will a head fit?

[trbig]

It shouldn't take any strength at all.. unless you try to turn the crank backwards. All you're doing is taking the slack out of a hanging chain and pushing up to the teeth on the crank sprocket. Maybe a few ounces of pressure? If there's a loop in the chain at the bottom of the crank, you can't get it by just doing this method. This is the problem I had before with Bohn Frazers bike. No matter what I did, it kept jumping a tooth on the crank. Your crank is pulling the chain down the back side of the motor and should be pulling it fairly tight to pull the cams.

Here's a really crude pic of what may have happened in your case, and what I think happened to me on Bohn's bike. The first pic is the cam chain with the adjuster out and the chain hanging at the front of the motor.





On the next pic, what could happen is you push in on the adjuster bar, and it pushes the chain against the crank sprocket on the bottom to where it grabs teeth, but there's still a loop on the bottom.





So then you have just one or two crank sprocket teeth trying to pull the chain and the cams along as you turn the crank clockwise.. which isn't enough links for it to grab.. and it jumps a tooth. You can solve this problem by having the valve cover off and advancing the exhaust cam. This pulls the slack up.. instead of just pushing it in. Then when you put your adjuster back in it pulls the slack from between the two cams..and pulls your ex cam back to the right spot... instead of pushing the slack between the ex cam and the crank.


Tod

[turbo3g]

OP^ you know what I was thinking of doing was to take the bolts off of the ex cam gear so that it can spin freely with out moving the cam and pull the chain all the was up to make sure that the crank sprocket and chain are fully touching and then have some on put the cam chain tensioner in. and as the other person is pushing it in, I slowly releave pressure on the chain. But still holding the tension, so as to not let the chain on the crank get loss and slip. then after there is enough tension on the chain that we're sure that the chain wont slip I'll put the bolts back on the ex cam and them recheck all the alignment and then turn the crank to the "c" mark before i tighten the cam chain tensioner. ( remember that i have a manual ajusting cam chain tensioner)

That's just my thoughts...

well on with my update, I took the head off and lo and behold I find bent valves. and boy was the motor in bad shape. there was a good 2mm of carbon build up in all 4 pistons. took a good hour to clean all of it off..
well as you can see in the pics where the intake valves here hitting the pistons.





and pics of the head..




in this pic you can see the space between the intake valve and the head. BENT...
stuff


well thats it for now. the new head and gasket is gona be hear in a week or so, so im just waiting now.

O and the bikes been sitting so long that the front master cylinder froze. SO it time for a rebuild...

[trbig]

you know what I was thinking of doing was to take the bolts off of the ex cam gear so that it can spin freely with out moving the cam and pull the chain all the was up to make sure that the crank sprocket and chain are fully touching and then have some on put the cam chain tensioner in. and as the other person is pushing it in, I slowly releave pressure on the chain. But still holding the tension, so as to not let the chain on the crank get loss and slip. then after there is enough tension on the chain that we're sure that the chain wont slip I'll put the bolts back on the ex cam and them recheck all the alignment and then turn the crank to the "c" mark before i tighten the cam chain tensioner. ( remember that i have a manual ajusting cam chain tensioner)

The amount of turning on the exhaust cam that you need to do to take up the slack, isn't going to cause a problem as long as you don't move the pistons. The exhaust cam will hold tension on the chain without needing someone else's help and will turn back the cam and still be in time when you install the adjuster. When you figure out how exact the cam sprocket has to be to line up with the cam bolt hole, I think you're creating a lot bigger headache than you're trying to fix, but each person has their own ways to do things. I would suggest not moving your crank until your adjuster is locked into place though. Also, you're going to have to rotate the motor one rev to turn the cam the 180 degrees to get the other bolt in the cam sprocket.

From your pictures, I can see where the valves hit the pistons. What the pics do look like, is you have put scratch marks into the tops of your pistons trying to get that carbon off. This could cause a lot of problems with hot spots and pre-detonation.


Tod

[turbo3g]

The amount of turning on the exhaust cam that you need to do to take up the slack, isn't going to cause a problem as long as you don't move the pistons. The exhaust cam will hold tension on the chain without needing someone else's help and will turn back the cam and still be in time when you install the adjuster. When you figure out how exact the cam sprocket has to be to line up with the cam bolt hole, I think you're creating a lot bigger headache than you're trying to fix, but each person has their own ways to do things. I would suggest not moving your crank until your adjuster is locked into place though. Also, you're going to have to rotate the motor one rev to turn the cam the 180 degrees to get the other bolt in the cam sprocket.

From your pictures, I can see where the valves hit the pistons. What the pics do look like, is you have put scratch marks into the tops of your pistons trying to get that carbon off. This could cause a lot of problems with hot spots and pre-detonation.


Tod

lol yea my idea is just gona cause more of a headache. I didnt think of the second ex cam gear bolt.
I haven't actually put scratch masks on the pistons its just the spots where there are no more carbon on the pistons. I'm not really do with cleaning them fully. Could you elaborate more on the hot spots and pre-detonation?
If I completely remove every last trace of carbon off the tops of the piston will still encounter a problem with hot spots and pre-detonation?
Ty

[bikerphil]

I've scraped carbon off pistons many times on these bikes and never had any problems as mentioned above. YMMV

[trbig]

No, removing the carbon isn't a problem, but it appeared you scraped into the metal on the piston. This can make hot spots here and if you scrape the aluminum in the head relief where the valves open and close at.. and can detonate the gas before the spark plug does.. causing knocking and pinging.

If it's just carbon you've knocked off, you're fine. What you'll need to do though, is determine why there was so much there.

Tod

[turbo3g]

No, removing the carbon isn't a problem, but it appeared you scraped into the metal on the piston. This can make hot spots here and if you scrape the aluminum in the head relief where the valves open and close at.. and can detonate the gas before the spark plug does.. causing knocking and pinging.

If it's just carbon you've knocked off, you're fine. What you'll need to do though, is determine why there was so much there.

Tod

yea Im not too sure why there was so much carbon buildup on the pistons.. the speedo says it has 50K on it.. So I dont know.. I dont think its the right speedo though..

Ty

[DiverRay]

Running premium fuel instead of regular WILL cause carbon build up. I would use a brass wheel to clean the top of the pistons. That will give a smoother surface, and give less for the "new" carbon to hold on to.

[turbo3g]

Running premium fuel instead of regular WILL cause carbon build up. I would use a brass wheel to clean the top of the pistons. That will give a smoother surface, and give less for the "new" carbon to hold on to.

thanks that great advise! ill do that.
So my new 1980 xs1100 midnight special head cam in today.
I have a couple of Q's
1- What is the firing order of the 80 MNS?
2 -Do i have to use my old cams from the 79 head? Or will the one from the 80 work just fine?

Thanks Ty

[trbig]

All the bikes from all the years have the same firing order. 1-3-4-2. For best results, use the cam and caps that go with the head. If you're using a 79 head, use the 2H7 cam. If using the 80 head, use the 3H5 cam.


Tod