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M

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Discussion Starter · #1 ·
Have a new high compression motor in the SR595. Having difficullty getting enough traction on starting rollers,so thought i would build one using a golf car wheel and tire, ala, the ones i've seen moto-gp bikes use. Any thoughts on the probability of this being succesful,or at least better? Using a Doc-Z dual motor roller last summer, it did alright except for the traction issue.Plenty of power ther but it took someone pressing on the tail to hook up. Thx Mike
 
R

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#2 ·
If you put it in gear release the clutch and push the bike backwards it will chug a couple of times then the wheel will lock up. What you have done at this point is move the piston a full cycle. So basically your just past TDC on your compression stroke if you spin up on your rollers now and dump the clutch in a higher gear than first you have a complete cycle before you hit compression again. This allows your crank/flywheel to build some enertia before hitting the compression stroke. I used this process on my old 600 single that was like 13.5/1 compression and it worked pretty good.
Pete
 
J

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#3 ·
Mike,
My Doc-Z rollers had a non-skid adhesive tape on the rollers that lasted maybe a dozen times before it peeled off exposing the bare metal. I have found that traction to be an issue when the tire is wet. Big improvement was to install scooter wheels to align the rear tire and reducing tire sidewall rubbing.
The rear roller seems to do all of the work despite to two starting motors. I also found there was definite learning curve as to what gear is appropriate for my R75 to start.
I should try to adhere rubber to the rollers maybe with rivets or similar. Knurling the rollers might help too.

Seems like Eric Prichard had a nice home-made version of the one you describe. Maybe he'd be intersted in letting go of it or at least give you some tips?

Jeff Marcoux
 
I

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4,350 Posts
#5 ·
I've been with mike trying to start his bike . . . . The backwards to tdc compression thing doesn't help. He needs weight on the back. Mike, just add 200 lbs to the bike!! It'll just slow you down a little.
 
F

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#6 ·
quote:
If you put it in gear release the clutch and push the bike backwards it will chug a couple of times then the wheel will lock up. What you have done at this point is move the piston a full cycle. So basically your just past TDC on your compression stroke if you spin up on your rollers now and dump the clutch in a higher gear than first you have a complete cycle before you hit compression again. This allows your crank/flywheel to build some enertia before hitting the compression stroke. I used this process on my old 600 single that was like 13.5/1 compression and it worked pretty good.
Pete
Click to expand...
The SR500 comes with a handy little window on the cylinder head that reveals a cam indicator for that specific purpose. It works really well. I will say that if you don't have good traction, you'll have a real hard time bump starting a high compression single. I always look for a hill, or at least the highest area, to pit at the top of.
I've never used a roller starter, but I would think if you can get the rear wheel rolling and bump it off in 2nd gear you'd be GTG.

FR
 
texmawby

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#7 ·
what pete said.....

when i wrenched with scuderia giannini we had high comp ducati and aermacchi singles 12 to 1, 13 to 1, etc....

we used the same method as pete, but we always were in 2nd or 3rd gear. some were tougher than others, but they always started.

good luck,

tex
 
I

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#8 ·
I used the cam indicator for a year, then I learned from Frank Crash camillieri the back up trick, and that worked like the tits every time, so I am now ditching the compression release, which you need if you are going to use the little window on the cam end.

But, Mike elliot chime back in here, they have never tried to start your bike. It's an experience you'll never forget.
 
F

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#9 ·
I haven't had a compression release hooked up on my race motor since I got it 9 years ago, never seemed to matter (as far as the "kick indicator" was concerned. Now that you mention it, I vaguely remember something about that. I guess I haven't read the owners manual in a while. Like since 1978, when I bought my first SR....



FR
 
M

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Discussion Starter · #14 ·
Thanks for the feedback, Just for reference, i start the bike in third, roll it back to just after tdc,get on the rollers, and ghuga chuga, it hits tdc, and the rear wheel locks, the tire smokes, and we start over. The head is a welded up ,bathtub design with .035 squish so no room for the old valve decompressor. What i am lacking is traction,which is why i am looking at a tired starting roller. This all started when i bought a newer van with posi rear end and couldn't use my rollers. So i tried various other peoples including eric's. His were too wimpy to turn it over. The solo rollers have the balls but not enoughtraction. Will try some combination of your suggestions and let you know what works! Thanks again... Mike
 
J

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#16 ·
Here some of the details of a set of giant 5" diameter rollers I made for Fritz Augustine to start his Guzzi, his real GP bike and a few others that he was having problems starting on a regular rollers.

I made up a whole manual for it, including the basic usage warnings.

JohnnyB


 
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