2003 Yamaha Wolverine 350 Engine Misfire

Hey all,

Still have my 03 wolverine 350.

Where to begin....

I'm trying to figure out why its missing really bad.

It was (still is, as you'll read later) missing real bad as soon as you got into it so I took it to my brothers place on my trailer because a mechanic from a Yamaha dealership is a friend of his and he was to stop by and look at it.

Well, I dropped it off (my brother only lives about 8 miles from me) when he wasn't home one evening. He called me next evening and said I was right that the thing didn't have NO throttle at all. I told him when I dropped it off it had about less than 1/4 throttle then it would miss and just act real ugly. So I drove down and sure enough it had no throttle, it just acted like it had a rev limiter on it as soon as you touched the throttle. It idles fine and it starts fine.

Anyhow, the next day the mechanic stopped by and went straight for the stock carb, there he found a pinhole in the diaphragm so i shelled out 100 bucks for a new diaphragm assembly online and close to that for another battery as oddly enough the battery was going also. Mechanic put it all back together and still no throttle. So he got to checking things and here the parking brake switch was going bad. Disconnected the 2 wires and held them apart and the throttle took right off (So he took the switch out and taped the wires apart). Took it home and 5 minutes into running it, it starts to miss again! Doing the same thing (I can putt around with it in the yard but as soon as i go to get on it it misses).

BTW, wasn't my battery, my starter is bad. Put new battery in and even jumped it from battery to starter and nothing so I need to Now rebuild the starter:aargh:

The Mechanic adjusted my valves and timing chain also when he worked on it. But like I said, I picked it back up brought it home because it had full throttle and he thought it was fixed, rode it for 5 minutes or less and its right back to the beginning and I'm minus a few hundred bucks.

I know thats a long as* story but I wanted to tell it because I don't think its a coincident that that dam PB switch went out just by putting it on the trailer for 8 miles on nice roads.

Does anyone think the PB switch was causing all this to begin with and now that its NOT IN IT AT ALL could it be why its running the way it is? And why did the starter pick the same time to go bad? Coincidence?

The week before it started acting up I had just put a new CV joint and bearings in the left front. Plus I had to bend my hub back straight. I must did it jumping or riding wheelies. I don't know when or how because I did'nt notice the wobble until I took it out on the main road one day. 2 days after that my 5 year old nephew was on it going the loop in second gear and it started shutting off. I parked it. Then next eve when I rode it, is when it was missing real bad. Not only was it missing but about half throttle it acted like it had a rev limiter kicking in. So then, thats when I took it to my brothers.

Coil and plug are new also. I need to figure this out because I'm really getting tired of putting money into this machine for parts I don't need. I also need to stop letting Mechanics from my local Yamaha dealer work on it!

I think theres more to this PB switch but I'm not sure how smart the cdi is. If you all don't think its related any Ideas would be greatly appreciated.

I don't know if this helps but it doesn't take long for the engine to get hot (but I think those 350 warrior blocks always seemed to run hot) you know like, don't ride with shorts on hot . My oil temp light does work but doesn't come on.

So more or less this Wolverines been down for a few months.

Thanks all.

What do you all think about it being the CDI or voltage regulator?

I think it could be that CDI box, you should have it tested.

* I changed your thead title to: 2003 Yamaha Wolverine 350 Engine Misfire

Im having the same problem, and now my bike is at the point where it will not run at all. Have spark, compression and fuel, but will not run. If you find out what the problem is would you mind letting me know? I will do the same for you as well. Ill drop you my e-mail address if it makes it easier. Im really frustrated with my bike too. Ive checked timing, swapped out CDI with new one, and still nothing. Anyway my address is [email protected] hopefully we may be able to help each other

i would check the fly wheel the magnet can come loose or lose its strength causing eratic running conditions

pfdloe, I started a new thread with your post, it is in this forum under 2003 Yamaha Warrior 350 engine misfire.

I had that same problem, its the switch not the PB switch but the one right above it! I had to replace my switch after I rolled my 2003 Warrior 350. 42$ later it fixed the problem. I was thinking it was a clogged jet, but had my wife's dad look at it (an atv and car mechanic) if you take the top switch on the left side of the handle bar, cut it and uncross the wires it will run fine. If you have it running fine, for kicks and giggles, apply your parking brake and then try and hit the throttle, it does the same thing! It prevents you from riding the quad under those circumstances. Like I said before mine did the same thing, the motor sounds like it cuts out constantly, but never dies, idles fine and will start all day but just doesn't run like it should.

I pulled the part number from Yamaha parts for your wolverine, its under the Handle Switch Lever category.

In my opinion I don't think that there is any coincidence between all that stuff going out at once. Starter and battery coincidence MAYBE, but Parking Brake and others, I don't think so.

Item # Location In the Diagram: 28

Item Part #: 4KB-82917-00-00

Item Description: SWITCH

It is the same part number as my 2003 Yamaha Warrior 350. I just noticed that. Check out my problems see if you know of anything to fix it.

http://www.quadcrazy.com/atvforum/yamaha-atv-forum/7210-2003-yamaha-warrior-350-overheat-gas-air-mix-problems.html

I have heard from a few ATV mechanics that the Warrior engine does have trouble with there flywheels. Check to make sure that it did not worp/bend.