Topic: Looking for opinions...... on a Speedway Racer

[HavocTurbo]

Some interesting food for thought there Bill.

I dropped the $$ for the BH trans specs this afternoon. I won't say how much because honesty it was too much. But might give me LOADS of insight. Who knows.

On another note.... do you think that using a car transmission might be too much rotating mass for a bike engine? At least from a dead stop?

The more I mull it over in my head.... the more I think a custom trans is probably in order.

[Ecosse]

yeah, probably with a bike mill a trans more suitable than n auto sourced boxa seems to make sense. probably something to consider with the BH design. although the specs might very well lead you to more promising options. isn't that the way it usually goes?

there just has to be something out there, and not exotic, that would fit your needs. patience is a useful asset.

at least if you were to use an out engine, you have transmission options available.

[HavocTurbo]

at least if you were to use an out engine, you have transmission options available.

Huh?

[Ecosse]

at least if you were to use an out engine, you have transmission options available.

Huh?

out=auto, geez havoc' get with the program! 

[HavocTurbo]

You know...

Maybe a modified goldwing transmission? Plus there's shaft drive.

So would a shaft drive stand up to 200+ speeds? Or would there need to be lots of modifications?

Thanks to everyone (including geeto) for your input. Keep it coming!!!

[Ecosse]

You know...

Maybe a modified goldwing transmission? Plus there's shaft drive.

So would a shaft drive stand up to 200+ speeds? Or would there need to be lots of modifications?

Thanks to everyone (including geeto) for your input. Keep it coming!!!

a short shaft especially would have no problem provided the parts them selves were of suitable strength. balance has to be right of course.

a thought just surfaced. my interest in cycle cars suggests there may be a trans for your purposes. many cycle cars use Guzzi v twins but some use HD v twins. those as you know have a transverse output, so there must be something to turn the power in the north/south direction.

i go hunt now.

[Geeto67]

bmw thinks a shaft drive can handle 200 mph otherwise they would not have put it on the k1200s. However if you have seen the size of the k1200s shaft the thing is like a car driveshaft in size.

The reason I don't think the shaft is a good idea is because of shaft jacking. BMW, kawasaki, and others employ very high tech suspension systems you limit the transfer of this to the chassis, something that I think would be too complicated to work out given your bike's specalized nature.

Instead of a convention suspension, what about an airbag suspension? That way you can adjust ride height and suspension rebound while you are moving. I don't know how you would do this with a conventional fork so maybe an earls fork design with twin airbag shocks upfront and a single airbag monoshock in the rear. it could be done with a small onboard compressor on a streetbike (they make them for harleys that run air suspension) or with a good sized bottle if this is to only be a racebike. 

[Ecosse]

moto guzzi has an elaborate set up for their higher hp bikes too. i've seen some pretty wild cycle cars but don't know what suspension they employ.

sorry havoc but it seems at least one company just uses a car trans. here's the site, fwiw.

http://cycle-car.com/index.htm

the search continues...

[HavocTurbo]

bmw thinks a shaft drive can handle 200 mph otherwise they would not have put it on the k1200s. However if you have seen the size of the k1200s shaft the thing is like a car driveshaft in size.

The reason I don't think the shaft is a good idea is because of shaft jacking. BMW, kawasaki, and others employ very high tech suspension systems you limit the transfer of this to the chassis, something that I think would be too complicated to work out given your bike's specalized nature.

Instead of a convention suspension, what about an airbag suspension? That way you can adjust ride height and suspension rebound while you are moving. I don't know how you would do this with a conventional fork so maybe an earls fork design with twin airbag shocks upfront and a single airbag monoshock in the rear. it could be done with a small onboard compressor on a streetbike (they make them for harleys that run air suspension) or with a good sized bottle if this is to only be a racebike. 

I see your point about the shafts. Hmmm...

As for the suspension, what about a girder design? Would retain side to side rigidity but still be able to benefit from an air based suspension. Or BMW's telelever thing or whatever it's called.

I am definitely on board for the rear air suspension. Given the practical applications on cars and HDs that should be easy to modify to suit my purposes.

So here's what I have so far....

Aerodynamic body work (a given factor) from carbon fiber.
Air based suspension.
Carbon fiber wheels (thinking from a busa or zx-14 based design)
I was also looking at adapting some motogp carbon-carbon braking systems (heavy heavy but wow)
Transverse inline-4 (for keeping things as slim-lined as possible.
Two or three speed transmission (leaning towards 3 speed for minor driveability in the pits)
Chromoly frame (or aluminum or whatever will support this beast)


In an effort to keep things as light as possible, I would be willing to dip into my Ti supply that I was going to save for my CB750 build. Maybe a Ti frame?

Everything kind of depends on engine and trans length.
I currently have a 93 GSXF600 Katana engine that I could cut up for a donor. But maybe something bigger?

I need to dig out my parts books and manuals for the henderson and see how they laid it out. Maybe I can make something more robust.

[Ecosse]

keep in mind that all the expert advice i offer comes from a non-expert. 

is carbonfiber a good idea? if this is to be road worthy i wonder about brittle unsprung bits meeting with impacts. as i understand it that was a problem with (real) mag wheels. that speed record bicycle running down that volcanic mountain? those carbonfiber forks reportedly shattered due to the driving surface.

another question, what is the cost & labor contrast between fiberglass and carbonfiber? i know the latter is more common than years past.

all said, i don't think 200 mph is unreasonable. not easy, but not out of the question.

this is interesting.

[754]

Where do you want to do 200mph? And do you plan on roadracing it?

 Re shafts, BMW hasnt worried abut them too much for over 80 years..
 Guess how many 300mph cars at Bonneville use them?

[HavocTurbo]

Well I would be laying the fiber myself.... So cost for me would only be in material. Not that it would be cheap either way.

Road worthiness was at first a goal to be met alongside track purpose. But we can throw the road out the window as far as I'm concerned.

Any NASCAR track in the USA that only makes one direction turns will be the goal. Make it as original to the boardtracker idea as possible as far as that's concerned.

And do you think that an air suspension would eliminate the faults of a shaft?

Something to keep in mind guys... sustained runs at 200+ at over 100 laps. Grueling pace I'm sure, but a goal none the less.

Any hits on the transmission? The post is too slow for me and the interweb doesn't hold enough info. 

[754]

If you want to run 200 or 200 +, start looking for a different motor..

[HavocTurbo]

If you want to run 200 or 200 +, start looking for a different motor..

Would a biturbo 1400cc be better??

This just in.... I am now a new owner of a wrecked 08 ZX-14. Suspension and tail section are junk as well as most of the plastics.... but it runs and doesn't leak or smoke.