Hotcam in 250sx????

[zombie_17]

I have a 1985 250sx with cobra pipe, uni air filter, and i just recently replaced all the jets and needles in the carb. i keept it with stock settings for the jets but moved the clip down one on the needle but this trike still does not have the power as my friends 86 250sx that appears stock but he bought it off of one of his "crazy" uncles so who knows whats inside the engine. anyways would it be worth it to install a hotcam- like the lowest model without all the extras like valves and springs or should my carb be rejetted to different sizes? i really dont know anything about the carburator but its not like the engine sputters or misses, it runs good and strong but seems to rev out much sooner. also is there a different cdi box that can be bought? thanks

[chris200x]

Hmm, If your gonna put the cam in there you had best better to the valves and springs. BOOM!!!

As far as the mods your running now. I suggest putting in the larger main and slow jet. I did this just last week..I think you'll be surprised... I'm running a supertrapp and K&N along with the rejetted carb. I also had to drop the clip one notch. It has awoken (if that's even a word) the motor alot. the front wheel comes right up in the first couple gears. A big change from stock.

[Dirtcrasher]

I run a Webcam with all the goodies, changed all guides, cam chain and sprocket, valves and performance springs/keepers. It is alot more fun than my stock 87 SX.

I also run a 350X carb and I drilled that main jet out 3 drill sizes larger than stock.

Your topend could be tired too, who knows....

[zombie_17]

Like i said before i am not to familiar with carburators and i was wondering what you meant by "larger main and slow jet" like one size up? which size would that be? I believe i know which one is the main jet but which is the slow jet-would that be the idle one? As for the cam i dont know if i want to spend that much for all the goodies. I live in Canada and the shipping kills me. would the cam alone be enough? thanks

[Tri-ZNate]

best bet would be to get a 350x carb. Best bang for your buck

[Dirtcrasher]

Like i said before i am not to familiar with carburators and i was wondering what you meant by "larger main and slow jet" like one size up? which size would that be? I believe i know which one is the main jet but which is the slow jet-would that be the idle one? As for the cam i dont know if i want to spend that much for all the goodies. I live in Canada and the shipping kills me. would the cam alone be enough? thanks


You'd be fine with just a cam, I went crazy because I'll keep my SX for a long time and wanted it to be tight. You do need to get a 350X carburetor though....

One size up is not enough, It's good to run no air box lid and aftermarket exhaust which require a big jetting change, The 350X in stock form seems to match those mods pretty well for someone that doesn't want to mess around too much. The air box lid really chokes the exhaust so I chuck them....

[chris200x]

Like i said before i am not to familiar with carburators and i was wondering what you meant by "larger main and slow jet" like one size up? which size would that be? I believe i know which one is the main jet but which is the slow jet-would that be the idle one? As for the cam i dont know if i want to spend that much for all the goodies. I live in Canada and the shipping kills me. would the cam alone be enough? thanks

stock main in the sx carb is 130. stock pilot is 38. I went up to a 132.5 and a 40.

read through this link... I too have trouble with carbs... :lol:

http://www.3wheelerworldforums.com/showthread.php?t=56744&highlight=revving+idle

[Dirtcrasher]

I believe the 350X stock main is 138 - I drilled it out a bit - may be like a 144 or greater now. The stock 350X main works fine, not spot on but these are 4 strokes so it's not as critical....