Jetting suggestions needed. 85 250r

[Louis Mielke]

Hey guys. I just got a 38mm pwk for my 250r to go along with my PT highrev pipe. Over stock its a vast improvment but I dont think I have the thing just right. The bike runs great from idle to about 3/4 throttle but then it just feels really flat after that.

I was assuming with this pipe and carb most of my power would be past 1/2 throttle but that doesn't seem to be the case. I'll be the first to admit carb adjustment is not my strong point. The carb came with 170 main and I just stuck with the needle were it came stock middle clip postion. The air screw was at about 2 turns out. I honestly only play with it till the bike seems to run clean so I may just not have it adjusted correctly.

Other than the carb and pipe my bikes still pretty stock.

Any suggestions. My father seems to think I need to go to the next main jet but I'm not sure. I did a few plug chops and it seems fairly ok. I'm looking at a light paper bag brown in third at about 3/4 throttle. I know I should have but i never did any at WOT and don't think I' gonna get a chance to untill tomarrow. I tihnk I'm gonna try and find the next two jet sizes today so i at least have them to play with tomarrow.

[Blown 331]

Is your air box lid on or off? If it's off that sounds about right to me but maybe a 172 or 175 would work. If your air box lid is on I'd say you need to drop down a few sizes.

[Louis Mielke]

I ride alot of pretty wet conditions (not mudding mind you or any kinda submersion just wet conditions) so i like the lid on.

I guess I'll see if I can get ahold of a couple jets, higher and lower.

[Blown 331]

If your lid is on I think you need to lean it out of course I didn't think about elevation or temp but I would say you need to drop a few jet sizes.

[Kintore]

I am by no means any jetting expert, But- I will give you all my collected pages that I have saved to try and teach me how to jet properly. Hope this helps some.
Tuning1
For a banhshee, but same principles
Tuning2
Theres also a link somwhere of !'s one thread all about 250r jetting, but I have seemed to of misplaced it!


Hope this helps some.

[BigGreenMachine]

Define falling flat? As in it bogs out? If it were lean you would still have decent power without bogging. Raise the clip position on the needle or find yourself a selection of smaller mains.

[Louis Mielke]

I wouldn't really call it falling flat I just mean all the powers is down low when I expected it to be father up the throttle. When I say falling flat I don't mean so much "bogging" as I mean it just stops pulling hard and seems like theres more to be had. If that makes any sense. I'm gonna play with it some this weekend. only annoying thing is that the weather has changed drastically now. blah.

[TeamGeek6]

I'm looking at a light paper bag brown in third at about 3/4 throttle. .

Not bad. IS it a stock air filter? If so, time for a K&N or UNI and order a few main jets to play with.

It could be starving for air or ignition. That ignition system starts to wimp out about 6000 RPM.