85 ATC 250R Jetting Question

[LockNut]

I just put a FMF Fatty Gold Series pipe on my 85 R. It is not responding well in low range (bogs) and does not give me a smooth response through the power band in 1, 2 and 3rd gears. No issues in 4, 5 and 6th gears.

My question is, does anybody know what jetting I should be using? I currently use a stock carb. I run a 32:1 mix. Is there something else that might be causing the problem?

Any help would be greatly appreciated.

[Macdiesel]

get on their website and check the tech part it should tell you roughly what jets to change to and where to change needle setting if needed

[whyzee]

sounds like a lean bog, take the needle clip and move it to the 3rd or 4th notch. If that makes it worse let me know. I will get you dialed. Also you should probably run a 148 main, but the clip first. Also What type of riding are you doing? Stock atc 250r's were jetted very very rich to begin with, unless you were wide open in the sand alot. PS, put a new plug in also and turn the airscrew about 1 1/2 turns from closed or until the highest idle is found, then turn in 1/4 turn .
Also a performance pipe will not jet well with a stock silencer. You need to do both!
Why are you running a 32 :1 mix???? switch to the stock 20:1 !!! a poperly jetted r will have little smoke if using good oil ( Maxima Formula K2) and absolutly no pipe spooge , guys may argue that todays oils can be run at higer ratios ( 32:1 etc) but the lack of powervalve on the R's means you can run as much oil Honda says ( 20 :1 ) If your bike gets jetted properly it will scare you. Don't mess with the pilot jet yet.
Gotta tell me the air temp and what silencer you are running. Bikes should be rejetted 2 x a day in the early summer and early fall when the temps swings more than 30 degrees

[LockNut]

I have it dialed in now. Needed a 145 Main and played witt the airscrew. Full power in all ranges. Wow what a difference. No shortage of power at any range now.

Thanks for the tips.

[doug122]

hey i have a 81 atc250r and was wondering about jetting, it seems to run fine and idle ok but it does not have any top end what so ever, the motor has a dg pipe and a wiesco replacement piston with the stock carb. can anyone help?