Oddball engines and prototypes

[ken seeber]

Sometimes wondered how the dudes mastered the art of gearshifting a 12 speed Kreidler with 3 and 4 speed separate gearboxes in series. So if the 3 speed was tacked on to the original 4 speed, we have the following arrangement. A1, A2 & A3 for the 3 speeder and B1, B2, B3 and B4 for the 4 speeder.

So, old mate starts in A1 and B1, then progresses to B2, B3 & B4. What happens next? OK he goes to A2, but presumably he’d want to go back to B1. How does do this. Is the shift drum able to continually rotate allowing it to go back to B1 after B4? Wouldn’t be possible in an internal push/pull rod type Jamathi style arrangement or would it ??

This link below tells of a handlebar selector for one of the gearboxes. So clearly no mechanism to allow seamless "interconnected" ratio changing from A1:B1 thru to A3:B4. This being the case, it’d have to be a head fuck to remember what gear one was in and the sequence of shifting.

http://www.classic50racingclub.co.uk...ities-50s.html

[guyhockley]

https://www.kiwibiker.co.nz/forums/s...post1130913246

I guess with the Kreidler it would be more, "down 2 foot, 1 hand for this corner" etc

[guyhockley]

The Kreidler name seems to have been resurrected as yet another chinese 125 engined range.
This is an oddball one.
Is the turbo just for silencing?
Is it to blow cool air at the engine?
Is it to blow cool air at the rider?
Is it just to make a cool noise?

[Frits Overmars]

Sometimes wondered how the dudes mastered the art of gearshifting a 12 speed Kreidler with 3 and 4 speed separate gearboxes in series. So if the 3 speed was tacked on to the original 4 speed, we have the following arrangement. A1, A2 & A3 for the 3 speeder and B1, B2, B3 and B4 for the 4 speeder.
So, old mate starts in A1 and B1, then progresses to B2, B3 & B4. What happens next? OK he goes to A2, but presumably he’d want to go back to B1. How does do this. Is the shift drum able to continually rotate allowing it to go back to B1 after B4? Wouldn’t be possible in an internal push/pull rod type Jamathi style arrangement or would it ??
This link below tells of a handlebar selector for one of the gearboxes. So clearly no mechanism to allow seamless "interconnected" ratio changing from A1:B1 thru to A3:B4. This being the case, it’d have to be a head fuck to remember what gear one was in and the sequence of shifting.

Let's call the 4-speed footbox F and let's call the 3-speed handbox, that was fitted at the exit shaft of the footbox, H. Makes sense, doesn't it? The footbox operates in the usual manner; the handbox is operated by a twistgrip on the left handlebar; you can twist it from 1 to 3 or from 3 to 1 without having to stop at 2.
You start with
F1-H1 and a lot of clutch slipping. Next:
F1-H2
F1-H3
F2-H1
F2-H2
F2-H3
F3-H1
F3-H2
F3-H3
F4-H1
F4-H2
F4-H3
Yep, counted 'm, that's twelve steps.
All is well as long as you're upshifting. You may not have a clue which gear you're in, but that doesn't matter. But imagine coming onto a corner, braking, footshifting down twice and handshifting up once. Or was it the other way round? With a powerband about 7 rpm wide, there's not much room for errors.
Imagine racing this Kreidler at the 187 corners of the Nürburgring... https://en.wikipedia.org/wiki/N%C3%BCrburgring
Kreidler later made life a little easier for the riders with a 2-speed handbox, coupled to a 6-speed footbox.
Suzuki built a 'straight-twelve' footbox, later followed by a 'straight-fourteen'. Much easier on the riders' minds. The snag was that they simply couldn't downshift 13 times quick enough whilst braking for a hairpin.
Jan Thiel played with the idea of facilitating two at a time-downshifts for his 9-speed Jamathi rod-and-pawl-operated box. But then the FIM enforced a 6-speed rule.

[guyhockley]

Just to elaborate on Andy's Ducati 'mono'. This is the third one he's built- he experimented with the original Ducati Supermono idea of a 'dummy' rod , but quickly developed the engine into a big Aermacchi, using the front cylinder only, balancing the crank using a split counterweight in place of the second rod, piston, etc. The engine is balanced to the standard Aermacchi balance factor of aprox 27%. This is because the cylinder is horizontal. When I first built up my 'macchi 40 odd years ago, Rob Selby (while he was at Denco Engineering) balanced it to standard vertical single factor of 50%, which led to double vision, hands vibrating off bars and frame beakages!
Andy's first mono was ridden by a 'friend ' a couple of years ago, and the 'rod bolts' connecting the two halves of the balance weight came loose, causing the engine to self destruct. There was adequate warning this was happening as you might imagine, however some riders are not particularly mechanically sympathetic!!
At Pukekohe this Feb, Andy had a 470cc and a 530cc version. I rode the 470cc bike, and it was lovely- smooth, torquey and revvy as well. It is probably nicer to ride than the bigger version. Andy has a 4 valve injected head in his cupboard- be interesting to see this one built!!

When I was living in Belgium there was a meeting where a load of french racers came along. Among them were about half a dozen "Halfcatis". These were watercooled ones with the reaer head replaced by a thick ali plate. One of the blokes said there was a standard recipe - bore a bloody great hole through the crown of the rear piston, replace the lost weight (inside the gudgeon pin, but our communication broke down a bit here and I didn't get how, exactly), plate over the barrel, throw away all the unnecessary bits.
Some of them had simple cantilever rear suspension with the top of the unit being where the rear head would have been, didn't understand why. I've got pictures. Somewhere...

