broken intake camshaft WTF????

[ufomoto]

After many $$$ going thru the motor (new bearing, forged turbo pistons, cam chain, porting and valve job, etc) it ran for 5 seconds then popped and died. Subsequent attempts to start it went no where. I did notice that it sounded different, like there was not as resistance to the motor spinning. I pulled the cam cover and found out 3/4 of the intake cam was not spinning. Pulling the caps I found the oem intake cam had broken about 3 inches from the cam sprocket. When I had Star Racing do the valve job they also installed new Carpenter Racing springs. Could that have caused the cam to break? The bike had 40K miles before the rebuild. Should I replace both cams? New or used cams? Any input is appreciated. Thanks.

 

[GIXERHP]

The springs have nothing to do with it.

Are you sure it was not dropped at any point?

 

[Boosted Cycle Perf]

I've never heard of this before. Manual chain tensioner?

 

[GIXERHP]

I have seen a cam break, but it was dropped on the floor, before the install!

 

[dadofthree]

U put all that money in it and ur thinking about going cheap on the cams ?

 

[icemansid]

Go with some new quality cams. I have heard of them breaking before as well.. I have a stock intake cam id let go pretty reasonably if your interested.

 

[1bondoman]

I've seen them break without ever being dropped.

 

[sportbikeryder]

I've broken them on the opposite end of the cam. I've also had what appears to be a bearing failure of the roller bearing that led to a broken cam on the drive end.

You should pull the head as well. Some valves are likely bent.

 

[OZBooster]

and check your not getting coil bind on the springs ,should be safe as houses with std cams and just about any race springs ,but pays to check