Board logo

Bike engined gtm rosaa
lvdxd00 - 27/12/19 at 01:25 PM

I’m thinking of getting a gtm rossa k3 and putting a bike engine in the place of the k series motor.
I want to retain the original gearbox, to enable me to have a reverse and keep the drive line.
I think the drive output from most bike engines is on the left and the k3s gearbox is on the right.
So I would need a shaft remote from both the engine an the gearbox linked via a chain either side?
What are your thoughts.
I’m guessing it’s a none starter, as if it was someone would have done this already
Cheers
Dave

Sam_68 - 27/12/19 at 05:27 PM

Apart from the gearbox input being on the opposite side to the engine output, I think you'll find that:
a) The overall length of the package would be too great to fit between the rear bulkhead and the rear axle line of the Rossa, and;
b) The gear ratios would all be to cock.

You might be able to correct (b) by using different sprockets on your 'lay shaft', but what with carrying the additional weight of the PG3 gearbox and the power loss through two chains (not to mention the complexity of keeping those two chains tensioned), it's not going to make much sense.

The K-series can be tuned to produce more power and LOTS more torque than any bike engine, so why bother?

lvdxd00 - 27/12/19 at 05:55 PM

Thanks for the info, as I suspected a none starter.
Tuning the k series sounds like an option.
What sort of power can you get from one?

Mash - 27/12/19 at 08:17 PM

Caterham managed 250 from theirs

SPYDER - 27/12/19 at 08:23 PM

quote:
Originally posted by lvdxd00
Thanks for the info, as I suspected a none starter.
Tuning the k series sounds like an option.
What sort of power can you get from one?


How deep are your pockets? A quick google will bring up DVA Power website. K series specialist. ( Many others available)
Up to 190hp off the shelf. 280hp bespoke.
£800 up to many thousands.

I'm not recommending DVA, just pointing out that two minutes on google will answer many a question.

lvdxd00 - 28/12/19 at 11:51 AM

My pockets aren’t deep enough.
I still like the idea of connecting a bike engine to the existing gearbox.
Just trying to figure out rotations.
Bike sprocket on the left with a anti clockwise rotation.
Gearbox on the right, don’t know input rotation direction.
Could spin the bike engine 180, putting the sprocket on the right, would that make the output rotation clockwise?
Dave

[Edited on 28/12/19 by lvdxd00]

Dingz - 28/12/19 at 10:23 PM

A K3 is not particularly light either.

pmc_3 - 29/12/19 at 11:55 AM

Did you see this on ebay? https://www.ebay.co.uk/itm/GTM-ROSSA-2-BIKE-ENGINED-RWD-PROJECT-/124018722213?u l_noapp=true&nma=true&si=sY5lH9PpocGzJVxbWcRUoHRsreg%253D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557

lvdxd00 - 29/12/19 at 12:33 PM

Ye, I saw that. It looked good, but too expensive for me

MikeRJ - 30/12/19 at 01:40 PM

quote:
Originally posted by lvdxd00
My pockets aren’t deep enough.
I still like the idea of connecting a bike engine to the existing gearbox.
Just trying to figure out rotations.
Bike sprocket on the left with a anti clockwise rotation.
Gearbox on the right, don’t know input rotation direction.
Could spin the bike engine 180, putting the sprocket on the right, would that make the output rotation clockwise?
Dave


The K series engine crank (and therefore the gearbox input shaft) turns in the same direction as the wheels i.e. clockwise when viewed from the crank pulley end of the engine. The vast majority of engines are the same, with some of the older Honda engines being exceptions (B and D series).

This means you could theoretically use a suitable Honda gearbox mounted on the left hand side of the engine bay and link it directly to the bike engine output sprocket. However I echo others sentiments on this; it's a poor idea since you are introducing another entire transmission's worth of power loss in the drivetrain, and getting a suitable final drive ratio may be difficult.

lvdxd00 - 31/12/19 at 11:03 AM

quote:
Originally posted by MikeRJ

The K series engine crank (and therefore the gearbox input shaft) turns in the same direction as the wheels i.e. clockwise when viewed from the crank pulley end of the engine. The vast majority of engines are the same, with some of the older Honda engines being exceptions (B and D series).

This means you could theoretically use a suitable Honda gearbox mounted on the left hand side of the engine bay and link it directly to the bike engine output sprocket. However I echo others sentiments on this; it's a poor idea since you are introducing another entire transmission's worth of power loss in the drivetrain, and getting a suitable final drive ratio may be difficult.


At this point in time, I’m only planning, getting ideas.
If I go down the bike route, I need to connect it to the rear wheels. I would need a diff and a reverse setup also.
Could be chain driven.
I was just being simplistic I suppose.
I would be interesting to try. I would have five gears to choose from. One of them might be right. Could also change the diff gear too.
Once the right ratio is found then gut the box of the extra weight
Probably over simplified.
Dave

StevieB - 1/1/20 at 08:48 AM

I seem to recall Z Cars did a Hayabusa conversion on an Elise some years ago, so it’s not beyond the art of the possible t9 put a bike engine in. Plus there’s a couple of front end conversions for mini’s that prove it’s possible to keep a bike engine and drive train in a compact package.

I know what people are saying about tunability of the K Series, but it’ll be expensive and highly strung to get anywhere near the power output of a reasonably modern thousand plus cc bike engine. Packaging the bike engine to fit might balance out the pennies though, depending on your fabrication skills and equipment (I.E. how much you need to outsource/commission one offs).

Another common conversion on Elise’s is a Honda Type R, and I know duratecs and Audi l7mos have been used as well - might offer an alternative?