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 :scratch:
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 :rolleyes:

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/design-and-construction-of-the-highwayman-f37-road-racing-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/design-and-construction-of-the-highwayman-f37-road-racing-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! :rolleyes:

[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 :laugh:), 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?

[Frits Overmars]

can I use "modern ish" geometry settings with steering angle , rake ectSure you can. Here are some racewinning dimensions.
wheelbase 1200 mm
fork yokes offset 0 (yes, zero) mm
rake angle 16°
trail 90 mm
Concentrate all masses so that the center of gravity will be directly in front of your knees.

[F5 Dave]

Whimper. 16. . , degrees?!?!


Please say its for Shopping trolley racing?

[Frits Overmars]

Whimper. 16. . , degrees?!?! Please say its for Shopping trolley racing?The decisive factor is the trail, not the rake angle. You can even have the same 90 mm trail with zero degrees of rake, but that would necessitate 90 mm offset in the fork yokes, which would place the total center of gravity of forks and front wheel 90 mm behind the steering axis.
I proposed 16° rake because that minimizes the offset, and with zero offset the steering inertia is also minimized, which is good for both swift steering and rider feedback.

[Grumph]

All good and correct, Frits but really only suitable for lightweight bikes - and riders...As the OP wanted.
But try that on anything heavier and you run into fork stiffness problems quite quickly.

Which leads us on to the land of funny front ends......

[Muciek]

Thanks Frits for all the info.I'm not so lightweight :lol: , with protective gear it's bit over 90kg. Any tips on rear shocks ? Bike should have around 30hp (125cc rotary valve).

[Frits Overmars]

All good and correct, Frits but really only suitable for lightweight bikes - and riders...As the OP wanted.
But try that on anything heavier and you run into fork stiffness problems quite quickly. Which leads us on to the land of funny front ends......Grumph, would you care to define lightweight? Below there's a picture of a friend of mine, next to a normal human being (me).
He tips the scales at well over 100 kg and he is a multiple 50 cc champion in the German SimsonGP series. The frame dimensions I quoted above went into this bike.
324208 324209 324210

PS: I love funny front ends.
Wenever I feel the need to take my mind off two-stroke development for a moment, I start sketching hub-centre front ends, lateral suspension, etc.

[husaberg]

Whimper. 16. . , degrees?!?!


Please say its for Shopping trolley racing?

People are more aware of very small differences in Trail than even notice rather large differences in rake.
(Paraphrased Foale)
There is some good oil in his book even your example is castor based

[Michael Moore]

Chris Cosentino started off with near zero rake with offset for trail with a Hossack/Fior FFE on his first Rotacular single (600+ Rotax) and later went to around 16 degrees with zero offset. He's using something around the latter for his Moto2 project.

http://moto2-usa.blogspot.com/

Unfortunately the daily grind doesn't seem to be providing enough extra cash and time to do anything on the V4 recently.

cheers,
Michael

[Grumph]

Grumph, would you care to define lightweight? Below there's a picture of a friend of mine, next to a normal human being (me).
He tips the scales at well over 100 kg and he is a multiple 50 cc champion in the German SimsonGP series. The frame dimensions I quoted above went into this bike.

PS: I love funny front ends.
Wenever I feel the need to take my mind off two-stroke development for a moment, I start sketching hub-centre front ends, lateral suspension, etc.

Define lightweight ? Well Frits, my daily bread is earned working on engines for big Post Classics which alone weigh more than that bike pictured...
Given also the limitations of correct period forks stuck on the front of said big mutha motors, fork stiffness is a subject of which I have considerable empirical knowledge...Oh, and the forks on that bike are lovely - much better than I'm used to working with.
I'm well aware that those dimensions given will work, but feel no driving need to transfer them to the big lounge chairs I work with.

I worked with John Britten (briefly...) and have no desire to go anywhere near a funny front end for the rest of my life thanks....

[F5 Dave]

I have to admit to being stuck in the mud, my experiments from early age really amount to dropping the front through the clamps until it started to self steer when leant over & then back a tad. I didn't have different offset clamps so found 23 deg was good. but I was also messing around with too long a wheel base but it was real short on the dyno so figured it must be ok. but was aware that I was really having to spang it far over when other bikes seemed to steer much shorter turning circle. too stupid to do anything about it, but I'm done now. I've won multiple NZ 50cc titles but clearly we're backwater compared to Europe. At 80kg I was always too big for a 50 racer. . . . but now I feel kind of inadequate.

[Frits Overmars]

I worked with John Britten (briefly...) and have no desire to go anywhere near a funny front end for the rest of my life thanks....I wish I had. We met in Italy in 1992 and I liked many of his views. But although the Hossack front end that he used does have some advantages over telescopics,
I would prefer a different solution: hub-centre or four-bar steering.

[WilDun]

I wish I had. We met in Italy in 1992 and I liked many of his views. But although the Hossack front end that he used does have some advantages over telescopics,
I would prefer a different solution: hub-centre or four-bar steering.

Trouble is, the good old telefork works (bit like poppet valves) they don't tick all the boxes but they work day in, day out, without a murmur! The hub centre jobs and the Hossack style are probably fine but susceptible to damage (small bent tubes etc.) which if damaged would knock the machine's ability to steer properly and are not really suitable for enconomic mass production.
And,......Let's face it, whatever they say, carbon fibre can shatter!
Or something like that! - I think. :yes:

[Grumph]

I wish I had. We met in Italy in 1992 and I liked many of his views. But although the Hossack front end that he used does have some advantages over telescopics,
I would prefer a different solution: hub-centre or four-bar steering.

Talk to Wob when you meet up. His experiences were much later on than mine - I was in there very early but the rot was visible then.

There's supposed to be a Britten "public teardown" at the ChCh art gallery today or tomorrow. Don't know who's doing it - but I probably know them.
Almost tempted to go and sit in the front row and ask awkward questions.....

[Grumph]

And,......Let's face it, whatever they say, carbon fibre can shatter!
Or something like that! - I think. :yes:

It was well known in the race crowd here that JB had repaired at least one Carbon fiber wheel...

It came up in discussion with Hans VonDer Marwitz (spelling sorry ) when a bunch of us sat for the FIM Tech Steward tickets under him.
As an active scrutineer who saw the bikes on a regular basis I was forthright when the IOM came up also.
I reckoned I'd have asked for all the Britten wheels - bare - inspected and marked them.
I'd have asked the team to log which rims were used each session - and asked marshals to observe any curb climbing incidents and report them.
As it turned out rims were the least of their troubles.

[cotswold]

Sure you can. Here are some racewinning dimensions.
wheelbase 1200 mm
fork yokes offset 0 (yes, zero) mm
rake angle 16°
trail 90 mm
Concentrate all masses so that the center of gravity will be directly in front of your knees.

I need all the help I can get so as me and Mr.JS were building up another FXR we have decided to go with these numbers J has cut and re-welded the steering head to steepen up the rake and we are just working out how much to chop out of the swinging arm. We measured J's bike and it is 1230 with work having been done to shorten the swinging arm so I reckon we can get close

[Frits Overmars]

I need all the help I can get so as me and Mr.JS were building up another FXR we have decided to go with these numbers J has cut and re-welded the steering head to steepen up the rake and we are just working out how much to chop out of the swinging arm. We measured J's bike and it is 1230 with work having been done to shorten the swinging arm so I reckon we can get closeCutting and rewelding the steering head will place the front wheel nearer to the engine. You will be able to get away with a fair amount of steepening because the steeper fork angle will reduce the horizontal movement of the front wheel in suspension, so you will need less clearance between the wheel and the exhaust header.
The new front wheel position will improve both the wheelbase and the front/rear weight distribution. The steeper rake will also mean that braking will charge the front fork springs less than before (imagine the opposite, an almost-horizontal front fork, and you'll see why), so you may be able to fit softer springs.

Shortening the swing arm may further improve (i.e. shorten) the wheelbase, but it will also counteract the much-needed front-biased weight distribution.
My advice would be to try the steepened rake, combined with fork yokes that give the desired trail, without shortening the swing arm yet.
You can always do that later on. Afterwards, it will have been the same amount of work, but you will have learned more.

[cotswold]

Cutting and rewelding the steering head will place the front wheel nearer to the engine. You will be able to get away with a fair amount of steepening because the steeper fork angle will reduce the horizontal movement of the front wheel in suspension, so you will need less clearance between the wheel and the exhaust header.
The new front wheel position will improve both the wheelbase and the front/rear weight distribution. The steeper rake will also mean that braking will charge the front fork springs less than before (imagine the opposite, an almost-horizontal front fork, and you'll see why), so you may be able to fit softer springs.

Shortening the swing arm may further improve (i.e. shorten) the wheelbase, but it will also counteract the much-needed front-biased weight distribution.
My advice would be to try the steepened rake, combined with fork yokes that give the desired trail, without shortening the swing arm yet.
You can always do that later on. Afterwards, it will have been the same amount of work, but you will have learned more.

Thank you for that Frits

[mr bucketracer]

Thank you for that Fritsdon't listen , he don't know what he's taking about ;-):niceone:

[Henk]

don't listen , he don't know what he's taking about ;-):niceone:

And you do? Mr drink this, it melts plastic cups?

[husaberg]

And you do? Mr drink this, it melts plastic cups?

Henk hes being sarcastic, if you look at the GPR frames, you will notice a much steeper head angle that the NX4 which they share running gear with.
Plus the firewater is just unbranded arthritis medicine.

[cotswold]

So if I were to raise the back up that would have the desired effect, would a slightly longer shock do it or am I barking?
Seems that dropping the forks through a bit and raising the rear plus the cutting and welding we've already done would be putting more bias onto the front?

[mr bucketracer]

Henk hes being sarcastic, if you look at the GPR frames, you will notice a much steeper head angle that the NX4 which they share running gear with.
Plus the firewater is just unbranded arthritis medicine.lol , you worked it out :eek:

[mr bucketracer]

And you do? Mr drink this, it melts plastic cups?ok only changes it colour lol

[mr bucketracer]

So if I were to raise the back up that would have the desired effect, would a slightly longer shock do it or am I barking?
Seems that dropping the forks through a bit and raising the rear plus the cutting and welding we've already done would be putting more bias onto the front?your bike is already to fast in a stright line let .

[Frits Overmars]

So if I were to raise the back up that would have the desired effect, would a slightly longer shock do it or am I barking? Seems that dropping the forks through a bit and raising the rear plus the cutting and welding we've already done would be putting more bias onto the front?Raising the back would slightly reduce both rake and trail, increase the cornering clearance and raise the center of gravity. The latter is not favourable by definition, though in most practical cases it has a positive effect on handling.
Dropping the forks will also reduce rake and trail, but it will also reduce cornering clearance. It will also move the front tire contact patch closer to the CG, so you'll put a bit more load bias onto the front. But moving masses like battery, fuel tank or radiator forward will help more. And moving the rider further forward will make a huge difference.
Take a look at the bike below; notice where the footrests, the seat and the rider are.
324371

[Frits Overmars]

your bike is already to fast in a stright line let .That's not racing. Even my daughter could do that. There's no fun without curves (pun intended).

[cotswold]

your bike is already to fast in a stright line let .

not this one, bog stock engine just pipe and carb
i was happy with the pace of the 50 that Terrene now owns but it had to make way for my CVT 50 that I'm keen to get going, hope that will be fast everwhere

[lodgernz]

Been thinking about what would be suitable wheels for a freetech 50 with 95/75r17s front and rear slicks. The Honda NS-1 came out with 17x2.15 and 17x2.75 wheels to take a 90 front tyre and 100 rear tyre. They're really cheap, probably fairly light given their size and readily available in Japan. They're the same design as the Honda NF4 RS125 too which I think look pretty cool. Thoughts?

http://www.cars-directory.net/pics/honda/ns-1/2003/honda_ns-1_a1240499402b2631202_2_orig.jpg

The NS-1 has a steel frame, as someone has mentioned, and the rear suspension has no linkage, so is not progressive. The spring is progressive-wound, but that's not the same thing. It's also quite long with a wheelbase of 1285 - 1315 depending on chain adjustment.
And yes, they are readily available in Japan, if you're very rich. They're highly sought-after.
I have an old one, and it will be my next bucket project, with quite a few mods. I use those same wheels on my NS50F and NS90F buckets, BTW, and although they are pretty much the same design as RS125 wheels, they weigh a ton. Roughly.

[Frits Overmars]

The NS-1 has a steel frame, as someone has mentioned, and the rear suspension has no linkage, so is not progressive. The spring is progressive-wound, but that's not the same thing.Indeed, not the same thing. There's nothing wrong with progressive springs, provided you fit them on dampers with the same built-in progressiveness, which is very difficult to achieve. So it's better to use a linear spring on a linear damper in a suspension geometry with built-in progressiveness.
A linkage system can provide any progressive behaviour, from zero to infinite, but with careful selection of the upper and lower shock mounting coordinates you can achieve up to 15% progressiveness even without a linkage system. And 15% progressiveness is sufficient for racing. In other words, you don't need a linkage system.

324559
If the distance from the swing-arm pivot perpendicular to the shock (the length of the yellow line) increases during suspension movement, you have progressiveness.

[Michael Moore]

Linkages are useful for packaging when you can't fit a direct-mount damper where you have space for it. MX and big touring bikes can benefit from the large amounts of progression that can be obtained. But they do also offer a very large number of bad choices, and sometimes those can be had by being just a millimeter or two away from the spot that gives you the curve you are looking for.

[dark art]

The NS-1 has a steel frame, as someone has mentioned, and the rear suspension has no linkage, so is not progressive. The spring is progressive-wound, but that's not the same thing. It's also quite long with a wheelbase of 1285 - 1315 depending on chain adjustment.
And yes, they are readily available in Japan, if you're very rich. They're highly sought-after.
I have an old one, and it will be my next bucket project, with quite a few mods. I use those same wheels on my NS50F and NS90F buckets, BTW, and although they are pretty much the same design as RS125 wheels, they weigh a ton. Roughly.

Mine is a Spain assembled model and is around 1350 or 1360 if memory doesn´t fail, with rear axle on center adjustement. The whole bike is heavy, around 95kg all stock except the pipe and lack or mirrors, I believe they can be made to wheigh lower 70´s with some work, including custom sub-frame.
A list of parts wheights for those interested:
front wheel w/o disc 4.3 kg
back wheel w/o disc and sprocket 4.6 kg
swing arm 4.3 kg
rear suspension unit ~255mm 1.9 kg
bare frame including welded subframe and rear footstands 14kg.

They are readily available in Spain as nsr75rr and Portugal as nsr 50rr, quite cheap, altough euro conversion and transportation may be difficult for New Zealand.

