CORSE swing arms---

I am going to talk only about swing arms found on '91-'94 Corse's- hopefully someone will provide pictures and technical information about the earlier swing arms.

It looks there were two style swing arms (with small variations) installed on the Corse's from 1991-1994. Before I started to study the bikes I had heard all kinds of stories of how many different swing arms there were over the years. I have only found these two with slight variations in dimensions.

One style has seam welds on the brace behind the shock running the perimeter of a plate welded to the back of the brace, another version has a welded seam from left to right dead middle of the brace.

The first style has fender support tabs spaced at 100 mm, the second style has the tabs spaced at 120 mm (like the street swing arm tabs). You need to trim a carbon fender to make it fit on the early swing arms.

From the bikes I have seen and bikes owner's I have polled, it appears that the very early frame number '91 bikes had the first style and from mid '91 on up, all bikes had the second style. It looks to me that the factory fabricated the first style by just cutting the back of the brace off and welding in a curved plate to give more room for the tire. Aside from fender tabs and the length all of the dimensions are close to the street swing arms. In fact, one early swing arm I measured even had the same length as a street swing arm. What is interesting to me is that I found these early styles only on Works bikes- I have not found them on an early frame number RRR's-- If anyone has one on a later bike please let me know.

By the middle of the production of the RR bikes it looks like the factory switched to the later style swing arm which has the seam in the center of the brace as seen on a street swing arm. As you see on my dimension list--- all of these style arms are the same width as a stock arm longer with a few of the later style versions actually a bit wider like my '93 Works bike. The axle is also longer. This allows you to actually pull off the rear wheel off without it getting hung up on the floating brake. Doing this on the stock width Corse swing arm you have to be very careful not to foul the paint on the rim.

Early style swing arm
Length- end-to-end 585 mm or 572 mm
Length-from pivot to beginning of axle slot 457 mm
Width- between legs 240 mm
Width between fender tabs 100 mm
# of chain glide bolts 2

Later style swing arm
Length- end-to-end 585 mm
Length-from pivot to beginning of axle slot 479 mm
Width- between legs 240 mm or 250 mm
Width between fender tabs 120 mm
# of chain glide bolts 3

Let us go to the pictures. Compared to a street swing arm the major difference are the length, the diameter of the axle holes, and the way the main brace behind the shock is formed. The width of the street and most of the Corse's are the same at 240 mm. The only wider one I have seen is on my '93 Works bikeit measures 250 mm.

The most interesting parts of the corse swing arm are the internal axle adjustment/holder blocks. They are fabricated from Magnesium. The right side has a flat head pin bolt that is used to locate and hold in position the floating rear brake support tube.

I have seen a few type of end caps- most are gold anodized and are the same as the street bike. I think everyone on this forum has seen the carbon fiber versions used on some of the '93 Works bikes. To remove the rear wheel and to keep the axle position many teams just used duck tape to hold the end caps to the swing arm. My '91 used setscrews through the bottom of the caps to clamp the screws to the caps- and at one time it looks they screwed the end caps directly to the end of the swing arm.

I invite anyone to add to this bit about Corse swing arms or any threads in the technical section.