Need opinions on a clutch shaft oil seal puzzle ???

[Wallowgreen]

This is on a 1980 GS250TT my son and I are trying to restore. We've come a long way already believe me to get to a point where we can turn the motor with the starter. Now we can do that, we've noticed an oil leak dripping out the bottom of the transmission cover towards the front. Taking the cover off revealed a right mess we had to clean up before we could even see clearly enough to track down where the oil was coming from. Turns out it's from the clutch rod seal. Looking at the fische part #17, it seems the seal consists of a rubber seal at the center of a metal insert that fits into the engine casing.

First part of the puzzle is I'm convinced the oil is leaking from around the metal part of the seal where it sits in the casing rather than the rubber part at the center. Does anyone know if that's a common occurance?

Biggest puzzle though is there seems to be a retaining plate completely missing but even if I get one I'm not sure how it would fit. Seems the casing is not predrilled to accept the mounting screw/bolt. This has me confused and am wondering if the seal has actually failed (which wouldn't surprise me) or whether the seal retaining plate is required to correctly provide the seal. However, the only boss in the casting that seems about in the right place to accept the mouting bolt for the retaining plate is not drilled or threaded

If I have to replace the seal, how do I get the old one out? Do I really have to split the casings just for that? There seems to be very little information about that in the manuals and I have both the workshop manual and the haynes for this machine.

So you can see what I'm wittering on about, here's a picture of the offending area with some annotations trying to point out what I've seen:



And the fische, the "missing" part is #24, seal is #17:



Thanks for looking.

[psyguy]

I dont think you have to worry about that retaining plate as all the clutch rod seals that i've seen look exactly like the one in your picture and never have that plate.

yes, it is possible to have a leak around the perimeter of the seal rather than its centre. a new seal + some silicon on the seal housing should fix the prob.

to pull the old seal out people sucessufully use two self drilling screws drilled into the oposite sides of the seal and pull it out with pliers

[psyguy]

ps. that plate might be inside the casings ?

the orientation of the screw #25 in the pic would suggest so!

[Wallowgreen]

ps. that plate might be inside the casings ?

the orientation of the screw #25 in the pic would suggest so!

Dunno, maybe, but it is shown towards the outside of the seal which is why I thought it was on the outside of the casing under the cover.

[rustybronco]

What is the composition of the round disc where it's leaking from? aluminium?

[Wallowgreen]

What is the composition of the round disc where it's leaking from? aluminium?

Seems to be aluminininium with a rubber insert in the center for the push rod and from what I could see by cranking the motor whilst watching, the leak was from around the outside of the aluminum disc where it mates with the engine casing.

I've found a picture of the retainer plate in my haynes manual at last. It does indeed bolt down to the two bosses in the picture (one below the clutch push rod and the other to the right of the layshaft) that are not drilled and tapped. I guess there could never have been one. Just hoping the seal isn't a flanged type, doesn't look like it from the fische and there's no mention of a flange for the 250 motor only the 450's. I'm going to order one and see what it looks like before I proceed.

[rustybronco]

Seems to be aluminininium with a rubber insert in the center for the push rod and from what I could see by cranking the motor whilst watching, the leak was from around the outside of the aluminum disc where it mates with the engine casing.

It sounds like they may have three bonded it in place when the two case halves were put together. no worries... if it's aluminum you can always drill and tap it, then carefully slide hammer it out.

[GregT]

I've seen the twins both with and without the retainer plate - depends on the market/version.
More typically they leak from the center - I've seen worn pushrods which were just peeing it out.

Greg T

[BassCliff]

Hi,

Here's something I've collected. Have a look here and see if it offers any insight...

http://members.dslextreme.com/users/storagecliff1/images/Gearbox_Sprocket_Oil_Seal_Replacement_GS550.htm

Thank you for your indulgence,

BassCliff

[DimitriT]

Here's another thread which might help.

I go through the process I used on m 550 (which had the plate, BTW):

http://www.thegsresources.com/_forum/showthread.php?t=151182&highlight=clutch+pushrod+seal

[Wallowgreen]

Thanks for the input chaps, all good information.

Kind of what I had in mind to drill the existing and hope to pull it out with something, was going to try my trusty pliers as psyguy mentioned. Might give in though and see if I can find some kind of puller tool to add to my collection.

I've got an OEM seal already on order with a piston set and o-ring seal to rebuild the front brake system. I'll wait until that gets here and examine the new one before I finally tackle taking the old one out. Hopefully that will increase the confidence somewhat further when I can examine the new one.

