honda 250 big red carb swap ?

[dustrunner]

would it hurt anything to put a carb off an 85 on and 86 big red ? i know they are a little different but i did this and seems to run well but i havent got the airbox and everything back on and ridden it yet ... also is the trx250 the same carb as the big red ? both 85 models ...

[Flyingw]

Swapping carbs between 85 and 86 is not a problem. The TRX carbs are not the same. The primary jet in the TRX carbs are not used so they are not drilled or populated. I have tried a TRX carb on one of my SXs and it wouldnt run unless I partially blocked of the inlet to the carb and even then it didnt run well so for ES/SX, stick to a QA01A, QA02A, QA07A, or QA08A carb.

[dustrunner]

how does the trx run without a primary jet ?

[Flyingw]

Primary and main jets are two different things. It has a main but the primary is blocked off. Primary is what the book calls it. The TRX carbs usually have a rubber plug capping off the undrilled hole. I'd be lying if I understood that but thats what they did. In any case, I'm not the only one who tried to run a TRX carb on an SX. A couple other guys reported exactly the same things as I did so for whatever reason, the SX doesnt like the TRX carbs or at least that configuration of carb.

[Flyingw]

See the factory SX manual. The top of page 4-9 shows the primary jet.

[dustrunner]

the carb on it now is a qa04a.. like i said it starts , idles and seems to run good.in the shop... but if you think it will be a problem i will get a kit for my original 86 carb as i lost the smallest jet ... i see alot of kits on e bay.. what would you reccomend moose, peekmoto, rj atv, off road idaho, shindy or other ?

[Flyingw]

Thats entirely up to you which carb you run. If the 04A carb works then run it. How does the throttle respond when you hit hard off idle? Does it fall flat on its face? Thats was the problem I had when I tried to run the 04A. Partially block the intake with my hand and it got better but still hesitated.

I buy all my kits from RJ ATV. No problems at all.

[djm0242]

I use a TRX300 carb on mine it's great.

[dustrunner]

Thats entirely up to you which carb you run. If the 04A carb works then run it. How does the throttle respond when you hit hard off idle? Does it fall flat on its face? Thats was the problem I had when I tried to run the 04A. Partially block the intake with my hand and it got better but still hesitated.

I buy all my kits from RJ ATV. No problems at all.

it didnt appear to fall on its face when hit hard but it's still in the shop without the airbox and such... i'll get it together today and see. thanks for the help flyingw.