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Piston and valve contact.

niclpnut

niclpnut

Forum Mentor
Past Site Supporter
83 1100ES

Recently lapped the valves and did a leak test and they held gas, so visibly don't appear to have any bent valves. Couple pistons showed some marks where valves had made contact in the past.

Tested the movement of the pistons in cylinders after they were first installed, and had a full 360 movement with no binding. Top of pistons 1 &4 at the "T" lined up flush with the top of the cylinders.

Installed the head, and torqued it down, and now it's binding after a 180 turn.

Using OEM gaskets that i assume are of the correct thickness.

Head hasn't been machined.

Any help would be greatly appreciated.


Nic
 
Last edited:
Presume its not a bigger bore/ gasket clearance issue. Cam chain all unravelled?
 
I went so far as to install cams, not having checked crank rotation. I took them out, and am testing things by holding the cam chain tight and manually rotating the crank.

Cam chain is unraveled.

I just backed off the head bolts and it free spins now. I don't think I'm over torquing as I'm going by the manual. 25.5-29ftlb. Am using a bit of WD when torquing.

everything is stock sizing no big bore.
 
niclpnut said:
I went so far as to install cams, not having checked crank rotation. I took them out, and am testing things by holding the cam chain tight and manually rotating the crank.

Cam chain is unraveled.

I just backed off the head bolts and it free spins now. I don't think I'm over torquing as I'm going by the manual. 25.5-29ftlb. Am using a bit of WD when torquing.

everything is stock sizing no big bore.
Click to expand...


Wait.

So you are saying, that with the valves fully closed (which they have to be, with no cams in) you spin the crank, and are getting interference?

This means it isn't the valves that are hitting.
 
WD is bad to use when torquing, take the head back off clean the stud threads and nuts with brake cleaner and re assemble. See if that helps at all, the WD is giving a lot more torque force.

I don't think the over tighten head is what is causing issues, you sure the motor hasn't been shaved down? look for any kind of odd stamped # on the cooling fins that is usually a sign of machine work.

Let us know what you work out on cam timing, maybe you have it 180 degrees off?

like mentioned if you get binding with no cams maybe the piston edge is hitting the head gasket, dbl check to make sure the gasket isn't encroching on the cylinder.

also some times even if you have the cam chain tight there might still be a munch some where so triple check cam chain for bunches.
 
Last edited:
I think I might have found the problem.

Damn frustrating.

I re checked the head gasket and it did look like it overlapped the cylinder some.

I went and checked the package that the gasket came in and the part number and lo and behold, it appears I was sent a head gasket for a 750. :clap:

Never had a problem with this particular parts vendor before.

Thanks guys. When you get frustrated you tend to get blinders on. :confused:

Nic
 
I did not remove the cylinders so my base gasket should be ok right? as far as having untorqued/retorqued head...
 
How about a round of applause? :clap: :D


Fortunately, I had another CORRECT head gasket. Going to try and get my money back for sending me the wrong gasket. :pray:

Ah well.

Everything is put back together and looking great...and more importantly turning freely, cams timed and valves adjusted!

Carbs O-Ringed, and the Mechanical is almost all done.
 
niclpnut said:
I did not remove the cylinders so my base gasket should be ok right? as far as having untorqued/retorqued head...
Click to expand...
Good luck with that. Many times, when you remove the head, you disturb the cylinders enough to break the seal. :o

.
 
I figure since it's a fresh rebuild and the engine has not been run, it will probably be ok.

But we shall see. :)
 
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