Race chassis

[mr bucketracer]

331418i never made to the last bucket meet but out the blue someone made this 50 frame and turned up with it , my brother said it went ok for its first time out , looks like some shorter forks would suit it , would be hard work on a kart track

[F5 Dave]

Yeah the guy brought it in from Holland, sort of Kreidler rotary valve replica with a Derbi type barrel and presumably replica frame. He said it flowed around the corners nicely. With that rake and seating position I would think that was just riding a small bike for the first time in 20yrs.
Was pretty cool though.

[Grumph]

Yeah the guy brought it in from Holland, sort of Kreidler rotary valve replica with a Derbi type barrel and presumably replica frame. He said it flowed around the corners nicely. With that rake and seating position I would think that was just riding a small bike for the first time in 20yrs.
Was pretty cool though.

Well that story answers the question I had as to where the fairing came from....Someone needs to get a mould off it quick.

[mr bucketracer]

Well that story answers the question I had as to where the fairing came from....Someone needs to get a mould off it quick.just about looks like my gt50 fairing

[F5 Dave]

In the same way a GSXR1000 fairing does. Put yer glasses on Scotty.

[mr bucketracer]

331423my last bucket build number 20

[mr bucketracer]

In the same way a GSXR1000 fairing does. Put yer glasses on Scotty.if you say so prity boy

[mr bucketracer]

331425gsxr1000 fairing lol

[Frits Overmars]

331418
someone made this 50 frame and turned up with it , my brother said it went ok for its first time out , looks like some shorter forks would suit it , would be hard work on a kart track

Yeah the guy brought it in from Holland, sort of Kreidler rotary valve replica with a Derbi type barrel and presumably replica frame. He said it flowed around the corners nicely.Flowing nicely compared to what? A Harley-Davidson? Going by the rake angle there can't have been much difference.
The frame itself does indeed look like a copy of a Van Veen Keidler, a very desirable veteran. I estimate that of the maybe 60 or 80 original Van Veen racers that were ever built, only 200 or so are still around :devil2:.
And Bucketracer is right about the forks: shortening them by about 150 mm would give the bike a more genuine look. It would also improve the handling, but still not nearly enough for a kart track. You would have to shorten the wheelbase another 100 mm and move the rider 200 mm forward in order to stand a chance.

In Europe we run classic 50 cc racers and the new Freetech-50 class simultaneously in order to make up the numbers and split the track costs.
The classics are lower and lighter than the Freetech bikes that are mostly built around a Honda RS125 chassis with tires twice as wide as the classics have.
On the straights the classics can hold their own but when a corner comes up, the Freetech bikes outbrake them and ride circles around them. And this is on long, flowing classic circuits. On kart tracks the classic guys won't even bother to turn up.

331426
Yours truly with a Van Veen Kreidler, some time (about an century) ago.

[F5 Dave]

331425gsairing lol
The GT fairing does look cool, but itsabout twice the height. The Kreidler one looks like the belly of a dolphin.

[F5 Dave]

I only saw the bike tied down in the van and it looked like it had an enormous head angle, but with the forks extended it looks like its trying to take off. But I was being polite as he seems a nice guy and its still the coolest classic 50 I've seen in the flesh here.

[mr bucketracer]

If more guys turned up on some classic buckets i would prombly bring the gt50 and rd50 out

[Grumph]

gsxr1000 fairing lol

I'd reckon that started life from a TA125 yamaha mould.

Aside from the well known 2 or 3 suppliers who advertise on trademe, does anyone know who's got moulds for small/odd size/classic fairings ?
Foxton fiberglass had a very wide range at one time - if that is a TA fairing, that's probably where it came from.
Even the factory early air cooled Honda 125 fairings were common at one time.

[mr bucketracer]

I'd reckon that started life from a TA125 yamaha mould.

Aside from the well known 2 or 3 suppliers who advertise on trademe, does anyone know who's got moulds for small/odd size/classic fairings ?
Foxton fiberglass had a very wide range at one time - if that is a TA fairing, that's probably where it came from.
Even the factory early air cooled Honda 125 fairings were common at one time.Foxton%20GP%201998.jpg
Got moulds for this bike

[Bert]

331423my last bucket build number 20

Looks good
I better update the GPR page at some stage.

When you say "my last bucket build" does this mean it's all over??? No more GPR frames?

I think Grump is right about TA125; I recall Pete telling me something about getting spares for GT sister bike.

[Grumph]

Yours truly with a Van Veen Kreidler, some time (about an century) ago.

Ah, the days of our youth, when we were slim....

Sadly, Scott and I amongst others here, are standard size Kiwis - large...

Either of us could loom up behind you and lift you and the bike.....Well I could, I don't know about Scott's back....

[mr bucketracer]

Ah, the days of our youth, when we were slim....

Sadly, Scott and I amongst others here, are standard size Kiwis - large...

Either of us could loom up behind you and lift you and the bike.....Well I could, I don't know about Scott's back....after chain sawing some trees today , my back is not great , but can suck it in

[mr bucketracer]

Looks good
I better update the GPR page at some stage.

When you say "my last bucket build" does this mean it's all over??? No more GPR frames?

I think Grump is right about TA125; I recall Pete telling me something about getting spares for GT sister bike.over building bucket bikes :brick:

[Grumph]

after chain sawing some trees today , my back is not great , but can suck it in

Ha - side effect of the pacemaker, they won't let me use a chainsaw. Apparently the rotating magnet magneto can affect the pacemaker's electronics...

But I still split my firewood with an axe....

[Grumph]

over building bucket bikes :brick:

Big ones aren't any easier.....

[mr bucketracer]

Big ones aren't any easier.....big or small i'm over them all (-; , maybe make a nice classic racer useing a honda 4

[Grumph]

big or small i'm over them all (-; , maybe make a nice classic racer useing a honda 4

You'd better plan on running it down here with CAMS then....Pop over and have a talk to Pete Sales about running a PCRA legal bike in the Register's "Classic 70's class. Much angst....

[diesel pig]

You'd better plan on running it down here with CAMS then....Pop over and have a talk to Pete Sales about running a PCRA legal bike in the Register's "Classic 70's class. Much angst....

Do you mean like building your own frame?

[Grumph]

Do you mean like building your own frame?

Well done for bringing the thread back on topic....

Yes, amongst other things. CAMS has a well established policy of "if it's built as a period style bike but not necessarily an exact replica, we'll accept it"
And given the number of specials built in the SI in the classic period, this is sensible. The register are not in favour of this I'm told...

Their "Classic 70's" class is supposed to be for their pre 76 stuff and the PCRA/MNZ rule book pre 72's. They've balked at a couple of MNZ legal bikes to my knowledge. I'm also told that for the upcoming CAMS visit North to race against the Register, CAMS will do the eligibilty for anything running under the MNZ rules. You should be safe Neil, LOL.

[husaberg]

Well done for bringing the thread back on topic....

Yes, amongst other things. CAMS has a well established policy of "if it's built as a period style bike but not necessarily an exact replica, we'll accept it"
And given the number of specials built in the SI in the classic period, this is sensible. The register are not in favour of this I'm told...
.

Even back when the south Island meets were run under the CRR banner the south island was always a lot less pedantic.
Those original Cust and South bridge and Greymouth and Ruatapu meets had a lot of stuff that would not pass muster up north, But we were not racing for sheep stations.....
the grids swelled though with the advent of CAMS as it allowed a vast array of cheaper yet competive bikes.

[F5 Dave]

There's nothing much more crap than a Honda 4. I'm just saying. . .


Well maybe those CZ parts I helped move out of the Good Lords residence. I assumed at the time they were a communist plot to sink the free world by shipping all the pig iron to us.

But have you ever tried lifting a 750/4? What a POS dead weight.

No offence.


To any Honda lovin homos.

I'm just saying:msn-wink:

[Frits Overmars]

There's nothing much more crap than a Honda 4. I'm just saying. . .Painting the fuel tank red, fitting four open pipes and calling it a classic racing bike; I hear you Dave.

[mr bucketracer]

There's nothing much more crap than a Honda 4. I'm just saying. . .


Well maybe those CZ parts I helped move out of the Good Lords residence. I assumed at the time they were a communist plot to sink the free world by shipping all the pig iron to us.

But have you ever tried lifting a 750/4? What a POS dead weight.

No offence.


To any Honda lovin homos.

I'm just saying:msn-wink:you have a Honda in your bucket . Just saying

[F5 Dave]

It has lots of Yamaha parts in it, but yes to my continuing shame.

[mr bucketracer]

It has lots of Yamaha parts in it, but yes to my continuing shame.oh and the frame wheels forks lol

[F5 Dave]

I'll just claim RS125 parts are made by HRC not the *onda company. :cool:

[timg]

I'll just claim RS125 parts are made by HRC not the *onda company. :cool: <iframe width="560" height="315" src="https://www.youtube.com/embed/ysmG_NfQVb0" frameborder="0" allowfullscreen=""></iframe>

[ellipsis]

...looks like a CAMS meeting Tim...

[Bert]

big or small i'm over them all (-; , maybe make a nice classic racer useing a honda 4

Yea I think this is a good idea...

RC211 replicas using all the FXR forks lying around...

[guyhockley]

Apparently, those funny people who race vehicles with TWO pairs of wheels are using lots of Docol tubing (and sheet), said to have the "advantages" of chrome-moly* but much easier to use. Just wondered if it had made any inroads into motorbikes. I have heard there are BMX frames made from it.

[guyhockley]

Titanium framed Guzzi.
https://www.youtube.com/watch?v=CypE7AP5gts

[Frits Overmars]

Things have been quiet here for a month and a half, so this is my chance to show the recently-discovered nightmare of the month: Gianni Pellegrino's concours-winning Ducati Monster (never has a designation been more apt).
It has everything you could wish for: no front suspension, no rear suspension, a non-steering engine-driven front wheel (note the chain) which makes anti-wheelie control superfluous, and a feet-steered rear wheel with no less than four confidence-building steering dampers and twin brake disks (very useful in case of a stoppie).
332820 332821

[Grumph]

At least I got paid to build the 4 - pipe Honda...And it's turned out fast....

