Lone Star Roundup Austin Texas

#5
Nice that rear tire will work well with the loose dirt. The long swingarm should help on the start. They keep you in the corner then start and go to the far turn. Just might be a little slow turning the corner but you could just go outside and out power the inside guys. I will look for your bike there.
 
#6
This bike has zero problems turning corners, swingarm is not to much longer than stock, the yami front end adds a bit of wheelbase also. Its definitely not the average Bonanza, the motor is a wicked little clone that spins this tire into oblivion. The clutch is a modified Mongrel and comes on around 4k rpm's, it comes out of the hole like the space shuttle.
I have a few different tire treads to play with, so far I think this will suit the loose stuff, might shave it a wee bit also
 
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#7
Have you watched those races the loose dirt is pretty deep probably 3-4 inches. a lot of them just spin, the type of tire you looks like it would work good if you shave it wouldn't it loose traction in the loose dirt?
 
#8
thats deeper than I thought, might leave well enough alone then.
I saw mostly people not really coming out of the hole with any speed at all, some even pushing off with the feet to get starting momentum, so thats why I went this route, it comes on strong from the word go :)
The clutch I have is a work of art in the centrifugal world. Its a heavily modifed Mongrel that the mods were not disclosed until I swore secrecy to Mr D.
 
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#10
ran it not raced it.
the rear is 72 I drilled and made a backing plate for.
The final ratio can be changed easily on the jackshaft by swapping gears and sliding the motor back in slots for larger gear and using same chain. Its set up in the 10 range right now, Austins track is short and I want to be rippin ass in a hurry
 
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#12
Do I spy an early 1940's Robbins Myers 12" fan?!

Oh minibike...right...very nice! You NEED to check out my minibike friendly shows in the south thread!
We run our minis in grass drag races and will be at no problme Raceway april 25th doing the same setup as lonestar Roundup!
 
#14
Is this the build you were documenting maybe a year ago? That is one really fine machine. I love the engineering in the swing arm and mono shock. What a neat bike. I hope someone takes some videos, especially those 4K RPM hole shots with dirt flying! :thumbsup:
 
#15
same bike, version II, tore it down and made some changes, shortened the swing by 6" and moved the suspension inboard, reversed forks to reduce wheelbase, also made a made a support to hold 2 more center bearings to reduce jackshaft flex, drilled rear gear, made backing plate, redid the brake set up, stripped it all down again and re-powdered again and am using the same motor. I will be done with the seat pan in a couple days and then off to the upholstery guy with it.
 
#16
same bike, version II, tore it down and made some changes, shortened the swing by 6" and moved the suspension inboard, reversed forks to reduce wheelbase, also made a made a support to hold 2 more center bearings to reduce jackshaft flex, drilled rear gear, made backing plate, redid the brake set up, stripped it all down again and re-powdered again and am using the same motor. I will be done with the seat pan in a couple days and then off to the upholstery guy with it.
Is that all? :laugh: Really show cased your talents with this. I'm a sucker for green too.
 
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