Building a race bike

Cam, your drawing proves that the design you drew wont work at all ................ and the forces you quoted, 4800N, are way over the top accordingly. The ten minutes you used to come up with the formula have been futile.

Here's how I came to those conclusions:
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Your gears have no teeth  :D
 
Hi Cam,

Have done a few calcs and come up with similar results to you,  I was actually expecting bigger numbers,
My little needle roller bearings, similar to the std Laverda outrigger clutch bearing is rated at 12700n and 15700 rpm each and using 2.
I am running the std cush in the rear wheel as well as the std cush in the clutch gear, the inner bearing housing is very big and very strong, so I have little worry it will cope.  The gears are rated at 150hp constant so a good safety here (hopefully) and that is before special treatments.

My engine torque will probably be quite low though,  I recon that "if" I actually get the revs and power I hope for, I would still be lucky to see 70nm torque.
However with the revs I will then get and the reduction by the time I gear it to the ground, it could be rather interesting for the rider!

I have taken a lot of info on the gear size etc from a Yamaha FZR engine I had a while back and my drive is a fair bit larger and stronger, but no idler gear of course.

We will see.  It only has to do a bit of racing, not last 10000km
Easy to monitor and check also.

Will be interesting.
Julian


PS.
The housing etc of my engine makes the FZR look like tin foil,  The ally is also welding very well so not crap by any means.
The clutch cover housing though is not so good and will be also bolting the bearing housing to the cover as well as welding.


 
bazzee said:
Cam,

julian's clutch(driven) gear has provision for shock absorbing rubber inserts so hopefully they will help prevent any damage...

bazzee
Click to expand...

Cam mentioned both cush drives in his presentation to the class, Bazzee. Pay attention boy!  :-* :-* :-* :-* :D

Can't you do a reverse analogy of nominal torque loading using electrickery terminology, Cam, like your pipes and volts/current/load one? Physics is too hard!  :P :P :P
 
Piranha Brother 2 said:
Can't you do a reverse analogy of nominal torque loading using electrickery terminology, Cam, like your pipes and volts/current/load one? Physics is too hard!  :P :P :P
Click to expand...

Blimey Quentin, that would be beyond me. No idea what torque would be analogous to in electrical terms  ???

Very interesting indeed Julian. I love a bit of creative engineering. I'd be like a kid in a candy store if I had access to your workshop!

I wasn't entirely sure whether you were going to have a fixed (stationary) shaft with the idler gear spinning on a needle roller, or a rotating shaft supported by bearings each end. But your comment about inner and outer bearing housings has clarified that. I reckon that's the better way to go. The idler gear will be much better supported and aligned if it's fixed to a rotating shaft with a bearing at each end.

Sounds like you've done your homework and it'll be a robust enough design. Obviously you'll need to weld material on the crankcase wall and inside the primary cover, into which you'll machine the bearing recesses. Getting the bearings perfectly aligned is a bit of a head scratcher though. I'm guessing you won't be able to line bore from the inside of the crankcase because there's a divider wall inside the lower case between crankshaft and gearbox that'll get in the way. Not to mention the other side of the crankcase. The alternative is to set it up in the milling machine, fit the primary cover and bore through from the outside of the primary cover. Am I on the right track?
 
I love it when the technical blokes get practical, that's a rare thing in my experience. The visa versa is also rare. Makes for a great thread.
 
Dellortoman said:
Blimey Quentin, that would be beyond me. No idea what torque would be analogous to in electrical terms  ???

Very interesting indeed Julian. I love a bit of creative engineering. I'd be like a kid in a candy store if I had access to your workshop!

I wasn't entirely sure whether you were going to have a fixed (stationary) shaft with the idler gear spinning on a needle roller, or a rotating shaft supported by bearings each end. But your comment about inner and outer bearing housings has clarified that. I reckon that's the better way to go. The idler gear will be much better supported and aligned if it's fixed to a rotating shaft with a bearing at each end.

Sounds like you've done your homework and it'll be a robust enough design. Obviously you'll need to weld material on the crankcase wall and inside the primary cover, into which you'll machine the bearing recesses. Getting the bearings perfectly aligned is a bit of a head scratcher though. I'm guessing you won't be able to line bore from the inside of the crankcase because there's a divider wall inside the lower case between crankshaft and gearbox that'll get in the way. Not to mention the other side of the crankcase. The alternative is to set it up in the milling machine, fit the primary cover and bore through from the outside of the primary cover. Am I on the right track?
Click to expand...

