81 XS1100 H series complete head

[crazy steve]

....but everyone was exactly the same length as they were checked before being cut at the machine shop..

The fact that they all checked at the same length proves to me that they didn't stretch...

Are you sure you have the right valves for the head? The '78-79 motors used a slightly smaller valve compared to the '80-81 (36mm vs 38 intake, 31mm vs 32 exhaust), and more importantly, do have longer stems as the chamber shape is different and the valves don't go as deeply into the head.

Keep in mind too that the 'range' of valve adjustement is fairly narrow; it's only 1.1mm between the thickest and thinnest shims (a bit over .040", and in reality it's even less as few motors came fitted with the thick 310 shims; 280-290 is more typical), so with badly worn seats you can run out of adjustment. Although with cutting .020" off the stems, you should have gained something back...

My bet is on wrong valves....

[pcmcse1]

re: head

The fact that they all checked at the same length proves to me that they didn't stretch...

Are you sure you have the right valves for the head? The '78-79 motors used a slightly smaller valve compared to the '80-81 (36mm vs 38 intake, 31mm vs 32 exhaust), and more importantly, do have longer stems as the chamber shape is different and the valves don't go as deeply into the head.

Keep in mind too that the 'range' of valve adjustement is fairly narrow; it's only 1.1mm between the thickest and thinnest shims (a bit over .040", and in reality it's even less as few motors came fitted with the thick 310 shims; 280-290 is more typical), so with badly worn seats you can run out of adjustment. Although with cutting .020" off the stems, you should have gained something back...

My bet is on wrong valves....

Hello all!

It's nice to have a great group that works toward one focus and that is to help thy neighbors....this is great! THANKS TO ALL!

Steve, I want to clarify here. This bike was found in a barn about three years ago by a truck driver friend. He bought one of these new in 79 and I loved the bike, an awsom ride back in the day.
I paid $250 for the bike, picked it up and hauled it home.

The bike had been abandoned there for 14 years, so I'm thinking there was never any work done to the engine. As I mentioned the head took me 7 hours to remove as the two inner head bolt ports through the head was so oxidized...it was a bear.

The shims ranged from .265 to .290 and every thing turned over well and engine was very clean. It didn't have the compression necessary for fire and run so I tore into it. Two bent intake valves and everything else was removed and labeled for re-assembly. So the valves were the same ones that came out of it except the two replaced.

I bought another head from a guy on eBay and the #3 spark plug port was stripped out and he said the head was ready to install......and he never even replaced the valve seals......so it wasn't ready to install afterall...

With the info you all have provided, I'm leaning toward the explaination as mentioned. Soft aluminum casting and the seat being beat into the casting....makes sense to me....along with the value and seat wear. More inclinde to think soft aluminum casting getting hot and softening as the culprit.


I have a 99 Road Star and love it, but I really want to get this thing running and want to see what kind of response I can get out of the bike with these racing carbs. See Mikuni RS racing carbs here: Model RS36-D8 -

http://dynoman.net/carb/mikuniRS2.html



The bottom line here is yes I need a complete head off a good runner someone has stripped and confirmed the valves are good and have a decent range for adjustment.

If I can't find one that will work for me here, I will be forced to scrap the project and move on. Therefore all part will be available for sale. This is an H series. So it's a full dresser and has been professionally painted. Lots of new parts, as well as new tires with Dyna beads installed.

Feel free to call (KJ @ 2176221930) if anyone has ideas/suggestions/questions, or complete good heads that can be dry fit and clearance checked prior to purchase.

This project has been strung out as my father was diagnosed with small cell lung cancer and since passed away. I would like to move forward with this project and hear it run.

I really hate to just give up at this point but with all the bad reviews about these heads and valve problems.....I almost just want to walk from this mess and cut my losses.

[BA80]

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

Yes, I know. That's why .

They are very close to the se size on the late head.

Just reporting what I read.

[barrelguy]

Engine parts

Sounds like a full blown project on your hands. I can't help you with any of the technical stuff but I do know that Andreas Weiss had at least 3 complete motors on his shelf last time I was there. LOTS of other bits and pieces and he is a treat to deal with. Highly recommended. I believe he is out of town for a couple of more days but send him a PM and he'll get back to you.

