hey guys i need a little help. i just picked up an 89 250r and it has an fmf fatty pipe and power core2 silencer. it bogs very badly at anything above 1/2 throttle through the bottom end of 1st and 2nd gear, and pretty much all the way through the rest of the gears. I do not know the jet sizes. What are the recommended jet sizes/needle position for a stock motor with the fmf setup? i run an 8 plug, and the bike starts on the 2nd kick every time. any advice?

 

Welcome to the forums, nice to see more San Diego people!

It's hard to say but I would take the carb off and fully clean it out. Also remove the bowl and clean that.

Then mess with jetting. Increase the main jet one size and see how it runs after it's cleaned out.

Good luck!

 

i believe clip position would also help in the 1/2 throttle ranges.

 

you need to read the plug, sounds like it is oily. first, what is your gas/oil ratio? 32/1? if that is ok you need to start with the needle for mid range, main jet is for full throttle. the plug reading is the key

 

put a new spark plug

 

Thanks for the tips guys. i pulled apart the carb and cleaned it all out. it was a little gummed up but not too bad. i also pulle the reeds and there was about a 1-2 cm gap b/w the reeds and the cage. i flipped the reeds and they sat flush again. after getting it all back together i fired it up and it seemed to have musc crisper throttle response. i havent had a chance to ride it yet but will do it tomorrow. Oh yeah i run 32:1 ratio fuel. is this ok even though it is stamped 20:1 on the tank.

 

that 20:1 sticker is for originality purposes only. ;-) yes, i run similiar ratios in the same area.

 

Pay no attention to the ratio on the fuel tank. You can run any mix ratio/oil brand you want to. I run Amsoil 2000 at 50:1 in both my Rs and never had a problem because of it and I've had them for over 10 years.
As far as bogging, now you have your reeds working better (replace them, you can get new Boyesens for less than $30!), put the needle in the middle position and then do a plug chop. That is the only way to find out where to go with your jetting.
Always start with a fresh plug, and I don't give a flying-rats-azz what the manual says, gap your plug down to .022. The weakest part of the R system is the ignition and a smaller gap will really help. Run NGK BR8ES or equivilent.

Good luck and have some fun doing this![img]i/expressions/face-icon-small-happy.gif[/img]

 

I have a 89' TRX250R also with the same pipe set-up. I'm running AmSoil at 100:1 and have since after break-in with no problems. Never been rebuilt and still runing strong. I'm running the 152 jet with the needle set at the 4th notch down. My mechanic said that this is where it needs to be to get to most out of the motor. To check for plug and engine temp, warm it up then run it up in 6th gear, turn off the run switch and let it stop while in gear. Pull the plug and look to make sure it's not running too lean. Good Luck!!!!

 

SoCal250R: how you doing with the quad?