The bike feel is on the very stable side, good for road, not so good for short tracks and the rear suspension is quite bad. Fitting a good quality damper and change the unit upper mount for more inclination and higher rising rate shouldn´t be hard.

[husaberg]

The NS-1 has a steel frame, as someone has mentioned, and the rear suspension has no linkage, so is not progressive. The spring is progressive-wound, but that's not the same thing. It's also quite long with a wheelbase of 1285 - 1315 depending on chain adjustment.
And yes, they are readily available in Japan, if you're very rich. They're highly sought-after.
I have an old one, and it will be my next bucket project, with quite a few mods. I use those same wheels on my NS50F and NS90F buckets, BTW, and although they are pretty much the same design as RS125 wheels, they weigh a ton. Roughly.


Mine is a Spain assembled model and is around 1350 or 1360 if memory doesn´t fail, with rear axle on center adjustement. The whole bike is heavy, around 95kg all stock except the pipe and lack or mirrors, I believe they can be made to wheigh lower 70´s with some work, including custom sub-frame.
A list of parts wheights for those interested:
front wheel w/o disc 4.3 kg
back wheel w/o disc and sprocket 4.6 kg
swing arm 4.3 kg
rear suspension unit ~255mm 1.9 kg
bare frame including welded subframe and rear footstands 14kg.

They are readily available in Spain as nsr75rr and Portugal as nsr 50rr, quite cheap, altough euro conversion and transportation may be difficult for New Zealand.

The bike feel is on the very stable side, good for road, not so good for short tracks and the rear suspension is quite bad. Fitting a good quality damper and change the unit upper mount for more inclination and higher rising rate shouldn´t be hard.


The Moriwoki MH 80 uses the NS1 frame.
http://micapeak.com/ysr/mh.html
http://micapeak.com/ysr/92mh80right.jpg
It was brought up earlier in the thread somewhere.

[Frits Overmars]

Mine is a Spain assembled model and is around 1350 or 1360 if memory doesn´t fail.
The whole bike is heavy... I believe they can be made to weigh lower 70´s with some work'some work' as in removing the engine and wheels? :D.


The bike feel is on the very stable side.....I'll bet it is, with a wheelbase slightly longer than the bike below.
325042

[dark art]

The Moriwoki MH 80 uses the NS1 frame.

http://micapeak.com/ysr/92mh80right.jpg


I remember read about those bikes a few years ago and one of the bigger problems was vibration, even with the cr80 engine rubber mounted.

In bike´s defence, the wheelbase is more around 1300 than 1360 like I stated on previous post, this time i did measured, not from memery :(

There seems to be two versions of NS1 frames
http://www.gravelrash.com/assets/Mybikes-history/_resampled/resizedimage600367-ns1.jpg
http://www.50cc-motorcycles.com/pictures/honda/ns-1-19.jpg

Mine is dual seat version, would love to get a single seat, though

Back to real racing frame stuff :niceone:

[Michael Moore]

For anyone who might find it interesting

https://patentimages.storage.googleapis.com/pdfs/99f8d966f70307edbff3/US4139072.pdf

is the US patent document for Tony Dawson's "Scitsu" bolted-up plate frame.

cheers,
Michael

[husaberg]

For anyone who might find it interesting

https://patentimages.storage.googleapis.com/pdfs/99f8d966f70307edbff3/US4139072.pdf

is the US patent document for Tony Dawson's "Scitsu" bolted-up plate frame.

cheers,
Michael


Thanks Michael, that frame design is featured the second pic in this thread.
Great to see some further info.
http://www.kiwibiker.co.nz/forums/showthread.php/145224-Race-chassis?p=1130221028#post1130221028

I just thought I would post these pictures of a couple of bikes I raced back when I was faster.
The Scitsu in the picture was not my one but I did ride it a few times, it is 2 aluminium plates bolted together with aluminium spacers in between, this one had a Kawasaki bottom end with an RG500 pot on it, my one had a Rotax in it and is owned at this time by Neil Hodsons dad, I know this as I got a request for some original photo's so he could restore it. The handling on the Scitsu was a little problematic at first with the front end tending to chatter through fast turns, this was resolved by altering the angle on the rear suspension. The bike was a little on the heavy side and there was talk of making one out of Honey comb but I don't think this ever happened. Tony Dawson and Nick Carpenter were the builders, Tony was also the Astrolite man I think.
http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=253307&d=1324623464

Tony Dawson wheel stuff is here
http://www.kiwibiker.co.nz/forums/showthread.php/145224-Race-chassis?p=1130221967#post1130221967

I had this Dave brought them up on a previous thread they belong here more then the 2 stroke thread.

interesting stuff bellow the breasts as well 3 vs 5 spokes alloy vs carbon fibre why the original Astralights were stopped, solid vs spoked etc
325480325481325482325483325478325479

[Michael Moore]

I'd be interested to learn what thickness plate and fastener sizes were used on the Kawasaki Scitsu. I've been interested in the concept since it came out.

I gathered up a bunch of photos of different bikes with plate and/or sheet frames and put them in a folder on my website:

http://www.eurospares.com/graphics/chassis/PlateOrSheetFrames/

Scitsu, Foale (both Tony and his son Tom), Fior, Segale honeycomb, Tesi, Offenstadt, etc. The frames are Scitsu style, full monocoque, large fuel-bearing side spars, and even plywood monocoques.

cheers,
Michael

[Grumph]

Thanks for linking that Michael. Performance Bike mag, UK, did a write up on a readers special which used what was probably a Dawson built frame for a TZ.
It ran an LC engine and was road legal. I'll see if I can find the copy I have here and send it to Husa to scan and post.

Having built several boats, a sheet frame using ply has great appeal.

[husaberg]

I'd be interested to learn what thickness plate and fastener sizes were used on the Kawasaki Scitsu. I've been interested in the concept since it came out.

I gathered up a bunch of photos of different bikes with plate and/or sheet frames and put them in a folder on my website:

http://www.eurospares.com/graphics/chassis/PlateOrSheetFrames/

Scitsu, Foale (both Tony and his son Tom), Fior, Segale honeycomb, Tesi, Offenstadt, etc. The frames are Scitsu style, full monocoque, large fuel-bearing side spars, and even plywood monocoques.

cheers,
Michael

Michael there is a few others on this forum chuck-em in there as well.

[Michael Moore]

Are they all in this thread or scattered around? I think I'm current on "I'd better save that photo" operations for this thread but I don't know which others might be likely suspects to have chassis photos. The photos I put in that folder are a subset of what I have, for example there are a number of other monocoque RR bikes, but I was mainly looking for a few representative photos to compare to the Scitsu-ish photos.

cheers,
Michael

[husaberg]

Are they all in this thread or scattered around? I think I'm current on "I'd better save that photo" operations for this thread but I don't know which others might be likely suspects to have chassis photos. The photos I put in that folder are a subset of what I have, for example there are a number of other monocoque RR bikes, but I was mainly looking for a few representative photos to compare to the Scitsu-ish photos.

cheers,
Michael

Yes Use the thread tools (up the top left) to search the pics.
I have had a good look arround your site. some of what i added to this thread are even from there. :laugh:
But there are many others you don't have on your page.
Remember click three tmes on Image
326001

[Michael Moore]

I wasn't aware there was an image search like that, it is very convenient. I ran it on the entire buckets forum and I'm 25% of the way through all of them.

I didn't see any photos of the 50cc Jawa Gimo so I've attached some.

cheers,
Michael

[F5 Dave]

Wow. They, certainly didn't care much for front end traction did they?

[Grumph]

Wow. They, certainly didn't care much for front end traction did they?

Not as bad as it looks, Dave. The "tank" is a dummy with fuel in the top tube. That front end won't be light either.
I'd pick that with rider prone, it'll be close to 50/50 weight distribution.

[F5 Dave]

The cut off tail section makes the seat look like its right back I'll grant thee.

The engine is what first grabbed my attention for positioning.

[cotswold]

I have a contact in the UK that has promised me some drawings, I'll have to get on his case.
I rode the RG/kX for Nick, had my own with the Doctor Joe Rotax and also rode the MBA engined version that Nick built for Mark Carkeek at at Silverstone one time
They were all beautifully built but were a bit heavy, with todays materials I'm sure that could be fixed

1st pic me on the Rotax one and Mark on the MBA at Snetterton I think
2nd is me and my chief sponsor best mate and mechanic at mallory with the rotax
3rd is me and my GF at the time with a pair of the RG/KX scitsu but not sure where that is
4th is me fumbling around with a misfire on RG/KX at mallory park

i have now got the drawings :D

[Grumph]

I see there's one of the Scitsu's is a monoshock. Did you convert it or was it done like that ? Most seemed to be twinshock as that is easiest with the full length plates.
Nothing says 1980's like white boots and skinny tyres, LOL...

[cotswold]

I see there's one of the Scitsu's is a monoshock. Did you convert it or was it done like that ? Most seemed to be twinshock as that is easiest with the full length plates.
Nothing says 1980's like white boots and skinny tyres, LOL...

nothing wrong with skinny tyres ;)
the mba was built with mono shock

[Michael Moore]

Thanks for the extra photos, and I'm interested in seeing anything else you'd like to share, especially construction details.

I tried to pull some more details out of one photo in Photoshop but didn't have a lot of luck.

cheers,
Michael

[cotswold]

Thanks for the extra photos, and I'm interested in seeing anything else you'd like to share, especially construction details.

I tried to pull some more details out of one photo in Photoshop but didn't have a lot of luck.

cheers,
Michael

if you pm me your email i can send you the photos i have of plate plans

[Michael Moore]

I've done that. FWIW, every page on my eurospares.com website has a mailto: tag at the bottom that will reach me, should someone need to do so.

cheers,
Michael

[Michael Moore]

A 50cc Scitsu (modern replica with advice from Dawson) that was in a UK show report

http://martinsquiresautomotiveillustration.blogspot.com/2015/10/on-my-second-trip-to-stafford-show.html


Whilst passing the Classic 50cc Racing Club this racer with an unusual frame construction
caught my eye. Built by Alan Leeson in 2010 with permission from Tony Dawson to see
whether it would produce a lighter frame, the result was that the frame weighed about the
same as a tubular example. This machine is currently raced in the Classic 50 cc class. Alan
plans to build another bike with this frame to take to Bonneville in 2016, and the idea
makes a lot of sense as the majority of the bike can be dismantled and packed into hand
luggage, I look forward to hearing how he gets on.

Tony Dawson raced sidecars in the 60s and is most famous for inventing the Astralite wheel,
a lightweight pressed aluminium wheel which started production in 1977 and by the end of
the 1980s over 1500 wheels were being sold globally per year. As well as designing wheels
Tony Dawson also formed a company called S.C.I.T.S.U. (Selfish Conduct Inhibits True
Sporting Union) in 1978. The company was founded to produce components for road race
bikes. This aluminium frame design was used on a number of Road Racing bikes back in the
1970's mostly using larger engines than this 50cc example. A bike with this frame design
appeared on Tomorrow's World in the Mid. 1970s. Tony patented the design and some think
that if he hadn't the Japanese may well have taken it on, as it is a design that could be
easily automated due to it being a series of aluminium plates bolted together. The ride
hight can be adjusted by changing the vertical plates, and the tank is sandwiched between
the top two plates. The construction is surprisingly strong, but still enables a certain amount
of twist that is needed to maintain grip on a road racing machine.

[husaberg]

Thanks for linking that Michael. Performance Bike mag, UK, did a write up on a readers special which used what was probably a Dawson built frame for a TZ.
It ran an LC engine and was road legal. I'll see if I can find the copy I have here and send it to Husa to scan and post.

Having built several boats, a sheet frame using ply has great appeal.

Here you go.
I must send your books back at some stage:shit:
326214326213
Click on them 3 times.

[Michael Moore]

Thanks, I should pull out my boxes of PB and go through the Readers' Specials to see what else I've forgotten about over the years. Here's a favorite of mine by Simon Martin:

http://www.eurospares.com/graphics/simotohonda4pb078975.jpg

cheers,
Michael

[husaberg]

Thanks, I should pull out my boxes of PB and go through the Readers' Specials to see what else I've forgotten about over the years. Here's a favorite of mine by Simon Martin:

http://www.eurospares.com/graphics/simotohonda4pb078975.jpg

cheers,
Michael

My fav Simon Martin was the all fabricated Single.
http://www.kiwibiker.co.nz/forums/showthread.php/145224-Race-chassis?p=1130228408#post1130228408
Try and find a photo of him not looking slightly manic

Although not Simon Martin this one is pretty special as well.
326219

[F5 Dave]

Those mags are boxed under the house. I painted my early 50 like the simoto. It looked about just as bad. Tastes change huh?. The single was a bit of a waste of time from all accounts yeah?

[husaberg]

Those mags are boxed under the house. I painted my early 50 like the simoto. It looked about just as bad. Tastes change huh?. The single was a bit of a waste of time from all accounts yeah?

Against the stan stephens harris 660 5 valve and a brace of supermono ducatis and also morris's self devloped bmw? yes, it was outgunned ,but it still is a work of art.

Do me a favour and find the one with the Yellow and White RZ250, thats was my original buckets first colour scheme too.;)
it was also in the two stroke specials or tunning issue.

[Michael Moore]

Here's the patent document for Peter Williams "Shell" frame concept

http://www.eurospares.com/graphics/chassis/PeterWilliamsShellFrameWO0189916A1.pdf

cheers,
Michael

[Grumph]

Here's the patent document for Peter Williams "Shell" frame concept
cheers,
Michael

Not exactly home workshop friendly is it ?
Very suitable for electric bikes though.
Enough published info on them for a separate electric bike page/folio on your site ?

[Michael Moore]

I don't know enough about electrons to put together a page on E-bikes. I can treat electricity like plumbing -- pour electricity into one end of a wire and expect it to come out the other end, so making a wiring harness is pretty much where I top out.

In his book Williams says he did a design for an early Bloor Triumph triple but found the center spark plug couldn't be accessed so that didn't go anywhere.

Here's the E-racer built using William's concept

http://www.motorcyclenews.com/news/new-bikes/2009/june/jun1909-what-the-lotus-ev-0rr-ttxgp-bike-finally-looked-like/

http://www.motorcyclenews.com/sport/tt-road-races/2009/june/jun1209-ttxgp-lotus-bike-unlikely-to-race/

http://www.motorcyclenews.com/sport/tt-road-races/2009/may/may1909-lotus-ttxgp-bike-update-/

cheers,
Michael

[husaberg]

Here's the patent document for Peter Williams "Shell" frame concept

http://www.eurospares.com/graphics/chassis/PeterWilliamsShellFrameWO0189916A1.pdf

cheers,
Michael

Peter was a very clever man, as was his father.
Both were responsable for a lot of the final development work done at Norton and AJS repectively.
I can't remember who peters co rider was at the time (likely Croxford) Peter was always saying to him to let him fettle his works Norton like his, The co-rider thought it was not needed untiil he actually tried Peters bike and found it to be a few seconds a lap quicker.
Peter actually went and worked for Dr Joe for a while after Norton to learn 2T's.

