rings snagging ports on a happy-time?

G

gone_fishin

Guest
just lately, it seems like i've seen a rash of inexplicable top-end damage, where the bottom-end, including the top-con-rod bushing, is still finer than fine.

i put some vibration dampers on my new roller-bearing "70" and what's the first new thing i noticed? an occasional light but FIRM "plink" that could really only be one thing...i think the rings sometimes snag the edge of a port.

i think i can fix this by ever-so-lightly filing a bevel on the ports.

discussion? as long as you're nice about it, you can even call me stoopid.
 


A

Alaskavan

Guest
I'd be real careful there Augie. Any messing around in there could lead to trouble. But I guess either you know what you're doing, or someone else will. Good documentation please.
 
W

wavygravy

Guest
you hit the nail on the head there augie ! just ever so slightly chamfer the port edges! i had to do this on all my chinese engined pocket bikes too! now if we could get the manufactures to do the same eh? just a little more attention to detail!
 
G

gone_fishin

Guest
wavy'...thank you...i have another jug i can experiment with...unfortunately on the back burner for a few days, but i will see what i can accomplish :)

van, if i take pics, how am i gonna make excuses when i screw it up? :p:LOL:
 
S

Scottm

Guest
Well it's a relief to know I didn't screw my motor up and that there is no lower end damage. You think like me Augi that this was my problem? That's where all the scoring was in my cylinder, just below the ports.
Now do I have to worry about it happening again with my new head and rings?

Has Duane been contacted?
 
G

gone_fishin

Guest
i can only answer that by trying a mod then listening, but i think yes.

not sure if and how it'll help, but it's 20:1 pre-mix for me until i figure this out.

(yes, there's a message on his machine, i left it for him even before posting)
 
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