Hi all,

I have just been out on the bike and after about an hour it began to run lumpy. It would not come down off the revs and when it did it sort of chugged instead of ticking over smoothly.

I loaded the bike up immediately and came home, expecting it to be a dirty carb I stripped it down but all was clean. Anyway on further inspection the bike has dropped all its coolent with no obvious signs of leak, so I drained the gearbox oil to find the oil was milky.

This leads me to beleive the seals have gone on the water pump? if this is right is it a major job to sort and expensive and could this/has this caused any other damage?

The bike is a 2002 290,

Thanks in advance guy's.

Have a look on splatshop they will probably have the parts in stock.

I'd flush the engine through now with some cheap oil to make sure you got all the coolant out.

Thanks, but would that cause the lumpy running?

As the coolant bleeds into the clutch/gearbox, less coolant remains to cool the engine until the engine begins to overheat causing your lumpy running.

Easy to fix, impeller casing off, side casing off, change the faulty seals and it's worth changing the impeller shaft while it is all apart as the seals often wear a small ridge in the old shaft.

Flush gearbox/clutch several times with cheap oil until it comes out the same colour as it goes in. Then put in the good stuff.

Not too expensive to rectify, parts

As the coolant bleeds into the clutch/gearbox, less coolant remains to cool the engine until the engine begins to overheat causing your lumpy running.

Easy to fix, impeller casing off, side casing off, change the faulty seals and it's worth changing the impeller shaft while it is all apart as the seals often wear a small ridge in the old shaft.

Flush gearbox/clutch several times with cheap oil until it comes out the same colour as it goes in. Then put in the good stuff.

Not too expensive to rectify, parts

Hummmm, an '02 model should not leak coolant into the gearbox side unless the drain(veny) hole between the two seals is sealed shut!

Doubt it would run well overheated

Edited March 13, 201115 yr by copemech

Priced it up and yeah comes to around

Edited March 14, 201115 yr by markieboi

So the question is it really nessacery to change the shaft?

The reason I ask is I'm getting a new bike in a month or so and I plan to break this one anyway so basically it's just to tide me by.

I've done this job a few times now .... Each time I've found the shaft was scored and needed replacing.

One time (in desperation) I tried to reposition the seal so it would not sit on the score. But it still leaked (straight away) so I wasted my time, still had to buy a new shaft and do it all again.

Best of balance.

Neo

I've done this job a few times now .... Each time I've found the shaft was scored and needed replacing.

One time (in desperation) I tried to reposition the seal so it would not sit on the score. But it still leaked (straight away) so I wasted my time, still had to buy a new shaft and do it all again.

Best of balance.

Neo

Thanks Neo,

That's answered that one then.

Hi, I had this on a mates sherco and to save some pennies I ended up putting shaft in lathe, clocking it and machining it down a little, then made a stainless sleeve to near original outer dimensions. I made the I.D with a slight interference fit (couple of thou) to the shaft, then heated the sleeve and chilled the shaft, then pressed the two parts together and finished with emery to final O.D back in lathe.

Bike has done 18 months now, regular use and no probs. So if you've got a lathe, or a friend with one or one at work or a friendly local engineering shop etc and an off cut of stainless, you to could save some pennies!

It all comes down to the time/money scale!

This is interesting feedback.

I tried to have the same thing done to my old shafts. But my fabricator friend my was concerned that the sleeve would not be hard enough compared to the original metal surface. But I'd guess that 18 months speaks for it's self ....so long as you don't have to pay more than

This is interesting feedback.

I tried to have the same thing done to my old shafts. But my fabricator friend my was concerned that the sleeve would not be hard enough compared to the original metal surface. But I'd guess that 18 months speaks for it's self ....so long as you don't have to pay more than £48 for the job.

Best of balance.

Neo

Was thinking about this very thing. Seems the shafts are standard soft steel(thus the wear) and the stainless alloy would work fine. The time vs money thing is the prob!

Still do not understand why his drain hole was not working?

Edited March 16, 201115 yr by copemech

The drain hole regularly gets rammed full of mud and with the heat of the engine it bakes in hard, it's had 9 years to get properly bunged up so I wouldn't worry about it to much.

The water pump shafts have changed a few times since the originals and they are definitely of better quality now.

Was thinking about this very thing. Seems the shafts are standard soft steel(thus the wear) and the stainless alloy would work fine. The time vs money thing is the prob!

Still do not understand why his drain hole was not working?

When I got the casing off it was like splatshop says, just absolutely full of mud and crap. Luckily enough when i got the shaft out it hadn't scored, but there was play in the bearing so changed that too.

Fingers crossed that'll be it, and thanks for all the help guys.