[Michael Moore]

If any of you have Tony's chassis software he's just released an upgrade which is a free download for owners of the older versions. You should be able to replace the old version and have the existing unlock key continue to work without needing to request a new one:


See http://www.tonyfoale.com/suskin/Update1_65.pdf

For those that already have the software just search your emails for the
original download instructions AFTER reading the above. It contains
important info. about the update. For anything else please contact me
directly.

Regards

Tony Foale

[Grumph]

Talking to Mike Sinclair a couple of times over the last two days. Asked a couple of questions as you do...
I'd read that when team Roberts went to the frame builder for the Modenas frame they were very specific about exactly what torsional stiffness they wanted. So asked where that came from...Plenty of measurements of existing frames...
Mike pulled out a pic of an alloy beam frame with holes cut all over. Answering the question, what happens if we do this ? How much effect on stiffness does this bit have ? Interesting. Paul Treacy was in on the discussion too, currently working on KTM's new bike for MotoGP.

I remembered to ask (for Husa) about the "adding weights to the Britten" story. No confirmation, but they both laughed and said that you got 3 weights with your works Yamaha. If you had patter, you could insert them into hollow spars in various places until the patter went away....pragmatic.

[husaberg]

Talking to Mike Sinclair a couple of times over the last two days. Asked a couple of questions as you do...
I'd read that when team Roberts went to the frame builder for the Modenas frame they were very specific about exactly what torsional stiffness they wanted. So asked where that came from...Plenty of measurements of existing frames...
Mike pulled out a pic of an alloy beam frame with holes cut all over. Answering the question, what happens if we do this ? How much effect on stiffness does this bit have ? Interesting. Paul Treacy was in on the discussion too, currently working on KTM's new bike for MotoGP.

I remembered to ask (for Husa) about the "adding weights to the Britten" story. No confirmation, but they both laughed and said that you got 3 weights with your works Yamaha. If you had patter, you could insert them into hollow spars in various places until the patter went away....pragmatic.

I read a real funny story the other day about KR-JR world title wining RGV500
It turns out it was made as Yamaha YZR500 as Suzuki would let them. right down to exhaust dimensions.
When they first tested the Suzuki they had a frame which gave no feed back ,so they asked if they could have a less stiff one (it was worse) they asked if they had either tested the frame stuiffness suzuki said No, So Willings had it tested the "less stiff" frame and found it was actually 15% stiffer.

[husaberg]

Found it on the web
Saved having to scan it
Note the number of frames they had made up until then.

326757326758

[Frits Overmars]

Found it on the web. Saved having to scan it.326757326758I finally read the lot. Now can you please post some aspirin?

[husaberg]

I finally read the lot. Now can you please post some aspirin?

Okay then

https://www.kiwibiker.co.nz/forums/showthread.php/181746-Kevin-Cameron
https://www.kiwibiker.co.nz/forums/showthread.php/151865-Old-multi-cylinder-bikes-of-the-50s-to-later-on-Japanese-British-Euro-etc

[Frits Overmars]

Okay then.
https://www.kiwibiker.co.nz/forums/showthread.php/181746-Kevin-Cameron
https://www.kiwibiker.co.nz/forums/showthread.php/151865-Old-multi-cylinder-bikes-of-the-50s-to-later-on-Japanese-British-Euro-etcAh, now you're posting scans that are actually legible. Good stuff to get me through the holidays. Thanks Husa.
Which reminds me: Happy New Year to all Kiwibikers :drinknsin.

[husaberg]

Ah, now you're posting scans that are actually legible. Good stuff to get me through the holidays. Thanks Husa.
Which reminds me: Happy New Year to all Kiwibikers :drinknsin.

Oh sorry i never checked that one. I thought you meant all the attachments in the thread.
That one was actually taken from the web, as i was being lazy.
To late for you, but I will replace it later, with one from the same mag i have here.

[husaberg]

There is going to be some cross over to the foundry and oddballs thread with these.
no details but it was i think for a TZ.

[husaberg]

Again i think for a tz

[husaberg]

The others that didn't fit
Mike Moore identified as Offenstadt.

[husaberg]

Shepard TZ

[Michael Moore]

The monocoque and USD fork is Offenstadt stuff.

The front damper mount on that TZ plate frame is a classic example of "don't put a load in the middle of an unsupported beam". I hope the plan was to add something to brace that against the steering head.

[husaberg]

The monocoque and USD fork is Offenstadt stuff.

The front damper mount on that TZ plate frame is a classic example of "don't put a load in the middle of an unsupported beam". I hope the plan was to add something to brace that against the steering head.
Cheers i should have picked that. Not that i could have spelled it.
re the plate frame, I missed that, it looks like a very long 8mm bolt as well.
That all cast Shepard frame sure looks beautiful through.

[Grumph]

Cheers i should have picked that. Not that i could have spelled it.
re the plate frame, I missed that, it looks like a very long 8mm bolt as well.
That all cast Shepard frame sure looks beautiful through.

The strength of cast frames always worries me. Getting sections thin enough to be light enough is always a juggling act - which can easily backfire.
Being in NZ - historically a very long way away from parts suppliers - has always made me sensitive to the crash worthiness of anything I build.
A frame which is a one season lightweight or won't survive a trip down the road is a non starter here IMO.

I looked at that suspension pickup and shuddered - Practise at Wanganui would break it IMO....I'm told two LCR sidecars had suspension breakages there this year.

[husaberg]

The strength of cast frames always worries me. Getting sections thin enough to be light enough is always a juggling act - which can easily backfire.
Being in NZ - historically a very long way away from parts suppliers - has always made me sensitive to the crash worthiness of anything I build.
A frame which is a one season lightweight or won't survive a trip down the road is a non starter here IMO.

I looked at that suspension pickup and shuddered - Practise at Wanganui would break it IMO....I'm told two LCR sidecars had suspension breakages there this year.

Belts and braces:rolleyes:
Don't go adding reality.
that said those Castech hondas seem to have survived all right.
327523327524
My berg has a spare swingarm i have yet to add but its a very light hollow all cast alloy swingarm made by Renthal supposed to be 1 kg lighter (its a 2001 modification )
327528327529
Most modern bikes are made of multiple cast sections welded to beam anyway, i see it being done with tube sections either steel alloy or Carbon fibre in between like a modern version of a lugged frame
327526327527
Plus there is some pretty exciting stuff being done with high tech Mg alloys now, it turns out they never really did much research back in the day.
http://www.cycleworld.com/2013/10/08/developments-in-magnesium-part-2
Even one of the new Beemer engines has a partial Mag alloy block
http://www.cycleworld.com/2013/09/10/developments-in-preventing-magnesium-corrosion/
http://www.mwerks.com/artman/publish/features/printer_960.shtml

[Grumph]

Husqvarna did at least one prototype frame with cast lugs and glued in tube. Pretty sure the castings were magnesium and the tubes may have been carbon fiber but memory....I do remember a picture of the bike in two halves held together by the cables....That was a fail.

[husaberg]

Husqvarna did at least one prototype frame with cast lugs and glued in tube. Pretty sure the castings were magnesium and the tubes may have been carbon fiber but memory....I do remember a picture of the bike in two halves held together by the cables....That was a fail.

The origional tigcraft frame that later went into productions as a MZ Skorpion had a glued frame. It used a lockite product ,the production model was pinned and maybe welded as well.
http://images.mcn.bauercdn.com/upload/992/images/mz_skorpianx1-01.jpg


The Skorpion was the result of an international collaboration, being conceived by British design firm Seymour Powell. The Skorpion's engine, electrics and switches came from the Yamaha XT660, with Italian Grimeca parts including brakes, forks and rear suspension. The strong tubular beam frame was unusual in using aircraft adhesives to save weight but production versions came with a welded frame. Skorpions were well-specified as standard, with adjustable bars and footpegs, alloy wheels, stainless steel silencer, rear hugger fender, and braided brake lines. Some early Skorpions were fitted with an Austrian Rotax engine.


What name do I address you by?.

I've tried a few different ways with the Headstock intake. The method you perfectly reasonably suggest comes out heavy as the box needs to be structural whereas the one on my Moto3 is made in 2mm 5083 alu riveted to the waisted fabricated (5 pieces) headstock. I made the duct /front fairing bracket in 1050 soft alu then took a mould and had a couple made up in carbon.

That 2mm 5083 subframe is real easy to make. I have NO metal forming stuff so I just form it over a convenient block of wood with a large soft mallet. At the 2nd race the bike had a horrendous crash (Both wheels knackered+ all the normal stuff) The subframe was useable later in the day.

I almost forgot the David had previously posted here
Please share the details on the glued frame...

[mr bucketracer]

looks like a goose:lol:

[husaberg]

looks like a goose:lol:

A little bit i guess
http://avtobest-moto.ru/var/cars/245051-tm1364545754.jpg

ps I put my RD250 frame cafe project into a DIY electrolysis tank today today.
Die rust die.....
So have you started on my TZ350A tank and seat yet?

[mr bucketracer]

A little bit i guess
http://avtobest-moto.ru/var/cars/245051-tm1364545754.jpg

ps I put my RD250 frame cafe project into a DIY electrolysis tank today today.
Die rust die.....
So have you started on my TZ350A tank and seat yet?i need to make my honda tank seat first , you could not work out what my new bike was anyway lol

[husaberg]

i need to make my honda tank seat first , you could not work out what my new bike was anyway lol
Just as long as you make the TZ fuel tank and seat i will be happy.
327540327541
I never knew i was meant to give the game away on the build?
It looks like you mocked/mucked up the air intake into the exhaust port.

[Michael Moore]

Another bonded frame was the one on the Lito X-cam scrambler:

http://www.eurospares.com/graphics/otherdirtbikes/litoxcam.jpg

http://www.eurospares.com/graphics/otherdirtbikes/litoxcam1.jpg

http://www.eurospares.com/graphics/otherdirtbikes/litoxcam2.jpg

cheers and Happy New Year (less than an hour old in San Francisco)

Michael

[mr bucketracer]

Just as long as you make the TZ fuel tank and seat i will be happy.
327540327541
I never knew i was meant to give the game away on the build?
It looks like you mocked/mucked up the air intake into the exhaust port.looks easy to make , moto 3 mate :devil2:

[mr bucketracer]

have you got a tz bike hus ?

[husaberg]

have you got a tz bike hus ?

nah just an old RD350.

[Grumph]

nah just an old RD350.

You are aware that Dave Morris in Invergiggle sells a range of TZ seats on tardme ?
It's good quality too.

[husaberg]

You are aware that Dave Morris in Invergiggle sells a range of TZ seats on tardme ?
It's good quality too.

Yip but oddly not the A/B/C seat

[cotswold]

Spotted this on face plant

[Grumph]

Made by Norgren apprentices ? How to go to extreme lengths to avoid welding...

[F5 Dave]

Maybe they smashed their welders with big hammers:innocent:.

Bit adjustable though.

[husaberg]

Made by Norgren apprentices ? How to go to extreme lengths to avoid welding...

First pic had me thinking Bert Greeves.

[Grumph]

First pic had me thinking Bert Greeves.

Well, up to a point...Greeves used the cast beams due to the poor quality of steel tube available.
One of those front beams would have sufficed - Looks like it has one each side.

[husaberg]

Well, up to a point...Greeves used the cast beams due to the poor quality of steel tube available.
One of those front beams would have sufficed - Looks like it has one each side.

Bert had a foundry as well.
Symmetry is often appealing.

[richban]

I have been wanting to build a farme for a while now. Its a new year so why not give it a crack.

I want to build 2. One for my F5 50 and one for my F4 90.

This is my inspiration. I have know idea what I am doing. Should be frustrating and very rewarding.

327918

[Grumph]

I'll tell you up front that that layout of what are effectively crossed girders will distort like buggery unless the right welding sequence is used.
It will be so stiff in a vertical plane that straightening - or adjusting the head angle - is damm near impossible.
I did a small Harris magnum style copy with the typical crossed triangulation at the head and hit major touble.

Tack everything up with the joints as tight and well shaped as possible and only finish weld when you're happy you've got it right.

What are you using for a jig ?

[F5 Dave]

They do look the shit. And Kaitoki is mainly right handers so if distorts, try to favour that.

[richban]

I'll tell you up front that that layout of what are effectively crossed girders will distort like buggery unless the right welding sequence is used.
It will be so stiff in a vertical plane that straightening - or adjusting the head angle - is damm near impossible.
I did a small Harris magnum style copy with the typical crossed triangulation at the head and hit major touble.

Tack everything up with the joints as tight and well shaped as possible and only finish weld when you're happy you've got it right.

What are you using for a jig ?

Yeah the distortion is one thing I hate when welding. When I was making my 300 pipes I started to embrace it a little. It helped pull things around a bit.

Jig. That will be Phase 2. Phase one will be designing the jig. In my mind I'm already trying to figure what colour the finished frame will be. Crack up. There are lots of good ideas for jigs on line.

Phase 3 will be designing the bike. I really like Frits's mention of Zero offset forks. I know from riding MTbs that a shorter stem / offest the more positive control, to a pont. But of course the most important thing will be getting that trial right. Well its all important!

One of the other many things I don't know how to do is the pipe bending. I have seen the sand method and heard of other ways to do it.
For the Bucket frames I want to use some 1.2 or 1mm wall steel tube. Anyway this will be a long drawn out sort of thing but I am looking forward to having a crack.


Any advice welcome. As soon as I have anything to show I will.

[monkeyfumi]

I love how despite having state of the art assembly area, they still support the sump with a block of wood.

[Grumph]

I love how despite having state of the art assembly area, they still support the sump with a block of wood.

But it's a clean piece - and cut to the correct angle.....and not with a chainsaw, LOL.

Thinking again, Rich, a GPR style tapering top beam with the front engine mount droppers NOT going to the steering head will distort a lot less....
Pipe bending - you may even be able to hire a hand bender, ask around.

[richban]

But it's a clean piece - and cut to the correct angle.....and not with a chainsaw, LOL.

Thinking again, Rich, a GPR style tapering top beam with the front engine mount droppers NOT going to the steering head will distort a lot less....
Pipe bending - you may even be able to hire a hand bender, ask around.

Some more pics. Quick look at the Wakefield catalogue and 19mm x 1mm wall steel tube weighs in at 440gms a per meter. 1.2 wall 520ish per meter. The frame will be holding an AM6 engine. It should be quite light.


