Right hand side of the bike behind engine is full of coolant over exhaust, frame and swingarm after every ride. Today it was so much it formed small puddle under the bike while parked. Removed sidecover and notice coolant reservoir level very high..just under filler cap. So it seems it must be coming out through the cap. Question is why is it so high when after the restoration I made sure level was between high and low marks? So now do I just drain some coolant or is there something else going on. Temp gauge maintains just under halfway mark while riding in our hot temperatures. Is the reservoir cap maybe not sealing properly?

Sounds like a head gasket Mc, I know you fitted a new one when you rebuilt it, didn't you? You can test your cap in some warm water to see what temp it opens at, start with cool water and add hot till it opens have a temp gauge in the water and work out at what temp it opens at.

do they have thermostats, I know the UK bikes do and they can seize closed

Thought they did Drewpy, might well be wrong, has been known to happen !!

Can it be head has not been retorqued since engine overhaul? (done bout 1400km)

The early UK spec 4L1/4L0 LC's Didn't have thermostats fitted as standard, it was only on the later YPVS models that they fitted them. As you have suggested I would try retorqueing the head when the engine is cold up to spec and in order of the numbers on the cylinder head. What torque did you do the head bolts upto ? The manual I have says 24Nm or 17 ft-lb. The level in the reservoir will go up as the engine heats up as the coolant in the rad expands and is forced out of the rad cap and into the reservoir and should be drawn back into the rad as the engine cools down.

I didn't do the engine YPVS..but will re-torque the head and see how it goes. Makes sense coolant being forced out of reservoir as engine heats up.

Normally the coolant will be between the FULL and LOW marks on the reservoir tank when the engine is cold and go up to the Full mark when the engine is up to temperature and then drop back down to in between the marks as the engine cools.

Yea..now its not going back down. Gonna re-torque the head..then have a look at the radiator cap as well as check level in radiator. I`m told a car`s cap also works if I have to replace it..don`t need to pay a ridiculous price from Yamaha.

Have a look at the rad cap. It should have a spring loaded flap/valve in the middle of the rubber seal that allows the coolant to be drawn back in to the rad from the reservoir tank when the engine cools down as shown here : http://s215.photobucket.com/user/cooper_man2/media/1063_PARTS_LEFT/1063-131.jpg.html

You should be able to carefully lift it up a small amount with your finger and it should spring back down.

Tony

That spring on the rad cap worked ok. Rad needed some water needless to say. But bad news..had a mechanic friend over and he suggested run the bike with rad cap off..we saw bubbles in the water. He reckons head must come off.

That's a pisser Mc, she looked sweet to. Oh well at least the nut's & bolts won't be seized.

Will go visit engine guy tomorrow..think the bike should just go to him to see what's going on and he can tune it properly for me as well. Good thing I haven't painted tank etc. yet.

Ok engine guy too busy so will have to do this myself. I have the new gasket and have been advised to use gasket maker around the cylinder/piston area. Open to any advice here and will post pics once head is off.

What's a "gasket maker" Mc?

Nice clean LC , I wish mine looked like that . Shouldn't there be an overflow tube on the expansion bottle ? Some of the newer type layered metal head gaskets seem to be almost impossible to seal properly .

Only get genuine headgaskets. Anything else will leak.

No gunk or funky tubes of gloop. Do it the way yam says and it will be fine. Handfull of bolts and some pipes. Simple.

mark the head mating surface with engineers blue or a felt tip pen and rub it on a piece of glass to check the heads not warped. no point putting it together if the heads warped and it only takes a few mins

Head was skimmed but will check it. No overflow anything on the reservoir.

It was suggested I get a copper gasket made up and overtorque the head using new bolts..but I don`t like this idea..I always try stick to manual as Cynic says..would prefer not to use sealants etc..but why did she leak with a skimmed head and new gasket?..and this guy only uses genuine Yamaha parts.

Ok head off today..here`s how things look.

New gasket from Yamaha

You guys see anything out of the ordinary?

Just saying here Mc, but should that black paint ? on the head go all the way to the inside edge? cos it has me thinking that if you try to torque that down then your trying to set it on to paint ! Or is that the residue from the original gasket perhaps? Or God forbid someone sealed it with a liquid seal when they rebuilt it !