Swing arm mod Z1/ZZR1200

swest wrote: With all the fantastic mods here, I felt left out. The Z1's were known for their high speed wobble. :ohmy: I've been in them and scary is not the word. :dry: All I could do was to give it a little more throttle, squeeze the tank with my knees and ride through it. I had one in Tehachapi last year, almost went down. Hopefully this will solve the problem along with some frame gusseting. :whistle:
Steve

Steve,
Nice cut, ballsy move, I like it. A little off topic, have you replaced your head set bearings with All Ballz bearings? I have heard it helps eliminate the warbles. I never had that issue but I replaced my bearings when I first bought the bike. Hit 120 mph multiple times and never had the issue, knock on wood.
Anyway, looking for 2 to your mod.

30 years ago we replaced them with off the shelf Timken tapered roller bearings. That helped. Also I replaced the swing arm bushings with bronze ones. The stock ones were regarded as SHT. There was a needle bearing up grade but they were new and expensive. That helped. The wobble seemed to grow when they happened. I got so I could tell when it would start and deal with it if I weren't in a turn or something. The most remarkable thing was at 93 MPH, it was prone to start, not 92 or 94-93! I would and still do my best to get past that point or stay below it. Some said it was the wheel base, others blamed the frame and weak swing arm. I welded bracing under the steering head and webbed the back bone on the original frame. This one I used L metal under the SH and welded some flat stock in three places on the back bones. I cut two out so my coils would fit right. They didn't seem to matter anyway. I have the metal stock I need for the gussets but I like riding so anything I do has to be bolt on. I'll take my time with the swing arm until I'm sure it's ready.
Meanwhile I'm going to RIDE THE PISS OUT OF IT. :woohoo:
Steve

atta boy turn and burn! :evil:




leon

Thanks mate.
Steve

As I said, I took off my old swing arm and rough fitted the new one while I was changing the tire. IT FITS. :woohoo: I will have to move back the shock mounts of course, fit a new brake stay and relieve the area where the brake arm is. I pulled it out a bit, 1/2" or so and it misses the arm. As I see it, I could put on a longer bushing or cut the arm and have a plate welded in. The pivot bolt is shot and I have my eye on another one. Might not need it if I have the bushings made. I'm open to suggestions.
Steve

I'm getting stoked. It's going to be one foxy a$$ swing arm. Before I put my old one back on, I'll take a sharpi and mark where the mounts go and the cutout will be. I think I have the bushing issue figured out for now. The old swing arm will be cleaned and painted for now.
BTW, the pivot bolt wasn't tight enough. Been a while since I've been down there. :whistle:
Steve

Ran into a snag. I thought it was hollow. It has two ribs going down the middle. No problem took a little more work and I had to have two cuts so they can be welded too. Got some 1/2" plate for the shock mounts. Ran out of daylight so I'll cut them tomorrow morning.






Jeff said he will weld it up tomorrow if I have it all ready. I think I have the pivot worked out as well.
That's next.
Steve

Hope that plate you got is 6061. I used 1/4" I believe

I'm not sure. It's very hard to work with. I'm thinking on putting 1/4" on the other side too.
Steve

Got some more homework to do. The plate will work fine. Jeff said he can penetrate to the ribs inside and fill the voids. I need to cut in notches for the welds. I'll also make another cut on the center brace. It's 9 3/16" at the axle. Stock is 9". There's a little binding when the pivot shaft is tight together. We should be able to weld the center brace and have the pivot shaft free. Welding it will be the tricky part. I need to pull the seals. Got the blocks cut for the shocks and the brake stay.






I made the blocks long enough to Drill and tap three settings. Once welded I'll pretty them up a bit.
Steve

A little more progress today. With everything tight the pivot was binding and the space at the axle was 3/16-1/4" too wide. I did a blade cut on the middle brace and it was perfect. Started to weld it and the pivot started to bind again. A grind here, a tack there and all was good. Got about 3/4 through the arm welds, ran out of argon. Jeff was roped into welding another's project yesterday and ran low. No hurry, We'll get back to it next weekend. It's where it needs to be so the rest is just clamp and weld. Pivot spins free and it's true. I want to strip off the old paint. What kind of stripper is safe on aluminum? I took some pics and clips.
Steve
BTW, Jeff's handle is Tunnel Vision Racing.

I asked this question in another thread. Do laying back the shocks lessen the effect they have on dampening and how they handle load? I've noticed most mods here have done this for various reasons. Some to lower the bike but in my case, to keep the same height due the the difference in the height of the arm itself. The arm is about 1 1/2" longer as well.
Steve