Search found 74 matches

by RobD
Wed Jan 07, 2009 5:04 pm
Forum: Lambretta Tech
Topic: Uber race crank
Replies: 57
Views: 9717

Re: Uber race crank

I see what you mean about the chamfering lessening the bottleneck to the gas trapped behind the crank with this race design. Can't get my head around the advantage of bell shaped webs though. What advantages do they bring? All I can see them doing is creating lots of turbulence and trapping charge b...
by RobD
Wed Jan 07, 2009 4:50 pm
Forum: Lambretta Tech
Topic: Uber race crank
Replies: 57
Views: 9717

Re: Uber race crank

That's what I'd pictured, at BDC wouldn't you have a cavity behind the webs with only the area around the big end for gas flow to occur?
by RobD
Wed Jan 07, 2009 4:43 pm
Forum: Lambretta Tech
Topic: Uber race crank
Replies: 57
Views: 9717

Re: Uber race crank

There's a limit to the amount of rotating mass you want to remove otherwise there won't be enough inertia to keep the engine going between power strokes and it won't tick over as I'm sure you'll know. Yes, we intend to do the race version as a 'bell' shape, following the contours of the weighted en...
by RobD
Wed Jan 07, 2009 3:47 pm
Forum: Lambretta Tech
Topic: Uber race crank
Replies: 57
Views: 9717

Re: Uber race crank

Hmm interesting. I agree that you'll lower primary compression if that's what you're aiming for. There's a limit to the amount of rotating mass you want to remove otherwise there won't be enough inertia to keep the engine going between power strokes and it won't tick over as I'm sure you'll know. In...