97 Venture won't wind up

Rocky18

Rocky18

New member
Joined
Dec 5, 2010
Messages
21
Age
83
Location
Rockford, IL
97 Venture 600 3300 miles. Starts and runs fine. Keeping speed slow and all is fine. Try to get above 30 and it goes but doesn't want to. By that I mean it acts like it's flooding.(I think). A new coil was just put on by Hammertime Yamaha. They said the coil was the problem. Did not help. It still runs poorly at higher RPMs. If it is pinned, best RPM is 6300. If the throttle is let off a bit, it seems to run better. Usually something between 40 and 50 MPH is all I get. Oxy switch set for Non-Ethanol. I am burning Ethanol free 91. One time today I saw 7000+ RPM, then a back fire when I let off.
I'm not going back to Hammertime. They get too much $$$$$$ and don't deliver. Any ideas appreciated. Thanks
Rocky18 AKA Mike
 
It is used very little. A bit around the place and then when one of my boys goes along on a trip north. This year it was "bad" after hauling kids behind on sleds all day. I thought fouled plugs…but not so. Then the trip to Hammertime. Didn't test it until Ironwood. My boy ended up on a rental.
Rocky18, aka Mike
 
SRX500kid,
plugs looked ok, but I put new ones in anyway. Same results. If I raise the machine, (track free to spin) It goes from 0 to 100 perfect….7000rpm. Both clutches look normal. On snow with throttle pinned, gets about 6000rpm and 50mph…sometimes less….
Only on occasion, if I "Nurse" the throttle, I can get 7000 rpm and 65 mph. This is not always possible to do. Thanks for the input
rocky18, aka Mike
 
OK… here's the "final solution" to the wind up problem. With my neighbors help, we removed the carburetors. This sled has "Smart Carbs" and a ton of wires etc coming off the carbs. Unable to find much info on the solenoids so a resistance test showing all 4 with roughly the same resistance satisfied us. Then when opening the carbs BINGO… one carb had a loose, very loose main jet. Cleaned them up anyway and back on the sled. It is a PITA dealing with all those wires and the air box. But it is done. The sled is back to it old self. Winds up fast…tops out at 85 on the speedo and we are heading to the U.P. tomorrow. My son will be on the Venture and I will be on the Vector. Yes, I am selfish. I am also old and need EPS. Many thanks to those who offered suggestions. This site rules
Semper Fi and Fairwinds
Rocky18, aka Mike
 
Well my Venture just bit the dust or the engine did. Had similar problems and did a carb clean out to see if that fixed it but no. Simple thumb over the plug hole and have someone pull it. Left side good compression but right side nothing!!! Now to fix this. I like this machine and was giving it to my son who had the 94 doo listed below which I am now driving. But I can't do that to him so I need to fix it first making it right again before its truly his again.

I'd like to do the repair myself but never done and engine before especially if the head is damaged. I am looking for info and posted on the NON powervalved section on the weekend but no responders there.
 
The rebuild is easy, but before you take it apart make sure you find the root cause. I don't know how many times I see people rebuild only to repeat the problem because the cause was not eliminated. I have a Rotax here that I still can't find the root cause for after several rebuilds thinking I found the cause.
 
Thx Ding

Oil was fine and if one cylinder is getting it the other should as its one pump. I talked to a private repair guy and said the carb may have went too lean and caused the problem and expected to see a hole in the piston. Not from looking in the hole with the plug removed and its not shiny or white on top either. Maybe a gasket issue but I would not see that until I pulled the top off (coolant hose goes into it), then the jugs or heads whatever as there are gaskets below them. I am assuming these small head have coolant flowing through them despite the size. I don't have a garage and basically have to work outdoors with a covered over shelter at best. Once I pull it just to see I am not going to be able to move the sled easily. Dragging with another machine only and never get it on the trailer to take it somewhere.
 
You can do a leak-down test. There are 2 types of this test. By blocking off all ports and putting 5 psi in the cylinder you can see if there is a case leak anywhere.

Build your self a cart to put it on. That way you can move it around. Also they are a lot easier to work on if elevated. Years ago I built a few stands out of used 2x6's from a deck. I still use these today.
 
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