I had been using a home made air clutch for some time then switched it to an MPS sort of lever. I got one that was missing a part so I copied the basic form from another. As it turned out, the MPS parts worked very well until I really started to get aggressive with the static pressures. There was not enough force to hold the lever in. Then the throw was just a little short. To solve it I went to the local salvage yard and hunted around for a larger cylinder. I found some that were made by ARO Fluid Power. Part number is 0176 1019 010 1038. These can be rebuilt and just screw together. So I chucked them into a lathe and shaved off a little material here and there. This one gives me about 0.2" longer throw so nothing is even close to a bind now. I can have lots of cable slop. The larger piston allows me to put more static on than I would ever use and it stays put.

It worked so well I plan to switch the Bimba out on the other bike.

This is the MPS air clutch with my home made bracket.


The ARO cylinder after mods next to the Bimba.

I played around with the MPS air-clutch setup like that, but I never actually got it to where I felt comfortable taking it to the track for testing.

One of the things I discovered is that there are a multitude of small air-cylinders in some of the larger copy-machines and printers, and if you have access to a "salvage yard" for that sort of thing, you may be able to find a cylinder that's the correct bore and stroke without modification.

...yeah, I know it's not extremely helpful/detailed info, but I was surprised to learn that those pneumatic cylinders are used in so many different kinds of machines...

Care to expand on this?

I have seen a few people use them. Many local people I talked with used an adjustable jet on the exhaust to slow down the release. I heard one person was doing well with the setup and then they decided it was a delay device.

I guess if your finger popped off or a wire broke with a slider or the air clutch, your in the same boat.

At the time I was running the stock aluminum chassis with a stretched arm (64" wheelbase) and I just didn't trust my guess at how large of an orifice to fit in the exhaust to keep from looping the bike.

I never re-visited it after I got the new chassis with the 7" slick and wheelie-bars.

No bars, that would be scary to setup!! I thought you were no box, is there a reason you were looking at using one?

No box, yes, but I was thinking that I could be more consistent sliding my thumb off of a button than letting go of a clutch-lever, and IF I happen to win the ROC or the team race at the division-finals, then the national final in Pomona allows delay-boxes (don't ask me why).

...and besides, someone let me have the parts to play with and I cannot resist tinkering with gadgets... 'specially when they don't cost me nuffin'.

Don't get me started on these box no-box rules. I will need a box to stand on.

I would think your right about being more consistent versus a stock hand clutch.

Are you ready for the new year?

Kindasorta, not really. It's looking like I won't get my new head prior to the first race, but the jury's still out on that...

ETI is day after tomorrow - I'm gonna go just to say hi and see who's racing what this year.

Our first race of the season isn't until Easter Sunday, but I'll be at the track on Fri night and all day saturday knocking the cobwebs off.