!So...drain the residual coolant, drain the gearbox oil, remove the side casing and then remove the coolant pipe for inspection.
On initial installation, I'd used a little high-vacuum grease to lubricate the O-rings (to aid in sealing and make sure they wouldn't get stuck and deform when plugging in the coolant pipe). The coolant pipe itself had been in near pristine condition, apart from the original plated exterior finish being a bit patchy, with just a hint of corrosion. So as to not look out-of-place with the bead-blasted and burnished cases, I'd painted the coolant pipe with black POR-15 paint, which gives a smooth hard finish.
On inspecting all the components, everything looks good. The O-ring is not broken or twisted. The socket in the casing is clean - no scores or other damage. The coolant pipe is not damaged or deformed and the O-ring grooves are smooth. There is no sign of any grit or swarf which may have prevented the O-ring in question from sealing.
Although it should make no difference, the O-rings are the correct genuine (and new) Kawasaki parts (EDIT: or so I thought!). When removed from their bag, they were supple - not hard or cracked.
Since the definition of insanity is to try exactly the same thing again and expect a different result, I decide to use a greater helping of high-vacuum grease on reassembly. To prevent wasting another side casing gasket if it doesn't work, I just refit the side casing and nip up four of the screws to hold it in place (if it works, I can just drain the coolant, fit a new gasket and then refill).
There is some perceptible (but smooth) resistance as the pipe is plugged into position, suggesting that the O-rings are sealing properly.
This time, I get to the stage where the whole system is full of coolant and no sign of any leaks! I decide to leave it for a while, to make sure it isn't going to start leaking again.
Imagine my dismay when, about 20 minutes later, coolant begins to drip from the same place! Oh well - time for a rethink.
I should mention that this engine had been running when I got the bike, with no coolant leaks! It is a low-mileage B1 and it looks as if the engine had never been split. I didn't find anything untoward when dismantling. I had been sorely tempted to run it as it was, but had decided instead to check out the internals and replace the pistons, which were surely the originals.
I rummage through my engine spares and find three coolant pipes. I pick the least cruddy one and give it a wipe off in preparation for use. Despite being a little cruddy, it is not damaged and the O-ring grooves are clean and smooth. I fit some new O-rings, with just a little high-vacuum grease to aid fitting and sealing. Again, it plugs into position nicely.
On filling the system with coolant, I get the same result as the first time, although it is now the hole beneath the right-hand cylinder that is leaking!
I drain the residual coolant, dismantle the side casing and remove the coolant pipe (again!). Re-inspection of the sockets in the casing reveals no damage or any indication why they should leak. The wet bead-blasting process which was used on the casing is very gentle - it won't even take paint off unless the nozzle is concentrated in one place for a long time. I therefore disregard this aspect as a likely cause of the problem.
Now, I decide to make some measurements. Using my painted coolant pipe and also the least-cruddy spare one, with combinations of old and new genuine O-rings, as well as new pattern O-rings, the outside diameters of the various O-rings when seated in the grooves are all within about 0.2mm of each other. None of the plug sections of the two pipes look oval - their roundness is confirmed by measuring the outside diameters at various points with O-rings fitted.
The coolant pipe barely rates a mention in the workshop manual. I assume therefore that there is no special procedure for fitting it. Has anybody else had similar trouble?
Have my new O-rings shrunk?? Do I need special oversize ones?? Should I stick to air-cooled bikes??
In the absence of definite advice, my next attempt will involve Silastic instead of grease when fitting. Surely that will work...won't it
? Suggestions welcome.Regards,
James
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