But that thing ? Just no, thanks.

[koba]

Things have been quiet here for a month and a half, so this is my chance to show the recently-discovered nightmare of the month: Gianni Pellegrino's concours-winning Ducati Monster (never has a designation been more apt).
It has everything you could wish for: no front suspension, no rear suspension, a non-steering engine-driven front wheel (note the chain) which makes anti-wheelie control superfluous, and a feet-steered rear wheel with no less than four confidence-building steering dampers and twin brake disks (very useful in case of a stoppie).
332820 332821

Drugs?

Oh, no, wait maybe they were aiming to take the piss and build something stupid to get attention.
Effective.

[Frits Overmars]

What amazes me most is that this 'thing' not only got attention; it won a concours! Makes me wonder about the creations that came second and third. And about the jury. They must have been smoking some really good stuff.

[190mech]

I guess that would be termed "Non functional ART"...:(

[WilDun]

I guess that would be termed "Non functional ART"...:(

Just keep studying it for a couple of months and it'll probably grow on you as your mind adjusts maybe? - (Yes I reckon just taking the piss and seeing where it might end up).
Picasso I'm told acknowledged that his own art didn't follow the rules imposed by society and to the average person it was crap, but he still made a very good living from it!
Harley Davidsons sell too! - in fact, the big boys copied them (ie their image) more or less.

[Muciek]

Bike from the beginning of this thread is for sale here https://www.racebikemart.com/adverts/SCITSU__1265102316.php

[guyhockley]

No idea if this is any good, the only apples I have access to are Bramleys and Lord Lambournes. It's an app for fork seals, found it while looking for something quite different.
http://www.skf.com/uk/knowledge-centre/engineering-tools/bikeseals.html?WT.oss=Bike%20seals%20app&WT.z_oss_boost=0&tabname=All&WT.z_oss_rank=1
Just noticed it says uk in the link, too. Maybe just go to skf.com and search for "bike seals".

[Michael Moore]

Triumph with plywood monocoque and a balancing system somewhat like that of a Buell (or MZ). From BIKE magazine. About 1.5 mb on the PDF

[Grumph]

Finally got a read of that wooden monocoque article. He's right about having done it the hard way. There's a long history of boatbuilding in my family - incl cold moulded laminates - and if you want them, double curvature panels are quite easy. Even single thickness ply sheets can be bent to double curvature - I well remember the effort required with our last keeler build where 3/8in sheets had to be curved two ways...
A small - bucket size - monocoque on similar lines to the "Bultaco" 50 would be comparaitively easy. Straight sides and a bag tank. Fabricated load points glued and screwed in.

Could be a problem at Greymouth though - you'd need to anchor it in the pits if it was the usual wet meeting....

[guyhockley]

Apart from aesthetics, I’m not convinced you’d want the complication of curved panels. Some scantling rules allow you a reduction in skin thickness for curved panels but that’s more about deflection of a boats skin. Would it make any difference to the overall stiffness of a bike frame? I doubt it, personally, but anyone who wants to have a go try googling “constant camber” or “cylinder moulding ”. If they turn out to be too vague try adding “boat”, “catamaran” or “trimaran”. Also, the book “The Goudgeon Brothers on Boatbuilding ” was available as a free (legit!) download which is kind of the bible of modern wood epoxy boatbuilding. I’m on my phone in the middle of nowhere so can’t provide links at the moment.
For an idea of just how far ply construction can be pushed try looking up sailing dinghies – the Inernational Moth or Cherub.
More relevant to bikes would be researching Frank Costin and Marcos or, possibly, Africar.
If, like me, you’re still in the stone age and don’t do FEA etc. You could try working from known examples. To convert from one sheet material to another of equal stiffness I use the formula of dividing the Youngs modulus of the old material by that of the new, then the cube root of the answer gives you the conversion factor. Apologies for the next bit, but I started out doing this stuff in imperial units and they are the ones I can recall.
All steels, from plain to fancy, are the same stiffness with an E (youngs modulus) of about 30000
I think there’s more variation in Ali but for the boatbuilding ones it’s about 10000.
Plywood is quoted variously as 1600 - 1800. I use 1500 and round up to the next actually available thickness as other factors like puncture resistance come into play for boats.
If that makes ply look like a non-starter, do the sums for Frits 2mm steel battleship of a monocoque and you would be looking at 6mm ply which would be a LOT lighter. Which is why Frank Costin started building wooden chassis cars...
You could go further and copy the De Havilland Mosquito. Birch ply is available in very small thickesses so the possibilities of a sandwich construction would be almost infinite.
That would seem only fitting as I believe there was a massive amount NZ involvement in the Mosquito and some of the world’s most cutting edge wooden boats come from there.
The other obvious way to use ply would be in a Tony Dawson style plate frame (very first picture in this thread?). I’ve actually built something like this, with 2 wheels and an engine... but it also had a propellor :-)
There are wooden bicycles of various sorts, too.
Sorry to ramble on so much, but I was supposed to be at the Bemsee open day at Brands Hatch, today, sorting out racing for next year and I’ve ended up on “stake out” outside a village hall craft fair so quite bored!
One final (hurray!) thought. Greg posted the excerpt from Mike Sinclair’s book about why carbon fibre frames weren’t that great so I probably just wasted your time, too!

[guyhockley]

Sorry if I've insulted/patronised, upset anyone or got my facts wrong, but, out in the sticks and bored. (Did I mention that?)

[Michael Moore]

Here's the boat book

https://www.westsystem.com/the-gougeon-brothers-on-boat-construction/

https://www.westsystem.com/wp-content/uploads/GougeonBook-061205-1.pdf

I was coming up with 1/16" sheet steel having similar stiffness (but more weight) than 3/16-1/4" baltic birch plywood, so that seems to track Guy's numbers. I wasn't able to find much detail on the Marcos chassis on the web. I think I saw a mention of them using Araldite 300

https://us.aralditeadhesives.com/index.php?option=com_docman&view=download&alias=186-araldite-ep-300-ab-us-e&Itemid=146&lang=us

[guyhockley]

Here's the boat book

https://www.westsystem.com/the-gougeon-brothers-on-boat-construction/

https://www.westsystem.com/wp-content/uploads/GougeonBook-061205-1.pdf

I was coming up with 1/16" sheet steel having similar stiffness (but more weight) than 3/16-1/4" baltic birch plywood, so that seems to track Guy's numbers. I wasn't able to find much detail on the Marcos chassis on the web. I think I saw a mention of them using Araldite 300

https://us.aralditeadhesives.com/index.php?option=com_docman&view=download&alias=186-araldite-ep-300-ab-us-e&Itemid=146&lang=us

The book is still available, then. There were chancers on Amazon still trying to sell hardback versions for way above the new price even after it was made available free. Sadly, the book about Frank Costin also seems to be in the collectible category.
https://www.amazon.co.uk/Flying-Four-Wheels-Costin-Designs/dp/0850597706/ref=sr_1_1?s=books&ie=UTF8&qid=1512928201&sr=1-1&keywords=frank+costin
Good read, at one point IIRC they built a single seater for an american customer but had to disguise the wooden monocoque by "cladding it in very thin aluminium - almost tinfoil" I think was the quote. Unfortunately he crashed it...

[Grumph]

Some years back, I walked into a friend's workplace - and there was a Marcos up on the hoist. Very interesting to study the linked boxes making up the chassis. I've also seen a Protos single seater. It turned up here for one of the big classic car race meetings. Interesting. McLaren's first F1 car was built from a part-wood sandwich composite too - Mallite ?
It's certainly a viable material for the home constructor. Cheaper than alloy sheet, probably a tad more robust re dents etc....And you could jig one up on a Black and Decker workmate table...

I always understood that the Mosquito ply construction was pioneered by DH Canada. I do know there's one being rebuilt hopefully to flying condition here in NZ so I'd guess that most of the current references on the net refer to that one.

[Frits Overmars]

To convert from one sheet material to another of equal stiffness I use the formula of dividing the Youngs modulus of the old material by that of the new, then the cube root of the answer gives you the conversion factor. All steels, from plain to fancy, are the same stiffness with an E (youngs modulus) of about 30000. Plywood is quoted variously as 1600 - 1800. If that makes ply look like a non-starter, do the sums for Frits 2mm steel battleship of a monocoque and you would be looking at 6mm ply which would be a LOT lighter.I didn't know this (along with a lot of other things) when I designed my steel monocoque in 1972. But even if I had known, there was one good reason to stick to steel:
I didn't know how to weld plywood. I still don't.

I don't doubt your stiffness comparison either, but I had no use for more stiffness in view of the skinny fork tubes, the spoked wheels and the threaded tires, all acquired second- or third-hand.
As it was, I think I already had the stiffest 500 cc frame at the time, and it was also the smallest, lowest, narrowest, lightest and most unreliable bike in its class.
And it was sooo easy to build: cut some 2 mm mild steel sheet, fold it, weld the bottoms in, that was it.
333806 333805 333807

[husaberg]

Some years back, I walked into a friend's workplace - and there was a Marcos up on the hoist. Very interesting to study the linked boxes making up the chassis. I've also seen a Protos single seater. It turned up here for one of the big classic car race meetings. Interesting. McLaren's first F1 car was built from a part-wood sandwich composite too - Mallite ?
It's certainly a viable material for the home constructor. Cheaper than alloy sheet, probably a tad more robust re dents etc....And you could jig one up on a Black and Decker workmate table...

I always understood that the Mosquito ply construction was pioneered by DH Canada. I do know there's one being rebuilt hopefully to flying condition here in NZ so I'd guess that most of the current references on the net refer to that one.


