cylinders scuff ... what cause that

[xc6rider]

Thats way too tight in my opinion. I gap every dual ring ive built loose, and never had problems. .028"

The .015", is what im referring to.

 

[rydningen]

x3 on too tight ring gap, I gap at minimum .020"...

 

[3beans]

Did you do the rebuild?? If you just had the cyl re done and threw a new set of pistons in without checking clearance then you most likely caused the issue.

 

[polarisperformance]

Did you do the rebuild?? If you just had the cyl re done and threw a new set of pistons in without checking clearance then you most likely caused the issue.

read all the post ....you will see that I check the ring gap and
The piston look good

 

[polarisperformance]

I found that the cheap gasket they provide in the durability kit are broken.
they mesure 0.010'' and the polaris oem are 0.015''.

 

[IQRIDR]

That is a tighter ring gap than I use with cast pistons in a loose bore, let alone for a forged pistons in a tight bore IMO. But everyone has an opinion. The vertical streaking looks exactly like the ring gap too tight on many motors I have seen. It has nothing to do with the outfit doing the re-nik.

 

[Carlos Randolph]

I would say that you could have some one re-hone the cylinder/s and try a new "looser" ring gap, slobber the whole works up with mineral based oil previous to reinstall and try it again. Hard to say without running my finger across the marks but the scuff marks don't look to deep at all. Interested in what the side of the pistons look like? Have to make sure, what ever you do, that you take it easy for a few tanks of gas (which should be premixed) to get the rings to seat.

 

[Powder Buster]

After reading this thread I decided to pull my head and check the wear on my durability kit. Less than 100 miles and I'm having the same issue. Both cylinders are scuffed in 2 places... exactly where the ring gaps are located. Gap was set to whatever bikeman had in the instructions. At least I caught it early enough, I hope the marks will just hone out.

If you have the "durability kit" i HIGHLY recommend you check your motor if you went with the specified gap!

Now the question is should I keep the kit and just re-gap with new rings, or throw it out and go for mtntek or rkt. A question for another thread I guess.

 

[BILTIT]

New rings re-gapped.

I just pulled my old Carl's 910 BB apart and it has similar markings. I wonder if that is why it was 40psi low on compression.


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