Water Pump Part Mystery

Riding last weekend I discovered large amounts of fluid leaking from the water pump area. I suspected a gasket or something, but instead I discovered a tiny hole underneath the waterpump, but on the crankcase side.

I was shure it was a bolt that had fallen off. Probably the draining plug I thought...

Back home I tried to find the part in the Yamaha OEM parts catalogue. This should list every part on the bike down to the washer. Right?

But to my sursprise I could not find the part in the catalogue.

I've been trying to fit an M4, M5 & an M6 bolt but it won't fit. M4 seems to be the closest, but it is to small.

Does anybody know what this hole is all about? And why is this part a non existing part if I look an the Yamaha spare parts catalougue? I own a 99' 250.

An overview of the water pump: http://www.cmsnl.com/yamaha-yz250l1-1999_model10775/partslist/A-09.html



thats a weep hole to let you know when your seals around the water pump are bad. if coolant comes out its the seal for the water pump side and if its oil its the seal towards the crankcase side. DONT try to put a bolt in there the hole is there to tell you when you have to replace a seal. sounds like you need to get your water pump seal replaced now. its an easy repair

go here and put your yeam and make in and check out the microfiche and youll see the seals i looked at a 06 model under the water pump and it shows a pic couldnt get it on here but heres the link, looked at that link and its the same as the one i saw #4 is your waterpump seal and #5 is the oil seal. if thats your model then you need to replace seal #4

Thank you very much for pointing me in the right direction! A couple of hours

of work and the problem is solved. The Yamaha Dealer even had the oil seal on the shelf. Talk about lucky. Looks like I'll be riding tomorrow after all!:ride:

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