cb 72 classic racer project
cb 72 classic racer projectHave been building this cb72 for classic racing. I have dunstall pipes on it which will be ghanged for race pipes.The engine is standard and i would like any information from the members on this site regarding race tuning the engine. I have read alot on the subject but it would be of great interest to find out the way people have tuned these bikes over the years. Another question is how to make a Megaphone. I did have the forumula for making a cone but have lost it, i have all the other formulas for length of header pipe ect depending on the exhust valve timings. Would be gratfull of any helpfull advice,all the best. Regards PT
Re: cb 72 classic racer projectAny chance ya can measure the length you want and cut these for the cones ya want?. ..........lm
cb72A piece of tin and a bit of brazing does not cost $120. Ive Another bike for them and they are good to get things up and runing while not making to much nosie. Do you have any imformation on race tuning.Or is one liners all your good for.
Re: cb72No and in your case YES. .....................lm
What we did with those engines back in the 60s included porting & polishing, milling the head to raise compression, bore out for Webco 350 cc kit, race cam (megacycle cams still makes these), heavy-duty valve springs and heavy-duty clutch springs & plates. Ran megaphones with stock carbs but larger main jets and race-type carb intake funnels. Many folks also did the transmission gear swap {I think it was a 2/3 swap) and some used larger intake valves. Disble ignition advance mechanism and set timing to full advance. Redline at 11K.
Here's an article on a more modern approach: http://motorbyte.com/mmm/pages/cafe/cafe41.htm Randall P.S. Swarbrick makes CB77 megaphones for about $200.
http://www.swarbrick-racing.co.uk/
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