Scratch on cylinder

[Tommyz125]

Hi all, while i am porting the exhaust port ive made a scratch on cylinder wall... Except reboring ,cause its a fresh bore, how do i repair that if i need to? I dont want to broke a ring there..

 

[joeak47]

I would finish your porting, chamfer all the ports, then have a new piston matched to the cylinder. That way you start your engine off with a fresh top end. You can always stick layers of masking tape inside the bore when doing porting work for those" just in case moments". That porting is looking very good! Take your time!

 

[joeak47]

I would be sure that all the ports are chamfered properly. You don't want to snag a ring. That will piss you off. The "zinger" you made on the top of the exhaust port can be removed (most of it) by doing a tall (about 2.5mm) chamfer. Make the chamfer angle into the exhaust port about .25mm. This will help tuck the rings in easier on the up stroke after they expand out into the exhaust port on the down stroke. It increases the longevity of the top end.

 

[Tommyz125]

I would be sure that all the ports are chamfered properly. You don't want to snag a ring. That will piss you off. The "zinger" you made on the top of the exhaust port can be removed (most of it) by doing a tall (about 2.5mm) chamfer. Make the chamfer angle into the exhaust port about .25mm. This will help tuck the rings in easier on the up stroke after they expand out into the exhaust port on the down stroke. It increases the longevity of the top end.

Thats exactly what i have done to make sure rings return progressivelly on the piston groove.