Author Topic: Beairsto & Forstall 3000 APS/G  (Read 20590 times)

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Offline Beairsto Racing

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Beairsto & Forstall 3000 APS/G
« on: July 20, 2011, 08:11:24 AM »
I've been meaning to start this thread for awhile...

Larry Forstall built the "Double" back in the early 90's. He made a couple of shake down passes with it...then an event got rained out..then life got in the way...then the Hayabusa came on the market and Larry got side tracked  :-D

In 2002, I sat with Larry and his team at the 200 MPH Club banquet and asked him about his earlier years at Bonneville. I was especially interested in the twin engine bike. Larry sent me a few photos and I kept at him for several years to sell it to me...nope it's been sitting too long, it needs too much work...well let me fix it up and I'll ride it for you! A few years went by and I happened to be working on a rig in Mexico, when Larry emailed me that he had reluctantly decided to sell it to me. He was attached to it, he had invested so much time into it. Bonneville has a history of multi-engine racers, I couldn't have been happier. I had it shipped from Pennsylvania up to my local Suzuki dealer in Alberta, I couldn't wait to get home.
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Offline Beairsto Racing

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Re: Beairsto & Forstall 3000 APS/G
« Reply #1 on: July 20, 2011, 08:35:53 AM »
I mainly work in the Middle East & Africa, so I'm not home much. I poked around the Double a little and tried to figure out how everything worked...lots of emails back and forth to Larry. Still it remained a curiousity in my garage while we worked on the other projects. I borrowed a boreoscope to check out the engine internals and was fairly certain we could make it run when we needed to.
I could have gone with a Busa body etc but I decided to keep it looking period mid 80's and ordered a first gen GSXR competition fairing from Airtech. We got it running just a few days before Speed Week '09, but the first time that I ever put it in gear and let out the clutch was on the start line!
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Offline Beairsto Racing

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Re: Beairsto & Forstall 3000 APS/G
« Reply #2 on: July 20, 2011, 09:01:33 AM »
I was pretty nervous riding it on the first pass but soon learned that Larry had built a very stable bike, I went @180mph. On the 2nd pass, I took it up to @190mph but the coupler for the 2 engines started making some noise and I shut it down. Further inspection showed that it got hot, we didn't have enough lubrication...the chain was pretty much welded solid...the bearing for the idler/tensioner was now loose in the aluminium sprocket. We spent the rest of the week trying various farm repairs to keep the bike running, we stayed on the short course, my fastest speed was 203 mph @7 grand. We had found the weak link but knew it would take some re-engineering of the coupler in order to make a serious pass.
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Offline ben james

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Re: Beairsto & Forstall 3000 APS/G
« Reply #3 on: July 20, 2011, 09:01:47 AM »
man i'm so interested in hearing about this bike,love double engined racebikes,
coolest custom bikes on the planet.
ben
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Offline Beairsto Racing

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Re: Beairsto & Forstall 3000 APS/G
« Reply #4 on: July 20, 2011, 09:20:10 AM »
I first went to Bonneville in 2000 with an '86 GSXR 1100 that had been road raced, drag raced and abused by many others before I restored it. With big dreams, I was sure that I'd run 190mph but soon learned it was alot harder than that. I ran 162 and Carl Francis went 163 on it. We were addicted and I knew I'd be back. I bought an '01 Busa off the showroom, promptly voided the warranty and came back with a 1397 in '02...when I went to fuel inection, I swore I'd never go back to carbs..now I have 8 of them!

The Double had a pair of 1255cc oil cooled GSXR engines, they worked fine and the bike couldn't hook up as is...but I think aftermarket big blocks on these engines are really cool. Nobody is making new performance parts for 25 year old GSXR's anymore. Sitting in Dubai, I searched for days, emailing and calling people across the USA, Europe and Australia..finally back to the U.S. and scored a pair of brand new blocks at Carolina Cycle.
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Offline oz

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Re: Beairsto & Forstall 3000 APS/G
« Reply #5 on: July 20, 2011, 02:09:57 PM »
Hey Scott how ya doin I didnt realise that was its first run for you on that bike in 09 I remember talking to you about the sync on the engines hope you get the linking sorted.
Way cool

Oz
Newcastle born and bred a City built on Coal and Steel and a people built of stronger stuff

Offline Beairsto Racing

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Re: Beairsto & Forstall 3000 APS/G
« Reply #6 on: July 21, 2011, 12:23:01 AM »
man i'm so interested in hearing about this bike,love double engined racebikes,
coolest custom bikes on the planet.
ben


Yes, I'm a big fan of them too!
I'm still in awe of Bob Moreland's twin engine Harley. It's huge, it's fast and it's gorgeous!
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Offline Rex Schimmer

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Re: Beairsto & Forstall 3000 APS/G
« Reply #7 on: July 21, 2011, 12:23:36 AM »
I happen to be a big fan of Kevin Cameron who writes in Cycle World mag. I am not even a "bike" guy but Cameron always has some interesting things to say and if you pick up the latest Cycle
World and read Kevin's page you may get a good idea about making your coupling chain live.

