Help with 253FMM Engine.

stoneshirt · 05-30-2017, 10:49 AM

Hello,everybody.
My PC keeps freezing up in the middle of composing a Post.So here is a rather weird way of doing one.

Weldangrind · 05-30-2017, 12:36 PM

Can you show us a pic of the engine, so we're certain to be on the same page?

ben2go · 05-30-2017, 04:23 PM

Bronze sounds like the valve guides are breaking up because of to much play between the valve stem and the valve guide. The valve will rock in the guide and break it over time. There should almost be no play in there. If there is, oil will leak past the valve and directly onto the back of the valve. The valve seal is there to slow down the oil flow onto the valve stem, not stop it completely, which could also the problem. The valve isn't getting any oil and it's chewing up the guide.

If that engine has hardened valve seats, running lean could cause the valves and seats to run hot and recede into the head quickly. This usually happens over time and why engines require valve adjustments ever so often.

Bending valves is from them hitting the piston. The valve timing is off a tooth or two. It will still run some but kill the valves.

05-30-2017, 12:36 PM	#2
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Can you show us a pic of the engine, so we're certain to be on the same page? __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
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05-30-2017, 04:23 PM	#3
ben2go Join Date: Jun 2011 Posts: 1,335	Bronze sounds like the valve guides are breaking up because of to much play between the valve stem and the valve guide. The valve will rock in the guide and break it over time. There should almost be no play in there. If there is, oil will leak past the valve and directly onto the back of the valve. The valve seal is there to slow down the oil flow onto the valve stem, not stop it completely, which could also the problem. The valve isn't getting any oil and it's chewing up the guide. If that engine has hardened valve seats, running lean could cause the valves and seats to run hot and recede into the head quickly. This usually happens over time and why engines require valve adjustments ever so often. Bending valves is from them hitting the piston. The valve timing is off a tooth or two. It will still run some but kill the valves.
	2