Cooling Problem.

[LC'Adam]

Right so,

My 125 still can't hold coolant.

As fast as I put it in the radiator it fills up the expansion bottle and then comes out the over flow.

It stays in the rad fine on tick over but as soon as you go for a short ride it fills up the bottle and starts pissing it out.

I have changed the base and head gaskets.

What else could it be?

Water is pumping around the system fine.

Could it just be air locks in the pipes?

It seems to fill up the bottle less and less each time I refill the rad.

Is there a procedure to follow when refilling an empty cooling system?

Am I doing something wrong?

Adam

[LC'Adam]

By the way, there is no water in the gearbox and no power loss. No fuel in the coolant and I don't think there is any gearbox oil in there either.

Also bubbles are coming to the surface of the coolant when when you run the bike with no cap on.

Also, I tried to start the bike with no cap on and at first it fired a massive jet of coolant out

One more thing, the coolant wasn't getting warm at first and now after refilling the rad and draining the expansion bottle a few times, it now gets hot as it should?

Adam

[seanrd]

IS the head gasket on the right way round? The TZR125 head gasket can be fitted both ways, but if you fit it upside down will block off some of teh water ways. Just a thought

[looey]

Sounds like Head Gasket is not sealing to me, can't see it being anything else ?.

If the Head Gasket is put on the wrong way around it doesn't fit on right, so will be sticking out the back or front by a little bit (can't remember which way) ?.

Did you use a genuine gasket, torque it down to the correct setting (gradually in diagonal pattern), let the bike tickover to operating temp, let it go cold again, then re-torque ?.

Think that's the recommended procedure and works for me.

Some put a very thin smear of clear instant gasket both side of the head gasket but I never have. In any case I think that will only help seal the water chambers from leaking externally as the cylinder is sealed with the ring in the centre of the head gasket.

Good luck

[LC'Adam]

Thanks guys, will look into getting a genuine head gasket and finding out which way the head gasket goes It can be fitted two ways looey. Both leave equal gaps at the front and back of head.

Adam

[looey]

Not so Mr Adam

There is a different distance between the front studs/front of the barrel and rear studs/rear of the barrel, it's only a few mm but it's different. I have a barrel, head and gasket in front of me and if I put the head or gasket on the wrong way around it sticks out at the back and leaves a bit of barrel exposed at the front !.

You also need to make sure the larger holes in the head gasket are at the front, as the coolant comes into the barrel at the right rear, travels to the front of the barrel, then up into the head (through the larger gasket holes), from the front of the head to the rear, then out the exit pipe on the right rear of the head.

You've probably got it the right way around but you can put it on wrong.

[LC'Adam]

Thank you sir,

I will whip the head off and check the gasket

If it is all in order I will assume the head is warped.

In which case I will use valve paste between the sealing surfaces of the head and cylinder and rub them together to reveal any possible warpige (warped part will not get polished) and then continue to rub them together until it is all polished. This will mean it is flat.

Learned that trick from John Davies (Lewis Hamilton's old kart tuner). I am currently on work experience at his workshop (Force Motorsport).

[Norbo]

If you remove the rad cap and smell it and it hay any wif of fuel at all its the head gasket if not then its not the head gasket .

have you looked at the water impella, does the rad have a large area of blocked fins by crap spraying up of the road . and if you have the old style small holls in that renteck have you tryed running it without the rad cover on at all .

[LC'Adam]

I think the water impella is functioning as it should norbo. You can feel the pipes buldge when you rev the bike.

Rad could be blocked or Rentec could be causing it.

But would those things cause it to fill the expansion bottle?

[looey]

Only if it's overheating and you haven't said it is ?.

[looey]

"Partly correct" you cheeky get ;D

The dimension from the front studs to the front of the head is larger than the rear studs to the rear of the head, so it is totally impossible to have a head gasket that can go on either way around without sticking out one side or the other.

I have genuine, Athena and a pattern head gaskets here and they all fit perfectly one way around and stick out at the rear leaving about 5mm of the barrel uncovered at the front.

And if you have a head gasket that covers both the front and rear of the barrel which ever way around it is put, then on the right way around it has to pertrude out a bit at the front so that when it's turned around the wrong way it will still cover the larger rear part ?.

Oh whatever....... I'm going down the Pub ;D ;D ;D

[LC'Adam]

Right so,

I have eliminated the possibility of the pressurising been caused by overheating.

Water is pumping round fine, coolant doesn't get too hot to put your finger in, yet it fills up the bottle.

Gasket is in order, coolant smells a little like fuel and has gone a darker color.

Started with an empty bottle and full rad.

Went round block. It had filled up to top.

Let some out so it when back to the full mark.

Topped up rad, and when round the block again.

Came back, bottle over flowing.

Coolant is luke warm to touch. Crankcases/clutch case not even had chance to warm up.

When I took off rad cap however a huge build up of pressure was released.

The head must be warped.

Will take it into work and check it with a d.t.i.

Adam

[Norbo]

sounds like something to do with the head if you have any kined of smell of fuel when you smell the rad top after removing .