Looking forward to seeing you on the salt.

Rex
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Offline Beairsto Racing

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Re: Beairsto & Forstall 3000 APS/G
« Reply #8 on: July 21, 2011, 12:38:57 AM »
After Speed Week '09, I went back to work for a few months but hoped to make the November event at El Mirage. The cheap and dirty fix was to replace the aluminium idler/tensioner gear with a slightly larger steel one and add a chain oiler. In the end, I never got back home in time for El Mirage. When I finally did, we decided to strip the bike, rebuild the engines and find a better solution to the coupler issues.
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Offline Beairsto Racing

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Re: Beairsto & Forstall 3000 APS/G
« Reply #9 on: July 21, 2011, 12:42:17 AM »
I happen to be a big fan of Kevin Cameron who writes in Cycle World mag. I am not even a "bike" guy but Cameron always has some interesting things to say and if you pick up the latest Cycle
World and read Kevin's page you may get a good idea about making your coupling chain live.

Looking forward to seeing you on the salt.

Rex

Thanks Rex,

Agreed..Kevin Cameron always makes for good reading!

Regarding the coupler...stay tuned..we are hopefully going in the right direction.
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Offline Queeziryder

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Re: Beairsto & Forstall 3000 APS/G
« Reply #10 on: July 21, 2011, 04:28:38 AM »
Scott,
Many years ago when my dad campainged a twin engined blown Triumph we gave up on chains, and went to gears to couple the engines.
I'm sure that Max has done something similar on the Black Lighning liner, so give him a shout, he can probably help.

HTH
Neil
Old enough to know better, but too interested in speed to care

Offline Koncretekid

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Re: Beairsto & Forstall 3000 APS/G
« Reply #11 on: July 21, 2011, 07:29:24 AM »
I would not trust that coupling chain past the garage door (sorry).  My little BSA 500  with maybe 40 hp uses a duplex primary chain, and I have broken it, as others have, and I ended up doing somersaults down the front straight at about 60mph because the broken chain wrapped around the clutch and seized the rear wheel. Duplex or preferably triplex, running in oil as a minimum.  Changing to larger sprockets of a size that you do not need an idler (spacing at an exact distance) would be safer, as that idler could self destruct in no time.  Larger sprockets will increase chain speed, but lessen the tension in the chain as well. Gears would probably be better, but then you'll have to add idlers with shafts with very stiff stub axles (supported inboard and outboard or double bearings inboard).  I'm not an expert on these things, but as a retired engineer, I see potential problems.
Tom
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Offline thefrenchowl

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Re: Beairsto & Forstall 3000 APS/G
« Reply #12 on: July 21, 2011, 08:45:50 AM »
Hi, Beairsto Racing,

Thanks for the insights on your twin engine bike...

Looking at your drive/coupling sprockets, my failing eyes can't quite count the number of teeth...

Looks around 25, which looks low to me since "agreed" minimum is 19, but with such power to transmit, a much higher count will help get rid of the destructive speed oscillations on the drive train and lengthen chain life...

Patrick
« Last Edit: July 21, 2011, 08:47:26 AM by thefrenchowl »
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Offline Beairsto Racing

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Re: Beairsto & Forstall 3000 APS/G
« Reply #13 on: July 21, 2011, 09:19:27 AM »
Gents, I appreciate your comments and experience. The pictures previously posted are from 2009. We never ran it last year. The coupler has recently been updated with an oil bath and a revised tensioner, it uses a 530 drag race chain.
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Offline Beairsto Racing

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Re: Beairsto & Forstall 3000 APS/G
« Reply #14 on: July 21, 2011, 09:28:14 AM »
When Larry built the bike, he made brackets by drilling lots of holes around the pattern on a drill press and finishing them by hand with a file. Now we just make a drawing and email it to the factory.

This is the current coupler set up.
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