81 XS1100 H series complete head

[pcmcse1]

Greetings all!

I have a unique problem and can't seem to figure this one out. So hang on and get a load of this one.

I purchased my 81 a few years ago and have it near road ready. The bike was abandonded in a barn for 14 years and I'm ready to hear it run.

Now for the good stuff. I didn't have the compression need to fire this thing up...so I pulled the head. Seven hours later and three broken fingers and two hammers I had the head off. The front two head bolt ports were so oxidized....well you get the picture I'm sure.

I had the head shaved here at our local machine shop (It's the NHRA Top Fuel racers shop, Tim Wilkerson) and had the head shaved .010.

Got the head back and lapped in the valves. All good to this point. Afterward I dry fit the cams, bolted them in place nad checked clearance.....and nothing. Even with the smallest shim I cannot get .001 to clear. I checked every valve on the intake and then did the exhaust and the same thing. So I took the head to the machine shop and had the mechanic from the racing team look at it and he is stumpped. We shaved .020 off the top of the stem and checked them again and still no clearance. I chacked to see if I could take off more and could only get another .025 off it and that wasn't enough either.

After talking the mechanic and looking over this with a great deal of though...we have come to the conclusion that these valves had to have streched on the stem somewhere.

Has anyone experienced this before?


The bottom line here is that I'm looking for a complete head off a good running bike with somewhat low miles. The head has to be complete and not disassembled except for the cam removals to allow for removal of the head.
Valve inspection from the bottom end should look clean with no signs of bent or burnt valves.

I have a new set of Mikuni RS racing carbs for this and would really like to hear it run.

The bike has restored and repainted, and will be awsom to see this old piece of history back on the road.

Anyone out there have a decent complete head I can buy?

[crazy steve]

....Got the head back and lapped in the valves. All good to this point. Afterward I dry fit the cams, bolted them in place and checked clearance.....and nothing. Even with the smallest shim I cannot get .001 to clear. I checked every valve on the intake and then did the exhaust and the same thing. So I took the head to the machine shop and had the mechanic from the racing team look at it and he is stumped. We shaved .020 off the top of the stem and checked them again and still no clearance. I checked to see if I could take off more and could only get another .025 off it and that wasn't enough either.

After talking to the mechanic and looking over this with a great deal of though...we have come to the conclusion that these valves had to have streched on the stem somewhere.

In the normal course of wear the valves recede into the head anyway, and lapping only makes that worse. So if your valves were pretty worn to start with, yep, that's what can happen. I doubt very much if the valves 'stretched'...

At one time you could get new replacement valves as a member was having them made in batches, but due to health issues he couldn't anymore. So these days you'll either have to find good used valves or a whole head. Check 'Andreas' posts in the 'for sale' forum as he usually has good used parts available (http://www.xs11.com/forum/showthread.php?t=34606), if not post to the 'parts wanted' forum. You can use either of '80 or '81 heads as they're the same. The '78-79 are different, as is the '82. Do try to make sure you get a complete head, as the cam caps should remain with the head.

[XS1100_OEM4ME]

Head

I am not saying I am right, BUT, it sounds like they "MAY have taken a little more off the top then you ask. I know it is a" high end shop", but they tend to break in the "new guys" on their low dollar stuff I do know someting about this as I had lots of experance with "high end shops" in my younger / racing days You can easly CC the head and see if they cut it short, just compair it to the CC of the stock head for your bike. If they did, I would be asking for some pay back is $$ to fix your problem. Not starting and argument about vavles streching (they drop before they do much) Just trying to help If you don't know how to CC a head and wan't too, PM me, and I will step you through it, it is easy and just a few bucks in hardware

Greetings all!

I have a unique problem and can't seem to figure this one out. So hang on and get a load of this one.

I purchased my 81 a few years ago and have it near road ready. The bike was abandonded in a barn for 14 years and I'm ready to hear it run.

Now for the good stuff. I didn't have the compression need to fire this thing up...so I pulled the head. Seven hours later and three broken fingers and two hammers I had the head off. The front two head bolt ports were so oxidized....well you get the picture I'm sure.

I had the head shaved here at our local machine shop (It's the NHRA Top Fuel racers shop, Tim Wilkerson) and had the head shaved .010.

Got the head back and lapped in the valves. All good to this point. Afterward I dry fit the cams, bolted them in place nad checked clearance.....and nothing. Even with the smallest shim I cannot get .001 to clear. I checked every valve on the intake and then did the exhaust and the same thing. So I took the head to the machine shop and had the mechanic from the racing team look at it and he is stumpped. We shaved .020 off the top of the stem and checked them again and still no clearance. I chacked to see if I could take off more and could only get another .025 off it and that wasn't enough either.

