Did my crank seals die of old age ?

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#46 Post by **smurph** » Fri May 11, 2007 12:33 pm

Remember to put anti-seize compound on the case bolts when you put it back together. This will prevent this from happening in the future.

Steve

daves500lc · #47 Post by **daves500lc** » Fri May 11, 2007 1:55 pm

What you need is an allen key adaptor for an impact driver or failing that cut off an allen key straight and turn it with an adjustable while somebody hits the allen key on the end with a hammer. This usually works as the allen head bolts tend to sieze on the head end and the shock is enough to loosen them. This worked well on the bolts holding the disks on as they are shallow and slip very easy. Hope this is of use in the future.
Dave

ross · #48 Post by **ross** » Sun May 13, 2007 4:58 pm

Well... I took the block to the bike shop I've used for 30 years and spent an hour with the owner trying to get those allen bolts out. Eventually... a lot of heat and me holding the block down while we tried to undo the bolts and... eventually... they let go their grip.

One was just flippin' tight and the other... the base gasket had been leaking and the bolt had rusted... not the threads fortunately, but enough.

Both bolts are scrap now of course, but at least it's all in bits now.
And finally... finally... I get to the oil seals that started this whole thing !

Next step... cranks and barrels off and then start putting it back together.

Ross

ross · #49 Post by **ross** » Sun May 13, 2007 4:59 pm

smurph wrote:Remember to put anti-seize compound on the case bolts when you put it back together. This will prevent this from happening in the future.

Hmmm... I've never heard of it. What's a good brand ?

Shaftoflame · #50 Post by **Shaftoflame** » Sun May 13, 2007 7:26 pm

Ordinary oil works, or coppaslip, vaseline - pretty much anything that will stop corrosion - particulaly electrolytic reaction between the steel bolt and the ally case - extra important if you uses stainless.

R

ross · #51 Post by **ross** » Tue Jun 05, 2007 11:50 am

Still waiting to get my barrels and cranks back (don't ask), and I was wondering.

When it came to taking the nuts off the flywheel and the clutch, we used an air gun. Seemed all very civilised. However... when you come to put things back on, how do you hold things in order to do the nuts up to the correct torque ?

Thanks

Gary Papesh · #52 Post by **Gary Papesh** » Tue Jun 05, 2007 9:10 pm

ross wrote:
smurph wrote:Remember to put anti-seize compound on the case bolts when you put it back together. This will prevent this from happening in the future.
Hmmm... I've never heard of it. What's a good brand ?

Ross,permatex makes an anti-seize compound which works great.It has molybdenum disulfide and other secret ingredients.looks like silver grease with fine aluminium powder in it. I sure wish Yamaha used it back in the day,those allen bolts are prime candidates.

cb4265 · #53 Post by **cb4265** » Thu Jun 07, 2007 1:21 am

WURTH do a fantastic anti sieze type product called HSP1400.

It is a non metalic semi synthetic anti seize that works with different metals and prevents gauling when stainless steel is present.
Temp range of the productis -40 - +1400* degrees celcius.

I have used it extensively all over my restoration, due to the multiple different metals and alloys encountered on our motorcycles.

It is a spray that is light grey in colour, and blends nicely into aluminium.

http://www.wurth.com.au/catalogueview.a ... 4_0509.pdf

Hope this helps. You will have to locate a Wurth rep in your individual countries, there is normally one quite nearby.

Craig

ross · #54 Post by **ross** » Sun Jun 10, 2007 7:08 pm

Hey !

I'm so glad I sent my cranks off to be checked when I took my engine apart to replace the crank seals, and discovered that my rear pistons had seized.

If I hadn't, I would never have discovered that in the 20 years of standing, the roller pins in the crank bearings had rusted and, in turning the engine over, had done for the conrods.

My... I'm so pleased I found that out.

the doctor · #55 Post by **the doctor** » Sun Jun 10, 2007 10:51 pm

Aren't you glad you took my advice and had them things checked??!!

lol. Are you having fun yet?

ross · #56 Post by **ross** » Mon Jun 11, 2007 6:48 pm

the doctor wrote:Are you having fun yet ?

Occasionally...

