Stuck cam on H-Cylinder (M900Sie)

[nomadwarmachine]

Just got a new motor into my frame and ran into a problem.  I have NOT started this bike yet, but I am not able to turn the cam on the horizontal cylinder freely by hand.  If I remove the belt and lower the piston, I cannot turn the cam up to TDC.  It feels like it does when the closer is too tight, and am hoping that that is the only problem.  Tomorrow I will check the valves and see if they move freely in the guides, but here is my question:

If I need to remove the horizontal head, can I do that without having to drop the motor? Any advice on a good technique for this?

I'm hoping that the valve is just too tight -- the piston moves up and down in the cylinder, so it looks like the valves are clearing the piston.  The cam will just not turn past a certain point.  Any ideas?

-Keith

[Capo]

Did you rebuild the engine prior to installation? If not do you know the history of the engine?

[nomadwarmachine]

Did not rebuild it myself.  The motor is a salvage engine that the seller had turning with a starter.  Here's the story:

1) the horizontal belt is on wrong.  the previous owner replaced them and got the horizontal one on wrong.  he believes (but cannot remember for sure) that he put the belt on AFTER cranking it (with plugs out).  If he put it on wrong and then cranked it, I will have to take off the head for sure.  If he put the belt on afterward then, there is just some binding in the head that the starter may have been able to overcome.

2) with the horizontal belt off and the cam near TDC, the motor turns freely, the pistons move just fine, so the piston is definitely clearing the valves.

Tomorrow I'm going to pull the valve shims and see if the valve spins freely in the seat and moves up and down.  If I cannot get the cam spinning again I will have to pull the head.

Can I remove the horizonal head on the M900Sie without having to drop the motor?

[Howie]

After you check valve clearances do a cylinder leakage test. 

[nomadwarmachine]

Howie,

I intend to do a full compression test on the bike once I get the valves set, but right now I just need to get the cam turning properly again.  Hope fully I will be able to get the shims off with the cam in the limited range it is in now.  Once I have them off and the cam turns I can get the clearances right again. 

Of course, I will make NO attempt to start the bike until I have the cam spinning freely and have done a compression test.  Just crossing my fingers that the valves are not bent and, if they are, that that is all that is wrong with the motor.

Can I get the horizontal head off without having to drop the motor again?

Thanks!
-Keith

[Speeddog]

Horizontal head can be removed with the engine in the bike.

You likely have a bent valve, that's why the cam won't turn.

[nomadwarmachine]

Speeddog,

I figure i have a bent valve too, though I am forever hopeful.  Is there any way for me to tell the condition of the valves without removing the head? 

If I have to remove the head (and I think that I do), do you have any advice for getting the stud bolts off while the engine is in the bike?  i assume I need to take off the airbox to access the studs.  I will also have to take off the injectors, right?  Not looking at the bike now, so I can't tell.

Any advice appreciated!!

-Keith

[Capo]

You likely have a bent valve, that's why the cam won't turn.

+1

[nomadwarmachine]

+2.  Speedog speaks sense.

So any advice on removing the horizontal head with the motor in the frame?  Tips and tricks?

[Speeddog]

Off of the top of my head:

Remove airbox.
Unhook throttle bodies from manifolds.
remove horizontal intake manifold.
Remove exhaust.
Remove head bolts.
*Gently* pry between head and cylinder, the goal being to get the head off without breaking the seal between the cylinder and the crankcase.
Don't rotate the crank after the head nuts are off, as that can push hard enough on the cylinder to break the seal.

May be a couple other things, tough to do without having it in front of me.

[nomadwarmachine]

Got it.  I just put this bike back together so it will not be hard to get the head off, but what about getting it back on?

Any advice on getting the head bolts torqued right while they are in the bike?

[clubhousemotorsports]

use a short torque adapter to re-torque the heads I have a snap-on version I modified to fit. pay attention to the changes to torque values with adapters/extensions.

you can get in there I have done it many times before.

+3 on the bent valve.
be sure to inspect the guides very well for cracks when you are in there the intakes are steel and crack/ break easily.

also look at the rocker,cam and closer shim for damage

[nomadwarmachine]

As I have completely run out of time to work on this bike, I'm going to finally bite the bullet and have the techs at Proitalia take care of this.  Since they do not need to actually drop the motor for this work,, there should hopefully not be too much labor cost involved in just removing the cylinder -- I may even remove the airbox and everything so that they can get right to work.

Anyone have any previous experience (with respect to cost) in having a bent valve in the H-cylinder replaced?  I actually have a spare head that works perfectly and which they could use for parts or just pop onto the cylinder.

Thanks again!

[Speeddog]

Give me a call if you like.

[nomadwarmachine]

Speeddog, you have PM.