Top End Job On Kdx220r Gone Bad

[Savysdad]

I just did a top end on my 2005 KDX220R (New Wiseco). When I was putting it together I noticed a few little scratches in the cylinder, but nothing real big. The tolerances were all within spec. Slapped it back together and ran it for awhile, but have not gone riding. I was reading on here about the circlip position and realized that I did not remember what position I had put them in. I took the cylinder off again to check them (they were ok), but there was a huge scratch in the front of my new piston and rings. Anybody ever have this happen? Is my cylinder toast? I know I can't put that piston back in like it is. By the way the factory piston had a slight crack in, so I took it out at the right time. Any help anybody can give would be appreciated.

Thanks,
Mike

 

[KDX200fromAUS]

Yes I have had this happen after a top end on my 200, didnt run it in enough, it nipped up then ran on, pulled the pipe off to check damage, bore n piston both scratched, but bike still started 2nd kick every time so i rode on, still going strong...( i have resleeved my bore though) ....so if it still starts then yeh ride on and get some use outta the piston n do a freshy later on...

 

[Savysdad]

Thank you for the reply. That sounds exactly like what happened. I am definitely going to be more careful next time. I will definitely ride on.

 

[glad2ride]

Hi. Thanks for yet another OEM piston cracking story. :-(

Where were the scratches on your cylinder? Any chance there was a flake of carbon that got caught between the cylinder walls and the new piston??

 

[Green Hornet]

Sounds like some type of matter was in there to score the piston

 

[Savysdad]

Hi. Thanks for yet another OEM piston cracking story. :-(

Where were the scratches on your cylinder? Any chance there was a flake of carbon that got caught between the cylinder walls and the new piston??

Your welcome. That is a possibility. I did clean the cylinder and the KIPS Valve. The only unfortunate thing was that Kawasaki had actually crossthreaded one of the bolts for the main valve, so when I took it out all the threads came with it. I had to use some thread making compound to repair as rethreading did not help as the hole was oblong. I did not clean the exhaust port super good and something may have got knocked loose when I was repairing the damaged threads. I was pretty ticked off and not very happy with Kawasaki. The offered no explanation other than to tell me the bike was out of warranty and pistons breaking was common on race bikes.

Thanks for the reply.
Mike