Hey Guys,

My Dad and I bought a used 2000 Yamaha Venture 500 a couple of months ago, and just this weekend we are having problems with it. I took it out for about 8 kms, and then the engine started to hestitate. I couldn't really get the sled above 50-60 km/h because of the hesistation. It was as if it was starving fuel, but there was plenty of fuel in the tank.

Anyways, I slowly drove it home, and and on the way there the hesitation was sometimes so bad that the sled pretty much had to stop.

When I got home, I took the car out and bought some Kleen-Flow gas antifreeze and new gas and put that in the tank (which took about 45 mins). I then took the sled out again and it seemed to be fine, until about 20 minutes later when it started to do the same thing. Weird :S

The sled has 8,500kms on the odometer. I had also just put in Valvoline 2-stroke snowmobile oil before I took the sled out for the day. I was running regular gasoline.

Any suggestions? Could it be something simple like a spark plug?

Thanks guys!
Bryan

It sounds like a problem with the TORS (throttle override sensor). A lot of people just by pass the TORS and it usually fixes the problem.
If you do bypass it, just make sure that the throttle doesnt stick before you start the sled.

Thanks for the suggestion Octane

My Dad is pulling the plugs and we will change them in the morning (probably needs to be done anyways). If that doesn't fix the problem I will try the bypass as you suggest.

I'm not really mechanically inclined . . . do you know where I can find the throttle override sensor? Is it something difficult to bypass?

Thanks,
Bryan

Its not at all difficult. If you have the owners manual, there should be directions on how to it. My sled did the same thing. Disconnected the TORS and no problems!

The problem is that I don't have a user's manual

Can anyone help me out?

Thanks,
Bryan

Theres 2 wires that go to your carbs. Disconnect them and plug them together.
You might want to wrap them with electrical tape so that they dont come apart.
If you decide to do this, I offer a warning: The TORS turns off the engine if the throttle sticks. If you disconnect the TORS and the throttle sticks, the engine will not stall. Make sure you check to that the throttle does not stick before you start the sled.
Even if the throttle does stick, its no biggie. Just hit the kill switch. (thats what I had to do last winter when the throttle on my Polaris froze and stuck open going into a sharp corner, thanks to a little quick thinking on my part Im here to talk to you today) I just want to make sure you are aware of what could happen if you decide to bypass the TORS.

Thanks man!

The kill switch is no biggie . . . that is the first thing I would reach for in such a situation anyways I think that a TORS is really unnecessary for me, but I guess if my less-experienced siblings were to have a stuck throttle, they wouldn't know what to do. Hopefully this is our only problem with the sled, and I will look into getting the TORS back into working order

Thanks for your help! I will take a look at this tomorrow afternoon.

Regards,
Bryan

By the way, I was able to find a user manual on the American Yamaha site . . . couldn't find it on the Canadian site.

Thanks again!
Bryan

As an update:

We bypassed the TORS today as suggested, and I took the sled out for a spin. The sled was OK for about 5-10 minutes, but then it started to hestitate again under hard acceleration. I noticed that the RPMs maintain and don't really drop. The engine also makes a strange sound which is really difficult to explain.

I still drove it anyways, as it wasn't as bad as yesterday. It never got to the point where I had difficulty making it up a hill, or moving from a stop.

I drove for about 20 kms or so, and then on the way home I noticed the problem had disappeared. I was able to open it up without any problems. Weird :S

Maybe there was just something caught in the fuel line or something and it made its way out on its own?

Thanks!
Bryan

Another update:

My brother-in-law took the sled out today, and all was well until it suddenly just shut off without warning and as it he had hit the kill switch :S A really nice snowmobiler helped him out by taking off the drive belt and towing him to the nearest road, and then he had to hitchike home :P

We put the sled in the back of a truck and brought it home and tried to get it running without any success. We changed the spark plugs, and put some ether into the spark chambers. We also reconnected the TORS. When cranking, the sled would burn the ether for about half a second and then just die. My Dad thought it wasn't getting any fuel because the spark plugs were dry or something.

We then brought the sled to a motorcycle shop (the only thing open), because the guy who works there used to work on sleds. He didn't have a chance to look at it, but he suggested that it may be that the tube that takes gas from teh gas tank may have become brittle and broken off, thus allow the machine to only extract gas from the top portion of the tank.

We took the sled to the gas station, filled her up, and tried turning it over a few more times. It started! Hmmmm . . .

So we bring the sled back to the cottage and my brother takes it out for a run. He is gone about 10 minutes and then it shuts off on him in the exact same way. Refilling the gas tank does not allow the sled to start this time.

Now we are baffled :S What possibly could the problem be?? Could it have something to do with a clogged fuel line or fuel filter or something?

Any help woudl be awesome!

Thanks!
Bryan