Forgive me if this has been covered before and I'm sure it has but can anyone tell me if the crank seals can be replaced without splitting the cases on the DT125 1977 1G0 engine.

Any experiences of this would be much appreciated.

Thanks guys

Yes bobby, remove the flywheel and stator plate for L/H side. and clutch and primary gear to see the R/H ,

That's what I was hoping to hear

She revs away when the choke is closed down so will do a vac and pressure test to pinpoint the air leak and change them if that's where it is. I suspect the L/H one as the condition improves when the cover is replaced although there was no crap or oil behind the casing when I removed it.

Thanks for the info blackhat.........much appreciated mate.

Just a quick conclusion on this one guys.

Did the pressure test and it wouldn't even pressurise so I rang my local seal and bearing merchants and they stock the seals at a fraction of the cost of Yamaha genuine parts. £6.25 inc VAT for BOTH sides.

Set to work and changed them both in about 2 hours at a steady and careful pace and pressure tested after each side. The difference is unbelievable and the bike now idles at 1500 revs and is as sweet as a nut.

She is now ready to go and will get her chance later in the week all being well.

A job I was dreading turned out to be pretty straightforward.

There is a great video guide for the right hand side which I followed and it made it really easy. Just follow it to the letter and you can't go wrong.

Well done bobby" all this info will help others in the future, ,, thats the beauty of forums , [shared info.]