[guggisbergfarms]

So my sled was recently rebuilt. And it suddenly start running poorly and would randomly cut out and shut off. So as an example you would get going 50 mph and then it would slow itself down and once it stop it would shut itself off. I then noticed the secondary was a little lose so I took two washers of and that made it tight again. But it didn't change anything and then it got worse and could only go 30 and then would cut out. I figured it was electrical so changed the ignition coil and the CDI box. Now it runs great but will go 30mph and won't go any faster and runs at 7000 rpms. The spark plugs also look different the side with the clutches is darker and wet but the exhaust side is a lot cleaner and is dry. Was wondering if anyone has any ideas what it could be.

 

[guggisbergfarms]

i have also change the secondary clutch out and the primary clutch spring. Still no difference . if you know anything please let me know.

 

[Yamaha440]

Start with cleaning the carbs!

 

[guggisbergfarms]

i had cleaned them when the first snow fall came but i can go through them again.

 

[Coolhand]

Check the secondary clutch as well, check belt deflection and try another belt also. Secondary has a spring and buttons also that people forget about. Check all that stuff, clean the VES Valves and Carburetors. The VES engine MUST USE Full Synthetic Oil as well otherwise it will really gum up those valves.

 

[guggisbergfarms]

Ok so i have an old sled that runs great but has a bad tunnel and bad track. so i switch the secondary but it still does the same thing. I will have to check the VES vavles.

 

[guggisbergfarms]

Check the secondary clutch as well, check belt deflection and try another belt also. Secondary has a spring and buttons also that people forget about. Check all that stuff, clean the VES Valves and Carburetors. The VES engine MUST USE Full Synthetic Oil as well otherwise it will really gum up those valves.

thank you

 

[TheBearAk]

Key words here are 7000 RPM and still only going 30 MPH. That is 90% clutching issue. It is not shifting into high.

BUT, do make sure the track spins freely. Lift the back of the sled off the ground and see if you can rotate the secondary fairly easily. If the track is to tight, for example, it can cause the clutches to not shift properly. Inspect the driveshaft and bearings. Tough to see, but you're looking for grease leaks or exposed bearings.

 

[Coolhand]

Maybe I was getting 7k and only 40-45mph out of my '98 Indy 440 a couple weeks ago and found that the CDI was cracked behind it. Swapped it out to new one and no issues so something else to think about.

 

[guggisbergfarms]

Key words here are 7000 RPM and still only going 30 MPH. That is 90% clutching issue. It is not shifting into high.

BUT, do make sure the track spins freely. Lift the back of the sled off the ground and see if you can rotate the secondary fairly easily. If the track is to tight, for example, it can cause the clutches to not shift properly. Inspect the driveshaft and bearings. Tough to see, but you're looking for grease leaks or exposed bearings.

i have just lifted the back up and it spin very nice it is the smoothest i have ever seen. It all looked pretty good so im going to take the secondary apart just to see if anything is wrong.

 

[Yamaha440]

If the engine is down on power, it'll absolutely affect clutching... it's why we need to adjust it with altitude! The difference in plug color also suggests that the problem is related to the engine

You've already replaced most of your ignition, so that leaves the fuel system (which is probably the most finicky system on a sled), VES Valves, or compression. Have you checked the compression since this issue started?

 

[guggisbergfarms]

If the engine is down on power, it'll absolutely affect clutching... it's why we need to adjust it with altitude! The difference in plug color also suggests that the problem is related to the engine

You've already replaced most of your ignition, so that leaves the fuel system (which is probably the most finicky system on a sled), VES Valves, or compression. Have you checked the compression since this issue started?

Yes i did and the clutch side has 10 more pounds of pressure than the chain case side. So the side that had a wet spark plug has more compression.

 

[tgsmartcows]

So my sled was recently rebuilt. And it suddenly start running poorly and would randomly cut out and shut off. So as an example you would get going 50 mph and then it would slow itself down and once it stop it would shut itself off. I then noticed the secondary was a little lose so I took two washers of and that made it tight again. But it didn't change anything and then it got worse and could only go 30 and then would cut out. I figured it was electrical so changed the ignition coil and the CDI box. Now it runs great but will go 30mph and won't go any faster and runs at 7000 rpms. The spark plugs also look different the side with the clutches is darker and wet but the exhaust side is a lot cleaner and is dry. Was wondering if anyone has any ideas what it could be.

First, the secondary is supposed to have side play on the shaft, at least. 040" to allow self alignment and prevent bind on the bearing from heat and negative clearance. So put that shim back in.
Next, if it's a clutch issue, check by putting magic marker on the faces of both clutches to see where the belt tracks.
If the marker doesn't rub off all the way up or down on both, you've got clutch service to do.
Then, with a new belt, check belt deflection and clutch alignment.

 

[guggisbergfarms]

First, the secondary is supposed to have side play on the shaft, at least. 040" to allow self alignment and prevent bind on the bearing from heat and negative clearance. So put that shim back in.
Next, if it's a clutch issue, check by putting magic marker on the faces of both clutches to see where the belt tracks.
If the marker doesn't rub off all the way up or down on both, you've got clutch service to do.
Then, with a new belt, check belt deflection and clutch alignment.

the secondary move a lot it would move back and forth almost and 1inch it would slide back in forth rather than wiggle.
But i will have to but the washers back in to see. I will have to try the magic marker trick top. Thank you!!!

 

[kccats]

Secondary sliding back and forth is a good thing.
Play front to back is play in the chain

 

[guggisbergfarms]

I am putting new exhaust valves in they are pretty rough. Hope that is the problem