04 450 won't do anything but idle!!

[FLjoyride]

04 450, stage two hotcams, zip ty fuel screw, gytr weighted flywheel, procom rev box... recently jetted to 170 main with blue slide (everything else stock) (sea level and its getting colder) but it was doing this before rejetting.

OK, runs great, pulls in ever gear just the way it should, then maybe 20 mins into riding it suddenly cuts out and won't do anything but idle.. shut it off and start it back up it runs great for another 10 mins.. got to the point now where I just pull in the clutch hit the kill switch and then pop it back up and it runs great for a bit. Sometimes it will go only 300 ft, other times it will go for 15 mins. First I thought I was sucking dirt or something into the main jet so I cleaned the carb (jets were clean), some sediment in float bowl but nothing too bad, then I thought maybe the neutral safety switch wire so that got checked, its ok. Thinking its electrical, maybe the procom box?? any help would be great its hard to track down since it only does it sometimes and then as soon as you shut it off it runs great again.

[desert-rat660]

sounds like an electrical problem to me also. ive heard bad things about the procom units. do u have the original cdi?

[FLjoyride]

original cdi crapped out 100% the third time I rode it.. thus the economy procom replacement. Never hit the rev limiter at least... oh and when its cutting out the idle is rough also and seems to be skipping or something.. going to double check the neutral safety switch again since I know the procom does the timing advance thing when its in neutral.. but it normally revs up decent even in neutral so I don't know, this one is bugging me and I am wanting to ride more (only ridden it about a dozen times in 2 years)

[desert-rat660]

id say check the tps but usually that would be a hard failure. u say when u shut it off and start it back up its fine again. really sounds like a cdi problem

[FLjoyride]

I was also thinking the cdi.. but It doesnt have many hours on it since its been replaced (maybe 30 at the most). yeah all I have to do is hit the kill switch, wait for the engine to completely stop turning then drop the clutch and it fires back up and goes like a bat out of hell. Had it kick back in one time while I was messing with the throttle and almost went over backwards

[desert-rat660]

lol, well when i was looking for a cdi for my rhino i did alot of research and people said they had problems with procom units, i ended up going with a dynatek i had over 200 hours on that cdi with no problems. id check ebay for a used cdi.

[FLjoyride]

Can't seem to find one on ebay, all they have is one for the YFZ

[FLjoyride]

wait, theres one for $279...

[desert-rat660]

http://shop.ebay.com/?_from=R40&_trksid=m38.l1313&_nkw=yz450+cdi&_sacat=See-All-Categories

[FLjoyride]

yeah, did that one too. I am going to go over the electrical real good tomorrow and check for loose wires.. just seems weird they usually go out 100% no spark. I do know wiggling the wires while riding doesnt help (at least the stator wires and ignition coil)

[desert-rat660]

but if the cdi is not advancing the timing it wont rev up correctly. looks like there are several cdis on ebay for around 60 bucks

[FLjoyride]

yeah I realize that but when its running good I can rev it in neutral and it cuts out at what 5000 RPM (never get that high just a tap to the throttle to get the oil moving once it idles for 30 secs or so) and when it cuts out on me as soon as I hit the gas it sputters and spits and pops and never really gets any higher than idle speed

[FLjoyride]

almost seems to run better when I just let it idle in 4th gear to get back to the truck...before I knew about the shut off temporary solution

[desert-rat660]

well there isnt much to the electrical sytem on these bikes. im still sticking witha cdi issue. u sure its not fuel related? i had a problem somewhat similar on my 06 450. it would sputter when i got on it, idled great and if i shut it off for a sec it would run good for a bit. turned out my fuel hose was touching the cylinder head and boiling the fuel i noticed this because there where bubbles coming up from the carb and i had alot of pressure in the tank.

[FLjoyride]

feul line is about 4 inches long and is not close to the cyl. head, I'm going to check the check valve in the vent line too.. but it doesnt seem like it would kick on and off that fast if it was a feul problem. come to think of it, first thing I checked was the feul, pulled the line off and checked the flow, was flowing great. BUT I topped it off first thinking it may have been splashing around being it was low.. the only thing is.. ive never heard of a cdi almost going out.. the only ones ive replaced have been out 100%, but I suppose theres a first for everything.

[FLjoyride]

thanks for your help, will keep you posted as soon as I figure this out. Any other suggestions will be appreciated.

[desert-rat660]

it almost sounds like the cdi is getting hot and causing problems, once u shut it down it has a chance to cool for a sec, but then quickly heats back up. anytime u are working with electronic parts even solid state devices such as a cdi u can get weird problems. heat is usually the main factor causing resistance in circuits to change. vibration is also another factor in failures of these parts. there really is no test in inspecting a cdi. the only real test is process of elimination. eliminating all the parts u can test will leave u with the only part or parts that can be faulty. sorry for rambling. i work as a mechanic and i build efi wring harnesses for desert cars so i like electrical problems

[FLjoyride]

Rojer that, that's how I pinpointed it the first time:D

[desert-rat660]

good luck man. let me know what u come up with

[grayracer513]

Just for fun, next time it acts up, unscrew the gas cap and see if that clears it up.

And, you might also check that the check valve in the vent hose is "pointing" the right direction (it's labeled).