Author Topic: Push starting  (Read 4129 times)

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Offline goingfaster5

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Push starting
« on: August 22, 2008, 01:03:50 AM »
We have been push starting our motorcycle, as we are getting good at it, we can  almost bump it off in the garage, expept that the garage floor is a little too slippery and the bike skids.  The sidewalk or pavement works fine.

This makes me worry that bump starting on the salt will be problematic.  The bike is light, say 350 pounds tops, and is a 500cc twin.  The static compression ratio is theoretically high, but the cam robs most of that due to long duration.

Can anyone relate there experience push starting motorcycles at Bonneville?

Thanks,

Eric


Offline Beairsto Racing

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Re: Push starting
« Reply #1 on: August 22, 2008, 05:15:54 AM »
Hi Eric,
tell us more about your bike and the class that you'll be running in.
I think your best bet and the safest option would be to fabricate a roller starter. Some teams use a vehicle's drive wheels and some rollers to start their bike, while others use a self contained starter cart with rollers and a 12 volt motor. You will find the salt surface far too slippery to push start and its too hot to be working hard like that. Good luck.

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bak189

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Re: Push starting
« Reply #2 on: August 22, 2008, 11:23:41 AM »
"Pushstarting"...  a big No No at SCTA/BNI events
Back when we raced with SCTA/BNI (now race BUB only) we ran a roadrace bike at Bonneville.....that we pushstarted in the pits.....
"official" told us NO pushstarts and No riding of
"race bike"...............the same old story "insurance will not allow it"........................................................
We had no other way to start the bike.....so we parked it, lost our entry money, and ran our other bike with elec. start...................SO you better get a
rollerstarter if you plan to race SCTA/BNI.............. 

Offline Dean Los Angeles

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Re: Push starting
« Reply #3 on: August 22, 2008, 11:43:22 AM »
The Buddfab 50cc streamliner uses a push start at El Mirage. They give it a short push to start it well before the start line, then take off under power when the starter lets them go.

I don't understand why you would push start anything. It takes very little work to make a roller set for the wheels with a 12V motor. I start my 250cc with a 12v starter on the crank. 500 rpm of motor power beats the heck out of 5 rpm of human power.
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bak189

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Re: Push starting
« Reply #4 on: August 22, 2008, 11:54:15 AM »
I stand corrected......."Insurance must NOW ALLOW it"

BUT how about pushstarts in the Pits???????

Offline goingfaster5

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Re: Push starting
« Reply #5 on: August 22, 2008, 12:34:34 PM »
Thank you for the feedback.  As I understand it push starting is permitted at BUB, as is riding the bike to and from the pits.  The SCTA/BNI apparently is different, but I am not going there.

The bike is a 1955 BMW R50.  We are running in 500 A/VG and APS/VG.  It has 13.5:1 pistons and a very long duration cam.  Mostly we are down to crunch time, with just a week before departure, we may not manage to get rollers made along with every thing else that needs to happen. 

We have a set of roller we put a car on top of, but I don't see how we will be able to use them at BUB.  The bike must be "race ready" in line. 

bak189,  how did the salt surface work for push starting?  It would be nice to know we could if we have too.

Thanks,

Eric


Offline desotoman

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Re: Push starting
« Reply #6 on: August 22, 2008, 01:21:02 PM »
Eric,

Opps, you aready have rollers.

Tom G.
« Last Edit: August 22, 2008, 04:31:53 PM by desotoman »
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Offline Seldom Seen Slim

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Re: Push starting
« Reply #7 on: August 22, 2008, 03:43:47 PM »
How is the salt for push starting?  Well, sure, it's a heck of a lot slicker than concrete, but a shove of a couple of yeards and the rider sitting down abruptly while simultaneously popping the clutch in second -- seems to work. 

Uh-oh, I'd better quit -- Pork Pie just walked into the pit!
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 (that's way up north)
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