Type II "Twingle"?

jensen · Post by **jensen** » Mon Nov 30, 2009 2:27 pm

Hi Clarenceada,

I understand and I didn't took that serious too.

It's just that I think that physics and formulas are not in place on this forum, just like on the oil debate.

It's a playground which is not open to the public, only for scientist and engineers, and that's discriminating, I never realized that until the oil debate.

There where a lot of arguments but none where based on physics, and that says it all.

Jensen

G-Man · Post by **G-Man** » Mon Nov 30, 2009 3:21 pm

Having read the Kevin ash stuff on the cross-plane crank for the R1. It seems that the tyre people are not big believers in the 'big bang' stick-slip theory. I'm wondering if some of the 'controllability' issues stem from the perception of lower engine speed and hence an ability to 'hear' what the motor is doing.

A CB77 'twingle' would sound like an engine running at half speed and the sound output would also sound 'stronger'. My V50 sounds like a 'slogger' but it idles at a similar speed to my CB400. Because of the 'lumpy firing interval (two bangs in 90 degrees) it has a big flywheel to carry it over three unpowered strokes.

How about a CB77 with pins set at 90 degrees? You get almost a 'big bang' but without the pistons accelerating and decelerating together like you get with a 360 or 180. I think that Triumph have done that with one of their latest scrambler twins for the US.

http://www.triumphtwinpower.com/triumph ... rspecs.php

Torque from the 270 (90) engine looks a little less than the Bonneville (360) at 1000 fewer revs

http://www.triumphtwinpower.com/triumph ... torque.php

Interesting stuff

G

LOUD MOUSE · Post by **LOUD MOUSE** » Wed May 12, 2010 12:03 pm

I weighed a CA77 crank and a CA72 crank.
20LB. 12OZ and 20LB. 10OZ. ............lm

brewsky wrote:Cliff,
Do you remenber how much additional vibration there was after the change over?

teazer · Post by **teazer** » Wed May 12, 2010 10:46 pm

LM,

That's interesting. Are the flywheels the same diameter on both of those cranks? Do you happen to know if they are the same diameter as CB cranks?

I have some different crank webs back in Australia and according to my old notes the new ones were 3mm larger than the smaller ones and the annular ring around the circumference were different.

LOUD MOUSE · Post by **LOUD MOUSE** » Thu May 13, 2010 6:39 am

I'll look into your questions when I have time.
How long ya been in the states?. ...........lm

teazer wrote:LM,

That's interesting. Are the flywheels the same diameter on both of those cranks? Do you happen to know if they are the same diameter as CB cranks?

I have some different crank webs back in Australia and according to my old notes the new ones were 3mm larger than the smaller ones and the annular ring around the circumference were different.

teazer · Post by **teazer** » Thu May 13, 2010 8:35 am

Thanks. No rush.

Since early nineties

sotxbill · Post by **sotxbill** » Thu May 13, 2010 4:18 pm

kind of like pushing a boat through the water..

one is a paddle stroke, then pull out of water, move it forward, drop it back into the water and paddle again.

the other is like a propeller where the push is smaller but more constant???