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FJ1100... Not another burnt valve?!

Started by mr blackstock, June 14, 2015, 12:25:35 AM

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mr blackstock


My old girl developed a hard starting issue after I topped her up with oil, she would only run on one pot.  I was not sure what to do so I drained out some of the oil, just in case I had over filled her, but it made no difference.

when I got home I thought to check the compressions to be sure, no.2 had nothing.  I thought better check the clearances and discovered more than a few were tight.  Ordered more shims, restored correct gaps and she is still no compression on no.2!

A couple of years ago she had an exhaust valve replaced from the same pot, the damaged valve had lost a piece.  What would cause the same problem to re-occur in the same pot?  The bike has never run lean, she burns oil out the exhaust a bit, but there are oil stains in the exhaust outlet of the head so I figure that is caused by worn valve guides.

Apparently the bike has a mild cam, as an after market cam shortens the overlap, would the valves be more suseptable to damage unless in perfect tune?
Should I consider buying a standard second hand cam to preserve future valves?

I am thinking that I will remove the head myself and get the valve guides replaced, lap the valves in myself and replace the cam chain.  Can someone point out a post about DIY replace the cam chain?

I would appreciate any thoughts, especially from those who have done the job or experienced similar valve issues...

Cheers, Gareth

Squeaky wheels always get the grease...

Yamaha FJ1100 1985