Rear Set Mounting Plate Design

[isleoman]

Well as most/many know my 82 GS1100 was rear ended Memorial Day Weekend and the frame was bent enough to warrant replacement.

Found a nice 83 frame locally and had it powder coated. One thing I knew going into this was that the 83 frame's mounting points for the stock driver pegs are in different locations than the 82 for the two rear mounting points on each side of the bike. So I knew my current rear set mounting plates would have to be revised to continue using ZX12R running gear. I chose the ZX12R brackets at the time because I liked the way they looked and I found a pretty cheap set.

So here's the 82 mounting plates that need to be replaced. Note that shift side and brake side plates are quite different in shape. Note also that on the shift side the plate is low enough so that it also caught the shift pivot shaft. In the picture below the shaft is obscured by the shifter arm.





For purists on the usage of the term "Rear Set" since these plates do raise the stock peg position one inch up and 1 inch back I think its safe to use the term. I didn't want to go too far up/back with them and make the position uncomfortable.

[posplayr]

Tom,
Those are very nice "rear sets". Judging by the length of the shifter extension bolt you are much further back than 1" from stock.

Looking at my bike, the stock position is just offset back (1 peddle width) of the swingarm bolt. Looks pretty racey to me.

Jim

[isleoman]

So back to the future.......

Both times I've done this drill I've mocked up the plate on pattern paper first so that I can cut things out quickly with scissors till I'm happy with shape and design. I probably went through 7 to 8 designs/shapes over several days till I felt I was getting close. Last night I had a "Doh" moment as I stood over the frame while it was laying on its side when I realized that on the 83 frame I would be able to use the same shape plate and hole locations on both the brake and shift sides. Woo Hoo!! We love standardization.

The next step was to trace the pattern onto a piece of 3/8" thick clear lexan plastic and cut out with a band saw. Again the point to this step is check the design and interference fit with the other mounting points and moving parts. The lexan is also easy and fast to cut and drill. The holes in the lexan are 1/2" dia. for the three plate mounting bolts I haven't cut the recesses for the bolt heads yet. The two shift bracket mounting point holes are 3/8" dia. (just tight enough to hold the bolts loosely in place with the bracket mounted. The final plates will be made from 3/8" thick 6061 billet aluminum plate and the threaded holes for mounting the ZX12R running gear will be heli-coiled to take the stresses.

The frame is laying on its side in these photos on a piece of foil covered bubble wrap I had laying around. The bubble wrap is just to protect the new powder coat finish. I know for a minute you thought I was writing this from the Twilight Zone.

The blue color on the lexan is the protective release paper they put on the face side. If I pulled it off it would be transparent, harder to mark on, and tougher to take pictures of.







This time around I plan to cut the shifter pivot shaft off flush with the boss. See second pic.

[isleoman]

Tom,
Those are very nice "rear sets". Judging by the length of the shifter extension bolt you are much further back than 1" from stock.

Looking at my bike, the stock position is just offset back (1 peddle width) of the swingarm bolt. Looks pretty racey to me.

Jim

Jim, you could be right. It does look like your shift side peg is in line with the forward down tube (tube that accepts the rear of the engine).

Call me "Racey" then. I did put 7K on the 82 frame with that set up and found it pretty comfortable. The further you push back the harder it will be to find a viable place for passenger pegs. Lately if the wife wants to go we take the FZ1 which is a better two up platform. If she doesn't I take the GS.

[isleoman]

Some shots of the same mounting plate moved over to the brake side. Using same monting hole locations on both sides will hopefully provide "Racy" symmetry.

Mounting plate Blue release paper is on top when the plate get used on brake side



Rear view of plate, Also note new Katana swingarm pivot bolt. Thank you Joe for that tip.

[isleoman]

Couple more from the brake side. Again remember that final plate will be polished aluminum. The tab at the bottom accepts the master cylinder (not mounted at this time.

Rear view


Return spring mounting tab on brake lever forced removal of some of the plate so the lower rear mounting bolt is a smidge closer to the outside edge of the plate than I would prefer. Now just need to figure way to mount spring between that tab and the brake light switch and I'll be done. My machinst buddy has agreed to make up new set.

[Mysuzyq]

Looking great! If you decide to let go of the '82 plates, please let me know.
Tony.

[jwhelan65]

Looking great! If you decide to let go of the '82 plates, please let me know.
Tony.

Tony,

I have a spare set for my 82 that I had made from Isleoman's original set. I also have them on file at a local machine shop. They are blank you would need to have them drilled for whatever rear set you use.

[jwhelan65]

Looking fantastic Isleoman! Again I cannot wait to see this thing, its motivated me to get mine back on track.

[Detroit Diesel Man]

Excellent workmanship..Nice Job!..Sweet lookin Bike..


DDM

[gs1150streetracer]

Rear Pegs?

Very Very,nice work just went threw the same thing,My CBR Friend wrecked my 1982 lost control in a turn and flipped it end over end about 3 times through a graveyard and bent the frame(Pictures in my profile i think),gsxr front end was fine ....no clue how,I found an 1983 frame at Baltimore Cycle Salvage with title so i bought it,everything went together fine until i went to mount the pegs and rear pegs,I used an old set of PMFR pegs from a dragbike i used to have for a simple solution.But no rear pegs for the lady freind.I was thinking of using an old set of zx7 rear pegs and weld small tabs to the rear part of the frame for easy removal.Any thoughts.?

[850 Combat]

Very nice.

I had no idea that '82 and '83 were different

[Mysuzyq]

I appreciate Joe's kind offer, but am also rethinking the mod due to lack of pillion pegs, which I seem to need several times a year. The '83 pegs and carriers are different (lighter, and more attractive) but I do not think they are significantly different in position, in reference to fixed datum points on both bikes.
Tony.

[Bad Kaw]

Isleoman,
Great thread! Subscribed. Thanks for posting the link over on the doctor's thread.
-KR

[bonanzadave]

Friend wrecked my 1982 lost control in a turn and flipped it end over end about 3 times through a graveyard and bent the frame

Ouch ! Thats a painful picture. Glad he didnt take up residence at the crash site.

Great work guys. Keep it coming.......