Whats wrong with Bamboo
Natures tube.
there are guys making MTB frames with it instead of CF it has a better ride according to them.
http://www.instructables.com/id/How-I-built-a-carbon-bike-frame-at-home-and-a-bam/
http://www.shopcalfee.com/calfee-bamboo-mountain-bike-small-sb0422/
It was good enough for Dick.
https://en.wikipedia.org/wiki/Richard_Pearse

The Mosquito also had a very small radar signiture it was stealth before it was even thought of......
Most don't realise it could also carry a bigger bomb load further and a dam sight faster than a B-17 could.

[guyhockley]

I didn't know this (along with a lot of other things) when I designed my steel monocoque in 1972. But even if I had known, there was one good reason to stick to steel:
I didn't know how to weld plywood. I still don't.

I don't doubt your stiffness comparison either, but I had no use for more stiffness in view of the skinny fork tubes, the spoked wheels and the threaded tires, all acquired second- or third-hand.
As it was, I think I already had the stiffest 500 cc frame at the time, and it was also the smallest, lowest, narrowest, lightest and most unreliable bike in its class.
And it was sooo easy to build: cut some 2 mm mild steel sheet, fold it, weld the bottoms in, that was it.
333806 333805 333807

Oh, dear. I wasn't being rude about your frame, I used it as it had been posted on the thread, you told us the material and its beautiful simplicity made it an easy example. I ignored the question of joining the panels and if the epoxy saturation techniques in the book were followed it would also add significant extra weight.
I actually think your frame would make a perfect engineering textbook study.
Improves on the previous model/competitors, simple, fast and cheap to make requiring no new techniques or tooling and probably could be as good today as when it was built unlike the rivetted ali monocoques which I believe go a bit floppy!
As I feel I've upset you (and Husa) at least a couple of times, I'm going to take a metaphorical back seat and let people with more knowledge and experience than me continue my (free!) education.

[Frits Overmars]

Oh, dear. I wasn't being rude about your frame.... I feel I've upset you (and Husa) at least a couple of times....I haven't seen anything rude at all. I'm not upset that easily and I've never even sensed any intent from your part. So no worries Guy :hug:.

[husaberg]

Oh, dear. I wasn't being rude about your frame, I used it as it had been posted on the thread, you told us the material and its beautiful simplicity made it an easy example. I ignored the question of joining the panels and if the epoxy saturation techniques in the book were followed it would also add significant extra weight.
I actually think your frame would make a perfect engineering textbook study.
Improves on the previous model/competitors, simple, fast and cheap to make requiring no new techniques or tooling and probably could be as good today as when it was built unlike the rivetted ali monocoques which I believe go a bit floppy!
As I feel I've upset you (and Husa) at least a couple of times, I'm going to take a metaphorical back seat and let people with more knowledge and experience than me continue my (free!) education.
I can honestly say i have never been upset by you or any of your posts.
I thoroughly enjoy your post and attachments.

Not a racer but interesting concept.
A rocking horse craddle frame.

https://www.youtube.com/watch?v=lbteMCDRnC4

Jack Lennie, a product design graduate from the Edinburgh Napier University has come-up with a motorcycle design that can be downloaded by anyone in the world. Called as Tinker (http://www.jacklenniedesigner.com/new-cover-page-3) this open-source bike can be made in your garage itself provided you have knowledge of CAD/CAM computer software. The main aim of this design is to minimize production cost and also the consequent part manufacturing costs.

[guyhockley]

Thanks, fellers. Think my sensitivity is a bit skewed as I've spent the last 4 years tip-toeing round a wife invalidded from work with an overwork/stress induced breakdown (Don't believe everything you hear about european civil servants!)
There was a discussion about the Tinker thing on Michael's chassis list. The swinging arm pivot position was queried as being a bit off IIRC.

[Michael Moore]

can be made in your garage itself provided you have knowledge of CAD/CAM computer software

the left out "AND you have CNC equipment in your garage along with it." Unfortunately, software alone will not create hardware. It sure would be handy if it did.

[Grumph]

the left out "AND you have CNC equipment in your garage along with it." Unfortunately, software alone will not create hardware. It sure would be handy if it did.

Yes...I've met a few people who lack the required brain/hand connection....

[Michael Moore]

Greg, I'm a lot better at typing than I am at fine motor skills in the shop. Differentially cranking the X and Y axis handles on a milling machine for a specific curve generally comes out far worse for me than doing it with CNC.

I try to let my robot servants do the fine work.

:-)

[F5 Dave]

Enjoy it while it lasts. . . . [Fade to distopic future where the relationship is inversed]

[guyhockley]

Ted Broad Monocoque replica.
Bloke in the UK is building one with the support of the family of Ted Broad (although the frame was actually built by a pair of sidecar racers, I believe)

Afraid it's F**kbook...

First post:

https://www.facebook.com/permalink.php?story_fbid=557581291011515&id=100002789483248

Follow up:

https://www.facebook.com/permalink.php?story_fbid=895697243866583&id=100002789483248

Most interesting bit?

https://scontent.flhr1-1.fna.fbcdn.net/v/t1.0-9/10940590_557569484346029_6008059733827192436_n.jpg ?oh=2e7fdd3a0b1111133b926a09225567c3&oe=5ACA24CE

[lodgernz]

It has lots of Yamaha parts in it, but yes to my continuing shame.

Yeah we hate Honda now, but just remember they did make some lovely 2-strokes in the short period between only making old shit 4-strokes and the current period of only making newer shit 4-strokes.
Mission series, RS125, MB100... just sayin'

[mr bucketracer]

Yeah we hate Honda now, but just remember they did make some lovely 2-strokes in the short period between only making old shit 4-strokes and the current period of only making newer shit 4-strokes.
Mission series, RS125, MB100... just sayin'what 2 stroke do you run in your
camper?

[F5 Dave]

Ask him if he has a 2 stroke or a 4 stroke car.

[TALLIS]

Ask him if he has a 2 stroke or a 4 stroke car.

I thought you were going to say "get a rota or its not a real motor"

[F5 Dave]

Nah more like. Don't go septic, buy an. . . ,

[lodgernz]

what 2 stroke do you run in your
camper?

Camper isn't a Honda, so I don't understand the question

[lodgernz]

Ask him if he has a 2 stroke or a 4 stroke car.

My car is electric, just like bucket bikes will be in a few years.

[mr bucketracer]

Camper isn't a Honda, so I don't understand the questionyour right , who would want to own a honda , ps whats your bucket (-;

[lodgernz]

your right , who would want to own a honda , ps whats your bucket (-;

Ummm.. getting off topic here. *cough*

So, What wheelbase do you usually aim for with the GPR frames?

[mr bucketracer]

Ummm.. getting off topic here. *cough*

So, What wheelbase do you usually aim for with the GPR frames?i think the hole kbiker of the topic (-; , i go for 1260 ish , over the rs125 at just over 1200 , for me the bike feels more planted on the track and seem to get away with murder

[lodgernz]

i think the hole kbiker of the topic (-; , i go for 1260 ish , over the rs125 at just over 1200 , for me the bike feels more planted on the track and seem to get away with murder

Thanks for that. Yeah, my little babies feel pretty comfortable at 1220-1240. Wouldn't want any shorter though.

[timg]

your right , who would want to own a honda , ps whats your bucket (-;
Yeah, ya poor bugger :( I’ll take that CBR150 off your hands so you’ll feel better for Xmas ;)

[Grumph]

i think the hole kbiker of the topic (-; , i go for 1260 ish , over the rs125 at just over 1200 , for me the bike feels more planted on the track and seem to get away with murder

I still think in inches for wheelbase - and by my standards 50in is short - that's 1270mm

But I'm not building for kart tracks...

[husaberg]

I still think in inches for wheelbase - and by my standards 50in is short - that's 1270mm

But I'm not building for kart tracks...


That MB100 you tuned was about 48 was it not?
Bet the rider still would have liked it to turn sharper around the hairpin at Greymouth.

[Grumph]

That MB100 you tuned was about 48 was it not?
Bet the rider still would have liked it to turn sharper around the hairpin at Greymouth.

A/ I was forced to use that chassis - at least I made it around 3 times stiffer than stock...But still not directionally stable at that power level - with me on board anyway. Frightening actually.

B/ That rider was/is under the impression that gutters and kerbs are part of a race circuit and are there to be used...If he was in the gutter at the hairpin, it was intentional...

[mr bucketracer]

That MB100 you tuned was about 48 was it not?
Bet the rider still would have liked it to turn sharper around the hairpin at Greymouth.i cant wait to drop the lap record by 5 seconds

[Grumph]

i cant wait to drop the lap record by 5 seconds

Husa will know - but I think it's Al Hoogie ? Let me know and I'll be there to watch you try.

[mr bucketracer]

Husa will know - but I think it's Al Hoogie ? Let me know and I'll be there to watch you try.apart from the last one 5 second would of been easy , make the stakes high i think lol , apart from i'v lost it

[husaberg]

Husa will know - but I think it's Al Hoogie ? Let me know and I'll be there to watch you try.

probably still is hoggie
but if revingtons hotel demolition goes ahead it might give the chance to run greymouth in reverse direction, As its removal would give a run of for the back straight.
Assuming they removed the kerbs. It might be great fun to wear out the left side of a few tyres.
It would be a dam sight faster as well. likely be even safer too.

[Frits Overmars]

then you remember you don't want to be like everybody else!I don't want to be different. But the missus keeps telling me that I am :p.


I still think in inches for wheelbase - and by my standards 50in is short - that's 1270mm. But I'm not building for kart tracks...Neither were Aprilia, Derbi, Honda and KTM (in alphabetical order).
But they all established that 1270 mm was too long for 125cc GP-racers on GP-tracks, and ended up with about 1215 mm (47,8" in Grumph currency).


