Valves hitting piston? With video..HELP

[Tron]

hey all, just finishing up the new build on my bike. Got some oil in there and just gave it a few kicks to see how smooth it is etc. Ignition is not wired up yet so obviously, I'm my trying to start it by doing this.

When I kick it, I get a sound that sounds very much like a valve hitting a piston. Now this would only happen if my cam was off, correct?

Well I checked double checked, and triple checked to make sure it was aligned properly upon installation of the cam. Top dead centre, and cam marks pointing vertical (12 o clock)

Could this possibly be something else or is it deffinitly a valve hitting a piston?

 

[Clarko]

is the cam chain tensioned properly?

 

[Tron]

Its adjusted, as much as I could with a cold engine.

Although, I just realized, its missing the copper washer.

But surely, that could not be the only thing causing the noise..?

 

[Clarko]

the only thing that could make a valve hit a piston is cam timing out of whack. set to tdc and check valve clearance, repeat for other cylinder. there are great posts for checking timing if you search.

the only other thing that comes to mind is something, that shouldn't be there, bouncing around in the cylinder.

 

[Tron]

But I mean,

If the engines at top dead center, and cam goes in with notch pointing to the sky, the cam should be timed correct.. Ya?

Ill recheck the cam chain, and valve clearances.. Im wondering If I possibly set valve lash on exhaust stroke rather than the compression...

 

[hotdog]

What piston did you set at T.D.C. ?? It should have been #1 piston - the left one.

The valve clearances aren't excessively loose are they.?

 

[Tron]

That's correct, but if I did happen to set it for tdc on the right cylinder, in theory would that mean the cam is off 180 degrees? Which to my understanding is ok?

 

[Tron]

That being said.. I set it using the stock alternator. and double checked with te ol straw technique!

 

[tonyc]

Back the valve adjuster off al the way and see if you still get this sound. If they are hitting you could have bent a stem.

 

[Tron]

Ok will do. although I did replace all 4 valves. Well, I had the local shop do it as they were hurting for business in the dead of the winter and I have a goo relationship with them.

on that note, they replaced the seals and valves.. any chance they muffed something up?

 

[tonyc]

Did you have your head surfaced?

 

[retiredgentleman]

I think you're just imagining something very bad , when actually it does not sound bad to me. Install a damper (copper washer) on the camchain adjuster that you say is missing.

No need to worry................get the ignition installed and fire up that bad boy. I'm betting your engine will run just dandy.

 

[TwoManyXS1Bs]

Hey Tron,

Try this: Put the engine at TDC, either side, doesn't matter, remove spark advance cover, shoot a pic of spark advance, and post it. If can't post pic, describe orientation of spark advance weights...

 

[Brian902]

Tron,

Try this;

1 - Remove spark plugs
2 - Rotate engine counter clockwise as viewed from the left side, standard rotation for XS650
3 - Watch for intake valve to open and close
4 - With long screwdriver in the spark plug hole, or your straw, feel for when the piston next reaches it's highest point
5 - Check both intake and exhaust valves, both should be loose, if not go to step 2
6 - You are now close enough to TDC on the compression stroke to allow adjustment of the valves
7 - Adjust valves
8 - Go to step 1 and repeat for right cylinder
9 - Replace plugs, start bike and adjust cam chain, plunger should be just below flush with some movement,
10 - Your done!!!

Then do a compression check. That will tell you if you have bent anything.