Donor Gearboxes

[F5 Dave]

Sometimes you have to go What the Hey, and just do it (Ferris Bueller reference).

. . . although, a small +++ on the keyboard and it could be a 500. . .

[husaberg]

Spreading the load over two mounts with the bracket seems potentially more sturdy
the weakest part of any v engine is apparently the thigh gap

[F5 Dave]

Yeah but he doesn't have two hoady 500cc overly complex pistons waving around.

[husaberg]

Yeah but he doesn't have two hoady 500cc overly complex pistons waving around.

Granted but I would personaly rather sacrifice a few gms of weight rather than recast and re-machine a set of cases.

[Grumph]

This is the point where you pause and reflect on whatever frame design you have in mind - and how much frame loading you're prepared to put through the cases.
If the answer is "some" then cast in lugs - albeit with a spacer between - are your preferred option
If the design isolates the motor then the bolt on plates - with maybe urethane bushings - will suffice.

The trick is to finish up with a nicely integrated design which both looks good and functions well.
And of course has access for servicing.....

[el chupacabra]

It's happening. . . Only the rear half to go.

[el chupacabra]

I am about to cut the pattern for the second half of the engine in the next week. I realised after some looking around that the gearbox from a 675 Daytona will also drop straight in, I can also make some modifications before casting to allow this to fit directly into a 675 chassis.

[el chupacabra]

I’ve been making progress on one of my other projects and in working on that, I’ve learnt more and more about how I wish I did the V4 in the first place (I’ll be using patterns on a match plate) . . . I’m about to cut my losses and do a complete redesign.

It will be designed like an RZ500 (each crank individually drives the clutch) except it will be a 90* vee angle, same triumph gearbox and Yamaha banshee cranks. I will also run banshee cylinders on the first edition. Making it a cylinder reed 700cc V4. It should make the design simpler and the overall size much smaller.

The only thing I’m wondering is if I will be able to balance it very well with the stock banshee cranks.

[husaberg]

https://www.kiwibiker.co.nz/forums/a...8&d=1411468044

always been a fan of how they built the RS500 Honda

[husaberg]

Then you have the Cagiva/yam Way. which is similar

[husaberg]

left feild option is to make it like a doubled up aprilia with center plates
RD cranks lend themselves to sliping in halves