Thumper Club Forum

Club House => Chatter => Topic started by: Propellor on October 05, 2015, 12:05:23 PM

Title: Crossplane crank
Post by: Propellor on October 05, 2015, 12:05:23 PM

Ok, thumper dudes don't have to burden their minds with such things. But who can't have noticed the fuss made by Yamaha with their R1 cross plane engine a few years back. At least one person beat them to it.

http://www.letrabe.es/Clasp/helmuth-faths-urs-500/

Title: Re: Crossplane crank
Post by: Propellor on October 07, 2015, 05:55:16 AM

Quite an achievement. Bet it sounded good.

Title: Re: Crossplane crank
Post by: Propellor on October 07, 2015, 06:10:29 AM

It does! (FF to about 5minutes in)

https://m.youtube.com/watch?v=WuPCONnIiVU

Perhaps I shouldn't be surprised that it sounds similar to the Yamaha M1/R1.

Title: Re: Crossplane crank
Post by: Moto63 on October 07, 2015, 10:20:52 AM

That thing sounds awesome, wot a genius, it says in the write up he did a lot of it while he was off after having a crash. Hhmmm, now wot kud I build??  Certainly nothing as good/nice as that. That's fir sure. Especially with a pot on each arm. 

Title: Re: Crossplane crank
Post by: Propellor on October 08, 2015, 05:37:49 AM

A lot of the credit for the detail design of the engine goes to Peter Kuhn I think.

I read this article a few years back on google translate. My google translate isn't playing at the moment, but it is well worth a read if you can either read German or get google translate to work!

http://www.winni-scheibe.com/ta_sport/urs_kuhn.htm

Title: Re: Crossplane crank
Post by: Propellor on October 08, 2015, 06:10:52 AM

I'm not sure what the second row of vertical velocity stacks do? They don't seem to going via a carburettor. Very odd. Anyone know?

Title: Re: Crossplane crank
Post by: CrazyFrog on October 08, 2015, 08:02:08 AM

Very interesting read. Thanks for sharing!

Title: Re: Crossplane crank
Post by: Moto63 on October 08, 2015, 11:17:11 AM

I don,t reckon those secondary velocity stacks do anything, reckon he just stuck em on for more street/racing cred.   Ps yes I am joking

Title: Re: Crossplane crank
Post by: Propellor on October 08, 2015, 05:52:43 PM

Quote from: CrazyFrog on October 08, 2015, 08:02:08 AM

Very interesting read. Thanks for sharing!

You're welcome mate. No problem.

Title: Re: Crossplane crank
Post by: guest564 on October 08, 2015, 06:37:55 PM

Quote from: Propellor on October 08, 2015, 06:10:52 AM

I'm not sure what the second row of vertical velocity stacks do? They don't seem to going via a carburettor. Very odd. Anyone know?

Quote

Bosch fuel injection was fitted, the first successful use of such a system on a racing motorcycle, while in a later development aimed at improving gas flow, Kuhn specified a second set of ‘air only’ down-draught inlet ports.

https://www.bonhams.com/auctions/14264/lot/644/

Title: Re: Crossplane crank
Post by: Propellor on October 08, 2015, 07:29:00 PM

Quote from: Rhinoman on October 08, 2015, 06:37:55 PM

Quote from: Propellor on October 08, 2015, 06:10:52 AM

I'm not sure what the second row of vertical velocity stacks do? They don't seem to going via a carburettor. Very odd. Anyone know?

Quote

Bosch fuel injection was fitted, the first successful use of such a system on a racing motorcycle, while in a later development aimed at improving gas flow, Kuhn specified a second set of ‘air only’ down-draught inlet ports.

https://www.bonhams.com/auctions/14264/lot/644/

Ah, cheers. The explanation was there all the time! Wood-trees etc.

So the carb set up succeeded the injection version.

And air only inlets. With injection I can see it. But with carbs..... How?

Tune the carbs deliberately rich?