GRM bike class...

sorta dovetailing the idea of a GRM Bike Challenge, I came a across a CL ad for two XS400 Yamaha 4-stroke twins stupid-cheap. The one had been partially dismantled and looked like a great candidate for a miniature Street Tracker, similar to its XS650 twin big brother. Started me thinking about how may 400 twins were out there and how inexpensive they are. I think all the Big 4 made them, in various versions. I thought you could make an interesting class for roadracing or dirt track with them... Prolly couldn't get one to go fast enough to seriously risk life and limb. Anyone seen such a thing?

NJ mini GP

Similar to your idea, but not quite the same. I've seen them running at NJMP while I was there for another event. It looks like fun.

There is, or was, a member here a few years ago that posted about a group running small bore bikes on kart tracks too.

I'd love to try something like this, and I'm surprised that more people aren't doing it.

I've done a few 4 hr endurance races on a xr100 on a kart track its a bell of fun. http://www-ihigh.blueframetech.com/pj99/opencontent_10169.html https://www.youtube.com/watch?v=iDHDzDTV63M

My vintage road race club (race-USCRA.com) also run events called MotoGiro-USA MotoGiro-USA Road Rally Two-day skills event for small displacement vintage motorcycles & scooters

AHRMA has a Cb350 class and this looks fun - http://www.motorcycleclassics.com/classic-japanese-motorcycles/vintage-motorcycle-racing-honda-cb160.aspx

HappyAndy wrote: NJ mini GP Similar to your idea, but not quite the same. I've seen them running at NJMP while I was there for another event. It looks like fun. There is, or was, a member here a few years ago that posted about a group running small bore bikes on kart tracks too. I'd love to try something like this, and I'm surprised that more people aren't doing it.

I just raced there yesterday! On a TTR125 in "stock 100" class- it's a lot of fun, the bike is under $1k, and tires are $200 and last a whole season. If anyone has questions fire away, I ran pretty much the whole season this year.

G&J Kartway in Camden, OH lets small bikes play on their track from time to time.

I've been searching CL and I'm finding TONS of XS400's, etc. at stupid-cheap prices. This would be a bitchin' class and I've got an active club racer (runs a 125 Honda GP bike) interested. Seems to me that you could let the rules basically be, stock engine and do whatever else you want to the bike. End of year claiming rule of $1000. If I buy one I'll start a build thread....