think i may be screwed...

[BA80]

Open a PHOTOBUCKET account and upload your pics either from your phone or a file on your computer to that account. Then just copy the IMG code and paste it in your post on ch. 11.

[natemoen]

Open a PHOTOBUCKET account and upload your pics either from your phone or a file on your computer to that account. Then just copy the IMG code and paste it in your post on ch. 11.

If you have a smartphone you can even get the photobucket app and it automatically uploads the pics you take to photobucket.

[James England]

the bottom side of the exhaust valves where they meet the piston have a pretty large gap .1" i would say maybe even an 1\8th of an inch. it

I think they're bent then, if the gap is only on the bottom but, as Greg has suggested, posting pix is he best way now.

At least your crank now turns and the pistons go up and down, This means the previous lock-up was definitely top-end.

Get those pix on!

[BA80]

If you have a smartphone you can even get the photobucket app and it automatically uploads the pics you take to photobucket.

Yeah, if your smarter than the smartphone.

[Nick7777]

actually just dropped my smart phone on thursday, screen no longer worked so i sent it in, not so smart haha. here is the link to the pics, if you look at the exhaust valve on the left of the third picture all four of them have this large gap on the underside.

http://s1097.photobucket.com/albums/g351/nick77771/

[James England]

Definitely something seriously amiss there. If the valves have a gap that big when 'at rest' then they are not closing fully. They may be rusted open in that position.

I'd say the head is knackered. It had no CCT, 3 of the exhaust valves are jammed open, you're missing a shim. I wouldn't waste any money fixing that head. I would buy another one on eBay. They go cheaply enough. I've sold several heads, in perfect working order, for under $50 each. I certainly would not be buying valves, shims, etc etc... it would cost too much. Get a new head...

[Nick7777]

the only head i have found so far is off an 80 and he wants 150 plus shipping. still looking though.

[Nick7777]

also which years will each year of head work on, im guessing there were differences between 78-81

[James England]

also which years will each year of head work on, im guessing there were differences between 78-81

I don't think there were any differences, although someone here will confirm the validity of what I've just said.


If I were you, I would look around for a head, ditch your OEM CCT and use a V-Max self-adjusting one (or Raptor). You could fiddle with a head for ages, spendloads of money on things and still find it's rubbish.

On a positive note... isn't it nice to know that your crank rotates, main bearings fine, pistons going up and down? That engine lockup might seem bad but at least it's only the top end. Easy fix, actually. If your lockup had been caused by anything lower down, I'd have said get a whole engine!
http://www.ebay.co.uk/itm/80-YAMAHA-...item3f15925182

http://www.ebay.co.uk/itm/78-Yamaha-...item2a18036957

http://www.ebay.co.uk/itm/Yamaha-XS1...item5d3121261e

[BA80]

I don't see any shim buckets there. Did you take them out?

I have a good XJ head that has the YICS ports plugged off you can have for $75 plus shipping.

[Nick7777]

man i hope your right with the any years work quote, just found one for a decent price. and im definitely switching to an ACCT. and the head came off so easy, i prefer workin on these over my cars any day

[Nick7777]

im not sure what the YICS ports are, and would that head work on an 81 MNS. and yes i did pull the buckets out

[BA80]

I don't think there were any differences, although someone here will confirm the validity of what I've just said.

The 78-79 heads had smaller intake valves and a slightly smaller combustion chamber. 80 -81 are the same and the 82 XJ is the same as those except for the YICS ports

[James England]

You'll find a head, complete with shims, valve buckets, camshafts etc, and ready to use....if you look on eBay and wait a while if required. I sold two like that and thought at one point I'd not be able to sell them at all!

Ideally, I'd go for the complete thing..... I wouldn't want to be using shim buckets and shims, camshafts etc of various bikes.

I believe the cam profiles were changed on some heads but I think you can run on just about any head.

[Nick7777]

so would the 78 head not work. and the xj head you have would... and also my 81 camshafts, will they work on any year head