water in gearbox

[rm125 for trail]

hi, i have a 1992 honda cr 125r, and noticed my bike was using too much water to be normal, and decided id drain the gearbox, when i did about 1litre of water (the same amount a had put in the radiator) came out of the gearbox. i took it apart and didnt find anythig very obvious as to why it would be doing this, any suggestions??

thanks, andy

[Domantas]

I would start by looking at water pump. The gasket might be bad. It's the only way the cooalnt can get to the gearbox. And that should be easy to fix.

[crider400]

water pump seal... i woud also replace the berngs and gaskets of course also

[RDZombie]

water pump seal... i woud also replace the berngs and gaskets of course also

+1, simple fix

[hird]

As already stated, sounds like you need to replace waterpump seal.

Make sure you change the oil seal as well and inspect the shaft for excessive grooving (if your shaft is toast you won't stop the leak with new seals. Don't even try) a new bearing is wise also why you have it all apart. Also inspect impellar (i.e no finns missing ect...) and be sure to use new gaskets. Easy job to do, just don't take any short cuts and follow your manuel for assembly.

Hope this helps

[1987CR250R]

A liter of water? The bike doesn't even carry a liter of oil in the crankcase. But, the water pump area is the only place for water to enter the crankcase on such a bike.

[rm125 for trail]

ive replaced the water pump seals, but it is still leaking. is there a bearing or water seal arond the shaft ??

[rm125 for trail]

its still getting into the gearbox i mean

[1987CR250R]

Well, failed bearings often cause failed seals. The water pump has two bearings which could fail. Also, if the shaft is grooved, that will cause the new seal to leak.

But... Your bike has a weep hole between the water side seal and oil side seal. If anything were to leak out either seal it would come out the weep hole. That is, unless, it's plugged with corrosion like the case on my CR 250.

Now, I've never laid hands on a 125 so I can't tell you too many specifics. But, I know that 92 and on CR 250's have a water passage from the right side crankcase cover to the crankcase. If this gasket were to leak, it is possible for water to get to the oil and I have seen this happen. There is a water passage through the center crankcase gasket and one into the cylinder but both of these would leak into the crankcase and water would go through the cylinder and not the transmission. The 92 on CR250's only have one water hose going into the water pump (the inlet). The water leaves the pump into the crankcase. I think 125's have a hose in and a hose to the cylinder so there are no crankcase passages.

Anyways, that basically leaves the water pump seals and housing as the only culprits. Check the housing very closely for cracks or pitts due to corrosion.

Oh, and once you get the leak fixed, it may take 2 or 3 oil changes for the oil to clear up. It takes suprisingly little water to turn oil gray.