Carb gangplate bushing material

[Jhurt]

The carb gangplate on the early GS bikes (mine is a ‘78 GS750) has what looks to be rubber seals or grommets over the bushings where the throttle shaft rides. I don’t see a part number for replacement on any fiche. I don’t think I can remove them without destroying them...here’s my question: Has anyone used cerakote/durakote or any of the bake-on finishes on a gangplate and did this material stand up to the heat-curing process? Is it just standard vulcanized rubber or something more stout?

This bit:

[Nessism]

I thought those seals were felt?

[Jhurt]

Well they definitely LOOK like rubber. Maybe they had a felt outer covering at some point? I’m going to bake them at 300 F for an hour. I hope they hold up or i guess I’ll be looking to source some seals...

[Nessism]

You don't need seals there. Those felt rings do next to nothing.

[Cipher]

seriously you think that Yoshi the seal engineer of Hammamatsu put em there for no reason? You think maybe his family had the market cornered on Japanese felt seal production and he was trying to build a family fortune by placing a design element that had no useful purpose? Im sure Mikuni could have an answer email them direct in perfect Japanese and when they finish laughing they will choose how and when not to reply.

[Jhurt]

The bushings behind the seals look like they might be pressed in bronze although im not positive. The seals would be to keep dirt/grit from scouring the bronze or whatever surface is there to maintain a smooth throttle control. Probably could get away without them BUT on restorations/builds like this details matter...

[Cipher]

you are correct its to stop the infiltration of tiny damaging particles that would introduce slop into the system
there has t be a source.

[GregT]

The bushings are I think oil impregnated bronze. Baking will at least drive out any oil that may be left....The seals are generally to keep the oil in.
I see two alternatives. Push an O ring up against the end of the bushing. Or carefully take a seal out and visit a bearing and seal supply house.
Actually visiting and speaking to a human who can search their in-house database is more likely to get results than an on-line search yourself.

[Nessism]

For an accurate "restoration" you should glass bead blast the gang plate, not paint it. If you want to paint regardless, I'd use some sort of catalyzed paint that does not require baking. There are lots of options that are quite durable. Regarding the felt "seals", you may be able to fabricate some or try to find a thin O-ring of similar dimensions. Good luck with that aspect and please be sure to post back describing your solution so others can apply it in the future.

[mikebgs]

Hi.I have just replaced my mounting plate felt dust seals for my 1978 GS750. The originals got messed up by the chemical soak.
I used 3mm A grade industrial felt.
!4mm hole punch .
10mm hole punch.
Dielectric grease.
Punch out the 14mm O.D. first. and then punch the 10mm I.D. hole in the middle of your 14mm disc.
Grease up the new felt seals and install in the cleaned recess.
I then installed the cup washers on the outside of the seal but back to front ,with concave facing inwards. This is because my material is thicker than the original felt seal and there was some resistance in the fit when assembled.
It seems to work nice now but is yet to be tested with carbs operational.

There is a youtube tutorial by Dude's garage. on how to fit the seals. Mike.

[Jhurt]

Interesting, thanks. I just finished the coating on the plate, went with Norrell’s Moly-resin in the “stainless” color. I’ll take on the bushings next.....

[Jhurt]

So I originally thought the seals were rubber or something else but they are definitely felt. I ordered some SAE grade F-1 felt through Grainger to replace them with. Bronze bushings are pressed out for re-oiling (41 years old...), 10mm socket is the perfect size for that.




Is all of this necessary...I seriously doubt it. Will it help me sleep....probably. Does it get me some time in the garage by myself...most definitely.

mikebgs’ reply sent me back into search mode and I actually did find a thread on here discussing the felt seals. I must have used the wrong search terms when I started looking a while ago.