327924


327925

[mr bucketracer]

At least it's a easy frame to make

[jasonu]

Some more pics. Quick look at the Wakefield catalogue and 19mm x 1mm wall steel tube weighs in at 440gms a per meter. 1.2 wall 520ish per meter. The frame will be holding an AM6 engine. It should be quite light.


]

Use 4130 chromoly tube.

[richban]

At least it's a easy frame to make

Really! Maybe for you. Looks bloody hard to me.

[richban]

Use 4130 chromoly tube.

I could I spoze. I wanted to try with the cheap stuff for the buckets. Then make a Chromo frame for the 300 F3 bike when I have my eye in so to speak. I have seen some of your fabrication work. Any tip on poor mans pipe bending?

[Grumph]

At least it's a easy frame to make

Yeah, minimal bending, small dia tube, knock one up in the lunchhour...


Use 4130 chromoly tube.

Been discussed to death here previously. Mainly straight tube, I'd use mild.

[Michael Moore]

Try and let everything you can distort from welding and then very carefully fit and weld in the last critical bits.

I've had reasonable luck with starting at the steering head and adding the swing arm pivot bushes as the very last thing. Other people work the other direction, fitting the steering head in as the last piece.

http://www.eurospares.com/graphics/Laverda/LavSF2RRMK5003a1.jpg

http://www.eurospares.com/graphics/Husqvarna/husqvarna500004a3.jpg

http://www.eurospares.com/graphics/Husqvarna/husqvarna500002a1.jpg

cheers,
Michael

[jasonu]

Any tip on poor mans pipe bending?

Where I worked we bought in the bends and hand cut them to fit. They were mandrel bent and not cheap...

[jasonu]

Been discussed to death here previously. Mainly straight tube, I'd use mild.

10 charact

[F5 Dave]

So to the important question; what colour will the jig be.

[Frits Overmars]

One of the other many things I don't know how to do is the pipe bending.One of the many things you should try to avoid in a frame is bent pipes.


19mm x 1mm wall steel tube weighs in at 440gms a per meter. 1.2 wall 520ish per meter. The frame will be holding an AM6 engine. It should be quite light.If you want light, use 25 x 1,25 mm tubing from head stock to swing arm. Than you can omit most of the cross members on the sketch below.
It saves material and, at least as important, it saves welding across the main tubes which should be avoided whenever possible.
327937
Funny story on the side: the first drawings done by the guy who later became a multiple German champion on this machine, showed a lot of bent pipes, both in horizontal and vertical planes. When asked why, he answered that he had tried to follow the shape of the tank. Explaining my view on the matter may have taught him some German four-letter words that even he had never heard before.
(actually, German four-letter words are always at least 12 letters long, 8 of those being consonants, and larded with never less than three exclamation marks).


Use 4130 chromoly tube.
Been discussed to death here previously. Mainly straight tube, I'd use mild.You don't even need seamless. Use furniture tubing.

[husaberg]

You don't even need seamless. Use furniture tubing.

Chairs Frits
Some more pics. They might look familar to you:whistle:
327938327939

[Grumph]

Agree with Frits - simplicity is king.
Agree re emphatic German too - the old man had a pretty good command of idiomatic German after 4 years as a POW. More than once i heard him let loose on someone....lot of moisture flying during that.

In my experience what will take longest Rich, will be machining up the hollow bosses for tube junctions at points like the swingarm. Mild steel is fine for those.

Colour scheme of my jig Dave, is nicely patina'd light rust....

[190mech]

The rear shock attach to the frame appears to be offset to the right down tube for pipe clearance,am I seeing that correctly?Nice frame design!!

[richban]

In my experience what will take longest Rich, will be machining up the hollow bosses for tube junctions at points like the swingarm. Mild steel is fine for those.


Yes for sure. Just like making pipes. Next set of pipe I will make the mounts nozzles and spring retainers first. I was thinking the same way with the frame.


One of the many things you should try to avoid in a frame is bent pipes.

If you want light, use 25 x 1,25 mm tubing from head stock to swing arm. Than you can omit most of the cross members on the sketch below.
It saves material and, at least as important, it saves welding across the main tubes which should be avoided whenever possible.
327937
Funny story on the side: the first drawings done by the guy who later became a multiple german champion on this machine, showed a lot of bent pipes, both in horizontal and vertical planes. When asked why, he answered that he had tried to follow the shape of the tank. Explaining my view on the matter may have taught him some german three-letter words that even he had never heard before.
(actually, german three-letter words are always at least 12 letters long, 8 of those being consonants, and larded with never less than three exclamation marks).

You don't even need seamless. Use furniture tubing.

Thanks Frits. Ok KISS it is. Shape of tank is so my style as well.

Although I do love these things.


327940

327941

327942

327943

I want to draw the version of this I have in my head. Now that laser cutting is so cheap and the materials. I'm sure with some smart design a mono frame could be made. Not sure how much Ali moves around when welded.

[Grumph]

I want to draw the version of this I have in my head. Now that laser cutting is so cheap and the materials. I'm sure with some smart design a mono frame could be made. Not sure how much Ali moves around when welded.

Mock it up in cardboard. I get card sheets from a packaging co - top sheets in a pack are often dirty and unusable for packaging, ideal for our use. Cheap too.

Not sure these days on Monocoques. With single shocks you finish up with a short box and a structural seat either in glass or alloy. Any tank should be separate too, either welded or a bag tank. Is this any better than a tube frame ? Some torsional flex is required if only to give the chassis some feel when laid over.
If you do a Monocoque, it doesn't have to be welded. A basic folder and then glue and rivet works fine.

[Michael Moore]

Robin Drury's Foale TZ twin, with Tony's lightweight LL fork. I spotted this on FB and there was no photo credit given for the period photo.

cheers,
Michael

[Frits Overmars]

Now that laser cutting is so cheap and the materials. I'm sure with some smart design a mono frame could be made. Not sure how much Ali moves around when welded.
Mock it up in cardboard. I get card sheets from a packaging co - top sheets in a pack are often dirty and unusable for packaging, ideal for our use. Cheap too.I started with the steel butterfly below. Cut it, fold it, weld in the head stock and the bottom sheets and you're done.
I used 2 mm mild steel because I had no aluminium welding equipment at the time (1972). Not many laser cutters around then either, so I cut it by hand.
2 mm steel sheet may sound heavy, but I had the lightest, lowest, narrowest and simplest 500 cc bike in Holland; not much bigger than its 50 cc cousin.
327961327962

[richban]

but I had the lightest, lowest, narrowest and simplest 500 cc bike in Holland; not much bigger than its 50 cc cousin.
327961327962

Nearly spat my coffee all over the screen then. (500) Holy crap. Do you have any pictures of that bike? Sounds a little mental. In the best possible sense of the word.

[Michael Moore]

Frits, 2mm steel does sound thicker than needed since 50-100mm steel tube spines will usually be 1-1.5mm wall. Did you use internal bulkheads or ribs?

The CRDC monocoques built here in California were mostly 1.25mm aluminum 5052 sheet riveted structures. The article said it was T4 temper but since 5052 isn't heat treatable that was probably an error, and I suspect it was more likely to be H32.

Matweb says 5052-H32 has yield and UTS of 28000/33000 psi. 1018 cold-drawn mild steel is 53700/68000 psi.

By the time you got the steel thin enough to give the same performance as aluminum it would probably very difficult to keep it from getting dented in use unless you used a lot of shape to stiffen it.

I'd be interested in seeing more photos of the monocoque if you have them available.

cheers,
Michael

[richban]

Some inspiration from another angle. The first MTB I fell in love with. I had the pleasure of riding one of these on the 1994 Worlds HD course Vail Colorado. Epic bike from way back then.

This has elements of what I was thinking. Main frame mono with bolt on sub frame. Maybe a better option for a more modern rider position.


327963

[husaberg]

I started with the steel butterfly below. Cut it, fold it, weld in the head stock and the bottom sheets and you're done.
I used 2 mm mild steel because I had no aluminium welding equipment at the time (1972). Not many laser cutters around then either, so I cut it by hand.
2 mm steel sheet may sound heavy, but I had the lightest, lowest, narrowest and simplest 500 cc bike in Holland; not much bigger than its 50 cc cousin.
327961327962

What engine powered that Frits, Suzuki 500?
edit one cylinder Maico?



Some inspiration from another angle. The first MTB I fell in love with. I had the pleasure of riding one of these on the 1994 Worlds HD course Vail Colorado. Epic bike from way back then.

This has elements of what I was thinking. Main frame mono with bolt on sub frame. Maybe a better option for a more modern rider position.


327963


http://www.carbonfibretube.co.nz/index.php?pr=Carbon_Tube_Prices

http://www.hexcel.com/Products/Honeycomb/
http://www.cgcomposites.com.au/Aerospace.html
http://www.nzcomposites.com/Products/Core+Materials/EuroComposites+Honeycomb+Core+Structural+Materials .html

The latest composites can be bent and shaped and glued with aradite products
Where is JasonU.

[Grumph]

What engine powered that Frits, Suzuki 500?
edit one cylinder Maico?


No carb visible - rotary valve ? If that's an Opel in the background it points out just how close the Opel and Holden of the period were....

[F5 Dave]

Mr Orr will be scoping eBay.ne or whatever equivalent as we speak.

[Grumph]

Mr Orr will be scoping eBay.ne or whatever equivalent as we speak.

ROFL - You've got a good memory Dave. Doubt Europe got the 308 V8 though....

[richban]

This was what I was thinking. Bit rough but you get the idea. Zero offset 90mm trail. 1200 to 1260 wheelbase. Ali mono frame with Tube Ali sub frame. I like how it looks.


Anyway good to get something down on paper / pixels.


327965

[Frits Overmars]

Nearly spat my coffee all over the screen then. (500) Holy crap. Do you have any pictures of that bike? Sounds a little mental. In the best possible sense of the word.Just a couple pictures, and not very good ones either. This is all I got.
NB: the front brake was way to small. But the bicycle bell on the left handlebar was mighty handy when manoeuvring through paddock: nobody there takes notice when they hear an engine behind them, but everyone looks around when they hear a bicycle bell :D.

[husaberg]

Just a couple pictures, and not very good ones either. This is all I got:

ah, Bultaco i never knew they want bigger than a 360.
What happened to it Frits does it still survive, or was broken into bits for other projects like most old race bikes?

[Frits Overmars]

Frits, 2mm steel does sound thicker than needed since 50-100mm steel tube spines will usually be 1-1.5mm wall. Did you use internal bulkheads or ribs?I might have done with a little less wall thickness Michael, but I've got a couple of excuses. First of all, I designed that bike 45 years ago and I was going to ride it myself so it should stay in one piece. Like I said, I had no facilities for working with light-alloy, and finite element calculations were out as well. Hell, I was lucky to have a pocket calculator then.
Next excuse: lack of equipment forced me to electrode-weld the frame, so a bit of wall thickness was welcome. And finally, you cannot compare flat-section sheet metal with tubing. Tubing is about the best shape when it comes to light, stiff constructions, flat sheet is about the worst. I used one internal bulkhead; no ribs.


What engine powered that Frits, Suzuki 500? edit one cylinder Maico?No sigar, but close, Husa. The engine came from a 360cc Bultaco El Bandido, the first Bultaco MX-bike with primary gears instead of the troublesome primary chain.
Alas, the gears caused problems of their own. Being helical, they pushed the crankshaft sideways until the bearing locating rings broke out of the crankcase.
Here are some pictures of the donor bike and engine.
327973327974


No carb visible - rotary valve ? If that's an Opel in the background it points out just how close the Opel and Holden of the period were....Yep, rotary valve and a home-made carburettor built by my friend Jos Disselhorst (he built and raced the 50 cc bike next to mine).
Why home-made? Because I wanted it to be 40 mm and very, very short. Nothing like that existed (and if it had, I wouldn't have been able to afford it at the time).
And yes, that's my Opel Rekord 1700 stationwagon in that picture. It held the 500, the 50, the fairings, the tent, the tools and the riders. The 500's front wheel between the seats served as an arm rest while driving.

[Frits Overmars]

ah, Bultaco i never knew they want bigger than a 360. What happened to it Frits does it still survive, or was broken into bits for other projects like most old race bikes?Bultaco built a variety of 360s. Or 363 cc to be precise, with 85 mm bore x 64 mm stroke (yep, way oversquare, exactly what I would not recommend today).
Based on the Bandido engine, they also made the TSS350 roadracer (picture below), with straight-cut primary gears and a five-speed gearbox.
I had to make do with the MX-bike's four gears but mine was better in acceleration anyway :D.
327975

My bike more or less survived. It's resting in my brother's haystack (because I haven't got a haystack of my own). The handlebars are missing because I used them on my 750 cc Kawasaki H2 triple.
The engine broke itself to pieces. Once I had convinced the crankshaft bearings to stay where they belonged, and the clutch to grab instead of slip, I could finally dial in some power and then the gearbox shafts got twisted to pieces, pushing the cases apart in the process. That was more than I could finance at the time.

[Frits Overmars]

This was what I was thinking. Bit rough but you get the idea. Zero offset 90mm trail. 1200 to 1260 wheelbase. Ali mono frame with Tube Ali sub frame. I like how it looks. Anyway good to get something down on paper / pixels.
327965That could work Richban. But since you're obviously planning to use a fibre seat, why not make a fibre tank-seat unit? It will give you a better contact with the bike than a bare monocoque. And if you shape the seat between your butt end your heels like in the Derbi picture below, you will be able to keep yourself in the saddle instead of being flung up into the air, in case of a highsider.

[Michael Moore]

Frits, I've no problem with overkill on the design since I'm not an engineer and I've got to go with "everyone else seems to think this is safe, maybe I'll make it a little safer". I have a tendency to want to triangulate everything where I imagine an engineer would look and ask what the extra 5 tubes are for. I thought that glimpse of head finning looked Bultacoish. Ducati singles can have similar problems with helical primary gear side thrust breaking the crankcase.

richban, your design looks familiar. FWIW, Tony Foale had a chance to talk to Eduardo Giro who confirmed that at least some of the frames (I can't recall if it was all of them) were welded Mg sheet, not aluminum.

If you make a combined tank/seat unit be sure it is secured better than the one on the Cosworth Norton that injured Peter Williams!

cheers,
Michael

[Grumph]

I might have done with a little less wall thickness Michael, but I've got a couple of excuses.

Yep, rotary valve and a home-made carburettor built by my friend Jos Disselhorst (he built and raced the 50 cc bike next to mine).
Why home-made? Because I wanted it to be 40 mm and very, very short. Nothing like that existed (and if it had, I wouldn't have been able to afford it at the time).
And yes, that's my Opel Rekord 1700 stationwagon in that picture. It held the 500, the 50, the fairings, the tent, the tools and the riders. The 500's front wheel between the seats served as an arm rest while driving.

