M8 taking its time for RPM to go down

[RobertTrivanovic]

So yesterday was the first ride in about 2 months that there was actualy decent snow. Everything was good and I had no real issue but was kinda confused because at times ago going wide open up a climb when I let off the RPM would drop but stay around 3500-4000 for a few extra seconds before dropping down the rest of the way. Not a real issue just wondering why its happening?

 

[XxXModRods]

Sounds lean right when the butterflys shut.

 

[RobertTrivanovic]

I'm running 22% more fuel up top with some rk tek porting and a head and speedwerxs piping and a bdx intake and boysen reeds. Sounds like a lot of fuel IMO

 

[XxXModRods]

What box

 

[RobertTrivanovic]

Boondocker

 

[XxXModRods]

Pm me your numbers if you have them.

 

[RobertTrivanovic]

Will do

 

[Arcticcat21]

Any update on this problem? I've got a 2010 crossfire with the same problem. It started after I blew a belt but I can find a cause for the hang idling in the midrange.

 

[RobertTrivanovic]

Yeah this could be your issue to if you have a fuel box, I dont know what but something caught and broke the ground wire so the box wasnt turning on, causing my sled to run way to lean. Fixed the ground and the sled runs perfect again. Maybe in your case a peice of the belt could of broken the ground. Check your plugs thats an easy way to tell.

 

[sunbather1969]

blown belt

crank seal

 

[kidwoo]

crank seal

How common is that?

The guy I bought my sled from blew a belt and it's started making kind of a whistle at idle. It goes away as soon as the clutch engages so I've been thinking it's the belt. I guess I need to pull the belt and see if it's still there but now you've got me thinking.

Makes sense though.

 

[RobertTrivanovic]

How common is that?

The guy I bought my sled from blew a belt and it's started making kind of a whistle at idle. It goes away as soon as the clutch engages so I've been thinking it's the belt. I guess I need to pull the belt and see if it's still there but now you've got me thinking.

Makes sense though.

Yeah mine was the fuel box and mine came out of nowhere, no blown belt or anything. But now that I think of it that makes sense that the crank seal could blow, not sure wouldnt it show a leak somewhere though? You must have some other sign IMO if that was it.

 

[Arcticcat21]

I was thinking crank seal too but I tried spraying carb cleaner behind the clutch at idle to see if it changed. It didn't seem to make any difference. I even pulled the drive clutch and inspected the seal. It had some belt dust around the outside but otherwise looked good. I will look into the ground thing but I don't have a fuel controller so I'm not sure if that's the issue. I do have a high flow intake and carbon tech reeds. Other than that, it's stock.

 

[RobertTrivanovic]

I was thinking crank seal too but I tried spraying carb cleaner behind the clutch at idle to see if it changed. It didn't seem to make any difference. I even pulled the drive clutch and inspected the seal. It had some belt dust around the outside but otherwise looked good. I will look into the ground thing but I don't have a fuel controller so I'm not sure if that's the issue. I do have a high flow intake and carbon tech reeds. Other than that, it's stock.

Pull your plugs and see if you are running lean even with minor mods.

 

[Arcticcat21]

Well I've got a new secondary clutch coming tonight. I hope that's the problem. I've heard of them binding up and not letting the sled backshift. The inner and outer sheeves on mine have marks like they've been rubbing together and binding. After talking to a few people they seem to think this may also be the problem. I sure hope so!

 

[RobertTrivanovic]

Well I've got a new secondary clutch coming tonight. I hope that's the problem. I've heard of them binding up and not letting the sled backshift. The inner and outer sheeves on mine have marks like they've been rubbing together and binding. After talking to a few people they seem to think this may also be the problem. I sure hope so!

Upload a picture of your secondary or us to see

 

[ND]

Well I've got a new secondary clutch coming tonight. I hope that's the problem. I've heard of them binding up and not letting the sled backshift. The inner and outer sheeves on mine have marks like they've been rubbing together and binding. After talking to a few people they seem to think this may also be the problem. I sure hope so!

Clean the primary, check for binding of moveable sheave and play in spider buttons to tower. Mine did the same thing, had a bunch of crud and some fibers from the fiberglass mat under the pipe heatshield all on the towers. Cleaned that up so the buttons in the spider could slide free and it got much better. Replaced my primary due to the worn out moveable sheave button and it totally went away

 

[Arcticcat21]

Fixed it!

Well I think I got it! I took most of the sled apart and checked basically everything I could have without tearing too far in to the engine. I took all the wire connections apart and cleaned them, cleaned the egt, cleaned the valves, checked the cables, took out the reeds and checked them and all the linkages on the throttle bodies. Then I replaced the driven clutch with a brand new one. So now I have brand new drive and driven clutches with stock clutching.
Took it for a test ride and all is back to normal. It back shifts and pulls the rpm on the engine right down. Crushing down the trail and tap the bricks and it instantly start back shifting and slowing down. Just how it should be.

So since I found nothing else that stood out to me, I'm going to go with the driven clutch as the problem. I have a big swamp ride tomorrow so I will let you guys know how it goes.

Here's a pic of the old driven stationary sheeve.

 

[m8magicandmystery]

WellI took all the wire connections apart and cleaned them,.

and packed them with dielectric grease..for that greater piece of mind

 

[Arcticcat21]

I went on the ride today and the sled worked great. Thanks for all the help fellas!