I have a recurring problem with my ZZR cooling system. Basically the hot water comes out the side of the block in 4 ports, rather than 1. The block is ally and has 2 small M6 tappings to hold the water rail on.

The water rail is a bit of pipe with 4 inlets welded into the side and a single outlet at the bottom.

The holes in the block are smooth and run to a slight taper at the end. The water rail inlets have a bead where a rubber o ring sits and forms the seal.

Basically it leaks. Not much, just drip drip drip. It tends to stop when the engine gets up to temperature, but it's not ideal.

I've taken it apart at least 5 times over the past few years and replaced all the o rings each time. All I ever seem to be able to do is move the leak from 1 port to another. This week it's no 1 cylinder, but last time it was no 3. Time before that no 2.

Question is, is there anything I can do to stop this leak? I wondered about that lumiweld stuff. Replace the o rings, stick the water rail on and then sort of weld it up? I guess the differential expansion rate between the ally block and the steel water rail is why it's mounted with rubber o rings in the first place.

Could I sikaflex it up?


Cheers

Mike

I think by now i would have smeered some sikaflex on as well as the o-rings to sii if it improves it. You must have lots of patience.

I cant see how that will hurt anything. Im guessing the rail is quite tough in case you need to remove it again afterwards (ie wont bend and twist i fthe sikaflex has a good hold).

JB weld might be another solution but maybe a bit more permanent. I used this to seal the gearbox gasket leak (pin hole) and its been great for 2 years now.

is the water rail oem part? what is clamping the pipes into the block?

I doubt you wil be able to get enough heat in to melt lumiweld.

is it not possible to drill and tap the block to use bolts and a ring to clamp down the pipes?

maybe try on a kawasaki bike forum to see if it is problem and how fixed?

I don't know how it's mounted to the block, but are you using a torquewrench to tighten it up and in the correct order, because if it uses only 2 bolts per pipe, then it can warp(very slightly) under heat up if both bolts aren't pulled to the same(and correct) torque, bit like a head that hasn't been pulled to correct torque or in wrong sequence.

I wouldn't do anything as drastic as attempting a weld of any kind. Assuming everything is factory, prior to assembly, ensure everything is clean, smeer the o rings in rubber lube - available in small tubes for assembling hydraulic components, that will enable everything to slide together properly, it also 'conditions' the rubber components and helps with th seal. I've used this method on many rubber / coolant applications and it works fine, allowing movement, or expansion differentials, between components where required.

do what Werner said and smear a little sikaflex on every face and O ring, it stopped my 4age waterpump to leak, and have been good for a few years now.

Grtz Thomas

Hi Mike,

Im with the Sika boys - I had the very same problem on my new CBR engine. I took the old pipes off the last engine after I mullered it to swap to the new'un and they leaked very badly.

I think the engine had come off a crashed bike and the pipes were distorted - they never went back properly but a smear (lot) of sika over the o-rings and pipe fittings has held so far.

Geoff

How about Thackary washers behind the nuts? These are using for Webers in a not dissimilar situation to make an airtight seal under vibration movement. The idea is to provide flexible pressure onto the O rings to keep them sealed.

Caber