Reversing an engine

Contra-rotating engines still used in MotoGP so they must give some benefits.
 
chrisk said:
??? No you wouldn?t. Put an idler gear between the crank and clutch ast standard rotation ang you?d go backwards very quickly
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You think about that before you typed, CK?  :D An idler gear between the primary and the clutch would give the same rotation as a chain ... which supports my case that the reverse running engine would then be running in the wrong direction (five reverse gears  :LOL: :LOL: :LOL:); the idler gear goes in the opposite direction, the clutch goes in the same direction.

  ... unless of course Mark and Red's plan involves taking final drive off the current layshaft!!!
 
Piranha Brother 2 said:
  ... unless of course Mark and Red's plan involves taking final drive off the current layshaft!!!
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Well, thanks a given  8)  The 'layshaft' will be the 'output' shaft

However, more cold beer will also be required to sort out just one or two more details eh  :-X
 
markQLD said:
Maybe we drive the lower pump gear and have the upper gear 'driven'? 
, just saying ...  (beer)
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Or run an external electric oil pump
 
Red,
was it only beer? :o
Distance of the crankshaft and the main gear shaft is to big to make it without primary chain. Intermediate gears- where to fix properly. And whats the reason? Do you intend to have a solid first gear shaft and use the second to drive the chain to the back wheel as other gear boxes do?

Maybe you are close before to build your own engine- look how John Britten did and he used a GSXR gearbox.
Andre
 
belt drive oil pump is a good idea, thanks Piet

yes, idea is to drive the rear wheel off of the rear gearbox shaft as per nearly every other modern bike does so just need to find a modern gearbox that is right hand drive with 6 speeds
we did consider using a Zane box but decided against that pretty quick as not being a good option
why machine new engine cases and cripple the design with a suspect gearbox

only beer is consumed in the workshop Andre, most times anyway  :D


 
Piranha Brother 2 said:
Do I get a prize for sussing that possibility?  :D
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I doubt it. Although Red didn't state it at the outset, that's the whole point of the idea to run the engine backwards in the first place. He wants to build a gearbox with separate input and output shafts rather than the existing setup with input and output on different ends of the mainshaft.

Ducati engines run backwards. Never heard anyone complain about the gyroscopic effect. I'd be surprised if it's an issue.
 
Dellortoman said:
.. that's the whole point of the idea to run the engine backwards in the first place.
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+1 , we assumed that bit may be obvious enough. no?
But I did consider to retain the primary chain to keep things simple?  If it ain't broke, don't fix it eh?  :-\

ay Cam, after observing your drafting skills I reckon your our detail man?
Dellortoman said:
I've done a couple of simple drawings overlaid on the chain primary drive so you can see what I mean.
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Would be great to bin the primary chain with gears but was thinking the clutch, on a triple, may be a bridge too far.
& your 'simple drawings' have confirmed that, thanks  (thumbup)
cheers, Mark


 
markQLD said:
Would be great to bin the primary chain with gears but was thinking the clutch, on a triple, may be a bridge too far.
& your 'simple drawings' have confirmed that, thanks  (thumbup)
cheers, Mark
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Keep crank in same direction and put in two extra gears ............. simple.
 
ay Chris, but two extra gears means increasing the power loss? no?
Reckon the only geared primary I would consider is to have the crank gear directly driving the clutch gear.... way more simple  :D
 
markQLD said:
ay Chris, but two extra gears means increasing the power loss? no?
Reckon the only geared primary I would consider is to have the crank gear directly driving the clutch gear.... way more simple  :D
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Don't know about that, Cam may be able to calculate it.

I did it on a machine here at work, it uses a mechanical micro-switch overload. Using chains to sprockets we would get regular overload errors.
Replaced chains and sprockets with two same sized matching gears, and we haven't had an overload yet. Meaning, the two gears work easier than the chain set-up.

But, I don't know what power using the stupid chain drive to clutch chews up.
 
markQLD said:
your 'simple drawings'
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Well, they were simple to do because I already had a CAD drawing of the chain primary drive. All I did was overlay the red outlines of the gear PCDs.

I did a bunch of CAD drawings of the primary drive several years ago when Red and I were talking about conversion to a Morse Hy-Vo type chain. I think Red got as far as actually buying the chain and (blank) sprockets, which weren't cheap. But Andychain's duplex Merc chain appeared at about that time, and it seems to be performing pretty well so the search for alternatives got shelved. I still think it would be interesting to give it a try though.

Here's a drawing of the Morse type primary drive if anyone is interested. It has the same chain pitch as the roller chain so has the same numbers of teeth on the sprockets. PCDs and centre distance all fit too.
 

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chrisk said:
Don't know about that, Cam may be able to calculate it.
.....................
But, I don't know what power using the stupid chain drive to clutch chews up.
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Correct, and I will concede that running two intermediate primary gears may be a tad more simple than reversing the crank?
But .....  :-\

ay Cam maaate, you are the mechanical engineer and detail draughtsman,
so my shout eh?  8)
 
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