After talking the mechanic and looking over this with a great deal of though...we have come to the conclusion that these valves had to have streched on the stem somewhere.

Has anyone experienced this before?


The bottom line here is that I'm looking for a complete head off a good running bike with somewhat low miles. The head has to be complete and not disassembled except for the cam removals to allow for removal of the head.
Valve inspection from the bottom end should look clean with no signs of bent or burnt valves.

I have a new set of Mikuni RS racing carbs for this and would really like to hear it run.

The bike has restored and repainted, and will be awsom to see this old piece of history back on the road.

Anyone out there have a decent complete head I can buy?

[crazy steve]

Shaving a head won't effect valve clearance any, but it's not a great idea to cut them if not needed as it does change the cam timing slightly....

[XS1100_OEM4ME]

Correct

You are correct on the head to cyl. I must have misunderstood, I thought he said they cut the valve seats? if so, they could have cut to deep. I think that effect valve to cam relationship, not claiming I know something, just thinking out loud?

[XS1100_OEM4ME]

Head

Don't know if it helps / fits looks fair with extra's
http://www.ebay.com/itm/Yamaha-XS110...sories&vxp=mtr

Greetings all!

I have a unique problem and can't seem to figure this one out. So hang on and get a load of this one.

I purchased my 81 a few years ago and have it near road ready. The bike was abandonded in a barn for 14 years and I'm ready to hear it run.

Now for the good stuff. I didn't have the compression need to fire this thing up...so I pulled the head. Seven hours later and three broken fingers and two hammers I had the head off. The front two head bolt ports were so oxidized....well you get the picture I'm sure.

I had the head shaved here at our local machine shop (It's the NHRA Top Fuel racers shop, Tim Wilkerson) and had the head shaved .010.

Got the head back and lapped in the valves. All good to this point. Afterward I dry fit the cams, bolted them in place nad checked clearance.....and nothing. Even with the smallest shim I cannot get .001 to clear. I checked every valve on the intake and then did the exhaust and the same thing. So I took the head to the machine shop and had the mechanic from the racing team look at it and he is stumpped. We shaved .020 off the top of the stem and checked them again and still no clearance. I chacked to see if I could take off more and could only get another .025 off it and that wasn't enough either.

After talking the mechanic and looking over this with a great deal of though...we have come to the conclusion that these valves had to have streched on the stem somewhere.

Has anyone experienced this before?


The bottom line here is that I'm looking for a complete head off a good running bike with somewhat low miles. The head has to be complete and not disassembled except for the cam removals to allow for removal of the head.
Valve inspection from the bottom end should look clean with no signs of bent or burnt valves.

I have a new set of Mikuni RS racing carbs for this and would really like to hear it run.

The bike has restored and repainted, and will be awsom to see this old piece of history back on the road.

Anyone out there have a decent complete head I can buy?

[XS1100_OEM4ME]

Shims

Man, you cant buy 8 shims that cheap, hope it helps

[TopCatGr58]

Okay, I'm taking this as another learning adventure for me! I remember from working on my head 10+ years ago how relatively soft the valve metal was and how easy it was to bend it! I remember that the clearances shrink as the engine wears, but I thought someone said it was the seats getting hammered into the aluminum head?

But now it seems like we're saying that the valves themselves flex/bend at the head allowing the stem to protrude farther into the head which reduces the clearance? I can see and understand that. Also like OEM said, either excessive seat or valve grinding can also cause the valve to stick farther into the head, hence the machine shop's idea to grind the ends of the valves.

Just wanted to see if I got that right?

Secondly, I remember someone posting about with a shaved head, that it will affect/retard the cam timing a bit because the cam chain will be a little longer than necessary from the crank to the cams. Don't know/remember if it is enough to worry about trying to slot and degree the cams/sprockets??

T.C.

[crazy steve]

...I remember that the clearances shrink as the engine wears, but I thought someone said it was the seats getting hammered into the aluminum head?

The seats are wearing, but I doubt if they're getting beat into the head; that would result in dropped seats. That will trash a motor right now; I own Jaguars, so I know (leading cause of dead V12s...)

But now it seems like we're saying that the valves themselves flex/bend at the head allowing the stem to protrude farther into the head which reduces the clearance? I can see and understand that. Also like OEM said, either excessive seat or valve grinding can also cause the valve to stick farther into the head, hence the machine shop's idea to grind the ends of the valves.

