will a head fit?

[turbo3g]

hey I want to know if a 1980 Yamaha XS1100 midnight special cylinder head will fit on a 79 special motor? I think my valves in my current head are bent. the tensioner broke and I think it messed with the came chain and that caused the timing to get out of sync which caused the valves to bend. Im not getting any compression in any of the cylinders.
Help

[bikerphil]

The 80 head is different than the 79, different valves, different combustion chamber, different cams, different pistons on the 80 engine also. It can be made to work, but you're better off finding a 78-79 head. JMHO

[DiverRay]

The 80 head will have a lower compression ratio than a '78 or '79. Other than that, it WILL work. Now, if you find a small turbocharger to install with the head, you will be ready to go!

[turbo3g]

thanks everyone. I think ill get the head. i found it on ebay for $100.
Hope it will work.

[skids]

It is a good time to also change that cam chain. (and maybe the chain slipper unit).

hey I want to know if a 1980 Yamaha XS1100 midnight special cylinder head will fit on a 79 special motor? I think my valves in my current head are bent. the tensioner broke and I think it messed with the came chain and that caused the timing to get out of sync which caused the valves to bend. Im not getting any compression in any of the cylinders.
Help

[turbo3g]

Well I rebuilt my cam chain tensioner with the how to on this board. So now I have a manual adjustable tensioner. What I forgot to ask is how do I put the timming back in place. I cant find the TDC on the timing plate. Can I just us a screw driver and put it in the spark plug hole and find TDC. Or will that not be acurate? I read the manual and its kind of confusing. I can set the cams with the timing marks but i'm not sure about TDC.

[mack]

head identification

I don't want to side track here but say there were four heads sitting on a table and you were looking for one to fit your bike. Are there serial numbers on them someplace which denotes the year and model it came from.

[turbo3g]

To OP^ Hmm I'm not too sure man. I think that the 78-79 are the same and the 80-81 and the same. They both look a little difrent from each other. But im not sure of they have serial #s But ill check mine and let you know.
lol are u saying you have 4 heads and need to chose one for you bike? lol if so make sure it looks like you old one.

[mack]

hard to tell

All the engines from 78 to 84 all look pretty much the same to me. I know they each have small differences but very hard to tell from a distance. My question is derived from the fact that we are all in the same boat when it comes to parts. They are used or don't exist at all. If your looking for a head for instance and you see one advertised on Ebay or a motorcycle wrecker and the seller thinks it's from a given year but has parts from several XS 11's laying around. How would an amature like me know if I needed one for a 79 and what he has is really from an 80 or 83, without asking for a stamp of some dicription to verify the year. It's probably a stupid question but I'm trying to learn.

[Lamric]

Mack, you'll get some good info from my part number site, usually with photos of the parts concerned.

For example, here's the XS1100 E Cylinder head and that page tells you that it's the same part as on the XS1100 F and SF models.

Then when you look at the XS1100 G cylinder head it tells you that the same part is used on the XS1100 H, SG and SH models.

[mack]

That helps

Still though your at the mercy of the seller to remember or correctly identify the style and year of the part source. Great site though. Had no idea it existed. You got anymore revelations that could be useful in my education?

[Lamric]

Hi Mack, There's a whole lot of info to be gained on that site from part numbers, microfiche diagrams, photo's and prices but I can't prevent eBayers misdescribing - best to compare their photos with the ones on the part number site.

Now I think we should return this thread to Turbo3g who had a question he wanted answering...

I cant find the TDC on the timing plate. Can I just us a screw driver and put it in the spark plug hole and find TDC. Or will that not be acurate?

[DGXSER]

Well I rebuilt my cam chain tensioner with the how to on this board. So now I have a manual adjustable tensioner. What I forgot to ask is how do I put the timming back in place. I cant find the TDC on the timing plate. Can I just us a screw driver and put it in the spark plug hole and find TDC. Or will that not be acurate? I read the manual and its kind of confusing. I can set the cams with the timing marks but i'm not sure about TDC.

Start by putting a straw, screwdrive, somethign in the no 1 (left side sittign on bike) spark plug hole and crank the engine over, no cams in place. Watch it rise and note the position of the pointer when it stops rising, now keep cranking until it starts to lower, mark that position. The center of those two marks is TDC. Should be pretty close to your T mark. If not, you can adjust the pointer so it is. (Note: not all of the timing plates have an actual T refer to the manual for what mark is on yours.) That should be accurate enough. You could also make a degree wheel, Dbeardslee did a write up of one he made a little while back. Same method really, just a pointer on a degree wheel instead of your stock pointer on your timing plate.

Once you know TDC, then install your cams so the dots on the cam shoulder lien up with the pointer on the caps, and reinstall your chain. Then turn the engine to the C mark and reinstall the tensioner.

[trbig]

Then turn the engine to the C mark and reinstall the tensioner.

I know he probably MEANT to say it, but DO NOT move the crank without some kind of tension on the chain. When doing this.. moving the crank to the "C" mark, stick your finger into the adjuster hole and push on the bar in there with a finger to take up the slack in the chain. Otherwise, it will jump a tooth on the chain. You'll have to spin the crank to get the other bolt on the cam sprockets.. just make sure you don't move anything without sticking a finger in that hole to hold tension. Just watch the cams initially. Make sure the cams are turning when you turn the crank. That chain can come off the crank sprocket at the bottom sometimes and be beside it.

Before installing the tensioner though, you'll have turned the crank back to the "T" mark. Make sure everything is lined up before you install the tensioner. It's easy to miss it by a tooth... several times in a row. lol.


Tod

[skids]

Maybe your finger is stronger than mine. I tried that and it jumped a tooth anyway...