loved the engine. He didn't think a more perfect engine could be made. It was still running hot on me. But I'm probably 255 lbs. in gear and there were a lot of uphill sections where I was just chugging up in first. I am running 50/50 coolant and was told to use Engine Ice.

HELP! soooo fustrated with my 300's jetting.I have read every page!...I ride 3000-7000ft...bike ran well duirng 50F ...JD's PWK 38AS,40pj170mj a/s out 1.5.....then it got really hot out and its a dog on top- it cuts out like it fuel starved but it isn't,i think its rich stumble! it will not rev-out....i have the red needle on the top clip,170mj/38pj /as 1.75......do i need to got to 160mj? 165? anybody else have a 300 and live in the idaho panhandle? washington? similar heat & elevation?

Ditch the Jd needle, get a Sudco CEL, and run a 175-178 mj and you will be good to go

I will try anything at this point....everyone raves about the JD carb...it was fine untill it got hot out..i actually thought it might be my ignition....hope the local ktm dealer has the CEL...175? really? i was thinking i would have to go the other way like 165-168..it really acts like it wont clean out....i tried the blue needle the other supllied jets and the leaner i set it up the better it ran...makes me scared it will seize...will check my local moto shops this monday.....thanks...or it will be back on the mikpuki...er mikuni

Do a plug chop and see but i ran cel/178 all the way to 6500 ft and it ran fine. At 7500 ft you might want 172/175 but that should be about it

Im down in the SLC area, so not a huge difference in elevation/temp changes. It is a little higher here in elevation. I am not sure what temps you have. But here is what I have:
PWK 38as
38 pilot
JD red on 2nd clip
160 main
recent temps in the 80s-90's F
Elev 4500-9000

I do have a pc pipe/silencer and high comp head. BUT ran pretty similar jetting prior to that. I was riding this weekend and was getting a rich blurb too. I am going to drop to a 158 or 155 main. these bigger bikes like it leaner. Especially since it has been hotter than hell and we are at altitude.

I would go back to 2nd clip from top on JD red needle, just as a baseline. Your pilot is probably OK. May not be perfect, but you are having issues at a different circuit. Then drop the 170 main. That is going to be too rich, typically, for out here in the Summer months. I would pick up a couple of jets starting at 155, 158, 160, 162, 165. Install the 165 and see how it runs and do a plug chop. You will most likely notice an improvement and eventually end up around the 158, 160 main size. Then you can work on the rest of the circuits as necessary, but I am willing to bet you are just too rich on top.

Now remember, every bike is different, but as a basis, you should end up pretty close. Feel free to PM me any time to come up to ride in Idaho. I have been dying to ride up there for a long time

Thanks for the post! I couldn't get a CEL needle in town, I might have to order one online, I do want to try the 175/cel combo Troffer88 suggested...I did get a few jets 162 and 165, and will try them out and see if she gets happy ...the 38 pilot was the sweet spot in the tight woods, so I suspect it will be leaner mj will cure the top end stutter/burble...I was glad to see your specs confirmed my suspicions ....I will be trying it out ...as for the riding up here ...it is incredible...dense green woods and miles,miles,miles of technical single track..of course it is only enjoyable when the husky is jetted happy...guess I will have to jet for summer and re-jet for winter ?

Yeah. I end up jetting a couple times a year. And am in need to do it again. I hear nothing but good things about Idaho. I moved out here about 2 years ago and am really happy with the amount of riding there is! Let me know if you are ever down this way. I would be happy to show you around.
Keep us posted on how your jetting works out. I would be curious to see how our bikes compare in the end.

ok...cured it...I am an idiot..the Leo Vince Spark arrestor had a removeable screen insert...I was cleaning up the spooge on the swing arm / pipe end and looked into the screen and it 1/3 clogged solid with coke and spooge.....took it out entirely and it finally revved out ..then started jetted back up to 42/170.3rd..probably could go 42/175 2nd clip with the red needle...I think it has been slowly clogging and losing power and i hadn't noticed...it was rich all winter and spooged but ran good,good plug color..so I never messed with it, untill it started to warm up this summer..I assumed from the spooge drip it was overly rich and over compensated. I run Maxima Super M @ 44:1..I am going to try the CEL/178 troffer reffered to as we have some of the same terrain/area/elevation..p.s. thanks troffer for the p.m. ...thanks for your help guys!

Sorry if this has been addressed, but I searched to no avail.\

How do I access the starting jet on the TMXX? I would like to try a different size on my WB 165, but the brass tube that it's encased in won't reveal to me the secret to its removal. Help!

Anyone have a good recommendation for a main jet on a 2012 WR250 for Supermoto? I'm guessing I need a lot more gas when I hit the main as its getting fairly hot if i stay on the main for any period of time with my current woods setup

At 76ft absl a 460 was to rich for my 09 wr 250.If that helps ya any.

I wonder if anybody here has seen this problem before. I have the PWK A/S I ran the bike with a DEK needle in the number 1 clip position. It ran very strong mid/top but seems to have a lean bog around 1/4 throttle the pilot is a 45. I put a CGJ needle in which is one step richer needle diameter. The problem now is that I had to turn the idle screw in to get it to idle. Will too big of a needle diameter cause this? Should I go back to the DEK and try a bigger pilot? Thanks!

A richer needle allows more fuel so ,at idle you should turn your air screw out more to compensate for more fuel.To big of a needle diameter will let less fuel in and more air causing high idle(lean).Thought those pwk a/s were hassle free?

Haha! Well I bought the carb used on ebay and am trying to figure out the jetting without resorting to a JD kit. I was under the impression that the pilot jet/air screw alone controlled the idle, but like I said I now had to crank the idle screw all the way in to get the engine to idle. So I'm wondering if a too rich diameter will cause this?

sounds like its flooding itself.What pilot is in it?I would try between a 30 and 35 to start with and putmthe needle in the middle.Question:was the carb cleaned before it was installed?I beleave the pilot air circuit controlls the idle and the needle takes over at about 1/8 to 1/4 throttle.