Re: [2cylinderhondas] bent valves

[friend]

It sounds like they were bent earlier and some one straightened rather than replace them.  And when your engine started up the valve stems were already weakened and over time became bent again.   When you removed the head did you notice any marks on the top of your pistons?  Most valves are bent because the cam chain dropped and the engine kept rotating causing the pistons to come in contact with the valves.
Bill

> -----Original Message-----
> From:
> 2cylinderhondas@yahoogroups.com [mailto:2cylinderhondas@yahoogroups.com] > On > Behalf Of > fedweezee > Sent:
> Wednesday, October 08, 2008 11:58
> PM
> To:
> 2cylinderhondas@yahoogroups.com
> Subject:
> [2cylinderhondas] bent valves
> i was wondering what would cause both my intake valves to become bent?
> i was running my 600 at idle then it just cut off and died, and was not
> able to start it again. after trying everything and doing a compression
> test and getting nothing i decided to pull the head and take a peak,
> found out that the valves were bent. i was really bummed about that
> one. the timing chain did not skip and was not loose but if i am right
> it had worn out sparkplugs in it at the time that made it run kinda
> rough. i am puzzled as to what happened so i was wondering if anyone
> would know a good explanation as to what happened.

[friend]

Dale;
    The Honda 600 engine is not free running, the valves will touch the pistons when not timed correctly or a warn timing chain jumps or drops and the engine rotates even once through a cycle with the valves open.   From what little information is given this is the case.  Because we are told the engine was running, valves still connected to the springs and all components in operating condition, the engine had to be out of time.   Or they were bent before and during operation rotated to a point that they are no longer sealing.   Even after I get a head back from a valve job, I always do a simple leak down test.  If fuel gets through then there is a problem.
Bill

> -----Original Message-----
> From:
> 2cylinderhondas@yahoogroups.com [mailto:2cylinderhondas@yahoogroups.com] > On > Behalf Of > goinhm@...
> Sent:
> Thursday, October 09, 2008 11:41
> AM
> To:
> 2cylinderhondas@yahoogroups.com
> Subject:
> Re:
> [2cylinderhondas] bent valves
> How much had you used this engine before the problem
> developed?   Is this a car you have driven
> recently and it quits while sitting at idle for a few minutes or is it an > engine which you just recently got
> running and it quits while idling?
> If this is an engine you recently got running and it is new to you, > it is possible the clearance between the valves and piston was too narrow and > after the engine parts have warmed to operating temperature,  the > clearances have all gone to less than zero causing the problem you > experienced.  Possible causes would be;
> 1)  wrong head gasket
> 2)  cylinder head or top of barrel has been milled
> 3)  piston installed backwards (look for the relief on the intake > and the word "IN" on the piston top)
> 4)  valve timing is off
> 5)  cam chain is stretched
> 6)  not using a stock intake valve
> Let us know what you find out,
> Dale
> > i was wondering what would cause both my intake valves to become bent?
> > i was running my 600 at idle then it just cut off and died, and was not
> > able to start it again. after trying everything and doing a compression
> > test and getting nothing i decided to pull the head and take a peak,
> > found out that the valves were bent. i was really bummed about that
> > one. the timing chain did not skip and was not loose but if i am right
> > it had worn out sparkplugs in it at the time that made it run kinda
> > rough. i am puzzled as to what happened so i was wondering if anyone
> > would know a good explanation as to what happened.
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