Hi there OldMiniBikes!
It has been awhile since I have posted anything so I thought a little update/introduction would be in order. Long time regular reader and browser of the site and I have learned so much from all of you and am thankful for being exposed to that knowledge and humbled by being able to see some cool builds.
For me it all started with a frankenbike mini-chopper that was a shop class project some 7 odd years ago. I was fortunate enough to inherit a stock Briggs Raptor 2 steel bore single ball bearing engine from my uncle to engine said mini-chopper. This would provide my friends and I a solid fun platform for a good amount of time.
Then came the summer of 2012 and the Raptor was looking a little tired. After reading up I decided to tear apart and rebuild the Raptor 2 with some more reliable and higher performing parts. Nothing too aggressive by any means but with the addition of an ARC billet rod, billet flywheel, 94-SS Dyno cam, billet lifters, welded lifter bores, and shaved eyebrows I now had a safe way to reliably turn some RPMs! Finished off in VHT titanium silver and black wrinkle paint. Boy was it fun riding on that fresh rebuild!
With great power came great responsibility, after a year and a half post-rebuild I had come to the conclusion that I was going to retire the mini-chopper as it was not too safe. A low ride height meant on most corners at reasonable speeds you were scrapping the frame and often this would result in it sliding out from underneath and sending the rider for a spill. So it went into storage. But, fear not fellow petrolheads, I was not ready to abandon the flathead and fun it provided. I had made the decision to make myself a homemade go-kart!
The plan was centred on a nice comfy seat taken out of a mid-nineties BMW. No back-breaking bucket seat for me, I wanted to terrorize the neighbourhood in luxury. And so it began. Thankfully through work I had a huge supply of Mil Spec aircraft hardware available and it was used generously throughout. Due to the mounting brackets of the seat I had to make the frame asymmetrical, a little bit of math never hurts. Solid 1.25” square tubing used this wasn’t going to be lightweight, but it would be able to take a beating! The drivetrain inherited the built Raptor 2 and power would be transmitted through the DBR manual clutch and a jackshaft to the live rear axle with some wide MG hard compound tires. I forget the actual gearing but it equated to approximately 10 kph (silly Canadians and their metric system) per 1000 rpm at the engine. She will gladly pull up to 7500 RPM so that gives me about 46mph, I think by then either the carb or the cam just hit the wall and say no more. Plenty of speed for me though. I feel the novelty of the manual clutch is wearing off and I may go back to a centrifugal unit and I may gear it taller, time will tell.
For now I found another used Raptor 2 that I will be rebuilding and putting on the mini-chopper that will now be put back into service. See my build thread for that here http://www.oldminibikes.com/forum/briggs-and-stratton-engines/113894-raptor-2-build-time.html#post954603
If you made it this far thanks for reading and here’s a video to end off the post. A good amount of wind noise but you can still hear that distinctive flathead sound; so addictive! Happy riding everyone
https://youtu.be/rMIgJ21tvNk
It has been awhile since I have posted anything so I thought a little update/introduction would be in order. Long time regular reader and browser of the site and I have learned so much from all of you and am thankful for being exposed to that knowledge and humbled by being able to see some cool builds.
For me it all started with a frankenbike mini-chopper that was a shop class project some 7 odd years ago. I was fortunate enough to inherit a stock Briggs Raptor 2 steel bore single ball bearing engine from my uncle to engine said mini-chopper. This would provide my friends and I a solid fun platform for a good amount of time.
Then came the summer of 2012 and the Raptor was looking a little tired. After reading up I decided to tear apart and rebuild the Raptor 2 with some more reliable and higher performing parts. Nothing too aggressive by any means but with the addition of an ARC billet rod, billet flywheel, 94-SS Dyno cam, billet lifters, welded lifter bores, and shaved eyebrows I now had a safe way to reliably turn some RPMs! Finished off in VHT titanium silver and black wrinkle paint. Boy was it fun riding on that fresh rebuild!
With great power came great responsibility, after a year and a half post-rebuild I had come to the conclusion that I was going to retire the mini-chopper as it was not too safe. A low ride height meant on most corners at reasonable speeds you were scrapping the frame and often this would result in it sliding out from underneath and sending the rider for a spill. So it went into storage. But, fear not fellow petrolheads, I was not ready to abandon the flathead and fun it provided. I had made the decision to make myself a homemade go-kart!
The plan was centred on a nice comfy seat taken out of a mid-nineties BMW. No back-breaking bucket seat for me, I wanted to terrorize the neighbourhood in luxury. And so it began. Thankfully through work I had a huge supply of Mil Spec aircraft hardware available and it was used generously throughout. Due to the mounting brackets of the seat I had to make the frame asymmetrical, a little bit of math never hurts. Solid 1.25” square tubing used this wasn’t going to be lightweight, but it would be able to take a beating! The drivetrain inherited the built Raptor 2 and power would be transmitted through the DBR manual clutch and a jackshaft to the live rear axle with some wide MG hard compound tires. I forget the actual gearing but it equated to approximately 10 kph (silly Canadians and their metric system) per 1000 rpm at the engine. She will gladly pull up to 7500 RPM so that gives me about 46mph, I think by then either the carb or the cam just hit the wall and say no more. Plenty of speed for me though. I feel the novelty of the manual clutch is wearing off and I may go back to a centrifugal unit and I may gear it taller, time will tell.
For now I found another used Raptor 2 that I will be rebuilding and putting on the mini-chopper that will now be put back into service. See my build thread for that here http://www.oldminibikes.com/forum/briggs-and-stratton-engines/113894-raptor-2-build-time.html#post954603
If you made it this far thanks for reading and here’s a video to end off the post. A good amount of wind noise but you can still hear that distinctive flathead sound; so addictive! Happy riding everyone
https://youtu.be/rMIgJ21tvNk
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