Prev: Round 5, FOAK: 1982 Kawie KZ550 C3 LTD Restoration Options
Next: Do you beleive these stats on Battery Voltages?
From: Nagarjuna's Cataskoti clawed me! on 15 Nov 2009 14:35
On Nov 15, 10:57�am, Bill Smith <squand...(a)comcast.net> wrote:

> Take the clutch cover off and remove the clutch. Behind it you will
> find a flat ring that's attached to both the upper and lower cases
> with three screws (this helps axially locate the transmission main
> shaft bearing), once you remove it (and the alternator along with it's
> cover, of course) you can split the cases. With both pistons at mid
> stroke you can lift the crank enough to replace the seals. When you
> drop the crank back in, make sure that the little locating �bumps on
> the bearings are in the recesses machined for them in the cases along
> the parting line.

What about the labyrinth seal between the two crankshaft halves?

Does it ever wear out and leak air back and forth between the two
crankcase sides?

From: Vito on 15 Nov 2009 17:28
"Bill Smith" <squandary(a)comcast.net> wrote
| Take the clutch cover off and remove the clutch. Behind it you will
| find a flat ring that's attached to both the upper and lower cases
| with three screws (this helps axially locate the transmission main
| shaft bearing), once you remove it (and the alternator along with it's
| cover, of course) you can split the cases. With both pistons at mid
| stroke you can lift the crank enough to replace the seals. When you
| drop the crank back in, make sure that the little locating bumps on
| the bearings are in the recesses machined for them in the cases along
| the parting line.
|
| This a quick and dirty (literally) way to do it, but I wouldn't
| recommend it. You must clean all the adhesive off the mating surfaces
| to insure a leak free assembly, if you don't you could have a lean
| condition and a piston seizure as a result. This is difficult to do
| with the transmission and crankshaft in place with a big possibility
| of crud in both of them after you're finished with the assembly.
|
| It doesn't take that long to do it right, these are hammer simple
| engines to work on. Disassemble it completely, inspect everything as
| long as you are in there and reassemble it clean, you'll be happier.
| Doing it right once is much quicker than having to do it twice.
|

This fits my recollections.

The man who tuned our TZ engines believed that at least some seal problems
were caused by worn main bearings that let the crank move up, down &
sideways in the seals so he recommended replacing the bearings and both the
end and mid seals whenever changing any of them. They used to be cheap from
a bearing supply house if not from Yamaha.


From: Pender on 15 Nov 2009 19:25

"Vito" <vito(a)cfl.rr.com> wrote in message
news:4b008070$0$4953$9a6e19ea(a)unlimited.newshosting.com...
> "Bill Smith" <squandary(a)comcast.net> wrote
> | Take the clutch cover off and remove the clutch. Behind it you will
> | find a flat ring that's attached to both the upper and lower cases
> | with three screws (this helps axially locate the transmission main
> | shaft bearing), once you remove it (and the alternator along with it's
> | cover, of course) you can split the cases. With both pistons at mid
> | stroke you can lift the crank enough to replace the seals. When you
> | drop the crank back in, make sure that the little locating bumps on
> | the bearings are in the recesses machined for them in the cases along
> | the parting line.
> |
> | This a quick and dirty (literally) way to do it, but I wouldn't
> | recommend it. You must clean all the adhesive off the mating surfaces
> | to insure a leak free assembly, if you don't you could have a lean
> | condition and a piston seizure as a result. This is difficult to do
> | with the transmission and crankshaft in place with a big possibility
> | of crud in both of them after you're finished with the assembly.
> |
> | It doesn't take that long to do it right, these are hammer simple
> | engines to work on. Disassemble it completely, inspect everything as
> | long as you are in there and reassemble it clean, you'll be happier.
> | Doing it right once is much quicker than having to do it twice.
> |
>
> This fits my recollections.
>
> The man who tuned our TZ engines believed that at least some seal problems
> were caused by worn main bearings that let the crank move up, down &
> sideways in the seals so he recommended replacing the bearings and both
> the
> end and mid seals whenever changing any of them. They used to be cheap
> from
> a bearing supply house if not from Yamaha.
>
>
I once seen a rather full bodied wild turkey blown cleanly into a Clorox
bottle during a hurricaine and it didn't even hurt the turkey.


