Yamaha 350 Engine (Big Bear?)

[blackhole]

I have recently picked up a go-kart with a Yamaha 350 from a 91 Big Bear four wheeler in it (I think). It was kinda podged together but I would like to do it the right way. Unfortunately I have no real knowledge of the Yamaha engine but I'm pretty mechanically inclined. I was just wondering if someone may be able to tell me what the different levers are for on the motor. On top of the transmission (on the right side) is a lever that was held rearward with a spring when I got it and appears to have a cable hook up on the end of it. Then on the rear of the engine near the lower motor mount there is another lever that appears to have two positions and seems to effect the drive cog. Then of course there is the shift lever (which I recognize) but does this have a clutched transmission or is it a sort of selectable automatic? I just would like to be educated a little but so I can figure out how to hook this up the right way.

 

[Winmac]

I should know this but I'm stumped by the two levers, one is the fwd/ rev selector, (some bikes had low/high/rev) I believe it's the spring loaded one and the second I'm stumped it's in the area where the speedometer drive cable is located.

There are two clutches in the engine one is centripetal ( disengages at idle) and the second is actuated by the foot shifter to allow the transmission to shift.

 

[blackhole]

I should know this but I'm stumped by the two levers, one is the fwd/ rev selector, (some bikes had low/high/rev) I believe it's the spring loaded one and the second I'm stumped it's in the area where the speedometer drive cable is located.

There are two clutches in the engine one is centripetal ( disengages at idle) and the second is actuated by the foot shifter to allow the transmission to shift.

Thanks for your help. After I posted this I went looking for some more pictures and diagrams and I found a picture which shows a linkage from the rear lever that appears to go up toward the carb. The other lever is not as visible but I have drawn some black arrows to show where I'm talking about. The other lever in question is on the other side of the engine and does not seem to effect much. Of course I have not had this engine running yet so I'm not sure what it may effect when it is running.

 

[Winmac]

That engine is not what is expect to see in a Big bear, they were all shaft drive at least in the Canadian market.

The clutch dose not work how I described it above, you have a manual clutch that's the other lever.

 

[Ivan49]

My Big Bear is shaft drive to the front and chain drive to the rear. I will try and remember to take a look today and see if I can find where the spots you posted hook up to. I know one of them will be for the Hi Low range lever

 

[MMagis]

I'm pretty sure all Big Bear ATVs were shaft drive.

 

[Winmac]

I'd guess the engine was from a 350 warrior.

 

[blackhole]

I'd guess the engine was from a 350 warrior.

Well that's helpful information. Is there anything else you can tell me about that Warrior engine?

 

[Chopperhed]

Well that's helpful information. Is there anything else you can tell me about that Warrior engine?

I believe it is a warrior engine. The same basic engine as the big bear but with a few differences. The big bear has a gear box bolted on where the sprocket is. The carb uses the same casting but the internals are different. The warrior carb uses a throttle cable that splits into two cables. Also the warrior does not have the dual range transmission, just forward and reverse. Thirdly the warrior uses a manual clutch.

The rod shown in your picture is the forward reverse shift rod with part of the shift lever assembly. There should be a clutch lever spline sticking out of the top of the right side of the engine. When I blow up the picture the clutch arm is where it should be. Originally the F/R shifter bolted to the right side of the frame under the tank.

The warrior will run with a Big Bear carb, but mine doesn't run well

 

[blackhole]

Thanks. I really appreciate you information. It lines up with (and enhances) a lot of the other research I have done. I know that my engine needs a starter and intake manifold (to start with). When it warms up a little I'll build an engine cradle and see if I can get it running before I put it in the kart.