I doubt if you lost anything worth worrying about by using 2mm sheet. I'm guessing that it might have finished up about 1 - 1.5kg heavier than if it was 1.6mm. Anything lighter gauge than that dents too easily and would have needed internal bracing IMO. And it still survives which a lighter gauge version wouldn't..

40mm carb was popular for big rotary valve singles...Cameron used a shortened 40mm Dellorto, as did Giro on the Ossa I think. But they were rare even new I believe.

There were a lot of those big Bultacos sold in Aussie - but not NZ - and a few were raced I believe. If you'd been in Aussie, your visually similar Holden would have had a 3 litre six in it to carry you to interstate meetings....

[richban]

richban, your design looks familiar.


327979

That thing is so so cool Michael.

I was also thinking of running tube through the sides. As I have a habit of parting company with my bike every so often, I will need some bike and track protection points on the frame for nylon sliders. So the tube gussets would be perfect for this.

The Question is:

Will it be lighter than a Tube steel fame?

How thick does the Ali have to be?

I think a tank / seat unit is a good idea. I do like to have a tank under me.

[Grumph]

The Question is:

Will it be lighter than a Tube steel fame?

Possibly - but the devil is in the details - Light forks, light swingarm, think light.....I was surprised to find that instead of the common 6mm fasteners everyone uses, John Britten used 5mm. How much saving ? don't know, but you get the idea...

How thick does the Ali have to be?

Depends if it's going to be formed like the Ossa or a straight sided box...Michael has already quoted gauges for a bonded and rivetted box. If it's formed and welded I would use 2mm. Largely depends too on what you can source if it's got to be formed into a shape. Soft 1.6mm is readily available here but i don't know about thicker gauges.

I think a tank / seat unit is a good idea. I do like to have a tank under me.

In principle for a bike monocoque I'd always advise a separate tank. It's hard to keep a welded monocoque "watertight". Which leaves either a separate tank outside or a bag tank inside. Bonded and rivetted ones always require separate tanks. Pretty sure your bro Kev will know where to source bag tanks...

[Grumph]

Actually, Rich's project raises a question in my mind - frame stiffness Vs feel. Any monocoque he makes is potentially anyway going to be stiffer torsionally than a tube frame. How stiff is desirable ?
Talking to Mike Sinclair a couple of weeks ago (yes, name dropping..) he confirmed what i thought - it is possible to go too stiff. He had numbers which he'd collected over the years from good and bad frames. The trouble is that as tyres change, so does the desirable range of chassis stiffness...
Asked, he said that the figures that they'd based the Modenas frame on, would not be relevant with the current tyres. He told me to have a talk to Magee who was there also. Mike said he's one of the best chassis setup guys he's struck. I didn't manage that but if they're all at the upcoming Auckland meeting, Rich might...

Then there's the question of kart track use Vs big circuits...Very different rider inputs required so you'd assume different chassis stiffness would be wanted.

Frits - We know that in the 50cc and 80cc classes, manufacturers went monocoque then back to tube from year to year. Did anyone actually come up with any hard data as to which was preferred - and why ?

[Frits Overmars]

richban, your design looks familiar. FWIW, Tony Foale had a chance to talk to Eduardo Giro who confirmed that at least some of the frames (I can't recall if it was all of them) were welded Mg sheet, not aluminum.To the best of myknowledge Giro used electron sheet for the Ossa monocoques.


Frits - We know that in the 50cc and 80cc classes, manufacturers went monocoque then back to tube from year to year. Did anyone actually come up with any hard data as to which was preferred - and why ?Van Veen Kreider started with tubular frames and never tried anything else. Derbi tried everything, going forward and backward (but then they were Spanish).
Jamathi started tubular, then went monocoque and never went back. The Piovaticci, Bultaco, Minarelli and Garelli 50cc and 125cc bikes all were monocoques.

Hard data, as in hanging measuring equipment on a bike? Nah. Putting the likes of Nieto, Lazzarini and Cadalora on a bike: yes. Those guys could really tell what was happening. They all had previous experience with tubular frames and they all wanted to stay with the monocoques. They all became world champion with 'm.

[richban]

Putting the likes of Nieto, Lazzarini and Cadalora on a bike: yes. Those guys could really tell what was happening. They all had previous experience with tubular frames and they all wanted to stay with the monocoques.

Thats a good bit of data right there. I have riden Steel frames with lots of flex and (feel). Feel as in like you could feel the front end flexing. And really stiff Ali beam frames with lots of feel. ( that feel meant you new what the trye was doing.) I prefer that later. If I build this thing I will not think to hard about it. I will simply try and find the cheapest easiest way to do it. 2mm sounds heavy. I will have to mock up a cutting list from a sheet and see what it weighs. 2mm full sheet weighs almost 14kg.

[Michael Moore]

Greg, I think that stiffness thing depends so much on the rider. I doubt that any frame could be too stiff for me as I generally can't tell if the tires have got a reasonable amount of air in them until they are about half flat. Everything feels strange for 15 minutes when I get on a different bike and then it seems normal and like I've never ridden anything else.

Building a bike for a sub-50th percentile rider opens up many options, because the bar is soooo low. :) It is (almost) all good.

Things that contain liquid are probably best kept easy to remove, clean, fix, and isolate from vibration. But I am tempted to do a fuel-bearing welded steel or aluminum frame some day.

Frits, isn't elektron a Mg/Al alloy? There may have been a little translation problem between Mg and Mg/AL and AL sheet by the time the info trickled down to my level.

richban, I was doing some weight comparisons yesterday, if you can remember the weight per foot/sq ft and that steel is 2.9X heavier than AL it is then easy to scale up/down as needed for different thicknesses:

1 foot of 1" x .062" wall is .626 lb
1 foot of 1" x .05" wall is .508 lb
1 foot of .75" x .062" wall is .459 lb
1 foot of .75" x .05" wall is .3748 lb


.080 wrought AL 1.123 lb /sq ft
.080 steel sheet 3.267 lb/sq ft

[Grumph]

Greg, I think that stiffness thing depends so much on the rider. I doubt that any frame could be too stiff for me as I generally can't tell if the tires have got a reasonable amount of air in them until they are about half flat. Everything feels strange for 15 minutes when I get on a different bike and then it seems normal and like I've never ridden anything else.

Building a bike for a sub-50th percentile rider opens up many options, because the bar is soooo low. :) It is (almost) all good.

You're not wrong Michael...Short story.
Some years back, first season of what became a very well known special here (Tony McMurdo's pink thing for the Kiwis..) When he got to the NZGP meeting I got a chance to ride it in practise as did the rider of my bike in the same class - F3. I'd built the motor for it.
My works rider thought it was great - he was lighter than Tony. I found it flexed most unpleasantly - I'm about 30Kg heavier than Tony...
So older slower - but heavier - rider could show up something that Tony only found at the extreme limit.
Solved with a shitload of aluminium welding...
Maybe all works bikes should be tested by a fat rider.....

[mr bucketracer]

You're not wrong Michael...Short story.
Some years back, first season of what became a very well known special here (Tony McMurdo's pink thing for the Kiwis..) When he got to the NZGP meeting I got a chance to ride it in practise as did the rider of my bike in the same class - F3. I'd built the motor for it.
My works rider thought it was great - he was lighter than Tony. I found it flexed most unpleasantly - I'm about 30Kg heavier than Tony...
So older slower - but heavier - rider could show up something that Tony only found at the extreme limit.
Solved with a shitload of aluminium welding...
Maybe all works bikes should be tested by a fat rider.....mine are tested by fat riders lol , i'm learning all the time (-;

[husaberg]

Bultaco built a variety of 360s. Or 363 cc to be precise, with 85 mm bore x 64 mm stroke (yep, way oversquare, exactly what I would not recommend today).
Based on the Bandido engine, they also made the TSS350 roadracer (picture below), with straight-cut primary gears and a five-speed gearbox.
I had to make do with the MX-bike's four gears but mine was better in acceleration anyway :D.
327975

My bike more or less survived. It's resting in my brother's haystack (because I haven't got a haystack of my own). The handlebars are missing because I used them on my 750 cc Kawasaki H2 triple.
The engine broke itself to pieces. Once I had convinced the crankshaft bearings to stay where they belonged, and the clutch to grab instead of slip, I could finally dial in some power and then the gearbox shafts got twisted to pieces, pushing the cases apart in the process. That was more than I could finance at the time.

I think i posted some stuff a while back on the ese thread about Bert? Floods el bandito.
Do you have any pictures of the engine and carb.




There were a lot of those big Bultacos sold in Aussie - but not NZ - and a few were raced I believe. If you'd been in Aussie, your visually similar Holden would have had a 3 litre six in it to carry you to interstate meetings....

Tony Tomasi used to race an el bandito in the early days of cams.
it had a double sided SLS front brake of a laverda or Moto Morini or similar.

[Grumph]

mine are tested by fat riders lol , i'm learning all the time (-;

Ever tested the stiffness of yours against one of the RS125 frames ?

[F5 Dave]

Thats a good bit of data right there. I have riden Steel frames with lots of flex and (feel). Feel as in like you could feel the front end flexing. And really stiff Ali beam frames with lots of feel. ( that feel meant you new what the trye was doing.) I prefer that later. If I build this thing I will not think to hard about it. I will simply try and find the cheapest easiest way to do it. 2mm sounds heavy. I will have to mock up a cutting list from a sheet and see what it weighs. 2mm full sheet weighs almost 14kg.

Perhaps 3mm steel sheet might be more in keeping. Scaling things appropriately. . . . I'm just saying:innocent:

[TALLIS]

Ever tested the stiffness of yours against one of the RS125 frames ?

We have found the honda rs125 and Yamaha tz125 frames are quite a bit easier to get a grinding disk thru. Unsure how that transitions to frame flex on the track. :facepalm:

[Grumph]

We have found the honda rs125 and Yamaha tz125 frames are quite a bit easier to get a grinding disk thru. Unsure how that transitions to frame flex on the track. :facepalm:

bloody heathens...you could at least test the next one BEFORE cutting it up.....

[F5 Dave]

Regan's tested at least one. Think the result was Earth1: HRC nil

[mr bucketracer]

Regan's tested at least one. Think the result was Earth1: HRC nillol yes clean break , he sold it with new frame and jay snaped that one to , like you said i would go 3mm alu ,already started a sheeted frame

[trevor amos]

When designing the monocoque structure of the Ossa, Eduard Giro, with his formal back ground in aviation, specified magnesium alloy sheets not available in Spain, but was denied an application for their import from another country. Such was the oppressive and paranoid regime of General Franco. Not to be deterred, he arranged the “clandestine import” of the material on the backs of mules using a smugglers route over the mountains from France. Don`t know if this tale is true or not, but if so then its another inspiring example of putting one over on the dictators of this world, and of a small team with limited resources achieving great success against the mighty Japanese factories!
Frits, perhaps you might be able to confirm or dispel the reality of this tale, and might I be able to detect some small influence from the Ossa concept in your own creations?

Cheers, Trevor

[Michael Moore]

Here's a Scorpion off-road bike from the early 1960s with a welded steel box frame. Don Morely says the designer, Paul Wright, was a race car chassis designer. He lists the weight of the frame as 11 pounds. With a standard iron barrel Villiers trials engine the bike was under 200 pounds. There is no mention of sheet thickness.

cheers,
Michael

[richban]

So after not much thinking I am going to build it. For no better reason than there is not one on the track here I know of. And I also need 2 light and nibble bikes to compete at the front. 50 and 90 AM6 engines.

Sketchy has kindly offered to put the frame through his fancy software to test safety / stiffness. Also the weight calculations of the frame and swing arm. So we can try different thickness Ali and see how we go on the computer before cracking into building. He has also recommended a good grade of Ali to use. Helpful chap that Glen.

I will now try and figure the foot peg and engine mounting then send it off to Glen for analysis. Work on top view in 2D and the swing arm.

If it all works out I would like to publish a cutting pattern for anyone to have a crack at.

2 important things missing are the front forks and rear shock.

I think RS125 front forks would be the simple choice.

I found these the other day as well.

327998

[Michael Moore]

richban, in Volume 2 John Bradley mentions the Foggy Petronas superbike frame is made from 2mm 5083-O sheet and the swing arm is 2.5mm. Other parts are turned from solid (presumably also 5083). Filler rod is 5356. He says 5083 is reasonably formable in H12 and "just" formable in H14. It does work harden quickly which is why O temper was chosen for the pressings. He thinks the alloy is underutilized for motorcycle applications. 5083 also has very good fatigue characteristics.

So you might keep that in mind as a starting point for your frame.

cheers,
Michael

[Grumph]

And in NZ 5083 is used a lot for boats.....but not common under 3mm thickness.

[Michael Moore]

If he went with the 2.5mm as a nice safe number for the frame material then having to use 3mm is a 20% weight disadvantage, but that might only be a pound or two. If he got serious he could attach the sheet with a belt sander. :) The peace of mind from the 3mm might be considered a plus.

A big industrial supply place here has 5083 sheet with .125" (+/- .007") being the thinnest they offer. They do go up to 1" plate for making machined bits. But they are stocking convenient sizes for quick ordering, I've not checked with an actual metals house to see what might be available from a specialist.

[jasonu]

If he went with the 2.5mm as a nice safe number for the frame material then having to use 3mm is a 20% weight disadvantage, but that might only be a pound or two. If he got serious he could attach the sheet with a belt sander. :) The peace of mind from the 3mm might be considered a plus.

A big industrial supply place here has 5083 sheet with .125" (+/- .007") being the thinnest they offer. They do go up to 1" plate for making machined bits. But they are stocking convenient sizes for quick ordering, I've not checked with an actual metals house to see what might be available from a specialist.

Availability may just make the call for him re. material type/thickness.

[F5 Dave]

I love a bold approach Richardson. Look forward to seeing the results.

In that vein WP made a single sided linear bearing fork . That would be a fun project too.
Never seen on a bucket. How can you resist?

[richban]

I love a bold approach Richardson. Look forward to seeing the results.

Ha ha. Well I did do some more drawing. The more I draw the more problems there are to overcome. As you will notice. I sort of start with what I think looks cool then slowly the practical problems dictate the design. When the new AM6 engine arrives I will be able to change the frame to suite the mounting points on the engine. Anyhow, these are just thoughts on paper at the moment. Turning circle will be a little limited I think. But hey, it will be so light i will just pick it up and point it where I want. ;)


328001


328002

[F5 Dave]

Ha. Autocorrect. Richardson.

