04 450r problems

[Trailrider400ex]

A buddy of mine has an 04 450r and we put a curtis sparks full exhaust on it over the summer. we jetted it and ran good all summer and now he has problems. Bike will run but not good. If you have the choke on it will run great. If you just smash on the gas it will cut off. Curtis sparks recomended a 190 main and it ran better with a 180, I tried dropping the main down to a 170 and still having same problem. I also played with a/f mixture no change. Also when you press on the hot start while is running it makes no change in idle speed, shouldn't the idle go up when you press the hot start whil running? Any help would be great!!!

[BSTURDIVANT]

Clean the carb!

[MAD450r]

As for the hot start it should actually lower the idle since it does the oposite of the choke and with the choke the idle will go up.

In the cold my R is kindof like that, Takes longer to warm up and it does seem to have a dead lowend. In the cold I have to kindof either roll on the throttle some or I have to only bounce it 1/4 throttle a few times then I can hit it open.

Mine was like that with the stock exhaust as well in the cold.
Well hrc exhaust since I picked mine up in march of 04 with hrc installed already. Had my sparks pipe here already when I got it, but didn't install it till after the first oilchange.

[trost66]

Just call sparks and ask them. Just tell them your problem and see what they say.

[jshtex]

It seems to me like the choke would be making it richer (same amount of gass but less air)??? Maybe you need to go up on the mj?

[QuadPunk450R]

it if was running good all summer and now that its cold out its not go up to the 190 jet....its getting colder denser air and it should be running lean

[ricks450]

IT SOUNDS LIKE THE CARB IS SOME WHAT CLOGGED. IF YOUR HAVING TO RUN THE BIKE ON CHOKE TO KEEP RUNING.WHAT YOUR DOING IS SLOWING DOWN THE AIR MAKING IT PULL THROUGH FUEL CURCUIT OFF THE CARB HARDER.WHICH WILL GET THE FUEL TO COME IF YOU HAVE PARSULE CLOG JETS. IF YOUR RUNNING OPEN AIR BOX WITH EXHAUST I WOULD'NT RUN LOWER THEN A THAN A 180 MAIN JET. BUT ALWAYS START OFF RICH SO RICH YOUR BIKE IS BOGGING.THEN WORK YOUR DOWN TILL YOU GET TO THAT FIRST JET THAT MAKE YOUR BIKE START RESPONDING GOOD AND PULLING GOOD , AND YOUR A/F SCREW IS MAKING A DIFFERANCE WHEN YOU TURN IT IN AND OUT. YOU KNOW YOUR ALRIGHT RIGHT THERE. I WOULD TAKE IT APART AND CLEAN IT REAL, WITH COMPREST AIR AND CARB CLEANER.GOOD LUCK!!

[flyboy62]

East Coast ATV did my dads full curtis sparks with no lid and a k & n w/ an outerwears cover with 180 jet and got the carb cleaned and it runs fine and loud!
my dad is sunco on here

[flyboy62]

jgfc