Mysteriously missing piston ? !

[shee-newbee]

long story short:

 

At the Dunes after replacing plugs cause the bike felt like they were fouled, the bike bogged down and quit. Kick starter was froze/ locked/ stuck.

 

Got home, pulled plugs and the right side looked as if I installed the plug with the side electrode and center electrode practically touching..maybe I missed it? Too many beers?

 

Anyway I assumed that the right side wasn't firing, gummed up, seized and kablooey smashed the piston all up. Well after that I looked a little more and realized that not only was the ring shot and piston cracked I was missing a good 2” x 3” piece of piston on the front half of it. Now when I pulled the head and cylinders off there was some aluminum shavings but I don’t think there was THAT many? Could that piece be hiding in the crankcase somewhere? Everything moves well when I kick it over ..I really don’t want to crack the case, I was planning on hanging the bike upside down and cleaning the hell out of the case with brakeleen..is that hokey?

 

Ok ANY help on this subject would be GREATLY appreciated!!!

[jbooker82]

You can split the case now to clean it right or do later to replace the crank.

[Fast-Fibers]

Yep split the cases. If you don't do it now you will definitely be doing it later for a more costly reason.

[Josh Z]

it only takes about 45 minutes to split the cases. it aint hard.

and I have a crank for sale if you want to replace it now.

Edited December 9, 2010 by Josh Z

[J-Madd]

Be sure to clean out your exhaust pipes. That's where a lot of the metal probably is.

[BUILDER]

Some will not agree but thats ok. I have seen that happen many times and know several of my friends who have turned there bikes upside down sprayed carb cleaner up in them and them blew them out real well and are still riding the bike many years later. The missing pieces went out your exhuast I am sure. Not say this is the right way to do it but know several people that have and it has worked just fine. Just realize when you do that you are taking a bit of a chance that you will loose a crank bearing if you miss a piece.

[Darthwall]

crack it open and look around really good I had this happen last year. bike leaned out in the cold melted the piston cracked a sleeve a knocked a hole in the cases it's better to look now and get it over with

[shee-newbee]

Be sure to clean out your exhaust pipes. That's where a lot of the metal probably is.

 

 

AHHH! Good idea, I'll check that out. It sounds like I may be cracking those cases

[Fast-Fibers]

I have seen all kinds of weird stuff, like little spot weld looking pieces on the crank and cases, complete rings in the exhaust, piston chunks in the exhaust. You could turn it upside down and get it all out........but what if you dont. It doesnt take much to destroy a motor...my 2 cents.

[frinkbc]

i would split the case, have the crank trued and welded ( or replace), then put it back together just my .02 good luck

[camatv]

split them now. replace everything. that way you know its all right. there are pieces all in the bearings now. and yea the rest is in the exhaust.

[midlifecrisis]

X100, split them!

 

I split my cases last year for the first motor build I ever did (thanks to all these guys), and put it all back together. Rode it for 3/4 of the break in, and had another failure. It seems like a roller bearing from somewhere was rolling around in my pipes, and it screwed my piston dome up pretty badly, so lucky me, I got to rebuild twice in 2 weeks. Clean everything right, forget the hanging of the bike, its not worth doing it twice.

 

Heres what a tiny roller bearing can do to a fresh rebuild