From: Bill Smith on 15 Nov 2009 20:49
On Sun, 15 Nov 2009 11:35:18 -0800 (PST), "Nagarjuna's Cataskoti
clawed me!" <macmiled(a)gmail.com> wrote:

>On Nov 15, 10:57?am, Bill Smith <squand...(a)comcast.net> wrote:
>
>> Take the clutch cover off and remove the clutch. Behind it you will
>> find a flat ring that's attached to both the upper and lower cases
>> with three screws (this helps axially locate the transmission main
>> shaft bearing), once you remove it (and the alternator along with it's
>> cover, of course) you can split the cases. With both pistons at mid
>> stroke you can lift the crank enough to replace the seals. When you
>> drop the crank back in, make sure that the little locating ?bumps on
>> the bearings are in the recesses machined for them in the cases along
>> the parting line.
>
>What about the labyrinth seal between the two crankshaft halves?
>
>Does it ever wear out and leak air back and forth between the two
>crankcase sides?

It leaks all the time, even when new, but not enough to cause a
problem since fuel air and oil are being exchanged between the two
crank cases. All the seal has to do is slow the exchange down a lot. I
always replaced them whenever I rebuilt the crank assembly.

Bill Smith




From: Lee K. Gleason on 15 Nov 2009 23:02

"Vito" <vito(a)cfl.rr.com> wrote in message
news:4b008070$0$4953$9a6e19ea(a)unlimited.newshosting.com...
> "Bill Smith" <squandary(a)comcast.net> wrote
> | Take the clutch cover off and remove the clutch. Behind it you will
> | find a flat ring that's attached to both the upper and lower cases
> | with three screws (this helps axially locate the transmission main
> | shaft bearing), once you remove it (and the alternator along with it's
> | cover, of course) you can split the cases. With both pistons at mid
> | stroke you can lift the crank enough to replace the seals. When you
> | drop the crank back in, make sure that the little locating bumps on
> | the bearings are in the recesses machined for them in the cases along
> | the parting line.
> |
> | This a quick and dirty (literally) way to do it, but I wouldn't
> | recommend it. You must clean all the adhesive off the mating surfaces
> | to insure a leak free assembly, if you don't you could have a lean
> | condition and a piston seizure as a result. This is difficult to do
> | with the transmission and crankshaft in place with a big possibility
> | of crud in both of them after you're finished with the assembly.
> |
> | It doesn't take that long to do it right, these are hammer simple
> | engines to work on. Disassemble it completely, inspect everything as
> | long as you are in there and reassemble it clean, you'll be happier.
> | Doing it right once is much quicker than having to do it twice.
> |
>
> This fits my recollections.
>
> The man who tuned our TZ engines believed that at least some seal problems
> were caused by worn main bearings that let the crank move up, down &
> sideways in the seals so he recommended replacing the bearings and both
the
> end and mid seals whenever changing any of them. They used to be cheap
from
> a bearing supply house if not from Yamaha.

Hmmm...given that, I might not want to do it myself. Anyone know a shop
in Houston that can be trusted to work on a vintage two stroke? I have
motorcycle T-shirts older than the mechanics in most of the places round
here, and I doubt most of them have ever heard of a two stroke...
--
Lee K. Gleason N5ZMR
Control-G Consultants
lee.gleason(a)comcast.net


First  |  Prev  |  Next  |  Last
Pages: 1 2 3 4
Prev: Round 5, FOAK: 1982 Kawie KZ550 C3 LTD Restoration Options
Next: Do you beleive these stats on Battery Voltages?