HELP water mixing with oil

[lee22]

Hi guys. Am having a bit of a nightmare. Ive just got into trails and i bought a 2002 gas gas 250 pro privately last week. On bringing it home i realised there was a few problems with the bike. I noticed on the oil level bubble glass that the oil was light brown in colour. I took the casing off to see it was cracked at the water pump. I got a new casing and thought my problem was sorted, but started the bike up and took the bike a spin round the house, to start off the thermostat blew off and there is still water getting into the engine. Ive took the water pump apart to find the impeller has stripped the threads of the shaft. Going to order a new impeller and water pump seal to see if that stops the water getting into the engine. If anyone could give me any help or advive i would be greatfull.

Thanks

Lee

[jse]

Hi guys. Am having a bit of a nightmare. Ive just got into trails and i bought a 2002 gas gas 250 pro privately last week. On bringing it home i realised there was a few problems with the bike. I noticed on the oil level bubble glass that the oil was light brown in colour. I took the casing off to see it was cracked at the water pump. I got a new casing and thought my problem was sorted, but started the bike up and took the bike a spin round the house, to start off the thermostat blew off and there is still water getting into the engine. Ive took the water pump apart to find the impeller has stripped the threads of the shaft. Going to order a new impeller and water pump seal to see if that stops the water getting into the engine. If anyone could give me any help or advive i would be greatfull.

Thanks

Lee

The video for the Pro W/P repair at http://www.trialspartsusa.com/youtube.html should help you. On a 2002 model you should probably replace the W/P shaft also.

Not sure what you meant by the thermostat blew off, but make sure the overflow tube off the radiator is not pinched by the underside of the fuel tank.

Jon

ps.Just remembered something else (when I posted the above, had just got home from a long 2-day event). If the small brass plug on the side of the pump has an Allen type center, you probably should replace it with the updated bushing (it is the outer support for the impellor shaft) that will have a Torx type center. Also check the W/P shaft where the seal lip rides with your fingernail to feel if there is a groove there and if you find one of more than a slight indentation, you probably want to change the shaft to the newer type. If you don't replace the shaft the new seal lip will ride down in the groove and contact tension will be lessened and the seal's service limit will be decreased considerably. The fingernail is surprizingly sensitive to small depressions/scratches on surfaces and is good for finding pits/cuts on fork tubes that are easy to overlook with the eye. I updated the pump on my 02' Pro with the newer parts years ago and have not had a problem since.

ps, ps (still waking up....) There is a very thin o-ring on the pump housing to keep oil from weeping from the trans. Be sure to grease the o-ring and put a little on the housing (and don't forget to index the pins on the W/P shaft to the slots on the crank primary gear). Carefully install the W/P housing in straight in order to not damage the o-ring, which is relatively simple without the hoses attached. If the hoses are attached, they will pull on the the right side of the housing a little and the pump will be canted so you will want to push a little on the left side of the housing and pull a little on the hoses to keep the pump straight while it slides into the sidecover. If you just push the pump in and it's not straight, when the o-ring (which is very thin) slides past the first part of the machined bore of the sidecover, it will shave/cut off part of the o-ring and cause oil weeping around the W/P eventually.

O.k., now I think I'm done......

Edited October 25, 2010 by JSE

[lee22]

Hi Jon, thanks for help. Ive ordered a new impeller and seal today and i will check the w/p shaft tonight. When i first saw the bike it looked in really good condtion but it probably hasnt been serviced in years. God knows what the rest of the engine is like. If i can sort the water problem out i`ll start taking off the barrel and hopefully theres no suprises. Also noticed that the fan never came on when it had been running for a while so i`ll check it to. The joys of buying a old bike. Am just getting into trails and didnt want to spend to much on a bike. Lesson learnt. Thanks again for your help, i`ll let you know how it goes.