[husaberg]

Here's a Scorpion off-road bike from the early 1960s with a welded steel box frame. Don Morely says the designer, Paul Wright, was a race car chassis designer. He lists the weight of the frame as 11 pounds. With a standard iron barrel Villiers trials engine the bike was under 200 pounds. There is no mention of sheet thickness.

cheers,
Michael

The Norton comando JPS was made in Stainless steel i have what the gauge was somewhere.


No carb visible - rotary valve ? If that's an Opel in the background it points out just how close the Opel and Holden of the period were....

Why did we miss on these
Opal GT 1972
328007328008328009328010
I have no idea what GM platform its based on if it even is, Maybe chevette, Gemini or the earlier Isuzu bellet?
What did we get from GM then HB torana and Viva.
How common were the opal GTs in Euroland Frits.

[Ocean1]

Why did we miss on these
Opal GT 1972
328007328008328009328010
I have no idea what GM platform its based on if it even is, Maybe chevette, Gemini or the earlier Isuzu bellet?
What did we get from GM then HB torana and Viva.
How common were the opal GTs in Euroland Frits.

It's a kadett. I had one in London, nothing special. The Manta was a better machine.

[Grumph]

Why did we miss on these
Opal GT 1972

I have no idea what GM platform its based on if it even is, Maybe chevette, Gemini or the earlier Isuzu bellet?
What did we get from GM then HB torana and Viva.

Kadette was I think same pan as HB Viva - which stretched a bit gave us down here the Torana 6 - then the fire breathing XU1 version - then the two prototype XU1 V8's....

This is actually very similar to what Rich is looking to do - first a 50, then a 90, then a fire breathing 300 twin.....

[husaberg]

Kadette was I think same pan as HB Viva - which stretched a bit gave us down here the Torana 6 - then the fire breathing XU1 version - then the two prototype XU1 V8's....

This is actually very similar to what Rich is looking to do - first a 50, then a 90, then a fire breathing 300 twin.....

Thats speedpro's punchline.


It's a kadett. I had one in London, nothing special. The Manta was a better machine.

thought the kaddet was the chevette/Gemini/
edit maybe not
https://en.wikipedia.org/wiki/GM_T_platform_(1973)

edit again oh i see there were two versons of the kadett
https://en.wikipedia.org/wiki/Opel_Kadett#Kadett_C_.281973.E2.80.931979.29

[Ocean1]

thought the kaddet was the chevette/Gemini/
edit maybe not
https://en.wikipedia.org/wiki/GM_T_platform_(1973)

edit again oh i see there were two versons of the kadett
https://en.wikipedia.org/wiki/Opel_Kadett#Kadett_C_.281973.E2.80.931979.29

Aye, individual marque model design got more or less submerged in badge engineering, (design by accountants) from about then onward.

The 1900 engine was the basis of the Holden Torana unit sold here, having been completely neutered for no adequately explained reason.

[husaberg]

Aye, individual marque model design got more or less submerged in badge engineering, (design by accountants) from about then onward.

The 1900 engine was the basis of the Holden Torana unit sold here, having been completely neutered for no adequately explained reason.

Have a read up what GM did to the Cosworth engine made for the Vega one day
Neutered by stupidity.

In April of 1974, just one month before the planned introduction, two of the three engines in the Emissions Certification test cars burned exhaust valves by the 46,000-mile mark, just before reaching the 50,000 mile limit (PDF) marking the end of the test. The third car was withdrawn from testing and a teardown of its engine revealed incipient exhaust valve damage as well. Bill Howell, of Chevrolet Product Promotion (aka Chevrolet Racing) and a fellow Cosworth owner, who together with Herb Fishel spent hundreds of dyno hours developing Chevrolet�s version of the Cosworth Twin Cam engine, twice criticized the decision that led to this failure.
In a rare moment of candor, when among a small group of Cosworth Vega enthusiasts in Akron, Ohio, he attributed the emissions test failure debacle to an irrational decision to run the timing substantially retarded on the test cars in an effort to provide a safety margin in the emissions numbers. That decision, which he had strenuously but unsuccessfully opposed, made absolutely no sense to him, and left him bitter. As he predicted, it dumped excessive heat into the exhaust valves and seats, and they predictably failed. He was convinced from all of his dyno work on the engines, and based upon all of the knowledge he had amassed during his impressive career, that they would have passed emissions with the timing properly advanced.
http://www.cosworthvega.com/cosworth_vega_history.html

Then again maybe the bock wouldn't have outlasted the valves

That Mike referred to the EAA, the Chevrolet Vega, as 'the stumbling block' was perfect, for the phrase amply sums up the debacle.
"It was extremely light compared to the BDA with its pressure die-cast aluminium block from Reynolds, but was not up to the ratings we were putting through it. Designed to be a two litre racer, we could not make the cylinder block live. There was nothing we could do."
" It started as a race engine with Chevrolet, dry sump, the whole works, and it was Chevy who productionised it for the Vega car, They even had problems with the engine in road trim just as they did with the standard engine. The project died but they are now collectors' items!"
Thus the first road car to carry the Cosworth name did not enhance any reputations. It was not the engine which was at fault, only the block, but that tends to be somewhat critical and the whole episode fated before it began. Hundreds of blocks were being delivered, many failing a pressure test Cosworth devised for them and littering up the place while a solution was found. It never was.
http://www.cosworthvega.com/the_cosworth_story.html

http://www.italian.sakura.ne.jp/bad_toys/cosworth/index4.html

[richban]

then a fire breathing 300 twin.....

Well I had a fire breathing 300 twin only 5 weeks ago. One broken back and a rather broken bike later I think the 50 / 90 are more my speed for a while.

328024328023

[Yow Ling]

Some sheet metal chassis that Jan Thiel made in the 70's , I think they are sheet steel but dont hold me to it.
Multiple world champion bikes "Jamathi" 50cc , dressed up as Bultaco in this link

http://www.elsberg-tuning.dk/bultaco.html

[husaberg]

Some sheet metal chassis that Jan Thiel made in the 70's , I think they are sheet steel but dont hold me to it.
Multiple world champion bikes "Jamathi" 50cc , dressed up as Bultaco in this link

http://www.elsberg-tuning.dk/bultaco.html
Ribbed for stiffness rather than pleasure
328031328032328033328034328035
http://www.jamathi.nl/
http://www.elsberg-tuning.dk/jamathi.html

[husaberg]

328036328037328038328039

[Grumph]

328037

Looks like an internal brace, lazy "Z" shape spot welded through the sides.

Early frames welded using fluxed rod, nice....and I bet that welder still has a bad back.
Lesson there - raise the workpiece, or sit down.

[jasonu]

Ribbed for stiffness rather than pleasure
328031328032328033328034328035
http://www.jamathi.nl/
http://www.elsberg-tuning.dk/jamathi.html

That makes a lot of the Buckets out there look rather over engineered...

[Frits Overmars]

When designing the monocoque structure of the Ossa, Eduard Giro, with his formal back ground in aviation, specified magnesium alloy sheets not available in Spain, but was denied an application for their import from another country... Not to be deterred, he arranged the “clandestine import” of the material on the backs of mules using a smugglers route over the mountains from France... Frits, perhaps you might be able to confirm or dispel the reality of this tale, and might I be able to detect some small influence from the Ossa concept in your own creations?I can't confirm nor deny the realiy of that smuggler tale but I can definitely confirm the Ossa influence in my own monocoque racer.


Some sheet metal chassis that Jan Thiel made in the 70's , I think they are sheet steel but dont hold me to it.Yes, the first Jamathi monocoques were steel sheet. Below are two pics of the first one, the 1972 model (the same year that I built my 500 monocoque, without Jan and me knowing about each others plans). The third picture shows the 1977 Bultaco, one of my all-time favorites. Because of the peculiar colour there were rumours about its frame being titanium. In reality it was stainless steel, sandblasted to take the shine off, so the buckling after welding was less noticeable :D.
328041 328042 328043

[husaberg]

That makes a lot of the Buckets out there look rather over engineered...
Maybe but tire tech and suspension has moved on heaps since the 70's. Not to mention the riders are likely a little bit heavier.


http://www.carbonfibretube.co.nz/index.php?pr=Carbon_Tube_Prices
http://www.hexcel.com/Products/Honeycomb/
http://www.cgcomposites.com.au/Aerospace.html
http://www.nzcomposites.com/Products/Core+Materials/EuroComposites+Honeycomb+Core+Structural+Materials .html

The latest composites can be bent and shaped and glued with aradite products
Where is JasonU.

[Grumph]

Maybe but tire tech and suspension has moved on heaps since the 70's. Not to mention the riders are likely a little bit heavier.

Ignition coils have got a lot smaller too...

But the best tuning trick is still to put a skinny kid on it.

And to follow Frits comment about blasting the stainless monocoque - never paint a frame silver unless the welding is absolutely flawless.
Silver will show everything up in horrible detail. Dull nickel is actually quite a bit better if you must have silver.

[jasonu]

The latest composites can be bent and shaped and glued with aradite products
Where is JasonU.

Lancair uses huge amounts of Hysol 2 pot glue to bond the carbon parts.

[husaberg]

Lancair uses huge amounts of Hysol 2 pot glue to bond the carbon parts.


Do they use a modern equivalent of the old Ciba Geigi M board ie honeycomb sheaved with aluminium?
Like this stuff.
http://www.pantah.eu/bilder_racing/segale/pantah_div_095.jpg


Ignition coils have got a lot smaller too...

But the best tuning trick is still to put a skinny kid on it.

And to follow Frits comment about blasting the stainless monocoque - never paint a frame silver unless the welding is absolutely flawless.
Silver will show everything up in horrible detail. Dull nickel is actually quite a bit better if you must have silver.

Gloss finishes much like lycra is not so great at hiding inperfections.
Pits, ugly rough welds and uneven finish far to much like a facet on a gemstone.
https://pbs.twimg.com/media/CCmgL00VIAAANwX.jpg
i love nickel especially when it ages into a sort of verdigris patina.

[Grumph]

i love nickel especially when it ages into a sort of verdigris patina.

Don't see a lot of that over here on the dry side of the hill.....

[jasonu]

Do they use a modern equivalent of the old Ciba Geigi M board ie honeycomb sheaved with aluminium?
Like this stuff.
http://www.pantah.eu/bilder_racing/segale/pantah_div_095.jpg



Gloss finishes much like lycra is not so great at hiding inperfections.
Pits, ugly rough welds and uneven finish far to much like a facet on a gemstone.
https://pbs.twimg.com/media/CCmgL00VIAAANwX.jpg
i love nickel especially when it ages into a sort of verdigris patina.

Mostly CF. They had other thickening materials that (I think) is made from kevlar. Basically it was 2 thin sheets sandwiching a corrugated sheet. They bonded it to the CF parts where thickness and additional stiffness was required. TBH I kept away from that part of the production process, fucking hate anything to do with the dust and slivers the composite materials created.

[Grumph]

Mostly CF. They had other thickening materials that (I think) is made from kevlar. Basically it was 2 thin sheets sandwiching a corrugated sheet. They bonded it to the CF parts where thickness and additional stiffness was required. TBH I kept away from that part of the production process, fucking hate anything to do with the dust and slivers the composite materials created.

For the short time I worked for John Britten, my small lathe was left on the premises. I'd come in mornings and it would be covered in black shit. At that point there were a lot of bits being made from what was basically fiberglass filler mixed with chopped CF. It actually machined quite easily - although a bit hard on cutting tips - but the bloody dust...evil stuff.
I was quite happy to let the tribe of night time volounteers breath it rather than me. I'd simply grab John's vacuum cleaner and do the lathe area before I did anything else.
Edit - just remembered that in the book, there's mention that much later on they used power files to shape CF parts. They didn't last long as the CF dust either stuffed the electrics or wore the gear drives.

[jasonu]

For the short time I worked for John Britten, my small lathe was left on the premises. I'd come in mornings and it would be covered in black shit. At that point there were a lot of bits being made from what was basically fiberglass filler mixed with chopped CF. It actually machined quite easily - although a bit hard on cutting tips - but the bloody dust...evil stuff.
I was quite happy to let the tribe of night time volounteers breath it rather than me. I'd simply grab John's vacuum cleaner and do the lathe area before I did anything else.
Edit - just remembered that in the book, there's mention that much later on they used power files to shape CF parts. They didn't last long as the CF dust either stuffed the electrics or wore the gear drives.

Yep. Once that crap gets into your clothes you may as well burn them, ya just can't get rid of its itchyness. It's worse than fiberglass.

[Yow Ling]

Yep. Once that crap gets into your clothes you may as well burn them, ya just can't get rid of its itchyness. It's worse than fiberglass.

Give them to the city mission

[F5 Dave]

Ignition coils have got a lot smaller too...

But the best tuning trick is still to put a skinny kid on it. . . .


So the 80kg old git used to use wasn't the hot setup? Bugger!
He was expensive in alcohol too.

[jasonu]

Give them to the city mission

Rotten sod!

[Grumph]

So the 80kg old git used to use wasn't the hot setup? Bugger!
He was expensive in alcohol too.

Nothing worse than a rider with expensive tastes...

The skinny kids all appear to live on "V" or similar energy drinks, god knows what their teeth are going to be like...

[WilDun]

Talking skinny kids and V, I notice that the kids bikes have moved away from ally and plastic now and the frames are all made "overkill" style from steel tube, is this because they find steel works best or cheaper to mass produce?
I do see the tips are full of little bikes (I do tend to do a bit of scrounging), which have not deteriorated at all and as sound as the day they were made!
Maybe motorcycles will follow suit - good old steel tube, safe, cheap and easy to work with!

[Michael Moore]

good old steel tube, safe, cheap and easy to work with!

Also readily available and if properly designed with an infinite (for our purposes) fatigue life. Steel is much more forgiving (and less expensive) for the DIY enthusiast.

cheers,
Michael

[guyhockley]

How it was done in 1958.

[husaberg]

How it was done in 1958.

Old hat old chap:killingme
LE Velocette
Ie the Noddy bike
1948-1970
328134
Grumph can likely remember a few more even earlier examples from when he was an Noahs apprentice.:innocent:

[husaberg]

I have been meaning to post some of Alf Hagons later road racing chassis
I posted a MX bike ages ago
I will post a bit of a blurb later
328137328138328139328140328141328142

[Grumph]

Grumph can likely remember a few more even earlier examples from when he was an Noahs apprentice.:innocent:

Bah, humbug.


I have been meaning to post some of Alf Hagons later road racing chassis

Wouldn't want to get at those carbs on the Honda...

[husaberg]

Bah, humbug.



Wouldn't want to get at those carbs on the Honda...

