Race chassis

[Bert]

we think its hydroformed

Agreed, no tooling marks so wouldn't think it's pressed.

Then everything else is rolled.

[Yow Ling]

Yep, Southern Gas. Easy folks to deal with.

About $160 for F size argon 5m3 from Southern gas $9 to deliver the next day

[cotswold]

not sure who made this but it looked interesting

[Grumph]

Where did you find those pics ? Got any more info ?
Looks like the engine started life as a small CZ/Jawa.

[cotswold]

Where did you find those pics ? Got any more info ?
Looks like the engine started life as a small CZ/Jawa.

I spotted it on a race bike for sale page, the guy was after information on it, so far Daf variomatic and rotary valve conversion have been mentioned but nothing definitive, most likely a one off home build

[WilDun]

I spotted it on a race bike for sale page, the guy was after information on it, so far Daf variomatic and rotary valve conversion have been mentioned but nothing definitive, most likely a one off home build

Is it from NZ or somewhere overseas?
I have seen front suspension done like that somewhere before (quite recently, by an American guy).
It seems that the bulky transmission? brake? blower? or whatever, is driven from (or drives) the gearbox output
That looks like shaft and bevel drive to ohc.(spindly shaft).
Would be a bit worried about the front brake, the rear subframe (he must have been a lightweight rider) and the fuel tank/frame though, but good on him for original thought!

Must have been done in the nineteen sixties I reckon and it looks like the kids have been clearing out grandad's garage! That's what I feel is going to happen in my case too

Whatever it is, it was a brave attempt at making something different with a lot of original thought (needed some development and refining though!).

[Frits Overmars]

Looks like the engine started life as a small CZ/Jawa.

so far Daf variomatic and rotary valve conversion have been mentioned but nothing definitive.

That looks like shaft and bevel drive to ohc.(spindly shaft). Must have been done in the nineteen sixties I reckon

The bevel shaft is driving a toothed belt to a vertical shaft that hints to a rotary valve rather than an overhead camshaft.
I'd situate it somewhere in the seventies. I can confirm Jawa/CZ front and rear hubs and some DAF variomatic components.

[Grumph]

The bevel shaft is driving a toothed belt to a vertical shaft that hints to a rotary valve rather than an overhead camshaft.
I'd situate it somewhere in the 'seventies. I can confirm Jawa/CZ front and rear hubs and some DAF variomatic components.

Most people building a special to try out an idea would only do one unorthodox thing at a time...
That has so many unorthodox features I suspect it was never finished.
I look at those shocks and wonder if work continued on it into the 80's.

[Michael Moore]

I have seen front suspension done like that somewhere before (quite recently, by an American guy).

Jeff Henise's F37 Kawasaki vintage racer. I made him aware of the DMW telefork with external damper and he took it from there.

http://www.highwaymanbikes.com/desig...acing-chassis/

cheers,
Michael

[Grumph]

Jeff Henise's F37 Kawasaki vintage racer. I made him aware of the DMW telefork with external damper and he took it from there.

cheers,
Michael

I immediately thought of John Wittner's Guzzi...Just shows there's nothing new.

[WilDun]

Jeff Henise's F37 Kawasaki vintage racer. I made him aware of the DMW telefork with external damper and he took it from there.

http://www.highwaymanbikes.com/desig...acing-chassis/

cheers,
Michael

Frits,
I do see your valve theory now, could it be a Froede type as tried by NSU?

YES Michael,
I realize now where I had seen that front end recently! Seemed like a good idea at the time and it still is a good idea (I like it).

My ideas about things can often be a bit incorrect, but they at least tend to bring out the real story behind all these uncommon setups! - this of course does reinforce what I say in the quote at the bottom of all my posts!

[Frits Overmars]

Frits,
I do see your valve theory now, could it be a Froede type as tried by NSU?

Could be, although my first thoughts went to an Aspin valve.
But your guess is as good as mine; I have nothing more than Cotswold's pictures to go by.

[Muciek]

Wanted to ask, I'm building something like bucket racer but there is a rulebook that states in that class no parts after 1984, right now I'm looking for rear shocks, any of You guys have any ideas for what (model of bike) ones I should look? Bike will be weighing around 85kg 18 inch wheels, we race mostly on kart tracks so I want to set wheelbase short around 1220 1200mm. Any help and opinions would be appreciated.

[Frits Overmars]

Wanted to ask, I'm building something like bucket racer but there is a rulebook that states in that class no parts after 1984, right now I'm looking for rear shocks, any of You guys have any ideas for what (model of bike) ones I should look? Bike will be weighing around 85kg 18 inch wheels, we race mostly on kart tracks so I want to set wheelbase short around 1220 1200mm. Any help and opinions would be appreciated.

Try to loose another 20 kg if the rulebook is OK with that.
Smaller wheels (Heidenau offers good 16" racing compound tires) will make the bike twice as nimble on those kart tracks, and a short wheelbase (<=1200 mm) will do the same.

[Muciek]

Wheels cannot be smaller than 18 inch, front fork tubes max 35mm ... Loosing another 20kg's I think is impossible (from the bike of course ), low 80's should be possible. People use here rsw heidenau tires (street super soft?) and they are great for those tracks (slicks are not permitted). I'm also thinking about fabricating emulators for the front forks (sth like this https://www.mikesxs.net/parts/img250/27-1086.jpg ) (Mz 250 front fork will be used). I'm wondering can I use "modern ish" geometry settings with steering angle , rake ect, or with certainly not "GP" suspension and other stuff I should stick with other settings?