KDX 200 Cylinder Repair

[zzmongo]

After sending off my cylinder and getting the incorrect one back, I finally got my repaired cylinder, new piston, ring set, wrist pin, etc. Time to get the bike back together and all was going well until I inspected the repaired cylinder before installation. There is pitting in the new nikasil! To make matters worse, there is a spot of weld at the bottom of the right power valve bore prohibiting valve installation. I sent the cylinder back and will not divulge who I'm dealing with until the final outcome. Is pitting a common thing after applying new nikasil coating?? I'm used to the old school method of re-sleeving, boring out, etc. Thanks for any comments!!!

 

[xtremekdx]

i had my cylinder replated at U.S. chrome. they did a great job. however, the paperwork that came with it advised that some pitting in the chrome plating was normal and did not affect performance. i check all measurements and they were to spec. I would recommend them.
lots a luck.

 

[JasonWho]

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[skipro3]

I've heard that the pitting can acually help by keeping a bit of oil on the cylinder walls and not being wiped dry. Be sure all the port edges aren't sharp. If so, touch them with a file. They can flake or chip off and cause some scoring. Mine did.

 

[zzmongo]

I'm concerned that the sharp edges will prematurely wear the rings, or worse hang and break a ring. Correct cross-hatch will contribute to proper lubrication as well as "break-in" of the rings. I just sent my cylinder back yesterday so the verdict is still out. Thanks for the comments.

 

[jdbrusch]

I see this alot with some of the small cylinders I deal with at work,chainsaws etc;most of the pits seem to be caused by air bubbles trapped in the material when they cast the parts.Sometimes there can be a few of them trapped in one area, when they bore the cylinder out it leaves a small pit in the side of the cylinder.
It could have also been caused from a repair of a damaged cylinder,if it was welded and they did not fill in the damaged area properly,when they machine it it could also have small pits.