revtothelimit - motorbike forum

derek badger wrote: Thu Dec 10, 2020 5:01 pm

You mad bastard! springs to mind but fun.

rodbargee wrote: Thu Dec 10, 2020 8:34 pm

derek badger wrote: Thu Dec 10, 2020 5:01 pm

You mad bastard! springs to mind but fun.

Snowmobile torque convertor, both cranks linked by chain drive. Mind your bell bottoms...

Genuine LOL

derek badger wrote: Thu Dec 10, 2020 9:59 pm

rodbargee wrote: Thu Dec 10, 2020 8:34 pm

derek badger wrote: Thu Dec 10, 2020 5:01 pm

You mad bastard! springs to mind but fun.

Snowmobile torque convertor, both cranks linked by chain drive. Mind your bell bottoms...

That photo is 1980s, fwd Ford Escort in the background

derek badger wrote: Thu Dec 10, 2020 5:02 pm

Nice

derek badger wrote: Thu Dec 10, 2020 5:01 pm

Weird

Julian_Boolean wrote: Fri Dec 11, 2020 2:09 pmNice

Isn't it just? I prefer it without the faring to be honest. I'd love something similar to this with lights/road legal.

derek badger wrote: Fri Dec 11, 2020 3:03 pm

Julian_Boolean wrote: Fri Dec 11, 2020 2:09 pmNice

Isn't it just? I prefer it without the faring to be honest. I'd love something similar to this with lights/road legal.

That's me done....

Is the left header kinked in for ground clearance? As it has separate header & exhaust (I hesitate to say 'silencer') for each cylinder, presumably they don't all need to be the same length? Or is it, that for two strokes, the entire thing has to be a certain length?

Well,sometimes just because you can doesn't mean you should..



Link to story.
http://www.bikebound.com/2019/05/12/kaw ... afe-racer/

Julian_Boolean wrote: Fri Dec 11, 2020 2:08 pm

derek badger wrote: Thu Dec 10, 2020 9:59 pm

rodbargee wrote: Thu Dec 10, 2020 8:34 pm
You mad bastard! springs to mind but fun.

Snowmobile torque convertor, both cranks linked by chain drive. Mind your bell bottoms...

That photo is 1980s, fwd Ford Escort in the background

Dont think so Julian....

David wrote: Fri Dec 11, 2020 3:28 pm

Julian_Boolean wrote: Fri Dec 11, 2020 2:08 pm

derek badger wrote: Thu Dec 10, 2020 9:59 pm

Snowmobile torque convertor, both cranks linked by chain drive. Mind your bell bottoms...

That photo is 1980s, fwd Ford Escort in the background

Dont think so Julian....

I think it's Australian. Ford Falcon estate or similar?

Horse wrote: Fri Dec 11, 2020 3:11 pm Is the left header kinked in for ground clearance? As it has separate header & exhaust (I hesitate to say 'silencer') for each cylinder, presumably they don't all need to be the same length? Or is it, that for two strokes, the entire thing has to be a certain length?

On a 2T they all need to be the same length if you want performance. It's less an engine and more of a musical instrument.

Read about Walter Kaaden's work at DKW.

derek badger wrote: Fri Dec 11, 2020 3:32 pm

David wrote: Fri Dec 11, 2020 3:28 pm

Julian_Boolean wrote: Fri Dec 11, 2020 2:08 pm

That photo is 1980s, fwd Ford Escort in the background

Dont think so Julian....

I think it's Australian. Ford Falcon estate or similar?

Looks like a US spec Escort

https://en.wikipedia.org/wiki/Ford_Esco ... _Wagon.jpg

cheb wrote: Fri Dec 11, 2020 3:41 pm
On a 2T they all need to be the same length if you want performance. It's less an engine and more of a musical instrument.

Read about Walter Kaaden's work at DKW.

They need to be the same frequency I think, not necessarily the same length? They look like they're different diameters.

Ducati made a marketing song and dance about using different bore headers on similar grounds ISTR.

Mr. Dazzle wrote: Fri Dec 11, 2020 4:10 pm

cheb wrote: Fri Dec 11, 2020 3:41 pm
On a 2T they all need to be the same length if you want performance. It's less an engine and more of a musical instrument.

Read about Walter Kaaden's work at DKW.

They need to be the same frequency I think, not necessarily the same length? They look like they're different diameters.

Ducati made a marketing song and dance about using different bore headers on similar grounds ISTR.

Depends on what you want to do with a two stroke, for instance, RD500s run the front cylinders in a different tune to the rear cylinders to boost the mid range, but they are effectively two engines joined together on a common clutch, whether you could get away with this on a single crank, I don't know, I think that eventually you'd twist the crank on it's centre pin. But for cylinders to run the same on any engine the exhausts have to have the same resonant qualities on each cylinder, there's a number of ways you can achieve this, especially on two strokes, four strokes are much easier to work out, where it's just the pipe length, diameter and taper that need to be taken into account, bends don't have a massive effect so long as you measure the length correctly - you have to average the inside and outside lengths of the bend - all this is theoretical, real world results may differ, and you can't beat someone with experience making you an exhaust.

Julian_Boolean wrote:I think that eventually you'd twist the crank on it's centre pin

Because some cylinders are more powerful than others?

In any multi cylinder engine, one cylinder is producing peak effective pressure and torque, while other cylinders are at negative pressure and torque.