i am looking at trading my 2 stroke for a crf450 but the guy who has it says that the water pump leaks a little bit, he said it leaked before and he replaced the water pump and gaskets and everything but it still leaks a tiny bit, he said he may have damaged the gasket or something when he put it back together, i dont know much about this stuff so my question is, is this an easy thing to fix or could there be more problems that are causing this???

Could be simple.. Could be a real big issue..

It really all depends on where the leak is and what is causing it.

I'd have him show me the leak. Run the bike and watch where the leak is coming from.

If it is coming from the gasket area, should be no problem to fix. However, if it's coming from the weep hole, you may have a whole other set of problems. Think warped head, blown head gasket.. and so on..

I'd say it all depends on how badly you want the 450. And how much money and time you are willing to spend fixing it.

None of it is really all that difficult to work on. But it can definitely cost some serious dollars if you are dealing with the head.

What year is the CRF450R? I have friends who all had a 02-04 450 at some time, and all of them had leaky water pumps. I all but one case, the water side seal was in backwards at the factory (3 in all). On the last one, the seals were just worn out and the water pump impeller shaft had a small groove it in. Another issue is old seals and higher pressure radiator caps. There is some talk about an impeller issue that affected the 02-04 450s and was fixed in the 05 (I think). Something about a cavitation issue and the newer ones had a small hole drilled in them to help with it. If the bike is not over heating and the coolant loss is ONLY at the leaky water pump, chances are it is worn seals and at worse case, worn impeller shaft or bearings. Not a big deal, all are mounted in the right crankcase cover (clutch cover) and can be done with the engine in the frame.

It very well could be the mechanical seal in your water pump. I have a 2000 yzf 426. It was leaking coolant when i bought it.well it all started with takeing the case cover off the nut had came off the counter balance shaft n that gear had gotten loose well i replaced the seals anyways but the impeller shaft had came out of the counterbalance shaft because of the nut that came off so i was not getting any water going through the water pump... so it was leaking now that is fixed and it runs like it should...