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By Ed Zeppeli
I picked up this quad after the previous owner couldn't get it going.
The issue is that I can't get it to fire at idle or at all.
- replaced plug. Decent blue spark. Also tested with spark tester inline.
- rebuilt the carb. PO had already bypassed vacuum lines from petcock. There's fuel at the cylinder
- Checked compression with new gauge. reads 190 psi
- cleaned all contacts I could access.
- am currently jumping with car battery. Solenoid jumpered.
- checked cam timing at TDC and adjusted valve lash
- put gas directly into cylinder to see if it will fire at least momentarily
Motor turns over well. Plug gets wet.
Motor may fire once or twice but smokes through exhaust a bit as if it's trying to fire or combusting.
This leads me to suspect timing. As mentioned I checked the flywheel mark versus cam marks. Perhaps someone has been in there before because I can't find a 'T' on the flywheel but there is a very visible paint mark which aligns with TDC position on piston. Possibly a slipped flywheel/woodruff?
Is it possible that if it had seen previous repairs, that the timing could still be off? I'm reluctant to dig into the flywheel/stator area if there's something else I could have missed but all signs point me to that area. Would a bad CDI cause spark timing to be off?
Anywhere else to diagnose incorrect spark timing?
I've scoured these forums and elsewhere but I'm posting just in case there's something I've overlooked up until now.
Thanks very much for reading!
By Chad Dickerson
I am goin nuts here! I have a 04 400 air cooled 4x4 , I'm a atv,car,truck,mower mechanic for yrs,just sayin. Ok it cranks and kinda fires now and again then after 5 min of cranking and stopping itl start if u touch throttle itl did then u start all over! If u let it warm up sumtimes u can throttle it up other times it just does! Just depends on it? When it stays running it runs awesome,no problems except it just does randomly like u shut key off? Sumtimes itl start right back up others itl do the no start thing! IV put new plug,adjusted valves and hot tanked carb? I'm at a loss here guys! Please any other ideas? I don't think it's anything to do with flywheel? It's not the auto it has a hi low reverse lever on left fender and foot shifter? Help please lol
Fixing up a 1998 King Quad 300. The rear brake was locked up, and the owner tried to force it free and snapped the axle.
I disconnected the brake cable, and tapped on the backing plate with a soft mallet to get the brake freed up. When I pulled off the brake drum a bunch of nasty rust water came out.
Once I had the axle out, I popped the boot off so I could see the inner u joint so I could phase/synchronize it with the outer. There was a flat steel disc floating around in the boot, looks like it used to be pressed into the end of the axle. Glad I got that out of there before it munched up the joint.
The book says the yokes should be aligned, I couldn't get mine aligned. They were always 7 degrees off from each other. A bit frustrating, maybe that's within the tolerance limits?
But I got it all back together and it runs great.
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