Hi there and best regards to everyone!
it has been many moons since I was last on this website. I wonder if anyone has some very good suggestions regarding the subject of safety removing the armature from the left side of the AT-1 models.
   I had a crankshaft seal literally blow out of place while I was out for a ride and the bike suddenly lost all power and was belching great clouds of blue smoke out the exhaust.
  When I removed the clutch cover for a closer inspection, I was rewarded with being able to clearly see the seal that gave up the ghost, so to speak.
  I removed the old seal and replaced it with an NOS factory replacement and reassembled everything and the bike started up immediately and idled normally. My biggest concern is that if the right side seal went “kaflooey” the way it did, I reasonably expect that the left side crankshaft seal is not far behind.
  I’m pretty good with these engines on the whole, but, before I do more harm than good, I would greatly appreciate any recommendations or ideas or perhaps some insight as to what the best way would be for me to remove the armature safely. 
  In the event that I were to damage the armature during the removal process, I have a few of them in my personal parts inventory. I would prefer not to damage anything, but, I am very keen on replacing the left side crankshaft seal.
  I would be most grateful for any assistance and sound advice!

    Many thanks in advance,
                                             Bob

M10 Fully Threaded - 70 mm - Hex Head Bolt.

Chances are very strong
you’ll need to order it through JEGS.

asco

 

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This eBay seller has them, eBay . . . . . Item number:  381789688313


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K&L Supply 35-5942 (old number YM-01111) is what I use.  They used to sell them on ebay.  I don't see them anymore.  I spoke to them in the past and they were very nice so you might try contacting them.

RT325 posted a picture and dimensions of original Yamaha puller bolt...  seems to be gone now.

P.S.  Enduronut posted a good link while I was searching for the K&L

 

Looks like the pic i put up at some stage. Pushes from the base of the hole

photos.app.goo.gl/xua5BzW6jinppUvc9

I have a posting for this exact item in wanted and for sale. Removes the armature with no issue (I have an AT1). PM me for purchase.

will the threads work for the AT1.  I thought I read that the pitch is different.  I think I need M10x1.25.  thanks!

I recon whatever the pitch is it will be the same for all armatures on all models. Yamaha wouldn't change things like that between twin or single cylinder with the essentialy the same or similar starter dynamo. Unless ya talking magneto like my AT1 which is 27x1 left hand thread.

The M10x1.25 will remove the armature on the electric start AT1's. I have an AT1 and removed the armature for LH crank seal replacement.

The link Enduronut originally had listed was good but seller that was making them had no way to buy them.  

Enduronut updated his post to show K&L is selling them on ebay again. That's the one I use and mentioned in post #4 (It is 10 x 1.25)



Link to puller on ebay