YouTube - Timberwolf 250

Around mid summer I noticed a gradual loss of speed on my Yamaha Timberwolf 250. Now it is just ridiculous and riding it isn't even fun anymore. I realize this is a 15 year old 250cc utility quad and I don`t expect Yamaha Raptor speed but I was fine with how it was when I bought it at the beginning of the summer.

I posted online quite a bit when this issue started to develop and several people from various forums suggested that most likely my clutch is slipping. So I took the cover off and did see wear on the centrifugal clutch pads so I did a total clutch rebuild using all OEM parts. It cost around 450 bucks with all new crank crase screws, new centrifugal clutch, new springs, plates, gaskets....

And it didn't change a thing. What else could it be? Maybe a top end rebuild could be needed? The engine has some what of a noise when it's running and I made a video trying to capture it to see if you guys could tell me if its normal. You hear it at the end when I hold the camera right up to the top end. If I were to describe the power loss it's like the engine is at high RPM's in fifth gear and wants to go but I'm just not moving that fast! It's not like I'm going 5mph but definitely not like when I bought it.

Also you can hear how crappy it idles in neutral and how it gets a little better when I put it in gear. Any ideas to what that may be? I've cleaned the carb adjusted everything and still it misses like that when it idles and you can hear how it doesn't come back to idle cleanly when I get off the throttle.


PLEASE HELP ME!!! I don't have a truck and can't take it to a shop and I don't want to. I am willing to do the work I just need to find what the damn problem is first

 

Have you checked the valve adjustment

 

No I haven't. I will get a set of feeler gauges and check to make sure it's within the specs of my manual. Thanks for the suggestion it will give me somewhere to start.

 

Still experiencing this problem on my Timberwolf 250. I checked the valve adjustment and they are right within the specs in my manual. The problem seems worse now when I accelerate there is a whirring sound in the top end and now a tick tick noise that I hear when in low gear. The engine sounds like it is never under load and doesn't have the nice pop pop to the exhaust that it used to. Could it be a leaking head gasket? There is liquid at the front of the head around the exhaust valve cover but it is not clear where it's coming from.

 

Have you pulled the plug to see what it looks like? Maybe a compression test would help too. Is it backfiring any? The plug will let you you know if its lean or rich. Does it sound like the engine is building RPM but the bike isnt going faster?

Ryan

 

Yes the engine builds up RPM's but it just makes a whirring noise and I don't go fast. The plug is black- carbon fouled even though I'm running the carb on the leanest setting.

 

If the engine is building RPMs and the bike isnt going faster, there is a clutch problem. They are slipping. Did you adjust them with the screw driver and wrench on the exterior of the motor?

Ryan

 

I adjusted that adjuster based on the clymer manuals instructions which says something to the effect of turning the screw all the way to the left then 1/8 turn to the right. I don't fully understand what it is this screw does. I know there is an arm inside that moves when you turn the screw. I assume that by periodically adjusting it you are taking up play or wear in the clutch? Should I just ignore what the book says and try turning it a few turns to the right or will wear out my new clutch even faster?

 

I wouldnt do that. I dont know what to tell you, but the clutches are slipping. I would tear the basket down and see if you see anything wrong or burnt marks on the discs. I am not familiar with the internals enough to give you anymore direction other than the cluches are deffinately slipping. Sorry.

Ryan

 

Thanks for trying man....I'm thinking a 12ga slug through the head might just solve this things problem