• Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password.

    If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?

Tell Me About This Piston

D

DEDGCOMB141129

Guest
Pulled the left jug today.....
65' R60/2...54K....
Miles of grime...no wrench marks...I think it's the first time she's got nekkid....
...ran great with low compression for 44 years...and now we can see der piston......
...any thoughts on how good...or bad...this bike runs...on what ya see?.....
 

Attachments

  • piston detail09a.jpg
    piston detail09a.jpg
    87.8 KB · Views: 269
From my limited experience, I don't see anything hugely wrong there. Probably your rings gaps had gotten pretty big and let some of the compression by, hence the discoloration on the sides. Piston crown...seems like they all look somewhat like that after a good number of milesl

You'll need to measure the ovality/dimensions of the cylinder and pistons to see where you're at considering stock sizes. You're probably need a rebore to the next size which also means new pistons and rings. There's a company, Bore-Tech, which does a good job at boring cylinders and then putting a carbide coating on the walls. It goes a long way to reducing wear on the walls.

Continue the cleanup and go from there.
 
My suspicion is an out-of-round cylinder - based on the pattern that looks like combustion gasses cooking the side of the piston below the rings near the wrist pin. Carefully check the cylinder.
 
Probably the wrong voltage brake light. That can cause the alternator to backfire,
forcing angry electrons out the wrist pins. Filling the tires with nitrogen can minimize
the problem, but the only real cure is to buy a 1984 F-150.
 
Please delete this thread

Dear Administrator,
It appears...I've made a mistake...
...buying the bike....thinkin' I could keep her going....hoping that some helpful fellows would impart some hard learned knowledge and experience...
...and parting with another $40 to join this club.....
I can spend a lot more than that...to get less asinine comments to my questions...
...I assure you...y'all won't be bothered by any posts from me again....
Please delete this thread...as it seems to not be suitable....
Thanks for All Your Help...:scratch
 
Pulled the left jug today.....
65' R60/2...54K....
Miles of grime...no wrench marks...I think it's the first time she's got nekkid....
...ran great with low compression for 44 years...and now we can see der piston......
...any thoughts on how good...or bad...this bike runs...on what ya see?.....

My suspicion is an out-of-round cylinder - based on the pattern that looks like combustion gasses cooking the side of the piston below the rings near the wrist pin. Carefully check the cylinder.

I would think Paul hit the mark with the problem being an out of round cylinder sleeve. What appears to be carbon build-up below the rings and above the wrist pin could result in the bike being ÔÇÿself healingÔÇÖ and running reasonably well before the tear down. The carbon builds up overtime as the uneven cylinder wear developed over time.

Before you give up on the forum all together I hope you tell us if Paul was right.
 
This Piston

I'm sorry you were offended by our smart-alecky replies. You have to have a well developed sense of humor to enjoy these forums, as well as a thick skin.

Your piston has a blowby problem. I can see that oil ring is worn, so the other rings probably are too. The next step is to see whether you need to replace the piston and rebore the cylinder, or simply do a ring replacement. Let us know how much more you need to learn.
 
...Back in my Day,
We just didn't beat up the new kid...as soon as he got there....
We'd get him to join the Hockey Team...then beat the Hell out of him!!!...
...It was Sport.....Team ......
...If I was that thinned skin...I'd be riding a Sporster!.....
 
Don't be over sensitive. The posts were funny; I laughed. Some posts are meant for the readers' amusement and not meant to be taken seriously. Have fun.
 
[mod hat=on]
Can we talk about the vintage stuff in the vintage area? The campfire stuff goes over in the campfire area. Thanks.
[mod hat=off]
 
piston

Dedgcomb:

Hope you stick around. They're actually a pretty mild bunch around here.:)

And they'll crack jokes on anybody's thread; keeps them going through the winter.
 
Back
Top