NC30: Coolant overheating?

[iArGod]

That the spring in the cap is of the specified weight.

you might have a 1.1bar cap.

you might have a 0.9bar cap - it would work fine, hold the head and the spring feel rigid

You might want to try a 1.2 or 1.3bar cap and see if it helps....

Both caps ive used have 1.1 written on them, i assume thats the bar because ones written in chinese, the other in japanese

Thanks, ill try this next!

[reverse cylinder jim]

Im also running a set of chinese rads and the pressure cap is 1.1 bar.
Ive also had similar problems with mine running hot and filling up my overflow bottle so will try another cap also.

[scotjell]

I've just been on a ride between work offices and noticed my knee had a spray on the right knee and it's the rad cap just letting pressure out a little. Just a thought now need to get a rad cap any recommends for supplier RO is favourite ATM.

[iArGod]

So ive just had honda look at it for £60 and tell me the cylinder head gasket was gone, it lets air into the coolant system and spits it out, thats why its leaking apparently.
Got home to look at the haynes manual to see what has to be done.. to find ive only changed the gaskets months ago?
Is there other gaskets that could have gone or have i likely buggered up putting the last gaskets in?

[missis sumner]

So ive just had honda look at it for £60 and tell me the cylinder head gasket was gone, it lets air into the coolant system and spits it out, thats why its leaking apparently.
Got home to look at the haynes manual to see what has to be done.. to find ive only changed the gaskets months ago?
Is there other gaskets that could have gone or have i likely buggered up putting the last gaskets in?

I haven't read all the thread so may have the wrong end of the stick here, but surely if YOU'D changed the cylinder head gaskets, YOU would remember it? Do you mean to say you changed the rocker/valve cover gasket instead?

[speedy231278]

You'd know if you'd put new head gaskets on because you'd have had to drop the coolant, take half the bike apart and spent about £35 a gasket on replacing them. Cam cover gaskets are 'only' about £16 each and don't need to be replaced unless they are damaged or have gone brittle. Head gaskets are a no brainer to change, if you don't, you're gambling!

The only way the engine will pressurise the coolant and cause the system to boil and/or develop air locks and/or vent coolant due to excess pressure is the head gasket failing and leaking compression into the coolant system. I don't know what it smells like, but from my experience with worrying about HGF with a Rover K series engine ('they all do that, guv'), it is said to be possible to smell products of combustion in the coolant as a dead giveway. If they were able to pinpoint which cylinder head was leaking, you may get away with only changing the one gasket, if not you'll have to do both. I'd be tempted to do both anyway just as a precaution. If one has gone, maybe the other will be from the same batch and develop the same issue. Don't leave it though, if the gasket goes completely, you can end up with the gasket letting the oil and water mix in a worst case scenario, and then you end up with the engine and radiators full off coffee coloured sludge which is a nightmare to clean out, with the added bonus that unlike the car, you're filling the gearbox with it too! Also, when the engine is off, if you do have a leak between one of the cylinders and the cooling system that's letting the engine pressurise it, then there's a chance it can go the other way, and starting a bike with a cylinder that's got a load of coolant in it will make a right mess!

[iArGod]

So ive just had honda look at it for £60 and tell me the cylinder head gasket was gone, it lets air into the coolant system and spits it out, thats why its leaking apparently.
Got home to look at the haynes manual to see what has to be done.. to find ive only changed the gaskets months ago?
Is there other gaskets that could have gone or have i likely buggered up putting the last gaskets in?

I haven't read all the thread so may have the wrong end of the stick here, but surely if YOU'D changed the cylinder head gaskets, YOU would remember it? Do you mean to say you changed the rocker/valve cover gasket instead?

Me and my dad did it, when the technician said cylinder head gasket i didnt think id gone down that far but looking at the diagram in haynes manual i recognised it, so i have changed the gaskets above and below the cylinder head.

Just rang honda and they said im on my own, the technician wont speak to me so they just want me to come in and spent more money.

[speedy231278]

So, you have changed the big flat gaskets between the cylinder head and the crankcase, and also the thin ones that go around the edge of the cam cover and around the plug holes? In which case, if there is a head gakset issue, it unfortunately sounds like one of both of them haven't been been installed correctly. So, a couple of quick questions, with apologies if they sound insulting:

Did you use genuine head gaskets? Pattern ones are renowned for being of extremely variable quality.

The gaskets have a right way up, as the waterways are different. You did check when fitting?

I can't remember off the top of my head, but there's probably a set pattern to tighten the head bolts, did you follow it?

Did you use a torque wrench when you did the head bolts up?

If you used pattern gaskets, odds are they were iffy. If you used genuine gaskets, clearly something has gone awry when fitting, probably one of the above unless anyone has a better suggestion?

Or, maybe the garage is after easy money....?

[iArGod]

I dont believe they were genuine no, pretty sure were right way up, used a torque wrench.
Honda did call me back and said hes certain its the gaskets so if ive already replaced them and its still happening then i might need my cylinder head machined to make sure its flat. My dad did have a look at it when we took it off to see if it was warped, he was sure it wasnt..

If this was you, what actions would you take at this stage?

[Neosophist]

I dont believe they were genuine no, pretty sure were right way up, used a torque wrench.
Honda did call me back and said hes certain its the gaskets so if ive already replaced them and its still happening then i might need my cylinder head machined to make sure its flat. My dad did have a look at it when we took it off to see if it was warped, he was sure it wasnt..

If this was you, what actions would you take at this stage?

Sounds like shitty gaskets. Never use the cheap ones unless are stuck in the middle of a desert. For the money you save you might have to do the job twice it isnt worth it.

Compression testing it would be my first point of action. See if you can track the leak down to the front or rear heads.

If your unlucky then it might only be minor and not show up well on the compression tester. If your luky youll see it a mile away.

If you can identify the bank that is leaking replace the gasket with a genuine Honda one.

If it were me i'd replace both with genuine gaskets but it is more time, effort and money.



Question though, why did you change the head-gaskets in the first place?

You could see the pistons of the bike right when you changed the head-gasket?

one of lukes pictures from his racebike build but this is how far youd strip the engine to change the head-gakset.