That MB100 you tuned was about 48 was it not? Bet the rider still would have liked it to turn sharper around the hairpin at Greymouth.There you go Grumph.


I was forced to use that chassis- at least I made it around 3 times stiffer than stock. But still not directionally stable at that power level- with me on board anyway. Frightening actually.Racebikes are not meant to be directionally stable. H-D are catering for stable.
The majority of 500cc GP-bikes were shaking like mad on the straight-aways, but when I asked their riders about it, they didn't even know what I was on about;
none of them registered unstable bike behaviour as anything peculiar. They were more concerned about their bike being too lazy turning in.


That rider was/is under the impression that gutters and kerbs are part of a race circuit and are there to be used...If he was in the gutter at the hairpin, it was intentional...That rider was right. I remember drifting against a kerb in a corner. The first time was unintentional, but then I realized I could give it full throttle while against that kerb.
You gotta use what you come across.

[Grumph]

I'd love to get you on that MB100, Frits, making a rubber band three times stiffer doesn't change it from a rubber band, LOL.

Yes, I do appreciate what benefits a short wheelbase offers. I do build as short as possible given the engines and suspension constraints I'm frequently forced to work under. I also understand the geometrical quandries that riders find themselves in when trying to get a bike to turn. Jack up the back - drop the front - then hang on for grim death.

As an interested observer, I've watched tyre development and talked to riders here. It would appear that some brands have adopted a carcase construction which is more directionally stable than others. Some turn very readily - which seems to mean that those brands suit a stable chassis better.

On coming back and re-reading Frits post above, I'd add that i'm not building for GP circuits either. Anything I build is very likely to be used on the street circuits here in NZ - which are littered with bumps. surface changes and manhole covers. Both from observation and talking to riders, a GP focused chassis such as Honda RS125's or TZ's are not a comfortable ride on those tracks.

[Frits Overmars]

Anything I build is very likely to be used on the street circuits here in NZ - which are littered with bumps. surface changes and manhole covers.
Both from observation and talking to riders, GP focused chassis are not a comfortable ride on those tracks.You should have a chat with Rossi :D.
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[Grumph]

This is one of my engine customers. While I'd love to talk to Rossi, I think I got the gist of what it feels like from this.

[Frits Overmars]

This is one of my engine customers. While I'd love to talk to Rossi, I think I got the gist of what it feels like from this.Yes, I see what you're up against Grumph.

[philou]

I bought a tube bender

I want to try this geometry :woohoo:


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.

Waiting for the 125 nsr engine that arrives :third:

[Frits Overmars]

Some pictures from a Freetech project by Dutchman Robin Wittebrood. He didn't buy a tube bender :D.
In case you're wondering why you can see right through the engine: it will get reed valves right and left.
335213 335212 335214
Robin is using very strong duct tape: Dutch tape. But he is considering welding the tube joints as well :p.

[Grumph]

Lot of work has gone into the fabrication combining engine/shock/swingarm mounts.

I'd wonder if it isn't quite a bit heavier than Scott's GPR frames where those functions are served by tubes.

[Frits Overmars]

Lot of work has gone into the fabrication combining engine/shock/swingarm mounts.
I'd wonder if it isn't quite a bit heavier than Scott's GPR frames where those functions are served by tubes.Maybe so, Grumph.
I liked the straight tubes, though I think the frame could have been even simpler and lighter if the rear suspension had been designed without a link system.

[Grumph]

Maybe so, Grumph.
I liked the straight tubes, though I think the frame could have been even simpler and lighter if the rear suspension had been designed without a link system.

Agreed - but so often you've got to use what is available - and affordable. If he's sourced an arm, shock and linkages as an affordable package it's understandable.
I do think that rear suspensions are too often overcomplicated. A friend has an ATK offroader which he's run for years now. He's also one of the top local suspension unit rebuilders/revalvers. He's often heard muttering about overcomplcated valving to compensate for poor linkage curves - and why can't they all be as simple as his ATK.....

[Michael Moore]

The curves I've seen published for modern-ish RR rear suspensions seem very linear and within what is possible with a conventional non-linkage suspension. Linkages seem like something you add if you need them for a specific reason such as packaging/locating the damper in a specific spot where you need the link for it to work correctly for the application. Long travel dirt bikes or big tourers where a large rising rate might be wanted seem like a good application for linkages. My guess is that on RR applications mass centralization is being given a higher priority, so in order to move the damper to a needed location they need a linkage.

Crichton deliberately used twin rear dampers on the Roton and it seemed to work OK. I've always like the looks of the Simon Martin (NWS) bike with a single rear damper -- put it on the side away from the chain and you can have a large cross section on the swing arm:

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

cheers,
Michael

[Grumph]

I don't disagree with any of your conclusions Michael. The Roton though had it's own unique packaging problem I believe. According to reports at the time the Spondon single shock frame suffered from shock overheating due to the very high temps close to the engine.

[husaberg]

Agreed - but so often you've got to use what is available - and affordable. If he's sourced an arm, shock and linkages as an affordable package it's understandable.
I do think that rear suspensions are too often overcomplicated. A friend has an ATK offroader which he's run for years now. He's also one of the top local suspension unit rebuilders/revalvers. He's often heard muttering about overcomplcated valving to compensate for poor linkage curves - and why can't they all be as simple as his ATK.....
Husaberg a and KTM with a few minor exceptions all are, they call it PDS. although i think this more applies to the shock nedding to have progssive damping characterstics
to appease the Supercross and MX markets they have had to go back to linkage of them for the same feel for the riders.


From what i understand the linkage rates on GP bikes became practically linear in the mid nineties.

Maybe so, Grumph.
I liked the straight tubes, though I think the frame could have been even simpler and lighter if the rear suspension had been designed without a link system.

That frame could have had the rear box cast in alloy (it still could)
Frits could encourage him to whip off a few patterns off it because he glues it together with weld.
Then he could run off as many copies real easily.

[Carel H]

Some pictures from a Freetech project by Dutchman Robin Wittebrood. He didn't buy a tube bender :D.
In case you're wondering why you can see right through the engine: it will get reed valves right and left.
335213 335212 335214
Robin is using very strong duct tape: Dutch tape. But he is considering welding the tube joints as well :p.

It's a good approach. Not that I would do it that way, but he comes close. It's motorcycle suspension, not rider suspension as with conventional twin shocks.

[Frits Overmars]

The curves I've seen published for modern-ish RR rear suspensions seem very linear and within what is possible with a conventional non-linkage suspension.That's right Michael.
Without a link system, just by choosing the proper geometry, you can achieve a maximum of about 15% progressiveness, which is sufficient for road racing.


Crichton delerately used twin rear dampers on the Roton and it seemed to work OK.When I was working on the suspension of the Garelli 125-single, which initially had the same twin-shock setup as the unbeatable 125-twins, it turned out that on the lighter single the gas pressure in the twin shocks alone already gave too much pre-tension. The twin shocks also had too much plunger rod friction.
This was the reason to adopt the mono-shock system, internally nicknamed RON (Jan Thiel may remember it as the abbreviation of "Recht Op en Neer").

[F5 Dave]

KTM persevered with PDS for like a decade but when even their factory bikes had a link it was clear. Must have been like Yamaha leaving 5v heads behind.

Messed around on my old 50 frame stripped out the linkage and lost a heap of weight. I'd also been inspired by the old ATKs. Played around with Springs and damping. Main problem was it twisted the frame up despite triangular bracing and stiff ally sw.

NF4 handling was miles better. But clearly suspension was behind others like GPR over stutter bumps.

[Michael Moore]

20 years ago I had a Kawasaki EX250 race project. I converted it to dual dampers and cut all the heavy linkage stuff off the swing arm and boxed it in with light sheet metal. I don't recall the exact number of pounds that saved, but it was lighter, and it made room under the swing arm/behind the engine for tucking the megaphones up and out of the way.

http://www.eurospares.com/graphics/ex250/exts3.jpg

http://www.eurospares.com/graphics/ex250/exts1.jpg

http://www.eurospares.com/graphics/ex250/exts6.jpg

Those 16" rims sure limited the tire choice.

If you've got an engine with side-draft intake not having the damper right behind the engine can free up room for a large air box.

cheers,
Michael

[F5 Dave]

Can' help but think that class would have been so much better with say TZR250 parallel twin engine.

[Grumph]

20 years ago I had a Kawasaki EX250 race project. I converted it to dual dampers and cut all the heavy linkage stuff off the swing arm and boxed it in with light sheet metal. I don't recall the exact number of pounds that saved, but it was lighter, and it made room under the swing arm/behind the engine for tucking the megaphones up and out of the way.

Those 16" rims sure limited the tire choice.

If you've got an engine with side-draft intake not having the damper right behind the engine can free up room for a large air box.

cheers,
Michael


Can' help but think that class would have been so much better with say TZR250 parallel twin engine.

Bear in mind Dave that CAMS down here has a 150/2T 250/4T class. Given that the 250 production Kawasakis are now obsolete by virtue of the 300's being adopted....I hope Michael's pics inspire someone.
Ah 16's....My GPZ500 F3 bike went onto 17's when it was transformed from a road bike. But it was raced for most of a season on 16's - Dunlop 591R's.
Not bad - but if you hit 7000 while cranked over, it went sideways....I'd got quite a lot more HP out of it while keeping stock cams/carbs but it was all up top.
When it was done properly with big cams and flatslides, it was actually much more pleasant to ride.

[Michael Moore]

I only raced the EX a time or two in 250SB, but small bikes like that are fun to ride on the track. A friend is having good times with his EX300.

The intent had been to eventually build a frame with 125GP wheels etc but the trick downdraft-intake head got stalled with my engine tuner (as did so many projects) and the window of opportunity closed on the project.

http://www.eurospares.com/ex2501.html

With CR carbs and race exhaust on the otherwise stock (and well-used) engine the bike was competitive in a drag race against a nicely ported/pistoned 250Prod EX (with my local club production meant any internal mods as long as you stay in the displacement limits, stock intake and exhaust -- that makes it a lot easier to police).

