Good 250r trail set-up?

[Dynofox]

I'm still in the process of making my R a good trail machine. I've been having problems with the running quality in tight woods where I am in 1st gear putting around. It will just quit (the plugs don't look fouled but once I install a new one it runs fine). When I do low rpm plug chops the plug looks a little lean which is confusing since the plug fouling problem makes me think it's rich. I have recently taken the full FMF system off and put the stock system back on (and jetting other than a slightly larger main jet) to see if this will make it run a little better in the tight woods. I'd like to get it set-up so I can ride slow in tight woods in 1st or second gear w/o fouling plugs. Anyone have any other tips?

[TimSr]

My first suggestion is to gear down so that your low speed riding is done at midrange and higher RPM's. I also run the needle all the way down to help keep it from loading up. As long as your main jetting is correct, its pretty difficult to do damage from running too lean at midrange.

Also, Ill clarify that there is no such thing as low speed and high speed jetting. Low mid, and high refer to engine RPM's, not speed. If you are geared low, and running slow in first gear at high RPM's, you are using top end, not low end.

[jeswinehart]

i'm not that good with engine mods but perhaps changing the primary sprocket or the rear to get a lower gear ration so you can still keep the r.p.m.'s up but have lower gearing to navagate tight trails might be a consideration.
that r i had didn't much care for slow lugging engine speeds.

john

[oddball3]

I would put a smaller pilot in it and or lower your needle.
My friends cr 250 use to do the same thing, plugs looked good but they were indeed fouled, went with a smaller pilot and havent had a problem since.
Or possibly your reeds are weak or bad.

If not get yourself a set of low end tourqe reeds.

[jeswinehart]

we all must have hit the enter button about the same time on our replys :)


john

[350x'inNY]

Hmmmmm.... I don't have a problem with my 82R in the woods... I did go back to the stock gearing... it had a 15 tooth front sprocket when I bought it! I only fouled a plug or two when I replaced all mt exhaust ring/gasket. Once I rejetted for that, I have had no problems. Even putting around for 1.3 miles in a parade didn't foul the plug!

Hmmmm... maybe you just need to trade the water pumper in on my 82R! :naughty:

[jenndnn3]

If none of those work, I suggest a flywheel weight. I need to get into my setup, I am stock right now and can lug around. But have yet to pull carb and see what is in there. Never had a need to. I use 2nd alot in some of the tight stuff. And 1st following the rugrats. And to get by cops in Florence, I go to third and really drown her for the sound stuff. (we are only allowed 93 dec there) I dont foul. So I think it is very possible to get there.

[ATC crazy]

*Coughbuyafourstrokecough*

:D

[Dynofox]

I would put a smaller pilot in it and or lower your needle.
My friends cr 250 use to do the same thing, plugs looked good but they were indeed fouled, went with a smaller pilot and havent had a problem since.
Or possibly your reeds are weak or bad.

If not get yourself a set of low end tourqe reeds.


I just installed some boyesen pro series reeds, so they shouldn't be causing problems. I'm going to do some testing this weekend with the stock pipe and go from there. Right now my jetting is all stock other than a 150 main vs the stock 142, and the only mod to my motor are the reeds. When I had my tri Z I could putt around in the tight trails w/o any problems, never fouled a plug with that. I guess I'm hoping to get it to where the Z was in the tight stuff. Thanks for the tips everyone! :beer

Timsr sorry for the confusion, when I said low speed I ment low rpm.

[hrc85250r]

get a coolhead and run a higher compression, or just get a cr250 head gasket to give you more compression....it works awesome for low end...i never ever ever foul plugs, and i can put around in first and even 2nd in tight tight woods trails...i never stall it and i am still running about 215 psi comression...get a low-end midrange pipe too....they work great...

[Old 179]

When you took the pipe off, that 150 main should had been replaced back to 145( 86 stock main). If you have after market air filter,a 148 might be better. Are you running 13-39 sprockets? What octane fuel? What 2cycle oil @ ratio?

[Dynofox]

When you took the pipe off, that 150 main should had been replaced back to 145( 86 stock main). If you have after market air filter,a 148 might be better. Are you running 13-39 sprockets? What octane fuel? What 2cycle oil @ ratio?


FMF actually calls for the stock 86 main of 145, not the 150. I didn't mess with it since it seems to run fine up top. I'm running stock gearing, a uni air filter, and 91 octane with klotz at 32:1.

[Old 179]

Your fuel sounds fine. You said 150 ran good top end, but your not using top end in the woods! I would try 148 with needle drop to 4th setting. it would lean you down in low and part of midrange. try that. You could also try to put your FMF silencer onto you stock pipe.(if it fits) I ran some tight fair races with that combo(different brand). had low end with a little kick on the upper end

[Dynofox]

Your fuel sounds fine. You said 150 ran good top end, but your not using top end in the woods! I would try 148 with needle drop to 4th setting. it would lean you down in low and part of midrange. try that. You could also try to put your FMF silencer onto you stock pipe.(if it fits) I ran some tight fair races with that combo(different brand). had low end with a little kick on the upper end

When I said it ran fine in higher rpms with the 150 that was when I was riding open fire roads (opening it up). Once I get back from testing this weekend I'll let you guys know what happens and then I will start with some of the suggestions on here if it still is having problems. Thanks!