Head Gasket

[gloves86]

Hi All,

Well, after doing a bit of research on here trying to diagnose what's wrong with the bike (H1), I think the head gasket may have gone. However, there are a couple of things that don't quite add up...

When the bike is ridden normally (i.e. up to the top of the rev range) for a few miles and I come to a stop, it sounds like the coolant is boiling. If I turn the bike off and then try to start it again, it just turns over but won't catch until the boiling coolant sound has stopped, then it will fire up. If I don't take it over 7k revs regardless of how far I ride, there's no boiling coolant noise and the bike will start up again with a tiny touch of the button if turned off. All this adds up to the head gasket having gone on the exhaust side from what I can gather.

However, from what other people have said the coolant level in either the expansion bottle or the radiator should be going down. I've ridden it a bit since I first heard the boiling coolant noise (probably about 100 miles in total)...but the levels in both my radiator and expansion tank are fine...and the coolant is still blue, not the horrible brown colour I was expecting.

The oil doesn't have any white gunk in it from what I can see (but I am struggling to get the filler cap off!), and the bike has never overheated (it gets hot so the fan comes on when in traffic, but the coolant has never sprayed all over the road as some have described).

I've stripped the bike down so far as the carbs (I think the idle mixture is out because the bike keeps trying to stall when I pull the clutch in and my eyes sting from the petrol fumes when sat stationary on the bike!).

I need to change the cam chain anyway, and as the bike is on 37k km I figured I would do as much as I could while the bike was in bits.

Does it sound like the head gasket's gone to you guys?

Thanks in advance for any help/advice

Rach.

[zimm]

sounds like the head gaskets gone between one of the combustion chambers and the water jacket, so at high revs its pressurising the cooling system causing it to blow coolant into the expansion tank, as it cools (de-pressurises) it sucks the water back into the rad, hence your minimal fluid loss.

the other symptoms also point to the head gasket...




however.. as you say it never pisses all over the floor, or gets too hot on the guage, and the fan kicks in reliably... it could well just be a tired radiator cap failing to hold sufficient pressure in the system.

[gloves86]

Thanks for the reply zimm...from what I have read you are the master of the head gasket change, so your input is greatly appreciated!

hmm...where do you think is the best place to get a new rad cap from? There's one on ebay, but it's a bit of a gamble buying another old one in case I have the same issue. Think I might try a new cap anyway before cracking the head open...

When the coolant is boiling you can hear the pressure trying to escape from the rad cap (kind of a high pitched squeal) - the seals look ok though. Will an L cap fit an H radiator? From what I understand those bits are one and the same on both bikes...

[cargo]

You'll get a new rad cap from Cradley Kawasaki.........................and a head gasket if you need one