[F5 Dave]

Bear in mind Dave that CAMS down here has a 150/2T 250/4T class. Given that the 250 production Kawasakis are now obsolete by virtue of the 300's being adopted....I hope Michael's pics inspire someone.
Ah 16's....My GPZ500 F3 bike went onto 17's when it was transformed from a road bike. But it was raced for most of a season on 16's - Dunlop 591R's.
Not bad - but if you hit 7000 while cranked over, it went sideways....I'd got quite a lot more HP out of it while keeping stock cams/carbs but it was all up top.
When it was done properly with big cams and flatslides, it was actually much more pleasant to ride.
Bear in mind Greg, i find it hard to get very excited about any four stroke, but the project was cool enough, just needed a smaller lighter more powerful engine.:innocent:

[Michael Moore]

Dave, the Dymags I originally bought for the EX250 project are sitting next to a 2015 KTM 250SX engine, hopefully that will get everyone's approval. The wheels, brakes, powerplant etc have yet to reach critical mass and implode into a rideable bike.

cheers,
Michael

[Grumph]

Bear in mind Greg, i find it hard to get very excited about any four stroke, but the project was cool enough, just needed a smaller lighter more powerful engine.:innocent:

Oh understood...And my F3 500 was about the same weight but 72hp at the wheel. The blown version was about 20kg heavier but had over 100hp at the wheel...

When I get access to my camera again, I'll post some pics of a 500 head lurking under the bench and dating from about '88 which will make Michael laugh....

[F5 Dave]

That's pretty handy for one of those. Wonder what TonyMcMu was getting from his?
I dynod Spargo's ZXR400 and it was nowhere near that on Ave but he'd had to give back the pipe which I think Tony had used on his 400. Or something.

[Grumph]

That's pretty handy for one of those. Wonder what TonyMcMu was getting from his?
I dynod Spargo's ZXR400 and it was nowhere near that on Ave but he'd had to give back the pipe which I think Tony had used on his 400. Or something.

I did the top end on tony's 500 - someone at Boyles set the bottom end up for him. When asked Tony admitted to "over 80" - but added it depended on the nitro percentage, LOL. My original 500 was on the Meth/Toluene that I set Tony up with to start. The blown one was on straight Meth.
I also did the first 400 head for Tony - all the ones he did after that were copies of mine.

[mr bucketracer]

i have Spargo's sister bike , i got 67hp from it from a dyno jet 150 when i bought it, had the f3 race kit on it , i did get 74hp in the end

[F5 Dave]

Yeah think it was like 65 if that but old pipe jammed on not setup ready to sell. Have it on pc backup somewhere

[F5 Dave]

That said probably on meth jetting before and just a guess.

Talking of meth, while we are clearly in the chassis thread. .
I remember the virulent Taylor letters to the editor of KR re the Dallas BMS Dookati vs TZ250 for F2. That bit somewhat.

[husaberg]

That said probably on meth jetting before and just a guess.

Talking of meth, while we are clearly in the chassis thread. .
I remember the virulent Taylor letters to the editor of KR re the Dallas BMS Dookati vs TZ250 for F2. That bit somewhat.

i still have those mags

[mr bucketracer]

That said probably on meth jetting before and just a guess.

Talking of meth, while we are clearly in the chassis thread. .
I remember the virulent Taylor letters to the editor of KR re the Dallas BMS Dookati vs TZ250 for F2. That bit somewhat.when i got mine it still had meth pilot jets in it , would not idel under 11000 lol . was not until we put in (murphy diesel )lol grinds on the cams it went real well

[Grumph]

That said probably on meth jetting before and just a guess.

Talking of meth, while we are clearly in the chassis thread. .
I remember the virulent Taylor letters to the editor of KR re the Dallas BMS Dookati vs TZ250 for F2. That bit somewhat.

I don't know to this day exactly who pushed for 2V 750's for F2 - but in the end even on Meth they were actually pretty evenly matched on most NZ circuits.

But that shitfight certainly helped lead to the banning of meth - which had far too many unintended consequences IMO. The balance of engine types in F3 immediately went haywire. Engine development costs went through the roof when we all tried to get HP on petrol which had been easy on meth blends.

[Grumph]

As promised for Michael to add to his collection of Kawasaki twin oddities....
This head was done about '88. The aim was to equal Tony's nitro motor but on straight Meth. It had already dropped a valve so there was plenty of welding incl a couple of new inserts. Valves were I think 2mm bigger inlet and 1-1.5mm bigger exhaust. Honda single valves straight off the shelf. Cams as per usual - the biggest Megacycle grind...R&D springs - which broke regularly. Pair of 40mm Dellortos. Inlets lifted as high as possible. Exhausts had considerable work too.
The comparo pic is against a '16-'17 L2 GSXR1000. We weren't far away, LOL. Memory says we used more valve lift in the Kawa than the kit cams in the GSXR - and spun it to 13k vs 14 for the Suzuki.
We probably did achieve the 80hp we wanted - but not for long. Insert dropped out as is visible.

Never been able to throw it out....

[Michael Moore]

Thanks Greg, it looks similar to the downdraft intakes on the 250

http://www.eurospares.com/graphics/ex250/ex250h2.jpg

Once you do that you get to deal with "are the carbs too tilted to work properly?" and "how do I squeeze everything back into the frame/under the tank?" That last was an incentive for my Laverda frame. After developing the engine on the dyno the intake tracts were too long to fit into the stock frame, and on the new frame (Mk 5 version) I had the back of the tank hollow for the bellmouths to not be obstructed:

http://www.eurospares.com/graphics/Laverda/LavSF2RRMK5012a3.jpg

[Grumph]

Thanks Greg, it looks similar to the downdraft intakes on the 250

http://www.eurospares.com/graphics/ex250/ex250h2.jpg

Once you do that you get to deal with "are the carbs too tilted to work properly?" and "how do I squeeze everything back into the frame/under the tank?" That last was an incentive for my Laverda frame. After developing the engine on the dyno the intake tracts were too long to fit into the stock frame, and on the new frame (Mk 5 version) I had the back of the tank hollow for the bellmouths to not be obstructed:

http://www.eurospares.com/graphics/Laverda/LavSF2RRMK5012a3.jpg

Yes, same idea as the 250. The angle is why Dellortos rather than our usual RS Mikunis.

To get back to chassis related topic - looking at your SF, you can see the attraction of an Ogier Laverda style tank in the rear subframe as it then leaves room for the carbs - and a possible airbox - in the usual tank position. But as usual a major component would need to be relocated - the pipe.
We didn't have space problems. This version of the EX went into the frame used for the blown one - a GSXR750J. Plenty of room under the std Suzuki tank.
No pics of that bike exist either blown or not. Built in a tearing hurry, tested in haste, developed at a frenzied pace - you get the idea, LOL
That rolling chassis was written off at the opening meeting of the extended Ruapuna circuit here. Owner had loaned it to a sponsor who'd stuffed an 1100 engine into it with RS carbs etc...throttle stuck open. Rider locked up the front and went down, rolled away OK. Bike stood up and accelerated...hit a pile of dirt and launched like an Exocet missile over the boundary fence. Couple of bounces later it finished up in a tree...very broken.

[Michael Moore]

I used that same exhaust on all 5 versions of the bike it wasn't broken so I didn't fix it.

http://www.eurospares.com/graphics/Laverda/LavSF2RRMK5014a3.jpg

I eventually added a horizontal panel in the back section of the tank to get a bit more fuel capacity. P. Williams-style pannier tanks would have been another option.

I've some nice photos of the Ogier Hossack that Norman sent me here:

http://www.eurospares.com/hossack.htm

[F5 Dave]

Despite being a dirty 4 stroke that Laverda looks great.

It reminds me of a daydream two days ago of what one would have done if left in charge of Triumph late 60s with no ability to design an engine but an otherwise obsolete product and looming competition. That would be a good starting point. Clearly with road gear.

[husaberg]

A while back we were talking abou the Plasma coated Aluminium brake discs that MV Augusta (Among others such as Kawasaki)used to run on the racers.
Looking through a Motorcourse from 1984 it looks like most of the 125's used to run Zanzani Brake discs.
http://www.motobi.com/zanzani_2015/dischi.html
336020
336013https://www.facebook.com/ZanzaniVintage/?hc_ref=ARQyYYSxtwcGlYdiJnQtJW_F7RJHjIwiUxBZFPz-3_JsZnYQCpICm_FHlzeH-ys5NDk

Other interesting tidbit was even back then Honda were running carbon discs on the works supported NS500 and NSR500's

[Frits Overmars]

How about 3D-printing a frame?
https://www.asphaltandrubber.com/news/bmw-s1000rr-3d-printed-frame/
336810

Surprisingly there is still some welding at the headstock.
336811

[Ocean1]

How about 3D-printing a frame?
https://www.asphaltandrubber.com/news/bmw-s1000rr-3d-printed-frame/


Surprisingly there is still some welding at the headstock.


Probably the only section requiring resolution better than the printer can provide, (bearing cavities).

I'd love to see the FEA work on that, I assume most if not all of the sections are hollow, in which case it looks like the result of a proper force diagram approach.

[monkeyfumi]

Bearing cavities will be machined after printing, so not a resolution issue.

It is probably as simple as being the limit of the build envelope for the printer. Too big, so needs to be done in two parts.

[Moooools]

I'd love to see the FEA work on that, I assume most if not all of the sections are hollow, in which case it looks like the result of a proper force diagram approach.

