Race chassis

**husaberg** · 6th February 2012, 10:38

Interestingly i read the other day that Fritz Elgi has the patent for the braced swing arm with a non linkage much like a squashed cantilever.
it appears both Honda and Yamaha pay license fees to use it.

Grumph the other day mentioned Wulfmuller and Heidebrand

Originally Posted by Grumph

Stephen.....you've gone a bit too inscrutable...spell out exactly what you're getting at please. Motor swapping from one frame type to another has been done since the Hildebrand and Wolfmuller first came on the market. The practicalities of it mean that until it's done and tested the average Joe won't know if the vibes are better or worse until he tries it. If you have access to massive computer capacity and the time by all means simulate it for us.....in the meantime, adjusting the balance factor until the PERCEIVED vibration is acceptable works for me....
Tying a motor in to a frame with a larger than normal number of mounts will all else being equal raise the resonant frequency of the whole thing...whether this actually helps reduce perceived vibration or the opposite depends on many things, most of which the builder can't change...One guy here with a BSA twin read some theory on the net and turned out with what looked like an Americas Cup keel on the underside of his motor - reckoned it was smoother....but he would say that wouldn't he.

This below has some interesting stuff on properties and design from Ken Sprayson original from Reynolds Home of 531

**Grumph** · 6th February 2012, 15:57

It's too late for me to take the Rudge frame to the village blacksmith...it's alredy painted LOL.

I recommended something similar to Kerry Reeves who rode Bob Harris's Enfields...I watched him go round the 500 with an enormous pair of ring spanners tightening all the frame bolts after a practise session. Essental to make it handle he said...
I told him next time Bob had the motor out, align and true everything up and bronze all the joints including the bolts....

The materials bit is biased in favour of high tensile steel as you'd expect. For normal use incl racing, mild steel is quite satisfactory.
Kevin Cameron said it best - the yeild point of the better steels is only about 5% higher...to get any benefit you've got to crash hard enough to bend mild steel but not hard enough to bend high tensile....

**quallman1234** · 6th February 2012, 23:13

this is cool, if no one has seen it...

http://www.facebook.com/pages/MJ-Wor...6964?sk=photos

**Brian d marge** · 7th February 2012, 01:10

Originally Posted by Grumph

It's too late for me to take the Rudge frame to the village blacksmith...it's alredy painted LOL.

I recommended something similar to Kerry Reeves who rode Bob Harris's Enfields...I watched him go round the 500 with an enormous pair of ring spanners tightening all the frame bolts after a practice session. Essential to make it handle he said...
I told him next time Bob had the motor out, align and true everything up and bronze all the joints including the bolts....

The materials bit is biased in favour of high tensile steel as you'd expect. For normal use incl racing, mild steel is quite satisfactory.
Kevin Cameron said it best - the yield point of the better steels is only about 5% higher...to get any benefit you've got to crash hard enough to bend mild steel but not hard enough to bend high tensile....

Sadly steel isnt in vogue any more, ( don’t tell em its actually pretty dam good !!!!)
I remember trying to make a foot peg , out of 4140 or something similar , and my tutor asking me why I was using it , cos its Strong says I ...... I got the "look"

its all about " I"

and those enfield frame were just about keeping a loose collection of bit is roughly the same area !!! fine for going to work, but that’s about all I’ve cracked one by using it in VMX ,,, the crusader frame is slightly better ,,,

Stephen

**Ivan** · 8th February 2012, 18:58

some legend is building this

**crazy man** · 8th February 2012, 19:36

Originally Posted by Ivan

some legend is building this

well done its looks not to far of. what kind of engine are you putting in it?

**gav** · 8th February 2012, 21:26

Saw this on FB, looks pretty cool, don't know much about it though .... except its not as big as you think at first glance, its a Honda Z50 motor.

**crazy man** · 9th February 2012, 01:21

Originally Posted by gav

Saw this on FB, looks pretty cool, don't know much about it though .... except its not as big as you think at first glance, its a Honda Z50 motor.

l like that good for a class just bigger than miney bikes like the indoor go-karts we had here in town years ago. l found a pic in a book of a guy that made a v twin out of one of though's motors . look like a small duke!

**Ivan** · 9th February 2012, 11:18

Originally Posted by crazy man

well done its looks not to far of. what kind of engine are you putting in it?

a bitsa honda single haha got 2 sl125 engines 2 xr200 heads witht eh larger valves and cam out of a xr200 one head has been ported ones standered and theres a bike i know of that threw a cam chain that was at the local recycling centre im trying to get

**crazy man** · 9th February 2012, 14:53

Originally Posted by Ivan

a bitsa honda single haha got 2 sl125 engines 2 xr200 heads witht eh larger valves and cam out of a xr200 one head has been ported ones standered and theres a bike i know of that threw a cam chain that was at the local recycling centre im trying to get

when you get them going fast they blow the oil filter in the engine

**husaberg** · 13th February 2012, 20:50

I am sure the older readers can remember this i don't know his last name but at the time it was super trick.
I am not sure how the the rear suspension works because it looks sideways in the pic but not mentioned in the blurb.

Some will know who Sean is I bet?

**Kickaha** · 13th February 2012, 21:02

Originally Posted by husaberg

I am sure the older readers can remember this i don't know his last name but at the time it was super trick.
I am not sure how the the rear suspension works because it looks sideways in the pic but not mentioned in the blurb.

Some will know who Sean is I bet?

Nardo, went for a couple of rides with him back in the nineties on Ducati club runs, he did a bit of work on the flying Kiwi sidecar which set a couple of records as well

Shock was sideways and compressed from both end I think, something Yamaha had done on the OW61
http://books.google.co.nz/books?id=8...ension&f=false

**husaberg** · 13th February 2012, 21:13

Originally Posted by Kickaha

Nardo, went for a couple of rides with him back in the nineties on Ducati club runs, he did a bit of work on the flying Kiwi sidecar which set a couple of records as well

Shock was sideways and compressed from both end I think, something Yamaha had done on the OW61
http://books.google.co.nz/books?id=8...ension&f=false

Bloody trick alright, Real hard to get the wheel base short on a Bevel so well done

**Bert** · 14th February 2012, 17:23

Originally Posted by husaberg

Bloody trick alright, Real hard to get the wheel base short on a Bevel so well done

Another instalment from MJworks (the guys that built the KTM 300 single; posted a while back):

http://www.facebook.com/media/set/?s...7106964&type=1

Sorry it's facebook but haven't found any other link to his work.