quad still sputters

[pro-rider46]

well my quad still is not fixed. i took it to the dealership over a month ago. they called this morning. and said they still dont know what the problem is. we took our other 450r in there to swap out parts and they swapped the stator, carb, the cdi, the condensor, and my timing is spot on. the valvles are spot on, my rings are at 9% leakage(normal is 5-13%), the only thing it is not doing right is it is only building 75psi of compression. when the other r is building 125psi, and both are on stock pistons.


what do you guys think it is

[400exrider707]

The poor compression would definitely have a negative effect...

[Chino886]

how are they checking the compression?

[pro-rider46]

they didnt say, my dad was the one talking to them. tomarrow morning we are going to pick it up. i think im buying a service manual and tearing it apart myself. i also think i might be getting a new piston, tommarow i will get the details on how the compression was checked and what not.

thanks for responding, i am in like a crisis right now because it hasnt ran right in over three months!

[Chino886]

I may be wrong, but my guess is they are checking the cranking compression, what the motor does on the kick start or by pushing the button...................I don't think (I may be wrong) but on a bike with a decompression mechanism you can not check compression like that.

The differences in compression on start could be in decompressor clearance.

Just my 2 yen!

[pro-rider46]

well i have a new cam in there, would that effect anything

[Chino886]

Originally posted by pro-rider46
well i have a new cam in there, would that effect anything

It could cause the decomp clearances to be different if you did not adj the valves after install.

I PMed you with some ideas to try!

[pro-rider46]

well i got the quad back today, and i am furious, the quad seems worse that before. it took close to 50 kicks to even get it started, and when it was started it would die in like 15 seconds, the throttle sticks slightly and it idles rough, it also has more vibration.
the stator side case i think it slightly leaking. but they did help the sputtering problem slightly. it only has a couple hiccups on hard acceleration. but when its at slow rpms and i go wot it just dies and the guy said he fixed that, because when you go wot the carb has a fast shot of gas shot into the airflow to keep it from dieing, he said the rod controlling this was stuck and he freed it. the other bike on the other hand has no problem running what so ever, still runs like a raped ape, with arm ripping power, well at least to mine.

my dad is probably send a letter to honda complaing about toms cycle. we kinda got a break and they only charged us like $150. but they didnt even fix anything! oh well i guess thats life.


can any of you give me an idea thats wrong. Any more help is greatly appreciated.

[pro-rider46]

well i think i found the problem, and i feel stupid now, but i had a 180 mj just laying around and i adjusted my stock needle on the fourth clip (till i get my jet kit), and i put on my exhaust and is still a little lean, but it runs awesome except it have a idling problem, and yes the idle is adjusted properly, the sputtering is no longer there, oh also i have to thank the dealership for fixing my headlight SO THEY DONT WORK!!!, and also putting not enough oil in the motor side, and to much in the tranny side, oil shot all over the bike cause it flew out of the crank case breather.

But all in all im happy

[pro-rider46]

i installed my new needle from the jet kit i got today, and it fells like a whole different machine now! i am so happy right now, it has a handful of torque. i love it.

[chad502ex]

cylinder compression and cranking compression are different.

when the engine is cranking, the decompression mechanism is set to reduce the compression for startup only. After the engine is running, the decompression mechanism disengages to build cylinder pressure while running.