Will be the result of topology optimisation:

https://solidthinking.com/inspire2018.html

I think there is a great case for creating a chassis from folded topology optimised sheet metal.
Most frames are made with complex manufacturing methods which allow for a wide range of geometries, but are limited by the designers ability to consider more than a few variables at once (ending up overweight and over/under stiff in some modes), and require a great deal of time to manufacture. But with an optimised sheet metal construction, a lighter chassis with the required stiffnesses could be quickly and repeatably manufactured for only a few hundred dollars, especially if it was made to be self-jigging.

[Ocean1]

Bearing cavities will be machined after printing, so not a resolution issue.

It is probably as simple as being the limit of the build envelope for the printer. Too big, so needs to be done in two parts.

Yes, I was simply pointing out that the printer wouldn't provide H7 level tolerances.

And yes, the constraint will be the capacity of either the printer or the machine center.

[Ocean1]

Will be the result of topology optimisation:

https://solidthinking.com/inspire2018.html

I think there is a great case for creating a chassis from folded topology optimised sheet metal.
Most frames are made with complex manufacturing methods which allow for a wide range of geometries, but are limited by the designers ability to consider more than a few variables at once (ending up overweight and over/under stiff in some modes), and require a great deal of time to manufacture. But with an optimised sheet metal construction, a lighter chassis with the required stiffnesses could be quickly and repeatably manufactured for only a few hundred dollars, especially if it was made to be self-jigging.

It's certainly got that avian bone structure look. Wonder if this year's budget will handle some CAD upgrades. :no:

Aye, monocoque structures are not only comparatively inexpensive but often seem to be a bit more... damage tolerant.

[lodgernz]

This is interesting

339526339525339524339523339527

The Kawasaki 250 engine is just a place-holder. It's designed to take a Ducati V-twin. The shocks are MTB.

[Grumph]

Well, it's certainly different. But I find it difficult to see the rationale behind it. It looks to me like the rear transverse bulkhead off a race car. But more complicated...
The rear geometry looks to me like it would lift under power - the heavily angled top link will transfer a lot of weight to the rear tyre which will lift the back of the chassis IMO.
The front appears to be designed to increase trail as it dips. Opposite to conventional teles which use the reducing trail to assist turning.

I'd have liked to see the builder's reasoning behind it.

[Frits Overmars]

The rear geometry looks to me like it would lift under power - the heavily angled top link will transfer a lot of weight to the rear tyre which will lift the back of the chassis IMO.
The front appears to be designed to increase trail as it dips. Opposite to conventional teles which use the reducing trail to assist turning.
I'd have liked to see the builder's reasoning behind it.I think trail will decrease when the front dips, but I don't think you could ever persuade it to dip; it looks like a massive amount of built-in antidive at the front and antisquat at the back. And I fear there is next to zero torsion stiffness in all directions. Let's just consider it a work of art :rolleyes:.

[Grumph]

I think trail will decrease when the front dips, but I don't think you could ever persuade it to dip; it looks like a massive amount of built-in antidive at the front and antisquat at the back. And I fear there is next to zero torsion rigidity in all directions. Let's just consider it a work of art :rolleyes:.

Works for me....

[F5 Dave]

Well funnily enough I bumped into this tonight. It does look great. A mate Roger had told me he was going to something like this. He is a Tesi owner.
Water jet some of it but largely by hand

2 bikes in the background now I look at this. One known for real bad handling. One for real good.

[Grumph]

Is it "Roger from Greytown" - or another one ?

Being a Tesi owner answers some questions...

[F5 Dave]

Nah he's just up the road somewhat.
His idea was that low center of gravity was no good if there we a high headstock. He just wants to try his ideas out, but in the flesh the aluminium is gorgeous. I didnt discuss why it was likely to be odd.
We weren't at his place. Another shed even closer to me, not to be disclosed, and it was over an hour before I even bothered to go over and have a look due to other bikes. I've been geeking out ever since at the, well one other bike.

[Frits Overmars]

At this week's MotoGP tests in Jerez, Ducati displayed a remarkable rear brake anchor rod. No questions were answered by the factory, but my guess is that the front of the anchor rod is not directly attached to the frame, but to the rear suspension link system. So that, if you use the rear brake, the rear suspension is compressed and the Center of Gravity is lowered. This reduces the tendency to wheelie and thus enables stronger acceleration.

Using the rear brake while trying to accelerate may sound crazy. But a MotoGP machine has too much power in the lower gears, where the aerodynamic downforce from the anti-wheelie spoilers is still limited. Using part of this power to lower the Center of Gravity, so that more of the remaining power can be used for acceleration, is a brilliant idea when you have power to spare.
339729 339728

[husaberg]

At this week's MotoGP tests in Jerez, Ducati displayed a remarkable rear brake anchor rod. No questions were answered by the factory, but my guess is that the front of the anchor rod is not directly attached to the frame, but to the rear suspension link system. So that, if you use the rear brake, the rear suspension is compressed and the Center of Gravity is lowered. This reduces the tendency to wheelie and thus enables stronger acceleration.

Using the rear brake while trying to accelerate may sound crazy. But a MotoGP machine has so much surplus power, especially in the lower gears, where the aerodynamic downforce is limited, that using part of this power to lower the Center of Gravity, so that more of the remaining power can be used for acceleration, is a brilliant idea.
339729 339728

They Probably still have a few guys in the Ducati MGP team that reinvented antidive back in the mid 90's with Cagiva.
339731
The issue with the 90 degree Ducati is they will never get the weight far enough forward.

[jasonu]

Well funnily enough I bumped into this tonight. It does look great. A mate Roger had told me he was going to something like this. He is a Tesi owner.
Water jet some of it but largely by hand

2 bikes in the background now I look at this. One known for real bad handling. One for real good.

Which end is the front?

[F5 Dave]

I think it is like one of those French cars Jason, where it doesn't seem to matter.

[Michael Moore]

I saw today that Dan Hanebrink died 29 Dec 2019 at the age of 80. He was a "name" in off-road bicycling for the last few decades, but started out making some innovative motorycles/parts.

Here is a picture of Dan Hanebrink's Monotrack Engineering monocoque racer. The frame is made of welded magnesium plate, and the 3 cylinder Kohler 2-stroke engine was rated at 100 bhp. Constantly variable transmission and synchro-belt final drive, Monotrack calipers and coated aluminum brake discs, hydro/pneumatic suspension, 16" Monotrack cast wheels, and "weight was scarcely more than 200 pounds".

Monotrack monocoque From the Monotrack/Target catalog

http://www.eurospares.com/graphics/monotrk1.jpg

A less grainy photo:

https://thekneeslider.com/images/hanebrink.jpg

Here's a 250 Yamaha with Monotrack wheels and brakes I saw at Laguna Seca one year:

http://www.eurospares.com/graphics/specials/MonotrackTA250076.jpg

[Grumph]

In retrospect, using 16in wheels led to lot of grief. From what I've read, by the time the tyre supply was drying up, so was his enthusiasm.

Definitely an innovator though.

[husaberg]

I saw today that Dan Hanebrink died 29 Dec 2019 at the age of 80. He was a "name" in off-road bicycling for the last few decades, but started out making some innovative motorycles/parts.

Here is a picture of Dan Hanebrink's Monotrack Engineering monocoque racer. The frame is made of welded magnesium plate, and the 3 cylinder Kohler 2-stroke engine was rated at 100 bhp. Constantly variable transmission and synchro-belt final drive, Monotrack calipers and coated aluminum brake discs, hydro/pneumatic suspension, 16" Monotrack cast wheels, and "weight was scarcely more than 200 pounds".

Monotrack monocoque From the Monotrack/Target catalog

http://www.eurospares.com/graphics/monotrk1.jpg

A less grainy photo:



Here's a 250 Yamaha with Monotrack wheels and brakes I saw at Laguna Seca one year:


I downloaded some stuff a week or two ago
Shame he was ahead of his time
I had a google arround those engines are big dollars.
340099340100340101340102340103340104

[husaberg]

340105340106340107340108
I have that write up and another i have posted years ago think both were missing last pages

[Michael Moore]

Greg, Hanebrink's triple does seem to be a good example of why picking the best tires available should be the first thing in the design process. IIRC the Goodyear 16" tires he got were left-overs/non-current which didn't help with things. The sharp bend in the intake tracts doesn't seem like a wonderful choice, but he probably didn't have many options at the time.

His Monotrack fiberglass seemed like nice quality work, a friend had a tank and seat on his RD250.

Happy New Year to everyone and I hope you all see amazing progress on your projects (as opposed to "I'm amazed I've made any progress") in 2019!

cheers,
Michael

[Grumph]

I've got an article in "Motorcycling Monthly" from September 1978. By Derek Picard (an aussie I think - in an English mag)

Which seems to be written at the end of play. Hanebrink talks about a Mark 2 using an OW31 engine and 18in wheels - but doesn't seem that keen on actually doing it. Action pics as published elsewhere, couple of workshop pics unique to this article. Hanebrink basically explaining the problems...

Re projects....I suspect it's an excess of christmas cheer, but there's been some discussion on other threads here about the CX Hondas....I have a newish mag here which has an article on the Dr John Guzzi following one on the CX650....Proximity leads to some dreadful ideas...I'll keep buying the lotto tickets....
If it ever gets built I've got a name for it - The pox doctors maggot.....

[husaberg]

Greg, Hanebrink's triple does seem to be a good example of why picking the best tires available should be the first thing in the design process. IIRC the Goodyear 16" tires he got were left-overs/non-current which didn't help with things. The sharp bend in the intake tracts doesn't seem like a wonderful choice, but he probably didn't have many options at the time.

His Monotrack fiberglass seemed like nice quality work, a friend had a tank and seat on his RD250.

Happy New Year to everyone and I hope you all see amazing progress on your projects (as opposed to "I'm amazed I've made any progress") in 2019!

cheers,
Michael


I've got an article in "Motorcycling Monthly" from September 1978. By Derek Picard (an aussie I think - in an English mag)

Which seems to be written at the end of play. Hanebrink talks about a Mark 2 using an OW31 engine and 18in wheels - but doesn't seem that keen on actually doing it. Action pics as published elsewhere, couple of workshop pics unique to this article. Hanebrink basically explaining the problems...

