A lot has been said and written in regards to the rough idle on the 550XP's. Mine is no exception. It seems to have been getting worse as time goes on. I have the had the ECU re-flashed which helped at one point but the problem has gotten worse. I now have a loud clunking noise coming from the bell housing area and the engine almost seems to shudder just off idle. It has gotten so bad that I pulled the transmission to check the drive coupler. I found the drive coupler badly deteriorated and a lot of rubber in the bell housing. The engine still is rough and clunky at idle even with the transmission removed.
I know there have been a few others on this board that have had some of the same issues and I was wondering if anyone has done anything to solve the problem. My dealer at one time told me that the magnetism is so strong in the stator that at idle it is causing problems. I still have to test that but am looking for some input before I pull my hair out.

Mine is pretty rough when you first start it but after a few seconds in smoothes out. It is still pretty loud but once it warms up it quitens down some. The mechanic I used reflashed mine and raised the idle a little and it really helped. He only raised it like 200rpm and it still shifts fine.

I have heard the same thing about the magnatism. My mechanic said it is so strong that the battery will charge at idle.

Ronnie

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I have heard the same thing about the magnatism. My mechanic said it is so strong that the battery will charge at idle.

Ronnie, thanks for the reply. I did try disconnecting the stator today and it made no difference. With everything I have done and checked it comes down to just a few things with the worst being internal engine. Is it possible that the balance shafts can be out of time?

Well it looks like I have the this problem figured out. It looks like the rough idle and shudder just off idle and all of the vibrations are due to the spike load damper (compensator).

After getting the bike back from the dealer to let them take a crack at it the only thing they could tell me was that 90% of the problem disappeared when they pulled the primary clutch and ran the bike. They had talked to Polaris and their next step was to pull the tranny and break it open to inspect the internals. So I brought it back home and did just that. Everything looked good. I remembered all of the reading I have done about the SLD causing problems. Without anything else to try I took a chance and bypassed the SLD and re-installed the transmission. WOW, what a difference. The idle is dead smooth, no more vibration or shuddering just off idle. I still have a slight knocking coming from the trans case but it is livable. I just need to compare it to another 550 when I get a chance. The only decision I need to make is do I spend the $240.00 for a new SLD or leave it as is with it bypassed.

This message has been edited. Last edited by: tbg120,

I think I would save the $240 and find some thing else to do with it.

Good work TBG120 What's the worse thing that would happen if you ran it without the SLD?