Loss of RPMs 2012 800

[JayPee]

Hoping to get some help on a 2012 Pro 800. Bought it from a friend this winter for my GF to ride. I rode it last year and never noticed an issue. Somewhere during the first couple of rides the RPMs dropped to 7450. I didn't notice it until I jumped on during the 3rd ride.

Tried changing to a new belt, no change. Pulled the primary off, checked the spring, not broken but probably the original and possibly worn out. Weight bushings look a bit ovaled. Checked compression, 125psi mag, 120psi clutch. 2500mi on it, looks to be all stock. 5th owner so who knows. Also found a spark plug nipple that was loose, changed plugs but haven't tested yet.

Any tips on order to troubleshoot so I'm not just throwing money at this? The clutch parts look a bit worn, not sure if I should start with a rebuild kit/spring. I know it is probably close to a top end, was hoping to get through the season

 

[Sage Crusher]

If your weight bushing are a bit oval- I would start there, and check the rollers for flat spots. All of these would hurt RPM's .
If your weights are not getting shift out they are getting hung up in the process.

 

[JayPee]

If your weight bushing are a bit oval- I would start there, and check the rollers for flat spots. All of these would hurt RPM's .
If your weights are not getting shift out they are getting hung up in the process.

Thanks, after really looking the clutch over, everything looks good besides the weight bushings and the weights were rubbing on the spiders a bit. I'll get those fixed up.

I have a list of stuff to check/clean/replace including exhaust valves, fuel filter, electrical connections that might cause low top end. Replacing both primary and secondary springs due to age.

If that doesn't get things working right then last stop is top end

 

[05rmksteve]

Also check the motor mount bushings.

 

[JayPee]

Also check the motor mount bushings.

Thanks, added to the list before the next test ride

 

[Sage Crusher]

Thanks, after really looking the clutch over, everything looks good besides the weight bushings and the weights were rubbing on the spiders a bit. I'll get those fixed up.

I have a list of stuff to check/clean/replace including exhaust valves, fuel filter, electrical connections that might cause low top end. Replacing both primary and secondary springs due to age.

If that doesn't get things working right then last stop is top end

That for sure is a big issue- weights dragging on the spider most definitely will effect the performance-
You can buy shims to place on each side of the weight pins to bring the weights center back to the rollers..
I personally would get new roller's ( or insert new roller bushings) and new weights,( you can get new bushings for those also).
If you weights show signs of scoring on the outside from rubbing on the spider - toss them as they are out of gram spec now.

Sometimes the weight pin will be worn so much you will get side to side play on the installed weight, even with new weights, as the tolerance on the pins are worn from letting it go to long.

How many miles are on this rig?

 

[JayPee]

That for sure is a big issue- weights dragging on the spider most definitely will effect the performance-
You can buy shims to place on each side of the weight pins to bring the weights center back to the rollers..
I personally would get new roller's ( or insert new roller bushings) and new weights,( you can get new bushings for those also).
If you weights show signs of scoring on the outside from rubbing on the spider - toss them as they are out of gram spec now.

Sometimes the weight pin will be worn so much you will get side to side play on the installed weight, even with new weights, as the tolerance on the pins are worn from letting it go to long.

How many miles are on this rig?

2500mi. 1 weight has decent scoring and another one has slight scoring. The spider has imprints around the weight pin hole of the bushing/weight. Seems to be causing a lot of drag

The 62s are probably a bit light for my lower elevation so I was going to swap to 64s anyways. I'll look into getting the shim kit

 

[Sage Crusher]

2500mi. 1 weight has decent scoring and another one has slight scoring. The spider has imprints around the weight pin hole of the bushing/weight. Seems to be causing a lot of drag

The 62s are probably a bit light for my lower elevation so I was going to swap to 64s anyways. I'll look into getting the shim kit

If you don't end up with new weights or bush the old ones- run your finger alongside the outside of the weight. Since that weight has made contact with the spider I bet those edges are sharp and will ruin the roller if you run them- for sure check the gram weight. I think you have at least found your issue - if not it's was going to cause you grief down the road.
2500 miles is way due for a rebuild - but seems like maintenance was sure lacking.