Re projects....I suspect it's an excess of christmas cheer, but there's been some discussion on other threads here about the CX Hondas....I have a newish mag here which has an article on the Dr John Guzzi following one on the CX650....Proximity leads to some dreadful ideas...I'll keep buying the lotto tickets....
If it ever gets built I've got a name for it - The pox doctors maggot.....

found it
340293340294340295340296340297340298

[Michael Moore]

Rick Denoon sent me some photos of his Honda 400/4 project of about 15 years ago. Not a racer, but still pretty cool. His current 400/4 project will be turbocharged and fuel injected.

Rick Denoon sent me some info on his 400/4 project and I've put his photos here:

http://www.eurospares.com/graphics/chassis/RickDenoon400-4/

----------------
From Rick: Here are some photos of my CB400F circa 2005.

"Egli/Foale" style frame - 3" diameter x .063 main tube, 1" x .045 wall for all other tubes. - all plain ER steel.

VF500 wheels/forks/brakes

NS400 fairing, 400F tank, Yamaha YZF750 tail.

Wet weight - 345lbs

54" Wheelbase, 25 deg rake, 98mm trail.

http://www.eurospares.com/graphics/chassis/RickDenoon400-4/nextcover.jpg

[husaberg]

That reminds me of the first or secong GM street race some had a Cb400 or 550 with leading link forks and i think a special frame any ideas who it was Grumph?
I think it was red and Blue very boxy tank might have even been monocoque
Kind of looked a little monortrack styled.
Ps real nice stuff Mike and thanks for te other stuff.
I asked a while back about your EX250 stuff and what you did with the ignition? Uou might have missed it.
Grumph was rebuilding a GPZ500 and his original ignition died i was thing maybe ex500 ignitor might work and have a decent curve

[Michael Moore]

The EX250 stuff was sold off a long time ago when the window of opportunity on the project had closed with no likelihood of being reopened.

I would have put a RITA on it since I imported them into the US at one time. But while they worked OK they were old tech (not so old then) and there's so many better options now for ignitions -- Ignitech, HPI.be, etc.

The EX250 rotor/stator ended up on a friend's Yamaha XS650 street bike. It turned out it was a great fit, and while he had a RITA mounted on the cam the EX 3-phase alternator let him eliminate the 'orrible XS650 brushed thingy.

Tony Foale did a 400 or two back when he had his frame business. The spine was more the size of those on the TZ250 frames than the big street bike frames.

cheers,
Michael

[Grumph]

Rick Denoon - I came across his site a few years back and had a brief conversation with him about one or two things I didn't like on it. He took it very well.
Nice guy.

EX ignitions - the 250 curve is too like the 500 one. No advantage using it. Locally made box coming with a much more agressive advance curve.
The problem with the 500's of course is that you've got to lighten that end of the crank as much as possible...

Husa - That Honda was a 500/550 built by Steve ...... surname's gone sorry. He was George White's sidecar passenger. That chair used a similar small honda on big jolts of nitro and is well remembered for giving the visiting NI outfits some huge surprises...
Russ Bleach has the outfit and told me he'd contacted Steve who was keen to help restore it. No signs of progress.

[husaberg]

Husa - That Honda was a 500/550 built by Steve ...... surname's gone sorry. He was George White's sidecar passenger. That chair used a similar small honda on big jolts of nitro and is well remembered for giving the visiting NI outfits some huge surprises...
Russ Bleach has the outfit and told me he'd contacted Steve who was keen to help restore it. No signs of progress.

Any chance of Finding a pic of it or describing it, i was only a kid at the time. Be interesting to see what it actually was compared to what i think it might have been 30 years later.

[Grumph]

Any chance of Finding a pic of it or describing it, i was only a kid at the time. Be interesting to see what it actually was compared to what i think it might have been 30 years later.

I think I looked at it seriously maybe 3 - 4 times - and most of those were when scrutineering it.
Leading link forks, Honda front disc - single I think. Frame not sure if it was fully homebuilt or had bits of the CB one incorporated.
Always remember it as having a very high front end. Tank was folded alloy. Wire wheels. Homemade 4:1 pipe - loud.
It had it's good days but those were at club level F2. He rode it at a few nationals - usually where He and George had the chair running.
I believe he's still got it so you may yet see it again.

[guyhockley]

Mole Grips are British/Welsh version of Vice Grips for those that do not know.

[husaberg]

Mole Grips are British/Welsh version of Vice Grips for those that do not know.

i couldn't see the mole grip correlation bit on thr initial look but second time glace there she is...... funny.
I guess its a natural progression from Hondas earlier version from the RC1116s
https://upload.wikimedia.org/wikipedia/commons/thumb/4/4f/Honda_RC116_cropped_caliper_brake.jpg/300px-Honda_RC116_cropped_caliper_brake.jpghttp://www.classic50racingclub.co.uk/image/2/1/1/6/6/2116680/00864889.jpg

[F5 Dave]

Yeah the brakes seemed a bit 'Grabby' until late we put a rubber band around the release lever :weird:

[Frits Overmars]

i couldn't see the mole grip correlation bit on thr initial look but second time glace there she is...... funny.
I guess its a natural progression from Hondas earlier version from the RC1116s..... Or maybe from this pincer version.
340486

[husaberg]

..... Or maybe from this pincer version.
340486

Nice i have seen the pic plenty of times yet never noticed it appears to be nail pliers. a mate modified my post driver with a motorbike disk pad honda cr125 and nut bolt with a teebar it works off the belt pulley, amazing something so simple works so effective prior to that the monkey weight was held up by controlling the belt to tension or slip with a lever or inserting a pin it was as dangerous as hell. it actually had a long since disconnected feature where it automatically dropped down when the weight reached the top of the mast.
this is a flash version. all the bells and whistles but the safety shield removed as they always are. my old girl is all cable and pto drive none of this hydraulic modern tech

https://www.youtube.com/watch?time_continue=34&v=_vxRZTR1lLw

[guyhockley]

i couldn't see the mole grip correlation bit on thr initial look but second time glace there she is...... funny.
I guess its a natural progression from Hondas earlier version from the RC1116s
https://upload.wikimedia.org/wikipedia/commons/thumb/4/4f/Honda_RC116_cropped_caliper_brake.jpg/300px-Honda_RC116_cropped_caliper_brake.jpghttp://www.classic50racingclub.co.uk/image/2/1/1/6/6/2116680/00864889.jpg
I had a very crude copy of that brake on my pushbike when I was a kid back in the 60s. Years later, V brakes became the latest thing in bicycling tech, probably someone was allowed a patent.
Also had front suspension (rubber band leading links) on the same bicycle.

[husaberg]

I had a very crude copy of that brake on my pushbike when I was a kid back in the 60s. Years later, V brakes became the latest thing in bicycling tech, probably someone was allowed a patent.
Also had front suspension (rubber band leading links) on the same bicycle.

Funny how fashion goes full circle, i had old dungers pushbike set ups like that but they always wore at odd angles and never seemed to bite equally some i guess was due to buckled rims.
it flasher set ups had additional lbrake inks to aplly the pads evenly.

I used to run a KTM50 for my son they have italian brand Formula brakes the calipers 2 piston opposed rear and 4 piston front are so light and small with tiny plastic pistons its amazing to hold them.
I think the calipers were devloped for MTB bikes. they work bloody well into the bargain.
The lil KTM's had Mazzocchi forks, it was said to read even with the MTB bikes money injections from Gabriel (who make the shocks etc for the Royal Endfeild) they have recently gone under.
Fox was the other big player in the MTB suspension world but i guess they make their Dollars out of clothing and fashion.
Mazzocchi were clearly also years ahead having used and having been ridiculed for using separate function forks way back in the 80's a good 30 years before ohlins and the Japanese discovered them.

[jasonu]

..... Or maybe from this pincer version.
340486

Looks like someone cobbled on a set of pliers.

[guyhockley]

I've got an article in "Motorcycling Monthly" from September 1978. By Derek Picard (an aussie I think - in an English mag)

Which seems to be written at the end of play. Hanebrink talks about a Mark 2 using an OW31 engine and 18in wheels - but doesn't seem that keen on actually doing it. Action pics as published elsewhere, couple of workshop pics unique to this article. Hanebrink basically explaining the problems...

Re projects....I suspect it's an excess of christmas cheer, but there's been some discussion on other threads here about the CX Hondas....I have a newish mag here which has an article on the Dr John Guzzi following one on the CX650....Proximity leads to some dreadful ideas...I'll keep buying the lotto tickets....
If it ever gets built I've got a name for it - The pox doctors maggot.....

I assume this is that article but I can't see magazine or author.
CXs have become a popular basis for customising in the UK, recently.

[Michael Moore]

One of the people on my chassis list is trying to find more information on this Ducati (851-916 he thinks) which has an FFE that appears similar to the ones Tony Foale used on his "Q" bikes. With the German caption and Metzler sticker it seems possible it was built in Germany.

Does anyone recognize it?

cheers,
Michael

[husaberg]

One of the people on my chassis list is trying to find more information on this Ducati (851-916 he thinks) which has an FFE that appears similar to the ones Tony Foale used on his "Q" bikes. With the German caption and Metzler sticker it seems possible it was built in Germany.

Does anyone recognize it?

cheers,
Michael

looks 851 due to crankcase colour i have never seen it.
As it Euro it might pay to ask on pitlane.FR

[Grumph]

I assume this is that article but I can't see magazine or author.
CXs have become a popular basis for customising in the UK, recently.

Yes, that's the article.
My Xmas indigestion has worn off - CX's revolt me again. I think you'd have to use a turbo one to get a reasonable power to weight ratio.

