i have a 4-1 system from a 750 f2, dont know if it would fit your bike though. it's possibly motad or similar. you can see a pic of it in the honda britain photo on page 2 of the 'projects' section under the 'phil read/honda britain' thread. yours for £60 if its any use. i'm up in london on 4th nov and oxford on the 5th if thats any good.