DT125R ARCHIVE

stomper · DTR Member

water in the gearbox AGIAN

dtrdave · DTR Senior Member

stomper wrote:

Hi guys back to the same problem of water getting into the gearbox this is the second time i have just replaced the impeller seal and was ok for 100miles but it started to overheat and lose water out overflow any ideas thinking the thermostat stuck closed and boiled up or head gasket its my daughters boy/f bike he got it 2 months ago and think he got stunk as it had water in box from day 1 thanks stomper

You can test the thermostat by putting it into boiling water to see if it opens.

When you replaced the waterpump seal did you fit the new one the right way round ?
Was there any pitting on the impellar shaft ?

I'm thinking you have two seperate problems!
If the headgasket goes,pressure from the cylinder will get into the waterways which will cause the water to be pushed out of the expansion bottle overflow.

Pretty sure that the only way water can get into the gearbox is through the waterpump oil seal.

dtrdave · DTR Senior Member

Just looked at your other post on this...

Looks like you just replaced the whole clutch cover from another bike ? Assuming this was also second hand ?

The waterpump seal only costs £4.50 (or £10 genuine yammy) and isn't hard to fit...

It's completely pointless fitting second hand used parts like this as they will more than likely be on there way out anyway.
Go order a new seal and renew the headgasket! (Depending when it was last done it would be worth replacing the piston and or rings while your on.)
Changing the thermostat won't do any harm either as there also cheap.

-- Edited by dtrdave on Saturday 7th of August 2010 05:13:52 PM

stomper · DTR Member

dtrdave wrote
Just looked at your other post on this...

Looks like you just replaced the whole clutch cover from another bike ? Assuming this was also second hand ?

The waterpump seal only costs £4.50 (or £10 genuine yammy) and isn't hard to fit...

It's completely pointless fitting second hand used parts like this as they will more than likely be on there way out anyway.
Go order a new seal and renew the headgasket! (Depending when it was last done it would be worth replacing the piston and or rings while your on.)
Changing the thermostat won't do any harm either as there also cheap.

-- Edited by dtrdave on Saturday 7th of August 2010 05:13:52 PM

yes i did replace the clutch cover as it had a bit taken out and fitted new yamaha impeller shaft and £28 seal £12 the seal has water side out on it so i know it was in the right way

satelliteone · DTR Senior Member

how about the cover gasket, is it sealing ok? like was said above, if the head gasket goes pete tong, then adverse pressure build up in the cooling system, will push past the seal, and then enter the gearbox.

very typical problem for a dtr. use only genuine head gaskets.

stomper · DTR Member

Thanks satelliteone yes i think this is the problem it has a lot of pressure build up so am going to rip it down and do the gaskets and have a look what about skimming the head good idea or bad i used to do the old TS DT two stroke on a sheet of glass and fine cutting paste but they were air cooled any pointers cheers

Dickhead · Nonce

i have used this method with glass and 240 wet and dry with good results

stomper · DTR Member

Hi Got the head off and it looks like the gasket had gone and was compressing the water jacket also the combustion chamber looks like the roads down here full of holes and chunks missing cheers stomper