wombat200 wrote:The 500 racer in Australia has almost 10kg of welding rod welded into the cases, just to allow for machining to fit that tranmission......... So lots of work.......
WoW!!
500cc CB77 Conversion - starting and reference points?
C.A.T EngineeringHello Have a look at this site www.cateng.co.uk follow the link to racing. I have just sent my cb77 barrels crank and cam of to to them. Ask for les, they do work at a very good price. A lot of the classic road racers here in ireland use him. He comes highly recomend. All the best Pt
C.A.T EngineeringHello Have a look at this site www.cateng.co.uk follow the link to racing. I have just sent my cb77 barrels crank and cam of to to them. Ask for les, they do work at a very good price. A lot of the classic road racers here in ireland use him. He comes highly recomend. All the best Pt
OK, So this post is a year late, but better late than never eh?
Several questions were asked and few were answered. 500cc CB72. I doubt that dozens were built. I saw the one Bill Horsman rode many years ago that was built by Jerry K. The first one I read of was the one that Terry Dennehy rode many years earlier. Mark Weiss in Melbourne was building his CB into a 500 about the time I moved to the US so I never got to see it finished. And of course the new one by Jerry. I'm sure there are others but they are not simple to build. Basically choose a crank you like and start from there. The barrels have to be bored out a long way for new sleeves and that barely leaves the ends of the fins so it's time to weld or glue something back and then machine it again. Then you need custom pistons Next problem is that the ports cannot possibly flow enough for a racing 500, so it needs bigger valves and there's no room, so the valve angles have to be moved and that means a lot of work in the head. Note: I have not built one but knowing the restrictions in a stock or ported head that's the way I'd be exploring. I want to do that for my next 350 unless I build an 8 valve CR replica instead. The trans will not live with the new HP, so choose a six speed you like and start welding and machining. And so it goes on. That's why most of us do not own a 500. A 350 is easy by comparison. Here's my recipe: Remove stock CB77 liners Bore barrels to take other larger liners (CB350, CB750, KZ650 or new) Machine the donor liners to size Insert liners Bore and hone to size Counterbore crankcases to clear larger liners Port head Fit new lighter valves Fit race spring kit with alloy or Ti top collars Lighten rocker arms Get a Megacycle cam- you have choices Sink valves into head slightly (stock, lightened or oversize, stainless or Ti) Cut squish bands to match pistons at the angle you decide would work best Machine piston crowns to a shape that you think will work Deepen valve pockets enough to clear valves. Assemble Check clearances Disassemble Machine some more Repeat until all clearances are where you want them Strip crank Rebuild with race kit cages or new replacements with new rollers Devise a new cam chain tensioner ( or let the rubber wheel explode as happened to mine more than once) Replace the primary drive with a Duplex from www.MPE07.co.uk And that was for a basic 350 and obviously I skipped a few steps Options include 5 or 6 speed cluster, dry clutch, self energizing or total loss ignition etc and then you get to start on chassis upgrades to get it around corners. There is absolutely nothing here that hasn't been done before. I built and raced my first 350 in 1980 and I built a few since then. You can skip a couple of the steps above for a budget racer with less power that last slonger, but there's a road map to follow. Oh sweet Jeebus I am glad to see this link!! I am sure I wil feel differently when I get the price though. lol georGe
Ton Up Club-Florida AHRMA #500 Road Race #G50 Cross Country
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