It seems i'm struggling every step of the way with this 73 MX250. I have a new crank seal, the one linked to here:



But for the life of me, it just won't go in evenly. I'm using a length of 2" capped pvc tube to drive it in but it just won't seat. After attempt #10 the seal is warped so I ordered another one.

I even put it in the chest freezer for a few hours beforehand. 

I'm all out of tricks, is there something i'm missing??

I've used my tusk crankshaft puller / installer to press the seal in, worked great if you have one
I have also used the PVC pipe with a PVC threaded pipe adaptor which has a nice shoulder, this worked too.

If you grease or oil the seal & the case it should go in without too much resistance. If you use a good solid flat steel plate with hole & a steel tube to drive it, then if it starts to go crooked just concentrate the pushing over that side to straighten it. Sounds easy--in theory--but not always the case.

What is everyone's vote on whether to put a light coat of black RTV or yamabond on the outer surface of the new seal? The metal mating surface has some slight imperfections and some irregularities that I can feel with my finger so I just want to be sure we're air tight.

Just replaced the left side crank seal on my DT2 last Sunday;

www.yamaha-enduros.com/index.php/forums/...-dt2?start=60#151628

I applied a generous amount of 2 stroke oil to the inner circumference of the seal after thoroughly cleaning the crank and seal seat. I installed the seal with the outer surface dry (no RTV or Yamabond), pushing it in as far as I could with my thumbs, getting it as square to the case as I could tell. I then slowly tapped it in using a small block of wood and a hammer working my way around the seal a little at a time. I was working it on the outside edge of the seal until it was just flush with the case. 

Alright got her seated with the following method:

1) Put seal in chest freezer (0 deg F) for a couple days

2) applied thin black rtv to outer mating surface of seal (very thin, only because of the imperfections in the case)

3) pushed in square as far as I could with hands

4) put metal plate with hole over crank

5) tapped in with 2" steel conduit and 3lb mini sledge hammer

   

I'm of the opinion applying the RTV is a mistake .
When I was young ( and dumb ) , I rebuilt my RD 350 engine , and RTV'd the seals outers .
During a race the countershaft seal popped out , lubing my chain and then tyre , until I discovered
" where the rubber left the road " .
On an RD the crankshaft seals have retaining lips , possible with horozontally split cases , so they wouldn't pop out ,
but in your case , you have provided a medium to allow the seal to do exactly that .

It's not backwards is it?

Yours appears to be in opposite of how I installed mine.

The plot thickens...

Here in the parts diagram it appears that I installed it correctly:

 

Anyone else want to help solve this?