How fast are your vintage bikes

markus

markus

Well-Known Member
#21
#21
back in 2010, this bike pulled a whopping 33mph on the 1/8 mile dragstrip.....that was with me reaching down and trying to overrun the governor manually because I was getting spanked so bad By sherri on her modded z50 :laugh:



The only thing that had been done to it at that point was a decarbon, carb rebuild and major tune up.

I sold it 1st of 2011, but I got the opportunity to get it back last year. I tore the engine completly down this time. It didnt need it but I wanted to do some light porting, do rings and seals and all that. The 2 speeds dont need much to get them going and porting a stock engine usually makes them a little weaker off the line so I felt I could get away with it and not suffer too bad. It was quite and improvement, I also got rid of some friction that was in the driveline. It was pulling wheelies easy and actually overpowering the 2nd gear clutch a bit. I didn't GPS it or run it on the track before I sold it off again but I feel it was pushing closer to 40 now within 1/8 mile flatland. Still had gov gears internally I just adjusted them out.
 
markus

markus

Well-Known Member
#22
#22


This 1969 CC charger GPS'd a consistent 42mph somewhat safely and personal best was showing 46mph. It was a sloppy HS40 that had been damaged on the exhaust port when the threaded in muffler outlet and come loose and ate the threads out of the port. the bike and engine were in pieces when I got it, prevous to me their fix on the port was to hog it out to a smooth port. They also did the intake so both of them were opened up alot farther than they should have been since the valves were still stock!

I wanted to try and save the engine because of the OG paint, so I slapped it together and crossed my fingers, I match ported the intake to the block and carb to intake, I transitioned the dog leg muffler to block as best I could at least (could not get a true match) Pretty sure I ditched the spark screen in the header as well. Modded the carb a little to pull some more and get butterfly to go full open, yanked the gov gears out of the block completely, and pulled the flyweight off the cam to totally loose the compression release. It was sloppy but ended up running really good. Clutch I had on it came on a little higher RPM so it still pulled out of the hole alright. no wheelies, but you didnt have to help it along or anything. Would have been a really fun bike with one of those manual clutches or maybe even a TC on it.

 
topnotch

topnotch

#28
#28
The Rupp Huslter is very fast image.png image.png image.png The Bonanza MX is super crazy fast this is the fastest mini in my stable for now. This Bonanza Engine started it's life out as a stock Briggs and Stratton world formula, until the world-famous go cart racing engine builder Nash decided to open it up and change every component in the inside of engine. If you can think of it, it has already been done to this engine. I must have been crazy to put this engine on this minibike. image.png image.png image.png
 
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Rupp 72

Rupp 72

Active Member
#33
#33
My TT500 with original H50 and optional Dellorto MB22A does all of 40 mph and maybe even a little more. Check iut the short video!
[video=youtube_share;YuitfYX_wRI]https://youtu.be/YuitfYX_wRI[/video]
 
Daniel Coop

Daniel Coop

Well-Known Member
#34
#34
Still seeing a bunch of Asian power in the vintage American minis. Seems like the only way to go fast without spending some serious cheese on an American made motor for usually still less HP...
My daily beater ARCO Easyrider, with it's new, improved clone's top speed is unknown, because it's motor is still pulling as the dreaded mini bike death wobble starts setting in around 50-55ish. Don't get me wrong... There's just something undeniable about the sound a built flatty​ puts out
but almost double the price of one of my clones, that would easily walk on my Briggs
 
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