valve clearance 750twin

Specs for valve clearances are 0.10-0.05mm, 3 are reading 0.051, one exhaust valve is reading 0.037. Since I don't have access to the valve holder tool and don't want to spend $60 to buy one, in order to change it I will have to remove the cam. If I do that I might as well remove both cams and bring all the valves closer to the 0.1 spec. If I do that I might as well remove the head and check that out. No obvious problems w/compression, rides very strong, no oil leaking from head/cylinder, 17K orig miles. Since I really don't want to do all that for minimal results, how bad is it that the one exhaust valve is 0.037 and if I do remove the head are there any simple ways to increase HP?
Any thoughts greatly apriciated
Thanks
Ron

if your valve seats are a bit pitted, lapping the valves will help performance( do this before changing shims) you could mill the head for a bump in compression, then you would have to degree the cams

ronjones wrote:

Specs for valve clearances are 0.10-0.05mm, 3 are reading 0.051, one exhaust valve is reading 0.037. Since I don't have access to the valve holder tool and don't want to spend $60 to buy one, in order to change it I will have to remove the cam....

Dude. I bought a shim tool for like $8 on z1Enterprises.com. It wasn't the greatest, but it worked.

Also, I had a valve at about that clearance on one of mine as well. I know it doesn't make sense, but I actually noticed a mild difference in idle performace after about 30 minutes of running.

The trick, however, is finding the required valve shims (32mm) for our twins...

Thanks for the reply, guys.
Your suggestions cause me to think of a couple of other questions. I know about lapping the valves but what does "mill the head" and "degree the cams" mean and how much would it cost? Sounds like maybe something I may want to think about for next winter.
Biquetoast, are you talking about that batwing shaped tool? How does it work and how hard is it to use?
I really don't want to remove the cams, at this time, if I don't have to. My used parts guy thinks he can come up w/the shims.
Thanks again

Mill the head means to use a flycutter or a face mill on a vertical mill to remove material from the cylinder head mating surface (the part that sits on the block).

When you do this, the cams are closer to the block, and that creates slack in the cam chain, the slack is taken up by the tensioner, because there is only one tensioner (on the front on the 750 twin), all the slack is taken off one side, and that causes the cams to rotate forward, throwing them out of time.

To fix this, you have to slot the cam sprocket mounting holes so you can rotate the cams back into position.
Since you can no longer use the timing marks on the cam sprockets, you have to use a degree wheel and a dial indicator to degree the cams (put them back where they go).

ronjones wrote:

...Biquetoast, are you talking about that batwing shaped tool? How does it work and how hard is it to use?...

Yep, I mean this:
www.z1enterprises.com/detail.aspx?ID=152

...it's really *simple* to use, but can be physically hard to use.
Since the thing with the ball on the end has to be crammed into the clearance against the shim, if your clearance is tight, it can be a bear. On the larger clearance once on my bike, it was easy. Once you get that in there, you stick the batwing thing in as a holder, and it's all gravy from there. Hope that helps...

...oh, and loosen your cam chain before torqueing your cover down to spec...

Again, thanks for the replies, guys.
Steell, thanks for the explaination. I think I understand mostly, what you are talking about. It really does sound like a thought for next year and doesn't sound like something I'm capable of doing. If I understand correctly, the cam sprocket bolt holes need to be elongated so the cam sprocket(s) can be rotated, back into it's original, TDC, position.
Is this something that needs to be done to both cam sprockets or just one, could this be done by just taking the head to the shop or would I have to bring the whole engine/bike and any idea what this might cost? My used parts guy tells me he could probably sell me an extra head, cheap. That way I wouldn't be messing w/the original and could swap back if I need/want to.
Thanks, also, for the tool info, Toast. I've ordered the tool, from Z1, and am going to try to replace the shims w/o removing the cams, at this time.

It involves removing the cams and valves from the head and taking the bare head and cam sprockets to a motorcycle machinist.

If I took the head and cam sprockets to the local motorcycle machinist, I'd expect to pay no more than $50 to have .030" removed from the head mating surface, and the sprocket bolt holes elongated by .1".

Fortunately I have a vertical mill in my shop so I can do the work myself, to bad it don't have enough travel on the table to do a four cylinder head though

Hi Ron:

I have exactly the same bike 1982 CSR 750 Twin. Yesterday I was checking the valve clearances and found the following. 1 @ .003inches 2 at .002 inches, and 1 with no clearance at all. It seem to me that the valve clearances are very tight on this bike. .1 mm = .004 inches and .05mm = .002, just .002 inches of valve clearance adjustment. Also does anyone have a drawing for the valve shim removal tool? I know that the manual says not to grind the valve shims but has anyone ever done it?

Thanks

Mike J.

I know that the manual says not to grind the valve shims but has anyone ever done it?

Seriously bad idea, the shims are hardened on the surface only. Two things likely to happen if you grind the shims are extreme wear, or the shim shattering. I don't think you want to deal with either result.

usguns wrote:

...It seem to me that the valve clearances are very tight on this bike....... Also does anyone have a drawing for the valve shim removal tool?....

I'd go so far as to say that if you have accurately measured them, your valves are dangerously tight. :blink:

Also, what do you mean by drawing? You mean of how to use it? I don't but the good news is that there are good instructions with the tool when you get it.

Hey Mike,
Welcome, there are a lot of great guys here, full of info about these old bikes. Steell is the twin guru around here and I'd take anything he says about twins seriously. I've seen quite a few other posts mentioning the dangers of grinding your shims. I was really surprised at how thin the guages are, I'm almost afraid I'm gonna tear them. That said and as a relative new bike michanic, I'd be real careful of riding that no clearance valve. I've been told that that can really burn your valve. My bike guy really encouraged me to do the shimming all the way around. Apparantly, loose valves are happy valves...a little clatter is a good sound. If you need the tool, Z1 enterprises has two varities. The one pictured in the manuel is $60 but they have a "batwing" type tool for $8. The link Biquetoast posted will take you to the cheap one. I've decided to get the cheaper tool.
Nice meeting another 750CSR guy...Are you the guy looking for the seat? I've been meaning to reply to that but have lost the thread.
Good luck