The Hagon frame is made from 6 separate sheets of aluminium and a headstock.
On some of the pics i have seen i would be more worried about my leg from the exhaust.
As some versions had it high level exiting above the shock beside the seat.
Pretty sure the carb falls into the undo clip and yank away whole carb/s club.
On my old MB5/H100 i used to have to first remove the dummy tank then the coil to get the carb off.
To get the head of you used to have to remove a rear mounting bolt to allow the engine to swing forward as well.
Funny enough if you ever need some oval tubing, the MB5 main tubes were actually oval. Were the MB100 oval tube?

328143
Whist i was prepping the Rd frame for paint the other day i found 5 separate welds than contained surplus mig wire, its amazing how lax the Quality control was in the 70's.

[Michael Moore]

Thanks for that detailed Ariel article, there's a lot of interesting information in it!

cheers,
Michael

[guyhockley]

Don't have access to my copy at the moment, but I think there's some stuff about pressed and formed steel frames in Irving's Motorcycle Engineering. I think he had something to do with Noddy bikes?

[Grumph]

Don't have access to my copy at the moment, but I think there's some stuff about pressed and formed steel frames in Irving's Motorcycle Engineering. I think he had something to do with Noddy bikes?

Yes, there is. The old bugger was very keen on pressed steel frames. Pretty sure he was part of the design/development team for the LE, certainly some of the problems encountered are mentioned in that book.
Looking at a couple of the drawings of possible pressed frame layouts always makes me wonder if J J Cobas had a copy.

[Grumph]

Funny enough if you ever need some oval tubing, the MB5 main tubes were actually oval. Were the MB100 oval tube?

Whist i was prepping the Rd frame for paint the other day i found 5 separate welds than contained surplus mig wire, its amazing how lax the Quality control was in the 70's.

MB100/H100 is round tube spine. Final version of Kevs was pyramid braced which made a vast difference particularly when using kerbs and gutters for passing at Greymouth....
My R5 frame was the same. pretty sure the R5/DS7 was Yamaha's first robot welded frame - and it showed it.

[husaberg]

MB100/H100 is round tube spine. Final version of Kevs was pyramid braced which made a vast difference particularly when using kerbs and gutters for passing at Greymouth....
My R5 frame was the same. pretty sure the R5/DS7 was Yamaha's first robot welded frame - and it showed it.


Its only the two outer tubes on the MB5 that are oval.
If he had tires that were made in the current decade he might be able to keep out of the gutters
The welds themselves are not to bad just the wire.
1970, I was not aware they were using the robots that early in the piece.
The later 78 RD250 frame i am playing with has about 6 extra gussets and silly pressed metal overlaping pieces than the old frame and the TZ's ever had.

[Grumph]

Its only the two outer tubes on the MB5 that are oval.
If he had tires that were made in the current decade he might be able to keep out of the gutters

17in BT39's, sticky as, bro....

Starting off the back in a field of 30 odd and coming through to 4th in 5 laps means passing wherever you can....kerbs, gutters, fallen riders...
Someone put up a video at the time, Kev appears and passes between the camera bike and the kerb - then disappears in the distance

Pretty sure all the big MB's I've worked on used round tube.

Edit - Found a pic of the filthy thing post bracing. Clean tube is the new stuff added....

[husaberg]

17in BT39's, sticky as, bro....

Starting off the back in a field of 30 odd and coming through to 4th in 5 laps means passing wherever you can....kerbs, gutters, fallen riders...
Someone put up a video at the time, Kev appears and passes between the camera bike and the kerb - then disappears in the distance

Pretty sure all the big MB's I've worked on used round tube.

Edit - Found a pic of the filthy thing post bracing. Clean tube is the new stuff added....

Oh thats belts and braces stuff, i would have thought the weak link would have ben the flimsy swingarm plates and the little rear axel, has it got decent forks? I can't remember.
The steering head appears to be a lot better suported than the 50 Frame as is the rear brace above the swingarm.
328168328169328170

[Frits Overmars]

If he had tires that were made in the current decade he might be able to keep out of the gutters.And let such beautiful opportunities go to waste?
I remember my very first 500 cc road race on a street circuit. No gutters there, but kerbstones; even better.
In one of the corners the straw of a torn straw bale made the road slippery as hell and I slid against the kerbstone.
You'll never find better lateral grip. I could give it full throttle whilst still leaned over :D.

[husaberg]

And let such beautiful opportunities go to waste?
I remember my very first 500 cc road race on a street circuit. No gutters there, but kerbstones; even better.
In one of the corners the straw of a torn straw bale made the road slippery as hell and I slid against the kerbstone.
You'll never find better lateral grip. I could give it full throttle whilst still leaned over :D.


https://www.youtube.com/watch?v=c3cAZ2qSiYA
I think he needs to work on the jetting as its 4 stroking a lot.

[Grumph]

And let such beautiful opportunities go to waste?
I remember my very first 500 cc road race on a street circuit. No gutters there, but kerbstones; even better.
In one of the corners the straw of a torn straw bale made the road slippery as hell and I slid against the kerbstone.
You'll never find better lateral grip. I could give it full throttle whilst still leaned over :D.

You'd get along fine with Kev, Frits. Unused pieces of the road are just opportunities...

Current thinking here for street circuits is to place the bales on the road up against the kerbs to prevent a bike moving them...
IMO it has had the side effect of narrowing some circuits too much. The long established circuits like Greymouth (Husa's home track) still have exposed kerbs in a lot of places. Most are too slow (tight) for it to be a problem but I can still remember Dale Wylie breaking a vertebrae against a kerb at Wanganui many years back. We're pretty lucky we still have street circuits here.

From a chassis point of view, if you can build a bike which will survive the bumps on Wanganui or Greymouth, you're doing OK, LOL. Two sidecars pulled out of Wanganui this year with damaged chassis. One an LCR with the top guy in the world driving...

[guyhockley]

Plate frame Triumph, lots more if you search using Bucephalus plus motorbike, custom, triumph, or similar.

http://www.ebay.com/gds/Building-Bucephalus-An-Interview-With-Loaded-Gun-Customs-/10000000178960559/g.html

http://www.loadedguncustoms.com/blog/2013/12/11/bucephalus

Apologies if it has been posted before and I've forgotten...

[Grumph]

Here in NZ, Bucephalus was a well known 350 manx based special built and raced by the late Dick Hurdeman.
Think open bottomed Duke Velo frame and you'd be close.
Don't have a pic but someone may.

[mr bucketracer]

https://www.youtube.com/watch?v=c3cAZ2qSiYA
I think he needs to work on the jetting as its 4 stroking a lot.ya could of put my race up :baby:

[husaberg]

ya could of put my race up :baby:

I was going too, but as you recall it was a little wet that day and i didn't want people to think it rains there.

[Grumph]

I was going too, but as you recall it was a little wet that day and i didn't want people to think it rains there.

Eighteen METERS annual rainfall doesn't give a hint ?

[husaberg]

Eighteen METERS annual rainfall doesn't give a hint ?

On the windward side of MT Cook, Maybe. We have excellent views of it though.:laugh:
Greymouth is 2500mm or 100 Inch av
Where i live is 2000mm or 80 inch av
Its a bloody veritable subtropical osasis over here.
Palm trees line the streets, 3 frosts in 2 years, no snow in living memory.
You live in rabbit country while over here its marpupial paridise
49 years since the last major earthqauake as well.

[WilDun]

49 years since the last major earthqauake as well.

Careful, careful! famous last words and all that! - I live in Auckland but would never say that! we all live in the Shaky Isles!
Guess if you were racing buckets in Greymouth and there was a quake, you wouldn't even notice. :msn-wink:

[husaberg]

Careful, careful! famous last words and all that! - I live in Auckland but would never say that! we all live in the Shaky Isles!
Guess if you were racing buckets in Greymouth and there was a quake, you wouldn't even notice. :msn-wink:

That would have me finishing the bucket build Will, far higher chance of an earthquake and a ice age followed by a nuclear attack than that ever happening.:laugh:
Auckland i would be more worried about the 100 or so Volcanoes Auckand built on top of:msn-wink:
Pretty much the whole of down town greymouth is a liqufaction zone. Its mostly backfill silt.
The bumps are better then they were ,the worst in the braking zones past the Police station have been smoothed out a little.
The Greymouth track is highly cambered not always in a helpful direction.
The local council are very kind in accomadating the race, With such things as removable traffic islands sand blasted whitelines and all sorts of stuff.
The team that does the work are a great bunch of people and are never given the full credit they deserve.

[WilDun]

Auckland i would be more worried about the 100 or so Volcanoes Auckand built on top of:msn-wink:


Yeah well, a fine example is the Mt Wellington track nestled right under Maungarei which has probably seen some pretty violent eruptions in its day! - but at the moment I enjoy living life amongst the volcanoes (that's probably the attitude the residents of Pompeii had too).


The local council are very kind in accomadating the race, With such things as removable traffic islands sand blasted whitelines and all sorts of stuff.
The team that does the work are a great bunch of people and are never given the full credit they deserve.

I went to Greymouth a few years ago and I think I missed the racing by about a couple of weeks unfortunately, - wasn't raining though!
Anyway, where I came from originally it rained nearly every day! and the people there did enjoy their bike racing big time and they also had genuine road racing - but strangely no actual street racing except when a town or village was part of a road circuit (but may have changed since I left over 50 years ago).
I think NZ is probably unique with it's motorcycle street racing :)

[cotswold]

stolen photo's from FB

[WilDun]

Probably I was getting off track, sorry about that!
I remember at the start of the thread you talked about a simple tubular backbone frame, saying that you thought that it would be great for buckets.
How much harder (or easier) would it be to construct a mono frame like you have just posted - how well would that stand up to the kinds of stresses involved on our street circuits?
I think Michael Moore was right about tubular steel - he said it was the easiest and most forgiving material, (I don't think it would be as easy to dent!).

[Grumph]

Depends really on what your home workshop is like as to which chassis construction method works for you.
I don't have a folder - but do have welding gear. Don't want to work with composites either...

FWIW I'm told the LCR failure at Wanganui was that it punched the front shock mounting out the bottom of the monocoque.
Points up how important it is to feed the loads into a monocoque appropriately - and over a large area if possible.
LCR are not novices at that method of construction - but I bet they never anticipated an F1 outfit built for the tracks of Europe would run on the streets of Wanganui...The 600 LCR which was there was fine - but it's built to run at the IOM.

[Michael Moore]

I suspect that most any type of frame will be adequate if properly designed and built.

Tubular steel seems pretty accessible to DIY builders. Various people have built riveted alumin(i)um sheet chassis for bikes and small race cars, not to mention for homebuilt aircraft. But it looks like you need a reasonable amount of knowledge of both how to feed loads into the sheet as well as what makes for good riveted joints.

You can do welded alumin(i)um frames if you are good at welding that material and you've got some idea of what kind of alloy and rod to select AND you keep in mind that alumin(i)um is 1/3 the stiffness of steel and often has a much lower fatigue limit (remember BSA's expensive in both money and championships experience with building titanium frames that were largely copies of their steel frames).

Composites that are glued seem to be another big jump on the amount of knowledge needed, and not near as accomodating to the "let me look around and see what other people are doing so I can copy them, with maybe a bit of an extra safety factor added" method of design.

So you've got to ask yourself "do you feel lucky (knowledgeable)?"

:)

But what do I know, I'm just a DIY enthusiast who doesn't want to risk my life any more than necessary.

cheers,
Michael

[richban]

So you've got to ask yourself "do you feel lucky (knowledgeable)?"

:)

But what do I know, I'm just a DIY enthusiast who doesn't want to risk my life any more than necessary.

cheers,
Michael

I here you Michael. Sitting here with a broken back having yet another feeling sorry for self beer. I will be making sure anything I design will go to the people that know about these things for a safety check. Then the only dangerous piece of the puzzle will be the lump of meat trying to ride it. :facepalm:

[Grumph]

Well, I've now read Mike Sinclair's book - and I have more questions...I must find a way of backing Mike into a corner and getting some answered.
Looking at the nuggets of info in there, there's a potential paper to be written by Mike and Tom O'kane on chassis dynamics. I'll suggest it to Mike but getting Tom to find time might be harder.
It was most interesting to discover why the carbon fiber frames didn't work also...

One major question raised is tyre internal damping (presumably carcase design). Mike is sure the current generation of MotoGP tyres have it due to the lower pressures they're running.
I'd like to know how far down the manufacturers tyre ranges the built iin damping extends.

[husaberg]

Well, I've now read Mike Sinclair's book - and I have more questions...I must find a way of backing Mike into a corner and getting some answered.
Looking at the nuggets of info in there, there's a potential paper to be written by Mike and Tom O'kane on chassis dynamics. I'll suggest it to Mike but getting Tom to find time might be harder.
It was most interesting to discover why the carbon fiber frames didn't work also...

One major question raised is tyre internal damping (presumably carcase design). Mike is sure the current generation of MotoGP tyres have it due to the lower pressures they're running.
I'd like to know how far down the manufacturers tyre ranges the built iin damping extends.

No idea but the Suzuki GP 500 that Roberts jr ran would not work with the 16.5 tyres.
traditionally the Michelin and dunlops have very different constructions.
From memory back in the 500GP days one(i think Michelin) used to have a very stiff carcass and relied on soft rubber while the other (i think)Dunlop was a soft carcass with a harder rubbber to get the required operating temps.
The Dunlops would slide and have better feel at the limit, while the Michelin generally had better grip but let go suddenly.
Dunlop generally had better fronts and Michelin had better rears. from what i understand current Bridgestone are made similar to Dunlops and use the same design philosophy.
one a side note
The Showa and the Ohlins forks and dampers also used to very different valving techniques to achieve a similar outcome.

[Grumph]

No ,but the Suzuki GP 500 that Roberts jr ran would not work with the 16.5 tyres.

Mike was still in the game then. He says in the book it came in after he left. So it's a 4T MotoGP development.

[husaberg]

Mike was still in the game then. He says in the book it came in after he left. So it's a 4T MotoGP development.

I am 100% The 16.5 tyre was in use in 500Gp rears in 2000
fronts i think even earlier.
Mike would know better than me, but Pretty sure he was with Willings at Suzuki at the time, turning the Suzuki into a Yamaha right down to exhaust pipes and porting.
They def had 16.5 tires then, and likely even before then.
http://www.motorcyclenews.com/news/2000/may/why-half-an-inch-matters/
https://books.google.co.nz/books?id=vJx62Tku9jMC&pg=RA12-PA5-IA21&lpg=RA12-PA5-IA21&dq=16.5+wheel+nsr500&source=bl&ots=LBayqaXylI&sig=g4xyXls8tV35wnPvGmM5PNLvJw0&hl=en&sa=X&ved=0ahUKEwiS4472gvrRAhWBSJQKHcaDCfQQ6AEIUzAM#v=on epage&q=16.5%20wheel%20nsr500&f=false
https://www.yamaha-racing.com/motogp/articles/reports/race/117766/abe-finds-fighting-form
Found this its rather cool to add the turntable.

https://www.youtube.com/watch?v=QKFnOr3bZqg

[Grumph]

To clarify. The internal damping in tyres is a 4T MotoGP development . Independent of tyre size.