Or, bore the hole in the crankcase on the mill, make up a taped spindle (think plum bob) that suits the bore, long enough that the point will interfere with the inside of the primary case (1-2mm deeper) and bolt up the primary cover, leaving a datum point in the inside of the cover.

Then do what has to be done from there.
 
Piranha Brother 2 said:
Cam mentioned both cush drives in his presentation to the class, Bazzee. Pay attention boy!  :-* :-* :-* :-* :D

Can't you do a reverse analogy of nominal torque loading using electrickery terminology, Cam, like your pipes and volts/current/load one? Physics is too hard!  :P :P :P
Click to expand...

mea culpa. I will make sure I read everything twice!

bazzee
 
chrisk said:
Or, bore the hole in the crankcase on the mill, make up a taped spindle (think plum bob) that suits the bore, long enough that the point will interfere with the inside of the primary case (1-2mm deeper) and bolt up the primary cover, leaving a datum point in the inside of the cover.
Click to expand...

I'm no expert in this sort of thing, but I reckon you need more than a datum point. You need the shaft alignment as well. You could use the primary cover joint face as a reference plane, but I doubt it would all be accurate enough doing it that way.

Anyway, I dunno why we're speculating. I'm sure Julian has it all figured out and will do it in a sensible and practical way that dimwits like us haven't thought of.  :D
 
Dellortoman said:
The alternative is to set it up in the milling machine, fit the primary cover and bore through from the outside of the primary cover. Am I on the right track?
Click to expand...

Spot on Cam,  been thinking about this and did think about datums etc and many other ideas but the simple answer is to simply bore straight through and plug the end afterward.

All welded up now and looking really strong. Pilot bored and ready for main boring.  Need to make up a bloody big jig first though to hold it square to the table for machining.  Oh what fun  :'(

Julian
 
Way bigger engine compression can be used, but it can require huge effects to contain it. Big studs, even brackets and connections above and below the cylinders.
 
It was being used to adulterate alcohol in a well popular Asian resort a while back with people permanently blinded.
 
The difference in jetting is that you need jets about five times the size of with petrol. The alcohol fuel has a different flow rate through the jet, apparently although I haven't researched it myself, and it can be hard to determine correct jetting up or down (all of this is from third party hearsay). This doesn't mean that you get one fifth of your mileage from the fuel tank. There are other issues with using alcohol fuels though, it can't sit in the carburettor and has to be drained after a race meeting. We aren't allowed to use it racing here in uber-green scandinavia which is odd. A big danger with alcohol is that you can't see the flames when it burns, bikes using it in other countries have a special sticker on their numberplates.
 
Hi,

In general you start with jets with about 100% more flow for straight Methanol over petrol and then play from their.
The thing is that the stoichiometric ratio for ideal fuel air is about 13:1  and with Methanol its about 5.5 or 6:1 
However the rich limit of Methanol (the point where it stops giving good power) is as low as 2.5:1 if you have a good spark. And it keeps giving more power all the way down to at least 3:1 so if you can keep the spark and have a good combustion chamber you can really get a lot more power from Methanol than the book actually says you can.
Methanol gives about 9500 btu/lb and fuel about 18 to 19000,  "The book says" if you run a little over double the fuel flow you get about 17% more power
However in practice, a really good engine can give a lot more.  You can run a CR as high as 15:1 although generally about 14:1 is a sensible limit.
You can go much richer as mentioned so about 3 or 4 times the fuel ratio because it caries its own Oxgen atom which is liberated in burning, so it is possible, and I have seen power raising a good 30% over high octane petrol / avgas on an unsupercharged engine.  But the subject is quite complex and never as easy as it sounds.
On a Blown engine then we are really talking!!!  Methanol has a massive latent heat of vaporization (about 480 btu/lb @ 50 deg C) and therefore cools the mixture down a lot on atomisation,  in a Blown engine it is a fantastic liquid inter-cooler and your charge density goes through the roof compared to using avgas etc so you can burn even more fuel.
(we regularly have ice forming on the blower after a race when using methanol and if the same engine is run on avgas you can't touch the blower without burning your hands.

Massive subject and I am no teacher but that is a very rough overview.

Julian

PS.
Do not worry about banging bearings out etc.  Methanol is a very stable and generally gentle fuel to work with, it burns very slowly and is relatively easy to control,  Remember you have a "burn" in the combustion chamber "not an explosion" That is called "Detonation" and it's not what we want in any engine.

Tippie,  we have to use a special blue dye in the fuel that makes the fuel burn with a coloured flame,  FIA regs.  And an Orange sticker.
 
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