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Re: ran good then cut off now wont start
Posted: Wed Jan 11, 2012 3:42 pm
by iceman77
i did another compression check today bc i had her running. not good 75 psi. the bottom piston ring is broke.
the cylinder wall only has a tiny scratch. thank the lord
Re: ran good then cut off now wont start
Posted: Wed Jan 11, 2012 3:57 pm
by iceman77
Re: ran good then cut off now wont start
Posted: Wed Jan 11, 2012 4:20 pm
by bonesv
The reason the ring broke is what I'd be concerned with. Possibly during installing the piston into the bore? Could be they weren't seated yet and too much rpm? 8-10 tanks of fuel before WOT is my formula. Not saying you did anything incorrectly. I would be sure to
slightly chamfer the tops and bottoms of the ports as they meet the cylinder wall. This helps to minimize ring wear over the life of the bore. I'd inspect for other fragments in the motor also. Buy two NEW rings and a 45mm flex-hone(amazon.com) and NEW base and head gaskets. Fun stuff, huh?
Re: ran good then cut off now wont start
Posted: Wed Jan 11, 2012 4:24 pm
by iceman77
bonesv wrote:The reason the ring broke is what I'd be concerned with. Possibly during installing the piston into the bore? Could be they weren't seated yet and too much rpm? 8-10 tanks of fuel before WOT is my formula. Not saying you did anything incorrectly. I would be sure to
slightly chamfer the tops and bottoms of the ports as they meet the cylinder wall. This helps to minimize ring wear over the life of the bore. I'd inspect for other fragments in the motor also. Buy two NEW rings and a 45mm flex-hone(amazon.com) and NEW base and head gaskets. Fun stuff, huh?
makes me wanny cry. she was running so good too.
i hate spending money.
Re: ran good then cut off now wont start
Posted: Wed Jan 11, 2012 6:10 pm
by Wheelman-111
Greetings:
Bones, thanks for the flex-hone - Amazon tip! Do you mean one
like this?
Re: ran good then cut off now wont start
Posted: Wed Jan 11, 2012 6:22 pm
by Bear45-70
You are aware that those flex hone balls will catch and break on the ports, then the metal end of the wire WILL scratch the cylinder walls. Never a good idea to use a flex on on a 2 stroke.
Re: ran good then cut off now wont start
Posted: Wed Jan 11, 2012 7:30 pm
by bonesv
You just keep finding out new stuff every day. You guys are the best! Bear? what DO you use to hone your 2-strokes with? I haven't had that experience with the flex-hone yet, but 'ya got me scared now!
Re: ran good then cut off now wont start
Posted: Wed Jan 11, 2012 7:43 pm
by Bear45-70
bonesv wrote:You just keep finding out new stuff every day. You guys are the best! Bear? what DO you use to hone your 2-strokes with? I haven't had that experience with the flex-hone yet, but 'ya got me scared now!
This is what I used on my outboard race motors but the bores were over 2".
http://www.google.com/products/catalog? ... CHoQ8wIwAA
So far all my scooter cylinders have been honed by the machine shop as I haven't had a "hone and re-ring" scooter jug yet.
This will work;
http://www.google.com/products/catalog? ... CHoQ8wIwAA
You have to be careful and make sure the stones always span the ports. I always taper the port openings while doing porting.
