750 cc commando lack of performance

Whistle blew for tea-break time at the works.

pvisseriii said:

This would appear to be a long inherent problem rather than a symptomatic issue.

I don't know why "Cam Timing" seems to jump out at me but it does. 11 rollers between the dots? If you can't get above 5000rpm you'll never feel that surge.

If motor, at least the top end, is fresh and the compression test is way low, then this may confirm cam timing retarded.

Click to expand...

Cam timing sounds favourite to me too. It's the most obvious thing that's going to give a lack of performance across the range but with no other apparent symptoms such as popping and banging, overheating or pinking at some point.

The workshop manual drawings can be a little misleading if you don't think it through.

I don't think this is very misleading.



Dave
69S

Lil' red paint dots still hangin' in there after 40 years of spinnin' in hot oil !

If it runs without any issues with OK power, I'm happy! A 600cc modern bike will kick its butt anyway! Just have a backup 1000cc modern bike if you want to go fast! :roll:

Lighten the flywheel and make it steel, put small port head Combat and bigger single carb and go hunt down them 600's and even liter bikes as they can't put down the power load as fast as this combo, though moderns can keep powering to higher speed but by then so what. I had to gear up to take advantage of mine. Then the handling issues to hang with moderns in sweepers can arise = which is whole 'nother subject.