XC500 SP won't hit peak rpm's about 50% of the time

[indy_500]

Great info...thanks...here's what I see after taking apart the primary:

# 8 (the rollers) roll just fine. They are nice and smooth and when I flick them with my finger they all keep spinning for a while. Sound OK?

# 11 (1321685 WT/BUSH.ASM,10-54) are all smooth and don't have much wear. However, how easily should these things "swing out"? I can swing them all by hand fairly easily, but get this: when I hold the clutch over my head, only 1 of them freely swings down with gravity. The other two stay put. If I flick them, they move easily, but they don't just "fall" with the gravity when I hold the clutch upside down. Is that significant enough to be causing my problem?

Any other things I should check?

The weights should move freely by themselves. take out the weight pin with an allen wrench. Note which pins and nuts go in which holes and the direction they point and make sure to put them back in the same spot. Take them out and slide the weight back on the pin. It shouldn't be able to wobble like a wounded duck. If you can see the bushings are ovaled out, I'd replace it. Many people remove them with the slp tool or a pin punch. Personally, I'm just VERY careful and drill the bushings out. I would spend an hour removing the old bushings and drilling them out takes 5 minutes. Have to have the perfect size drill bit, a little smaller then the I.D. of the weight. 3 weights w/bushings are about $75 new i believe from Pol.

 

[superski]

Yes XCR 1250 is the guy. Sure go a head and pull the clutches and carbs, but unless those clutches are realy filthy I'd be surprised if at 1900 miles that was the problem. I don't know about you, but if someone suggested a simple fix like spark plug caps I'd at least check that and try it before going through clutches and carbs, it worked for me and a couple other guys. BELIEVE ME those caps can act really wierd and seem like dirty carbs or clutching issues. If ya don't buy the idea I could care less, I was just trying to help

 

[cardinal43]

Thanks to all... We are heading to Munising on Thursday so I am going to do some more clutch work today and just replace the spark plug caps. I won't have much time or snow to test ride so I'm going for it all on these fixes! Plug caps are an easy one, so might as well do those too!

 

[ezra]

you did mark a line on the clutch when you took it apart so you know how to put back together didnt you?
they are balanced and if the cover is not put back on the same place or the spider is not put back in the same place it will be out of whack and then you can have some real issues with your crank bearings and seals over time.
I send all my clutches out to Indy specialties to be tuned balanced even when brand new heck especially when brand new.

 

[xcr440]

you did mark a line on the clutch when you took it apart so you know how to put back together didnt you?

There are 'X's on each piece that should line up, I know they can be hard to see, so I normally do as ezra said and mark each of them.

 

[cardinal43]

Thanks guys....yes, thankfully I was aware of the balance issues so marked everything with a sharpie to put back the same way...I cant imagine putting this back together out of whack....poor motor and crank. Then I'd really have a problem!!!

 

[cardinal43]

I don't think I need to go any further....I think I found the problem.

The weights and their pins were all gummed up with black belt residue. They really were not moving very freely. After taking them out and cleaning the pin and the weight with carb cleaner, they swing like they are on ball bearings (smooth as glass, like they are supposed to, right?).

If the weights were sticky and gummed up, would that have caused my problem?

PS - Where can I order a stock primary spring for overnight delivery? I'm going to replace the spring but there really doesn't seem to be any other major wear in there.....I mean, the sled only has 1900 miles on it....right?

 

[indy_500]

I don't think I need to go any further....I think I found the problem.

The weights and their pins were all gummed up with black belt residue. They really were not moving very freely. After taking them out and cleaning the pin and the weight with carb cleaner, they swing like they are on ball bearings (smooth as glass, like they are supposed to, right?).

If the weights were sticky and gummed up, would that have caused my problem?

PS - Where can I order a stock primary spring for overnight delivery? I'm going to replace the spring but there really doesn't seem to be any other major wear in there.....I mean, the sled only has 1900 miles on it....right?

Yes, the weights sticking could've been your problem. I get my springs from EPI for $25. Dennis Kirk carries them, always takes 2 days to ship anything from them to my house.

 

[xcr440]

I don't think I need to go any further....I think I found the problem.

The weights and their pins were all gummed up with black belt residue. They really were not moving very freely. After taking them out and cleaning the pin and the weight with carb cleaner, they swing like they are on ball bearings (smooth as glass, like they are supposed to, right?).

If the weights were sticky and gummed up, would that have caused my problem?

PS - Where can I order a stock primary spring for overnight delivery? I'm going to replace the spring but there really doesn't seem to be any other major wear in there.....I mean, the sled only has 1900 miles on it....right?

As noted, sounds like you nailed it.

I wouldn't get too wound up about a new spring for a 1900 mile sled if you are just taking it out for the first time this year. That spring is probably fine for what's left of this season.

 

[cardinal43]

Final feedback: It was the sticky weights on the primary. The belt dust accumulated and kept the weights from swinging freely. After cleaning up the weights and their pins with carb cleaner, sled shift normally and runs like new!

THANKS TO ALL FOR YOUR HELP!!!!!!!!