Cam and tappet issues.

[grabntwist]

found out it was a bent valve that caused the carnage. Sucks big ones. Well the heads off to the speed shop to get reworked all new. Then its just a matter of bolting it on.



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[rubbersidedown]

found out it was a bent valve that caused the carnage. Sucks big ones. Well the heads off to the speeds shop to get reworked all new. Then its just a matter of bolting it on.

cool, just a bent valve. They'll check an' replace the guide if nessecary? Stab it, an slab it.

what caused the meltdown gerard?

 

[grabntwist]

found out it was a bent valve that caused the carnage. Sucks big ones. Well the heads off to the speeds shop to get reworked all new. Then its just a matter of bolting it on.

cool, just a bent valve.  They'll check an' replace the guide if nessecary?  Stab it, an slab it.

  what caused the meltdown gerard?

Rub, don't know what caused it. Maybe beatin' the ba11s of the bike. Not really sure though. The thing gets fresh oil every 750 miles or after a tough weekend. Last valve check was fine @ 5k on the clock. It only has 8400 now.

Im confident that the whole head will be pulled apart and re-worked. I don't want to leave anything unturned.

 

[grabntwist]

oh yea the piston and cylinders were in excellent shape. Still had some cross-hatch goin on. Good thing it didn't wad up the piston

 

[grabntwist]

nudda of the port job.

 

[Glamisman]

I am not 100% sure that the bent intake valve is the cause of the problem, I kind think it is the other way around. I will try to explain my though process and if I am wrong, well I will have learned something new today...

Did you verify that both of the retainers are present on that valve and that the tightly wound portion of the spring is facing down toward the head ?

In theory...

If the valve was bent, pre cam lobe destruction, the follower and the bucket assembly would always sit lower in the head due to the reduced overal length of the valve thus no mechanical interferance to wear out the cam and follower and why only one intake valve, they both open at the same time...

I think that the wear of the follower and the cam lob has allowed for extra distance between the two. With the follower to slap around some 8 to 10 mm by the looks of it. With nothing to control the assembly, I think that the lifter happened to push the valve open just enough at the wrong time to nick the piston.

Harmonics has a funny way of making things happen... that is why the tightly wound coils are put towards the head and one spring is wound clockwise and the other counter clockwise.

If I was you, I would like to be present when it is dis-assembled, just to check the basics, not point fingers or cast blame.

 

[grabntwist]

I am not 100% sure that the bent intake valve is the cause of the problem, I kind think it is the other way around. I will try to explain my though process and if I am wrong, well I will have learned something new today...

Did you verify that both of the retainers are present on that valve and that the tightly wound portion of the spring is facing down toward the head ?

In theory...

If the valve was bent, pre cam lobe destruction, the follower and the bucket assembly would always sit lower in the head due to the reduced overal length of the valve thus no mechanical interferance to wear out the cam and follower and why only one intake valve, they both open at the same time...

I think that the wear of the follower and the cam lob has allowed for extra distance between the two. With the follower to slap around some 8 to 10 mm by the looks of it. With nothing to control the assembly, I think that the lifter happened to push the valve open just enough at the wrong time to nick the piston.

Harmonics has a funny way of making things happen... that is why the tightly wound coils are put towards the head and one spring is wound clockwise and the other counter clockwise.

If I was you, I would like to be present when it is dis-assembled, just to check the basics, not point fingers or cast blame.

definitly have a good point there. Although the piston absolutly shows no sign of contact with the valve. Im not sure, maybe a small problem cause the valve train to go "outta whack" causing a premature opening during combustion and vapor locked some how. Im no engine genius but I know a thing or two. As far as my builder goes.. I dont know he's been in business for some 30 years. Could he have made a mistake?.. Possible, but why would the head start beating itself to death this late after the build (about 5-6k later)?

What I can say is the whole head is being tore down and redone from scratch. Anything that is ever so slightly near or out of spec will be tossed for new. The cam chain shows no wear the other tappets are ok but they will be replaced as with several other components.

 

[Glamisman]

Everyones makes mistakes at one time or another, the only thing is being humble or smart enough to admit to them and pay the freight on the results.