Hopefully, this is my last problem. There I was, thinking that as I had the thing stripped down as far as I have, I would replace the gearbox output shaft seals and check for any problems in the 'box.

So... I undo all the allen bolts (some mighty corroded) and see the bit in the book that says "Caution: line up the star-shaped thing with the protrusions on the case". So... that's what I did. Then... bit of pine and a hammer and some gentle tapping (man... I hate using a hammer on an engine), the cases split.

The cases start coming apart and then stop. Hmmm... so I tap the cases back together and take a look at that star-shaped cam do-hickey again. It hasn't moved, each point lines up with a raised part of the casing. I look at the exploded diagrams and it seems that the shift cam shaft comes out with the star-shaped bit. So I turn it a bit so it's not lined up with the cases, and start again.

Tap... tap... tap... check. Looks good. Then it stops moving. I turned the engine around and give the cover a little tug and it's loose. A little gentle tug and a something big and heavy inside goes "thunk !".

Ooops...

No choice now - it's coming apart. So... there's enough room to get my fingers in and support the shafts while I gently remove the gear-box cover. It comes away cleanly... and leaves all the shafts in the case...

I'm sure that's not supposed to happen. All the pictures show the shafts on the cover

So, I stick my hands in the cases and hold as much of the internals as I can, and gently ease the shafts out and gently put them on the bench.

I can't see anything amiss, hardly any wear anywhere. No apparent rust !

So... once I've put the new seals in, hopefully it all goes back together easilly. However, never having had a gearbox apart, I guess the manual is clear about how you put it together in neutral ?

And finally... did I do a silly thing ? The manual is really not clear about what you line the star-shaped thing's points up with.

Ross

Luther · #57 Post by **Luther** » Mon Jun 11, 2007 7:32 pm

From what I remember the casting is shaped so the star will only fit through with gearbox in neutral. Its normal to have to use a mallet on shaft ends to get the case sealer to seperate so the gearbox cassete case will come out. Since you've got the gearbox out you might as well pull out the 2 shafts that the forks slide on and inspect for wear. Pull the shift drum out to test fit it through the casting and you'll see it only fits one way. You should assemble the cassete gearbox and fit it back in the case once or twice just to be sure you've identified all the shims and that it has some shaft endplay. Its in neutral when the sliding gears are in thier middle positions and the shafts spin freely from each other.

ross · #58 Post by **ross** » Wed Jun 13, 2007 5:16 am

Luther wrote:From what I remember the casting is shaped so the star will only fit through with gearbox in neutral.

Well... I thought that might be the case, but it would seem that if I offer up the selector cam to the case, that star-shaped bit goes through the hole six ways. In fact, before I took the inards out, the shift roller arm was resting on the pointy bit that has the top missing. I took this to be neutral, but in that position the star's points don't line up with the cut-outs on the case (and hence my original mistake getting the shafts out).

What if I built up the shafts into the gearbox cover, and take my neutral position from the neutral lamp switch ?

This may be obvious, but can the selector forks only go in the box one way ? I haven't taken them off the shaft (so they're still in the correct orientation with respect to each other, and numbered 1-3), but, while I've been careful, I'm worrying that I'll get the shaft in the box the wrong way around.

Of course, when I put this lot back together, I may find that it will only go back one way... or maybe not.

Thanks,
Ross

steve · #59 Post by **steve** » Wed Jun 13, 2007 9:50 am

As someone who has done this several tines recently - never one to get it right first time

- the gearbox will always go back together with the notch representing neutral position. make a note of the numbers and position of the three selector forks - and it should always go back correct - just leave that hammer in the toolbox.

Steve

ross · #60 Post by **ross** » Sun Apr 27, 2008 5:29 pm

My, has it really been so long ?

Things are going back together, and my little piles of new bits are getting smaller. Clutch back on today. I've never rebuilt a clutch before. My word, that workshop manual is hardly clear on the topic. Does it really matter where the springs go, so long as the last one is the only one lined up with the two dots ?

The motor's back in the frame, and I'm moving on to the flywheel shortly.

I must get this finished before the classic bike meet at Chimay this summer.

Ross

500 Two-Stroke Tech

Did my crank seals die of old age ?

I'll hold the hot air gun, you hit it...

Nevr"Seez

This is as far apart as it gets !