86 250R carb question

[brddog7683]

Can one of you experts on the 250R's answer a carb related question for me? I have a 87 TRX 250R carb that is nearly brand new and want to use that on my 86 250R (old carb was bad). Do you think If I put the factory jets for the 86 (145 main and 42 slow) in that carb that would get me close for starters. I dont know what the factory jetting was for a 87 TRX but right now that 87 PJ carb has a 150 main and 45 slow.....should I make the change or leave it as is and see?

Mods to the bike are 30 over piston, reeds, uni filter with stock box (holes in lid)

Thanks for any input!:p

[Old 179]

87-pj07a had a 152 main, 48 slow with a 1 7/8 turn out on the air screw. Your 86 turn out was 2 1/4 out and same jets as you mention. The 86 TRX 250 R carb used a 150 main with the needle in the 4th clip position, rest same as your 87 carb. I would think you are thinking right with the jet change as you mention, the four wheeler carbs were set differently for various reasons. I would not think your mods would change the jetting from stock setting. Always take plug readings on new changes!!! Hopefully someone will chime in that has done the switch that your doing
Good Luck
OLd 179

[brddog7683]

thanks for your help...so your saying that yes, I should put the 87 carb to specs of the 86 and go from there?

[Yamahondaman]

is the "old " carb round or "oval" like the 87 ? .. i think the jetting you said was in the "round" "ATC "85" Carb ? .. what is the no's on the needle's ?

[brddog7683]

no the old carb was a flatside, not round and those specs of 145 main a 42 slow came from the 86 shop manual. I may remove the 150 and 45 in the 87 carb and put in stock jets for the 86 that was really my question if I should do so for my mods.

[Old 179]

thanks for your help...so your saying that yes, I should put the 87 carb to specs of the 86 and go from there?

Yes, I believe I would