MilesJ

I am thinking about using a legends thunder roadster as a basis for a DM car for SCCA Solo autox. The 13b is allowed in DM and the thunder roadster comes with yamaha 1250cc engine which is not allowed in DM. However, DM only disallows non-automotive CVTs so the sequential trans from the TR is allowed.

I was wondering if there is a way to mount the 13b to the yamaha trans or any other motorcycle trans like the hayabusa trans?

If nothing else I know I could use a 2nd gen 13b with the stock 5speed for this car, but I want to keep the weight down and keep the fast shifting motorcycle trans.

Any thoughts?

Striker-7

iTrader: (3)

Aside from the mounting issues, motorcycle transmissions lack one feature road cars need from time to time: a reverse gear. I understand that Solo and ProSolo courses (autocross in general) don't use reverse, but there's that little thing of pits, paddocks and such.

http://grassrootsmotorsports.com/pro...s/berzerkeley/ for a few thoughts on the subject. They were using a GSX-R750 powerplant / transmission, might have something to bring to the table.

eastcoastchaos

A motorcycle transmission is built into the motor, it is sandwiched between the 2 case halves and to even access it you have to strip down the whole motor (Head, cylinder, clutch, water pump, generator etc.) then split the cases. There are some with reverse, like a goldwing or most sport atv's which I know isn't a motorcycle but the engine's are pretty much the same.

low12lightning

Search rotorcycle. Someone made a 13b powered motorcycle a few years ago.

TeamRX8

iTrader: (25)

Don't bother, it didn't use a motorcycle trans

http://www.mazdatrix.com/rotorcycle.htm

The only stand-alone motorcycle transmission I can think of was the early Harley Davidson box. There us a company called Ultima that makes gearboxes for some bikes, but you have two big hurdles for that idea. First, the rotational axis of a motorcycle engine is oriented 90 degrees different than a car engine (perpendicular to the vehicle rather than parallel/inline). You could mount the engine perpendicular to overcome this so maybe no bid deal depending on the packaging constraints. Second, they were likely never intended to handle the load of a rotary engine so reliability may be an issue.

If you are really serious I would recommend calling Taylor Race Engineering in Plano, TX. They have done a lot of unique trans and drivetrain projects and would probably have several ideas on how to do what you need.



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mwood

How about a race Powerglide with a 7" converter and 8000rpm stall?

You may think I'm kidding...only partly

FastFreddy61

The Glide weighs around 50 kilo's and has 2 forward gears, very little engine braking, why would he even contemplate this? Miles, I assume you've looked into other automotive sequential transmissions?

mwood

A race Powerglide weighs closer to 95lbs and, for autocross, the lack of gears/engine braking is of less importance. In an autocross environment, quite frequently first gear is for starting, second is used the rest of the run...but, yes, it is a strange choice. There are also off the shelf solutions for bellhousings etc., as the 'glide is widely used by 13b powered drag racing cars.

Even an early Mazda 5spd may end up weighing more, factoring in the trans weight, plus flywheel, clutch, master and slave cylinders, plumbing, pedal etc. Like I said, I was mainly kidding, but the idea is interesting. We've seen a number of successful modifed/prepared autocross cars with 2spd transmissions of various types.

fastmike

A late model CVT snowmoblie "trans' MIGHT hold up.
Lots of 250hp sleds running around out there but snow and or ice slips. Still, they do drag on concrete and asplalt.
Thundercat or Skidoo 1000 should be tough. Electric reverse could be incorporated. You have to put the rotary "sideways" but it is pretty short. Chain or a shaft drive might have to be incorporated.
Gold wing might work ok. Or just go all Gold Wing since it is already a flat 6 and has the shaft drive. Getting that shaft drive to work at the rear end of the car would require some work since motor cycles only have 1 wheel back there but you see the Wings with the 2 rear wheels from time to time cruising around usually pulling trailers but I think they replace the rearend.
Reverse would be taken care of too if you went all Gold Wing.
Not sure if the Wing motor is legal though.
Look how Norton did their most recent rotary bike Still, you got the 90 degree thing at the rear of the car tot take care of and i have my doubts that the tranny/clutch/output shaft etc would hold up.
FM