[XS1100_OEM4ME]

Head

Long story short, you need a new head with all the goodies inside, I will let others pipe in on if this one will fit your bike, but if so, looks good for the $$$

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?

[BA80]

That's the early head. Smaller valves but will bolt on.

[XS1100_OEM4ME]

head

That was my understanding, the valves are smaller but the bike had better qrt mile times, could have been comp ratio or other not so de-tuned stuff as the years went on, but a plug and play either way

That's the early head. Smaller valves but will bolt on.

[cywelchjr]

That was my understanding, the valves are smaller but the bike had better qrt mile times, could have been comp ratio or other not so de-tuned stuff as the years went on, but a plug and play either way

But also a far greater chance of the valves hitting the pistons (or was that a problem the OTHER way around?). As I recall, the pistons are also a little different as well, and with the early head you will NEED to change to the early ignition components or it won't perform well at all. At least this is my understanding.

[natemoen]

But also a far greater chance of the valves hitting the pistons (or was that a problem the OTHER way around?). As I recall, the pistons are also a little different as well, and with the early head you will NEED to change to the early ignition components or it won't perform well at all. At least this is my understanding.

I think it is more that the cams and the advance need to match.

[XS1100_OEM4ME]

Cams

If he is useing the same cams and advance that came on the bike and going to a slightly smaller valve, I would think his pistons would have the larger valve indents so shouldn't the smaller valve clear just fine I have never swaped a head / year on one, so I will let others who have / know advise, It was just that head looked like a good deal $$ and was just trying to help out

I think it is more that the cams and the advance need to match.

[Lonerider62]

Because there are several variations within the engines between 1979 and 1981, I'd be taking a lot of measurements when replacing any internal engine components. Another issue is the history of any engine that's been sitting around abandoned. Even the bike I just got had two previous owners in addition to the guy I bought it from and it was clear he didn't know the history of the bike as far as maintenance, or lack of, goes. Assuming something is or is't, will make trying to put together different parts to make a whole very difficult. The valves and seats on these old motors aren't even close to the current valves and seats used in engines. They are much softer and require a lot more attention. If my FZ1 needed to have it's valve clearance checked every 4000 miles, they could never had sold the things. On the XS11, I couldn't even get a single Sunner's trip in before I'd need to check my valve clearance. I love to tinker on my bikes, but for the average guy who bought one of these machines 30 some years ago, I sense that many were treated pretty poorly from a scheduled maintenace standpoint and it's amazing so many are still in service.

[BA80]

it's amazing so many are still in service.

Speaks volumes for the longevity of this engine doesn't it. From what I have seen the biggest problem with these engines is people trying to make them BETTER.

If it ain't broke don't fix it.

[crazy steve]

...The bike had been abandoned there for 14 years, so I'm thinking there was never any work done to the engine....

....The shims ranged from .265 to .290 and every thing turned over well and engine was very clean. It didn't have the compression necessary for fire and run so I tore into it. Two bent intake valves and everything else was removed and labeled for re-assembly. So the valves were the same ones that came out of it except the two replaced...

Well, at 14 years of sitting, it was parked when it was 16 years old, so I wouldn't assume it was unmolested. The PO may have had issues with the valves and tried to replace them with the early valves and didn't know the differences between the different years, which could explain your current problems and also the two bent valves. Having no luck with the wrong parts, it got shoved to the back of the barn and forgotten...

Again, check with Andreas (http://www.xs11.com/forum/showthread.php?t=34606), he'll sell you a good used correct head at a fair price.

[trdriver71]

I am wondering what the thinnest shim you used in the head as you mention you had from 265 to 290 i did my valve shims last summer and i now have a 240 in there now and there are even some guys with way thinner shims in there bikes too. JAT.

[sthomag]

It seems to me that it should be possible to grind the shims a little thinner. Check the clearances between cams and buckets without the shims first to see. They're hardened all the way through.

Finish them up with successively finer grades of wetted sandpaper on plate glass, using a mic to make sure the thickness is even. If you finish with 1000-grade, you'll get a mirror-like finish. I've used the sandpaper trick to thin shims a couple of thousands with great results.

First, though, I'd check to make sure you don't have incorrect valves.