Thanks for all the information guys, seems I shall be doing a lot of measuring before this gets put together. Have been busy repairing my CB72 after its trip to France, when on doing an oil change I found bits of primary chain in the oil and the oil filter sprocket nut loose and the tab washer missing its tabs .. hopefully all fixed.
Gordon - just seen the photo of your bike in Tansha .. very tasty !!
Phil
Should a CB77 head be machined for a 350cc Kit ?Should a CB77 head be machined for a 350cc Kit ?Hello phil,
Can you tell me which month of 1971 MotorCycle Sport Quarterly Technical magazine was for the big bore kit. thanks. Hi 305alp,
The Magazine is marked as "Motorcycle Sport Quarterly - Fall" 1971 and was $2.00 in the US, can't remember how much I paid here in the UK. The cover ( before it fell off ) had a picture of the then new HD XR750 alloy engine .. I'd seen Cal Rayborn thrashing the life out of the iron barrelled bike in the GB-US Match Races .. great times. Its one of the most interesting editions of any bike magazine I've read with articles about :- Analysis of the new XR750, Seeley Condor, Triumph 750 conversion, Building a 149mph Bridgestone 360, Electronic Ignition, uses for the new chemicals like silicon sealant, and the 350cc Superhawk conversion. I've looked for other issues on US Ebay but never seen any. If you can't find a copy ( unlikely ) PM me and I can post you a scan of the article and the MCI Read Titan one. Phil
350cc CB77Hello Phil
There are some earlier pictures of the CYB race kitted bike thats in Tansha on the race bike thread on this site. It currently has a 350 kit fitted using Italian ASSO pistons that Dennis Muirfin supplied and a modified CB72 head. Another couple of thoughts, make sure you get the valve pockets at the correct angle / position that way theres a bit less chance of bending a valve if something touches and watch out with the skimming business as sometimes you can get (as the racers will tell you) a situation of diminishing returns, ie. skim head / cyl. = comp. up. valves touch piston, deepen valve pockets = comp. down. I know some of this is probably not a worry on a road bike but I think it's still best to get a decent squish band even with a lower piston crown. Again, hope this all makes sense. Gordon SAFOJ Hi Gordon
Thanks, and yes it makes sense; I'll do a dry test check on the combustion volume and clearances before I assemble the motor, its currently second in the queue of bikes to work on. I've got a CB77 frame in the loft so the long term plan is to build the lot up as a CB77 and then register it with an age related plate. Rather than do it as a standard roadster I quite fancy fitting a long race tank and making it look like the road legal CR93 that Honda did, with red frame etc., and a silver tank, mudguards and side panels and black ceramic coated exhaust pipes and megaphones, but I can't see it being together till next year. cheers Phil
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