[husaberg]

To clarify. The internal damping in tyres is a 4T MotoGP development . Independent of tyre size.

No idea, but the different construction of the two leading tire makers then resulting carcass strength has always been a major point of difference.
Pretty sure thats why plenty of outstanding racer couldn't make a sucessful transition from the two different tires.
Beatie and Caladora spring to mind, as ones that stuggled to go from Michelin to Dunlop but they were both 250 esk riders. Even demi god Rainey struggled on Michelins.
Does the book cover anthing on transitional dynos?

[Grumph]

No idea, but the different construction of the two leading tire makers then resulting carcass strength has always been a major point of difference.
Pretty sure thats why plenty of outstanding racer couldn't make a sucessful transition from the two different tires.
Beatie and Caladora spring to mind, as ones that stuggled to go from Michelin to Dunlop but they were both 250 esk riders. Even demi god Rainey struggled on Michelins.
Does the book cover anthing on transitional dynos?

We're talking apples and oranges. The changes to tyre construction went far past the difference between Dunlop and Michelin. Tom O'Kane went to Dunlop and ran tyres on the rollers simulating chatter. He proved it involved the whole tyre and tread vibrating back and forth on the rim - not just the contact patch.
By introducing internal damping into the tyre you remove/reduce the unknown variable spring which has been the tyre.
Looks like all the companies got onto it around the same time but it seems to have been a very quiet introduction. Perhaps some of the current probs with Michelins come down to a different method of damping resulting a different frequency of response - and a different "feel". Because there is internal damping of the carcase, pressures can be lower, footprint bigger.

Dynos - Mike says great progress was made when Bud Aksland changed to an inertia dyno.

[husaberg]

We're talking apples and oranges. The changes to tyre construction went far past the difference between Dunlop and Michelin. Tom O'Kane went to Dunlop and ran tyres on the rollers simulating chatter. He proved it involved the whole tyre and tread vibrating back and forth on the rim - not just the contact patch.
By introducing internal damping into the tyre you remove/reduce the unknown variable spring which has been the tyre.
Looks like all the companies got onto it around the same time but it seems to have been a very quiet introduction. Perhaps some of the current probs with Michelins come down to a different method of damping resulting a different frequency of response - and a different "feel". Because there is internal damping of the carcase, pressures can be lower, footprint bigger.

Dynos - Mike says great progress was made when Bud Aksland changed to an inertia dyno.
I think the tyre construction differences actually lead to the tires internal damping progression.
There was a history of dunlop and other tires in Cycle world that covered it right back for the TT100 days. I was going to post it ages ago but not sure that i actually did.
I am not sure but i think the transitional dynos are a lot more complicated than an intertia dyno but i can't find out much about them, think like a inertia they use a roll on progression but i think there is a lot more to it.
I found the quote about how different Showa and Olhlins design philosphy works.
The major suspension makers have acquired their own separate traditions in such matters.long serving vetern race engineeer warren willings once described showa as the rigid suspension
This is because Showa prefers to support loads and control motions with spring stiffness,while Ohlins tends to seek softer spring rates while controlling motions dynamically with damping.

https://books.google.co.nz/books?id=J7tQp2LtsYIC&pg=PA131&dq=the+major+suspension+makes+have+separate+tradit ions&hl=en&sa=X&ved=0ahUKEwiFx-_asfrRAhWMbbwKHVlfBlkQ6AEIHTAA#v=onepage&q=the%20major%20suspension%20makes%20have%20separa te%20traditions&f=false

I am pretty sure cameron covers the tire stuff later as well.

my understanding is the introduction of the 16.5 lead to it because it was more prone to causing chatter.


Michelin first introduced its original 17in tyre back in 1984 – at a time when most teams ran 18in wheels. The 16.5s didn’t appear until the early ’90s. 1993 world champion Kevin Schwantz was one of the first converts and became the first rider to win using a 16.5in tyre on his Lucky Strike Suzuki at the 1994 British GP at Donington Park.
The smaller tyre was developed because riders wanted more grip to cope with ever-spiralling 500 power outputs. Tyre technology just couldn’t keep up with engine developments and riders were constantly highsiding. The results were frequently painful as tyres slid when riders powered out of corners and then suddenly snapped back into line – launching their victim over the top of the bike.
Michelin’s initial answer was to increase the tyre-to-Tarmac contact patch with a 19cm wide 17in tyre. One of these was used to good effect by Australian Daryl Beattie to win the 1993 German GP. But this wider tyre was heavier and technicians had to make radical changes to the suspension set-up.
Going for a smaller diameter tyre allowed Michelin to keep the wider contact patch and keep weight at previous levels. The 16.5’s profile is radically different to the 17’s with a triangular shape that puts more rubber on the track when the bike is cranked over on its side.
Michelin’s motorcycle competition chief Nicolas Goubert explains: " The 16.5s allow increased corner speeds. The larger contact patch also keeps temperatures more consistent, so riders can generally use a softer compound. "
So if 16.5s are that good why isn’t everyone using them?
Goubert has the answer: " The 17 offers better driving traction once the rider has lifted the bike back up and opened the throttle. Most riders still prefer this characteristic. "
And while 16.5s offer more grip in corners, it’s the 17s which turn in better because the tyres are narrower.
" There are still some aspects of the 16.5 on which we need to work, " Goubert admitted. " The extra rear-end grip can cause the front tyre to push, resulting in understeer. And the 16.5 can cause front-end chatter. "

The next devlopment was in 2005 when they even went further leading to even more chatter

Bridgestone, its factories far from Europe, had to aim its technology at developing tires with a wider performance range. Michelin went the other way, raising performance by narrowing operating range. This would be a crucial accident of history.
The following year brought more disturbances from tire development. At the end of 2005, Honda was out of traction—its bikes spun instead of going forward. Michelin replied with an even bigger, lower-pressure, softer-carcass rear that laid down an unprecedented footprint. Honda initially found chatter with this tire but overcame it. Yamaha’s early tests on the tire went well, but suddenly there was chatter that did not respond to its strongest countermeasures. At the first GP, Jerez, there were no Michelins on the front row. Bridgestone performance was not yet uniform; they performed best on high-grip tracks.
“Emergent properties” is a term used by evolutionists to describe novel results of an evolutionary line—results unpredictable from original conditions. Bridgestone’s concentration on wide range and Michelin’s upon narrow now essentially separated riders of each into distinct groups. When the Michelins worked, they performed incredibly well, leaving the Bridgestone riders behind. When Michelin missed the mark (resoundingly at Laguna Seca and Misano), they were useless. The result was no longer competition but rather taking turns.


found this

Adding a kilo at the extreme rear of the bike could damp out chatter, because the moment of inertia increases by the square of distance, so a small weight that far from the centre of the motorcycle would have a significant effect.
Marlboro Team Roberts learned this by coincidence in the late 1980s, during the very early years of datalogging. Wayne Rainey’s Yamaha YZR500 was equipped with a datalogger during practice, but not during the race, because it weighed a significant amount – about two kilos. Rainey would have a great two days of practice and go to bed full of confidence on Saturday night, while his mechanics removed the datalogger. The race would be completely different, Rainey would struggle with chatter, get beaten and return to his pit baffled. At first his crew thought he had got a bad tyre, but after three races they realised what was going on. The datalogger was housed in the set hump and cured any chatter.

There is scuttle butt that this is what the Dukes have on the rear of the latest motogp bike
the Rainey era anti chatter device
http://www.motorsportmagazine.com/opinion/motogp/it-s-vinales-versus-marquez

plus a thesis on chatter
https://www.researchgate.net/publication/232951082_The_chatter_of_racing_motorcycles

http://www.cycleworld.com/2012/04/26/jerez-questions-chatter-chatter-chatter
Modern moto gp bikes have to be changed to suit the control tire some bikes will chatter more than others as will chatter will effect some riders yet not others its a dynamic interaction

[F5 Dave]

Have to replace my copy of Sinclair book. I'm troubled by guilt, blah blah blah, rightful owner, blah blah you know the sort of thing.

[guyhockley]

[QUOTE=Grumph;
It was most interesting to discover why the carbon fiber frames didn't work also...[/QUOTE]

It would be!

Please?

[Grumph]

Quoting Mike.
This method of assessing a frame in isolation by anchoring it in a jig and then applying stress and loadings was adopted by most team and, as a result, the concensus was that aluminium was preferable when compared to carbon.This was not only as a result of the FIM raising weight limits. Admittedly,aluminium had the advantage of being cheaper, but it was also easier to produce a structure with the desired bending-twisting behaviour. Did we need the extra stiffness potential that carbon offered ? No. Carbon also has a reflex response range (in hertz) that you don't want motorcycle frame componentry to be in. In some carbon structures, like a yacht mast, you need that rapid reflex response, so when the wind powers the sail the mast rebounds quickly. When a motorcycle is on it's side going over bumps in a corner you don't need that sort of rapid reflex, we want the frame to unwind in a predictable way.
When you get a frame that has no feel,it may be a brilliant machine but they are only riding it (at) 95%.

Quoted for information only - and not to stop you going out and buying a copy. Please buy one....

My own thoughts on this are that slowing the reflex response works because it better matches the response of the human pilot. If we had synapses as fast as computers we may be able to live with very fast reacting frames...

[190mech]

Perhaps in the future we will have pilotless motorcycle races like aviation is coming to now...How exciting!!

[husaberg]

Quoting Mike.
This method of assessing a frame in isolation by anchoring it in a jig and then applying stress and loadings was adopted by most team and, as a result, the concensus was that aluminium was preferable when compared to carbon.This was not only as a result of the FIM raising weight limits. Admittedly,aluminium had the advantage of being cheaper, but it was also easier to produce a structure with the desired bending-twisting behaviour. Did we need the extra stiffness potential that carbon offered ? No. Carbon also has a reflex response range (in hertz) that you don't want motorcycle frame componentry to be in. In some carbon structures, like a yacht mast, you need that rapid reflex response, so when the wind powers the sail the mast rebounds quickly. When a motorcycle is on it's side going over bumps in a corner you don't need that sort of rapid reflex, we want the frame to unwind in a predictable way.
When you get a frame that has no feel,it may be a brilliant machine but they are only riding it (at) 95%.

Quoted for information only - and not to stop you going out and buying a copy. Please buy one....

My own thoughts on this are that slowing the reflex response works because it better matches the response of the human pilot. If we had synapses as fast as computers we may be able to live with very fast reacting frames...

My own research also pulled up the frames were not repairable in the event of a crash, They were not so great at absorbing vibrations either , as the harmonics are totally different from alluminiun just as steel is totally different from aluminium,
Also they needed a complete new frame, if they wanted to change a few variables ie mount location or geometry. Aluminium and steel are much more forgiving
There was also at times “noise” issues with electronics.
I know the Britten suffered from this also as well as some other electric issues until someone twigged carbon fibre frames were quite a useful electrical conductor.

With regards to the flex response i believe its to do with the suspension not working very well when leaned over at extreme angles thus with some less laterally less stiff chassis, this chassis flex, along with the tire carcass, becomes part of the suspension system

[F5 Dave]

Just ordered my own copy

http://www.fishpond.co.nz/Books/Mike-Sinclair-King-Kennys-Spannerman-Kerry-Swanson/9781869539566

$35nz free delivery in nz but pounds to dollars will still be a cheap book to UK .

[husaberg]

Just ordered my own copy

http://www.fishpond.co.nz/Books/Mike-Sinclair-King-Kennys-Spannerman-Kerry-Swanson/9781869539566

$35nz free delivery in nz but pounds to dollars will still be a cheap book to UK .

What does he say about the dog Coaxial swingarm chassis that had them having to run off and get ROC chassis that were actually acopy of their old ones.

[F5 Dave]

And that I can't remember but was covered. There was the bit that they measured and found the supposedly flexyer chassiswas stiffer. TThat'swhen they realised the concept was a bit lost in ttranslation.


I gave the copy back Friday.

[Frits Overmars]

When a motorcycle is on it's side going over bumps in a corner... we want the frame to unwind in a predictable way.
With regards to the flex response i believe its to do with the suspension not working very well when leaned over at extreme angles thus with some less laterally less stiff chassis, this chassis flex, along with the tire carcass, becomes part of the suspension systemYou guys nailed it. With a bike leaned over, we need lateral flex over the bumps, hence the search for the optimum amount of frame flex, as opposed to maximum frame stiffness.
But for that frame to unwind in a predictable way we need damping. Better still: we need a frame that won't twist, equiped with additional lateral dampened suspension.
Then we can forget about 'optimum frame flex' and build alu/steel/carbon frames with maximum stiffness again.
Take a look at this:
https://www.facebook.com/Suspensionsmith/photos/pb.622479384510016.-2207520000.1486981874./860396700718282/?type=3&theater
https://www.facebook.com/Suspensionsmith/photos/pb.622479384510016.-2207520000.1486981874./1206104982814117/?type=3&theater
328521 328520

[guyhockley]

Just ordered my own copy

http://www.fishpond.co.nz/Books/Mike-Sinclair-King-Kennys-Spannerman-Kerry-Swanson/9781869539566

$35nz free delivery in nz but pounds to dollars will still be a cheap book to UK .

Cheaper to buy direct from NZ with shipping costs than from the UK supplier!

[guyhockley]

There you go... a chassis with stiffness reducing holes!
328566

Seriously, though, I was at a party at my brother-in-law's and one of his relatives had been working for Lotus. He knew the bloke at TWR in charge of dealing with Team Roberts. Apparently the car people were initially quite condescending until they saw the huge amount of data and detailed specs TR had. The real eye opener for them was being given a range of stiffness for chassis parts as car design normally aims for the maximum possible.

[Grumph]

There you go... a chassis with stiffness reducing holes!


Seriously, though, I was at a party at my brother-in-law's and one of his relatives had been working for Lotus. He knew the bloke at TWR in charge of dealing with Team Roberts. Apparently the car people were initially quite condescending until they saw the huge amount of data and detailed specs TR had. The real eye opener for them was being given a range of stiffness for chassis parts as car design normally aims for the maximum possible.

The pic Mike showed me at Levels of a 500 Yamaha frame "swiss-cheesed" was from Paul Treacy's collection and unfortunately isn't in the book.
But it did indicate the lengths they were prepared to go to in search of hard data.