going around in circles !!!

smittyman76 said:

Hey everybody....I'm having some issues with my evo engine. Put a new top end on. When it runs I have a nasty hollow sounding knock coming from the cylinders. Pulled the plugs so I could turn it over with the back wheel. Sounds like when the pistons reach the top of the stroke and start back down there is a bit of a clunk clunk.the rest of the way through the stroke it sounds normal. Any ideas ?

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Did you do this work yourself????????

Yep sure did. I suppose I'm gonna get the rundown on how I shoulda took it to a "certified dealer". Just thought maybe someone had an idea what to look for.

smittyman76 said:

Yep sure did. I suppose I'm gonna get the rundown on how I shoulda took it to a "certified dealer". Just thought maybe someone had an idea what to look for.

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In the end its your bike, If it was me I'd have to take it back apart..lol

Best luck to ya!!

smittyman76 said:

Hey everybody....I'm having some issues with my evo engine. Put a new top end on. When it runs I have a nasty hollow sounding knock coming from the cylinders. Pulled the plugs so I could turn it over with the back wheel. Sounds like when the pistons reach the top of the stroke and start back down there is a bit of a clunk clunk.the rest of the way through the stroke it sounds normal. Any ideas ?

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Did you check bottom end for excessive wear? Top of connecting rod worn? opcorn

smittyman76 said:

Yep sure did. I suppose I'm gonna get the rundown on how I shoulda took it to a "certified dealer". Just thought maybe someone had an idea what to look for.

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Not a lot of us are big on "certified dealers". < really means nothing.
However. If you have little to no experience in this type of work. Or "all" that is involved in doing it right the first time, as touched on by SoftailBilly.
Then taking to a good Wrench is always recommended.

What type pushrods?

Did you follow the service manual procedure for installing the rocker supports?

Do a compression check.

Check torque on compensator nut.

Did everything exactly as the book said or by part manufacturer instructions. Haven't done a compression check but I will. Definitely not coming from the valve train. I checked it by turning the motor over with the back wheel without the lifters and pushrods in it. Definitely in the cylinders or the bottom end.

You think you did everything exactly as the book said...

The fact that you have a knocking noise in the engine makes me a little skeptical.

Pull the head off the offending cylinder, maybe a valve is bent.

I don't think it is the bottom end. If you are turning the engine over by turning the back wheel you are not forcing the piston hard enough for the connecting rod to jump and clunk back down on the bearings. You never said if you had this sound prior to any work being done. This sound could be transferred from the transmission because you are going through it by turning the back wheel. Other than that, I'm clueless.

I'm wondering if the piston is slapping the cylinder wall as it changes direction. Maybe the piston pin is the culprit. Maybe the snap ring popped out and fell to the bottom of the engine and the piston pin is slapping side to side.

Could possibly be wrist pin bushings worn and have piston slap or wall diameter to large without using over sized rings to many variables to guess, I would tear it back down and check your work for clearance issues ect.

One of the things that should always be checked when the jugs are removed from an EVO engine is the con rod play, up and down movement on the crank pin. Also that the rods don't bind on the crank pin. When balanced upright they should drop to the low side, not stick in an upright position. Pistons need to be removed from the rods first.
No mention as to how many miles are on the engine either.

Every time I see the thread title I picture someone who forgot to unlock their forks.
Sorry..... :dunno

Thunder~Struck said:

Every time I see the thread title I picture someone who forgot to unlock their forks.
Sorry..... :dunno

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Quite the visual, be a 3 Stooges moment.......:nod:cheers

Thunder~Struck said:

Every time I see the thread title I picture someone who forgot to unlock their forks.
Sorry..... :dunno

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I pictured the same thing. :laugh