Think I cleared up the mystery of the retainer plate though for those interested. I have both the haynes manual and the suzuki workshop manual for the machine. The haynes manual supposedly contains a pictorial description of the 250 motor tear down and rebuild but does cover 400 twins as well. I found a picture in that showing the retainer plate mounted to the two bosses in the photo I posted that are not drilled or tapped (one under the clutch push rod, the other to the right of the layshaft). Searching further I found a different picture in the suzuki manual (which only covers the 250) of the same area in which there is no retaining plate and those same two bosses are left undrilled, just like mine. I assume from that the haynes manual is either in error or the retainer is only used in europe or something. Either way I'm now convinced this machine just should not have one so I can sleep easy again!

[Wallowgreen]

Long post, sorry, but the plot thickens. To reiterate, this is on a 1980 GS250T I'm trying to restore...

I ordered a replacement seal as shown on the fische in the first post, here's a picture of it:



A shot showing the original seal before removal:


Here's the original stuff that came out and a right bugger it was to get out. Threads from others that have replaced this seal talked about drilling to the side of the push rod, screwing in a self tapping type screw then pulling it out with pliers. Let me tell you there was no way on earth I could drill this stuff. The washer part broke two drill bits whilst only skating around on the surface and when I tried to drill the rubber part around the rod, it disappeared into the cavity behind. In the end I had to pick enough of the center rubber part out to get the smallest hook on my slide hammer in far enough to get behind the washer, two swift whacks later and the washer was on the floor somewhere off in the distance. The washer was a press fit, is 4mm thick and is chamfered around the circumference to mate with the bore in the casing:


Measuring the metal washer part of the old seal, it was 32.44mm diameter at it's widest part, the new seal was only 31.31mm and square at the circumference, a difference of 1.13mm. Hmm. When fitting the new seal, I coated the outside surface with permatex hoping that would be good enough to seal the seal if that makes sense. Pressed the new seal in with just finger pressure which didn't seem right, was hoping it would feel tighter than it did, interference fit at least somewhere in the bore. Anyway, pushed it in until the outside face was flush with the casing and left it overnight. Next day we fired the engine and watched, for about 10 seconds we watched and all was well. Then the oil seal blew out under the pressure and oil pumped out. I didn't realise there was going to be that much pressure behind there. Since then I've seen a post from Nessism stating there was a rather high pressure behind this seal on a 450 he was doing the same or similar job on. If I'd have seen that first I probably wouldn't have even tried the permatex without something else intended to retain the seal.

Now we get back to the original question in the thread. There's a retaining plate shown on the fische but my engine casing is not drilled or tapped to accept the mounting bolts. I've ordered the plate and original bolts from the fische as I'm intending to do a "modification" and fit the retainer. I am concerned still that with 1.13mm tolerance between the seal and bore, permatex might not be up to the job. Anyone got a better suggestion? So called motorcycle mechanic guru's round here suggested JB weld which might work but what if I need to replace this seal again? I asked at the dealers but I had more interest and certainly a far more viable response from my mother when I mentioned it to her. Idiots!

The manuals I have for the machine are contradictory, the suzuki workshop manual shows these pictures. The bottom two at the right on the first page and the top one on the second page clearly show the area with what looks like a black seal without any retainer plate:



In contrast, here's a picture from my haynes manual for the same machine which clearly shows there is a retainer plate:


Now I'm wondering if I have the right seal or whether a service bulletin was issued for a modification from what was original on my machine to the new type seal with retainer plate.

A similar set up is used on the 450 twin engine but they have a different part number for seals that use the retaining plate to those that don't. The 250T parts list only lists one which seems to be for use with the retaining plate. Confusion reigns!

I'd appreciate any suggestions on a way forward, especially from those that may have done this before and come across similar issues.

Anyone???.....

[chef1366]

Do you have the bolt holes for the retaining plate?

[bwringer]

Haven't seen this before, but personally, I'd source a seal that fits correctly from a seal supplier. You'll probably have the best luck finding a seal to fit in that metal disk.

This is a place near me (located in a suburb just north of Indy) where I've gotten several metric seals I didn't feel like waiting for:

http://www.metric-seals.com

I don't know if there's a similar place near you, or if Metric Seals will work with you over the phone.

Also, McMaster-Carr has a limited selection of metric seals and a lot of inch size seals:

http://www.mcmaster.com

Or perhaps you could visit an old school auto parts store, like CarQuest or Napa, and see if they can help you.

[Nessism]

Sounds like the seal will work as long as you can keep it in the hole. You obviously need to fashion some sort of plate to fit over the seal like the OE plate. That boss on the crankcase could be drilled and tapped pretty easily. Using JB Weld is also a good idea. Epoxy's like that break down pretty easy with heat so I wouldn't worry about getting it off again some day - a quick hit with a propane torch or a heat gun will allow you to remove the plate.

Guess I'd wait until the OE plate you ordered comes and then figure out the best way to attach it to the engine. Shouldn't be too hard.

Good luck.