ok fellas i am going to be putting head back on soon so any good tips from you well be welcome

how ive done it in the past is

stanley knife blade on old gasket carefully no scratching etc

new head gasket

old base gasket with high temp sealer

torque head down in 2 stages in the order in manual from inside working out .

3 questions

1. does anybody use sealer on the head gasket ?

2. the torque setting for the head nuts is 25nm do you half that for the first stage or maybe 18 or 19 nm ??

3. the old head gasket has left an image stain on the head but i cant feel any raised bits with finger nail so do i leave it at that or do you use some sort of thinners etc to get it spotless?

thanks for all ur help by the way lads

dave.

Don't call me shirley ... :)

I'd use a new base gasket but sealer might do the job. The image stains on the head won't come off with out a skim, dont worry about it just get it clean.
I have never used sealer on a head gasket and there's no mention of it in the manual.
Good luck.

Base gasket is what ?............£10

Head gasket is ...................£35 plus.

Time.........they give away free for hobbyists...........shop time is money.

If the reused base gasket leaks its back to square one for the sake of a tenner.
You can get away with it but it depends how good or how compressed and hardened the old one is.
That gasket might have been on there and compressed/hardened for 25 years.

No sealant on the head gasket.

Do the torque up to 20Nm first then in the same pattern tighten to final torque.
In theory they should be retorqued after a few miles running but it is never done nowadays.


Sounds like the tacho fault is coincidental......

This is yet another reason to snap up cheap spares when available.
A £20 set of used clocks kept on the shelf costs the same as 3 gallons of fuel.........paltry.
A set of carbs for £50 say, put through a sonic bath and fettled at leisure then fitted at a service and road tested.
Taken off again at leisure, drained and dried, sprayed with a bit diesel and wrapped up in rags/boxed.
How much are they worth when you do (its not like having carb faults on small 4cyl. engines is a rarity) need
them ?
Might ? have saved an engine out/gasket set/frustrating fook on. (not conclusive yet in this case )
How much is a TCI ? only takes 10mins to fit and test !

I am fortunate; I have a few bikes I can swap bits over on if they start to act the goat.

General synopsis;

So many buy these bikes and spend time and money fixing performance problems only to loose heart and sell up.
Not moaning like; its how I got some of mine cheap !
If your gonna keep one; invest in some spares, remember Yamaha won't make no more !
You rarely get money back on spares; but by fook, they are worth their outlay when (not if) you need them.

Skim the head and top of the barrels, then they're flat. They won't have been done before. Never reuse a base gasket unless they're unobtainable.
I do the head nuts up to a low torque then do them in sequence a 1/4 turn each upto another torque then finish them, but everybody's different.
Sounds like you you know what youre doing just try not to cut corners

I always smear base gaskets with grease,
Do not put anything on head gasket.

thanks lads

have done em before and as has been said we all differ slightly .defo gonna get new base gasket due to work involved in taking the thing apart again etc .
also is it necessary to skim barrels and head if i didnt have a problem in that area before.

gonna do torque to 15 then 20 then 25 in quarter turns like you say . sound good ???

Dave, Boris was being slightly over cautious with the skimming IMHO.
If you were building a motor from unknown parts or a mix/match and were unsure of compatability ;yes.
If you had gasket problems;yes.
If it was a very high compression or tuned comp. motor ;yes.
If it was a diesel engine; yes.
In your case; there have been no previous gasket problems and you are not running high spec internals.
Ally heads are pretty "plastic" and pull down well anyhow.
Cast iron is a very different matter.

A skim would be nice but hardly warranted; you have to stop somewhere !
See; I say this coz the next thing is; should the big end shells be replaced ( Ive already got the barrels off) ?
Getting the drift here ?
Price up a skim of both surfaces and decide !
Personally I would rebuild as is ( I know how CDO you are)



An easy test for warpage is to place the face on a sheet of PLATE glass.
Scrap shop fronts are an ideal source.(owt over 5mm is usually plate and extremely flat)
Bit of grinding paste and 10 mins. in a circular motion by hand gives a excellent finish.

Bill.

Thanks bill. If it ever runs properly am gonna come over and check out ur collection mate .

Dave; has all this fuss started becuase it was left unstarted after last season ?
You had it running like a swiss watch after the engine swap did you not ?