[ken seeber]

Frits, thanks for your, as usual, well explained response. However, the question still remains for me as to the primary, in this example, transition from H3 to H1 without going thru H2. A double lost movement? Either way, full admiration to the riders of the time.

[husaberg]

When I was living in Belgium there was a meeting where a load of french racers came along. Among them were about half a dozen "Halfcatis". These were watercooled ones with the reaer head replaced by a thick ali plate. One of the blokes said there was a standard recipe - bore a bloody great hole through the crown of the rear piston, replace the lost weight (inside the gudgeon pin, but our communication broke down a bit here and I didn't get how, exactly), plate over the barrel, throw away all the unnecessary bits.
Some of them had simple cantilever rear suspension with the top of the unit being where the rear head would have been, didn't understand why. I've got pictures. Somewhere...

Thats how a MVX was balanced a huge big gudgeon on the single upper cylinder.
http://www.mcnews.com.au/wp-content/...F-Pistons1.jpg
http://www.mcnews.com.au/wp-content/...F-Pistons2.jpg
http://www.mcnews.com.au/wp-content/...s-1024x935.jpg

[Frits Overmars]

Frits, thanks for your, as usual, well explained response. However, the question still remains for me as to the primary, in this example, transition from H3 to H1 without going thru H2. A double lost movement? Either way, full admiration to the riders of the time.

My pleasure Ken. The 4-speed footbox was the primary box in the 4x3 Kreidler; the 3-speed handbox was the secundary one (in the 2x6 Kreidler it was the other way around; there the 2-speed handbox was the primary box and the 6-speed footbox was the secundary one).
Below is that 4x3 version once more. You can see the cable-operated shift lever top left. When shifting from H1 to H3 or vice versa, you did go through H2, but you could do it in one sweeping move. There was no positive stop in the box; just a couple of notches and a springloaded ball. The positive stop was built in the twist-grip handle and it was released when you pulled the clutch lever, just as in most mopeds of that time.
(I wasn't quite so fortunate; my moped had only two gears, so I had to rev it to 15.000 rpm before shifting to top (2nd) gear. Yes, that did draw some attention in 1964.
But it was enough to outrun the police ).

[guyhockley]

Thats how a MVX was balanced a huge big gudgeon on the single upper cylinder.
http://www.mcnews.com.au/wp-content/...F-Pistons1.jpg
http://www.mcnews.com.au/wp-content/...F-Pistons2.jpg
http://www.mcnews.com.au/wp-content/...s-1024x935.jpg

Was that only the 250 or wasn't there a 400 before the NS?
Always seemed like one of Honda's too clever by far tricks to me.
Has the Ducati V-One been on KB?

[Grumph]

Has the Ducati V-One been on KB?

No...Andy's not on here. Kiwimacchi and I are both ChCh, Andy's Auckland so meeting up doesn't happen often.

[Grumph]

(I wasn't quite so fortunate; my moped had only two gears, so I had to rev it to 15.000 rpm before shifting to top (2nd) gear. Yes, that did draw some attention in 1964.
But it was enough to outrun the police ).

The joys of a wide ratio twistgrip changed gearbox....The NSU Prima scooter was a heavy, sluggish pig of a thing which had to be revved hard to stay with traffic - and it was easy to miss the 1-2 hand change...
But they had a Siba starter/generator on the end of the crank. Rev it too hard and segments came off the commutator on the armature.
During my high school years, the Prima sold well here. I had a flourishing business repairing the armatures for the local agents.
Never heard of one outrunning the Police though.

[husaberg]

Was that only the 250 or wasn't there a 400 before the NS?
Always seemed like one of Honda's too clever by far tricks to me.
Has the Ducati V-One been on KB?

it was the 250 i think the NS400R used a similar crank set up though
Later MVX from what i can peice together had a same diameter as the other pins but solid.
there is some stuff on them here.
https://www.kiwibiker.co.nz/forums/a...hmentid=303391
https://www.kiwibiker.co.nz/forums/a...hmentid=303390
https://www.kiwibiker.co.nz/forums/a...hmentid=303389
https://www.kiwibiker.co.nz/forums/a...hmentid=303380
https://www.kiwibiker.co.nz/forums/a...hmentid=303381

[guyhockley]

No...Andy's not on here. Kiwimacchi and I are both ChCh, Andy's Auckland so meeting up doesn't happen often.

Oops, sorry, I meant the Bart Crauwels one that turned the rear pot into a blower to feed the front one.

https://thekneeslider.com/ducati-v-o...le-conversion/

[ken seeber]

Here ya go, a 4 stroke, a 2 stroke and a 0 stroke all in the same chunk of complexity:

https://newatlas.com/camcon-digital-...-system/55827/

Still, as with any exhaust valve in the head, can't see it having the max power performance of a piston ported exhaust 2 stroke (maybe unless well supercharged), that we know and love.

[tjbw]

Here ya go, a 4 stroke, a 2 stroke and a 0 stroke all in the same chunk of complexity:

https://newatlas.com/camcon-digital-...-system/55827/

Still, as with any exhaust valve in the head, can't see it having the max power performance of a piston ported exhaust 2 stroke (maybe unless well supercharged), that we know and love.

Reminds me of Freevalve:

https://youtu.be/S3cFfM3r510