That's not what I was trying to say... While there's probably slight flexing of the valve stems, enough to cause this problem would result in the heads falling off. What you're seeing is wear, i.e. the 'margin thickness' disappearing on the valve face (measurement 'D', page 7-4 of the FSM) as well as valve seat wear (the manual states that the seats are 'subject to severe wear'). As usual, the manual only gives the minimum measurements for the valves, but I'm sure it starts out considerably thicker than .7mm. The part I find interesting is there's no allowance for replacing the seats; once they're worn beyond specs, you replace the head. The manual also makes no mention of shortening the valve stems or giving a minimum/maximum length, which leads me to believe they don't want you doing that. Many valves have hardened tips, so you can't take much (if any) material off the ends. They do specifically say that if the end is mushroomed any, replace the valve.

Secondly, I remember someone posting about with a shaved head, that it will affect/retard the cam timing a bit because the cam chain will be a little longer than necessary from the crank to the cams. Don't know/remember if it is enough to worry about trying to slot and degree the cams/sprockets??

A light cut (up to .010") shouldn't cause enough change to make any difference; but if you start cutting a bit heavier (to maybe get a compression increase), then you probably would want to check cam timing and maybe slot the sprockets. Yes, this can retard the cams. One big problem is Yamaha didn't give cam specs beyond lift; you need to know just what the timing events are (open at X degrees, closed at X, overlap). If you're cutting to simply clean up a warped head, you can compensate for the cut by stacking base gaskets under the cylinder (a trick the Harley guys use to set deck height; you can buy different thickness gaskets for those).

[BA80]

I read about another member having a similar problem and it turned out he had put the exhaust valves in the intake side and vice-versa. They looked right and fit good but the clearances were just as your saying....JAT.

[XS1100_OEM4ME]

Hey

Hey, before I get into trouble, I know less then nothing, I was just trying to figure how a factory spec. head became unuseable You guys are way beyond my understanding. I was thinking, factory spec. head / machine shop work/ , no more factory factory spec Well, you must forgive my dumb thinking I was just thinking out loud got to stop doing that

[pcmcse1]

re: head

I am not saying I am right, BUT, it sounds like they "MAY have taken a little more off the top then you ask. I know it is a" high end shop", but they tend to break in the "new guys" on their low dollar stuff I do know someting about this as I had lots of experance with "high end shops" in my younger / racing days You can easly CC the head and see if they cut it short, just compair it to the CC of the stock head for your bike. If they did, I would be asking for some pay back is $$ to fix your problem. Not starting and argument about vavles streching (they drop before they do much) Just trying to help If you don't know how to CC a head and wan't too, PM me, and I will step you through it, it is easy and just a few bucks in hardware

Okay to clairify, shaving the head will have absolutley no affect on the valve clearance to the cams. The valves seats were not cut, just lapped and there is no explanation except for the valves being to hot and streched.....but everyone was exactly the same length as they were checked before being cut at the machine shop.

Surely this problem has cropped up before.....I've been working on engines most of my life and never seen anything like this.

Also the mechanic/mechanist was one of Tim's race mechanics on the road for seven years.....so I trust his work and experience.

[pcmcse1]

re: head

I read about another member having a similar problem and it turned out he had put the exhaust valves in the intake side and vice-versa. They looked right and fit good but the clearances were just as your saying....JAT.

Sorry but the valves are different diameters.....intake large and exhaust small

[CaptonZap]

Common practice when cutting valves and seats is to use Prussian Blue on the sealing surface to check seat width and overlap.
If that procedure was followed, it would be obvious that the smaller valve head did not fit the larger seat, and therefor there was something wrong.
Even lapping with compound, if visually checked, would indicate the wrong size valve being in a particular seat.
If that was what happened, it would indicate a serious breach of procedure on the part of the machinist doing the work. And it would be a shame that usable parts would have been ruined. CZ

[jwhughes3]

Y'all missed the point...

He isn't looking to figure out what happened, he wants a complete replacement head with good valves so he can hear it run.

I can sense the frustration of being Soooo close.

Greg sure one of those engines doesn't have a good one? You have like a warehouse of engines....

With his racing carbs (what makes them "racing carbs"?) I would think he would want the 78 head with increased lift/duration for more power. (goes along with swapping the advance unit to a 78 also)

Maybe the shims got mismarked and they are all designed to stump you

John