[Grumph]

One of the people on my chassis list is trying to find more information on this Ducati (851-916 he thinks) which has an FFE that appears similar to the ones Tony Foale used on his "Q" bikes. With the German caption and Metzler sticker it seems possible it was built in Germany.

Does anyone recognize it?

cheers,
Michael

If it is an 851 - or from that family, How long will the cases last ? Not the engine I'd have hung front suspension off....
Is the large luggage container above the rear wheel the fuel tank ?

[husaberg]

If it is an 851 - or from that family, How long will the cases last ? Not the engine I'd have hung front suspension off....
Is the large luggage container above the rear wheel the fuel tank ?

Pretty sure one of the Tesi was a Ducati
Althought the tesi side stepped the cases a bit ,likely after the thin walled die cast VF400 honda ones broke
https://www.motorcycle.com/blog/wp-content/uploads/2015/10/102115-bimota-tesi-1d-sr-engine.jpg

[Grumph]

If that's the Tesi, I'd argue the frame's doing a good job of holding the engine together...
From memory it wasn't till the second gen of the 888 engines that Ducati got stronger cases homologated.
Up till then you needed deep pockets to race one. Actually, that didn't change, lol, but at least the cases lasted longer.

[husaberg]

If that's the Tesi, I'd argue the frame's doing a good job of holding the engine together...
From memory it wasn't till the second gen of the 888 engines that Ducati got stronger cases homologated.
Up till then you needed deep pockets to race one. Actually, that didn't change, lol, but at least the cases lasted longer.

I will fix my typing later, i think pretty much every model got stroger cases 851 twice 916 twice and 996 at least once the cases and cylinders got so much heavier that by about 97 even with the same weight as the fours the Ducati stopped carryinng lead ballast. which buggered up the weight distribution, but much less oil wss spilled.


Pretty sure one of the Tesi was a Ducati.
Although the tesi side stepped the cases a bit ,likely after the thin walled diecast VF400 honda ones broke

TRhe 916's frame also went around the swngarm pivot to lessen the stress a little.
From what i understand the major weakness was that the cases had to carry the preloaded bearings as well as the lack of metal as each engine grew.
The supermono with smaller lighter cases and bigger bores but plain main beearings gave no issues, The 916 was meant to have plain mains, but there were no lira for retooling.

[guyhockley]

One of the people on my chassis list is trying to find more information on this Ducati (851-916 he thinks) which has an FFE that appears similar to the ones Tony Foale used on his "Q" bikes. With the German caption and Metzler sticker it seems possible it was built in Germany.

Does anyone recognize it?

cheers,
Michael

Does this look like the same front end?
It's a VV BMW raced in european Battle of the Twins series. Ulrich Volkel (or Voelkel). Did a quick Google but only found that he now runs an engineering company in Shanghai and 2-ventiler.de is a forum for BMW airheads (no comment!).

[guyhockley]

Just noticed: Metzeler logo on the BMW tank, too?

[Michael Moore]

Guy, that does look the same. I only had photos of the VH (not VV) FFE and it has the lower arm attaching above the axle (I think like Parker/GTS).

thanks,
Michael

[Frits Overmars]

Guy, that does look the same. I only had photos of the VH (not VV) FFE and it has the lower arm attaching above the axle (I think like Parker/GTS).Michael, here are some Parker pics, with two versions of front suspension.
340794 340793 340792

[Michael Moore]

Thanks Frits, Parker's prototype did have the arm attach below the axle, unlike the later ones

[husaberg]

Just a simple Aussie Girder
https://thekneeslider.com/yamaha-r1-aluminum-girder-front-suspension-from-suspensionsmith-of-australia/
I see hes used tonys software.
340799
His test mule a Fireblade powered FZR400

340797340798


https://thekneeslider.com/yamaha-r1-aluminum-girder-front-suspension-from-suspensionsmith-of-australia/

https://www.youtube.com/watch?time_continue=128&v=W0mSy4QbGe8

hes even doing a hybrid mx bike
https://www.facebook.com/Suspensionsmith/?tn-str=k*F

https://www.youtube.com/watch?v=ogzIzpj2gqg
340800

[Michael Moore]

Here are some more V V photos, this time of a Guzzi racer

cheers,
Michael

[husaberg]

Here are some more V V photos, this time of a Guzzi racer

cheers,
Michael

That last pic, They have welded up around the Piston on the caliper?

[guyhockley]

This is the article I got the VV BMW picture from, finally got the pdf to convert to images...

[husaberg]

Magni did a para rear end on Guzzis in 85
http://www.magni.it/storia2.htm

In the 1985, driven by market demand, Magni bikes became completely Italian with a long-lasting relationship with Moto Guzzi for engines.
The first Magni model with the new engine was the "LeMans" incorporated a full fairing, contemporary lines and a innovative rear suspension system designed by Magni called the "parallelogrammo".
This new suspension system eliminates the reactions normally induced with shaft drive motorcycles. The "parallelogrammo" suspension enables the bike to perform much like a chain-drive unit.
From then on, other similar systems have been developed by other manufacturers.
340909340910340911340912340913

[layton]

Magni did a para rear end on Guzzis in 85
http://www.magni.it/storia2.htm

340909340910340911340912340913

i have an obsession with the large BMW and Guzzi engines. something about them....

[husaberg]

i have an obsession with the large BMW and Guzzi engines. something about them....

Engines pointing in strange directions at odds with convention?
if you like CX hondas as well you might have a problem:clap:
They all do have a symmetry that's appealing to the eye.

[layton]

Engines pointing in strange directions at odds with convention?


Yep.....i do seem to like unusual things. maybe its relate-able?
:clap::weird:

[Michael Moore]

Don't forget the Lambretta 250GP L-twin

https://opimedia.azureedge.net/-/media/images/mcc/editorial/articles/magazine-articles/2017/11-01/what-might-have-been-the-lambretta-gp-racer/lambretta-1-jpg.jpg

One of Phil Aynsley's great photos from

https://www.motorcycleclassics.com/classic-italian-motorcycles/lambretta-gp-racer-zm0z17ndzhur

cheers,
Michael

[husaberg]

Don't forget the Lambretta 250GP L-twin

https://opimedia.azureedge.net/-/media/images/mcc/editorial/articles/magazine-articles/2017/11-01/what-might-have-been-the-lambretta-gp-racer/lambretta-1-jpg.jpg

One of Phil Aynsley's great photos from

https://www.motorcycleclassics.com/classic-italian-motorcycles/lambretta-gp-racer-zm0z17ndzhur

cheers,
Michael

Better than their other attempts.
https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1130430283#post1130430283

[Michael Moore]

FYI, Tony Foale is having a short sale on his chassis book/software bundles per this email that I got a few hours ago:


Since the beginning of March the checkout on our website has not been working correctly due to an automated update of the web software. I think that the problem has now been fixed. So if you had a problem please try again now.
To celebrate the problem being fixed we are offering an extra 10% discount on all of our bundled products for one week from today. So even if you were not affected by the problems, now is a good time to order.

Go to https://motochassis.com

cheers,
Michael

[Grumph]

Almost the first 100 pages - and I'm referencing page one...

Plate frames.
Has anyone seen any information on plate thickness used ?
In theory, the side members could be pretty thin and still be adequate for beam strength - but less so for torsional loadings.
As usual it's a tradeoff, the thinner the side members, the more important the bulkheads become.
And yes, I'm considering one. Just because I can, LOL.

Thanks

Greg

[husaberg]

Almost the first 100 pages - and I'm referencing page one...

Plate frames.
Has anyone seen any information on plate thickness used ?
In theory, the side members could be pretty thin and still be adequate for beam strength - but less so for torsional loadings.
As usual it's a tradeoff, the thinner the side members, the more important the bulkheads become.
And yes, I'm considering one. Just because I can, LOL.

Thanks

Greg

yip..............
Built like a wing
but why not use the same materials as a wing
that m Board that the segale and the heron and ohters used is still used in planes (well modern version
Fits fro his bike use 2mm ms
Norton for the SS monocoque used some rear thin material as well.
https://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=289817&d=1384415253
They have wonderful strong glues and flush rivets these days.

Eric Offenstadt. did wonderful looking creations
341366341367341368341369341370

[husaberg]

If you are meaning just plate frames
341371341372341376341377
the beauty of these would be the bits you can cut out double up and easily alter
Not only that woth the cross tubes you can move around the bracing and i think you can get big rivets like those eyes on tarpaulins

[Frits Overmars]

I've seen a couple of these 'plate frames' in action. Without a proper closed-box construction they had the torsional stiffness of a wet newspaper.
341382

[Grumph]

I've seen a couple of these 'plate frames' in action. Without a proper closed-box construction they had the torsional stiffness of a wet newspaper.
341382

Thanks Frits - I'd had that suspicion. I haven't seen a pic of one with what I'd consider proper bulkheads.
And when you factor in proper load bearing bulkheads, eventually you come up with a full monocoque.

[HenryDorsetCase]

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

Random click of the day - happy. Epic boobs.

[husaberg]

Random click of the day - happy. Epic boobs.
Reminds me of that episode of Seinfeld.

https://www.youtube.com/watch?v=BL2PicT9Kng
To be fair my main motivation was the story was pretty decent as well to be fair.
3 spoke vs more etc.

[HenryDorsetCase]

I've seen a couple of these 'plate frames' in action. Without a proper closed-box construction they had the torsional stiffness of a wet newspaper.
341382

I was looking at that and wondering if the engine had to be a stressed member for it to work properly.... but if you think of the long lever attached a the steering head and swingarm even those hefty pipes don't look like enough.

[husaberg]

I was looking at that and wondering if the engine had to be a stressed member for it to work properly.... but if you think of the long lever attached a the steering head and swingarm even those hefty pipes don't look like enough.

It certainly doesnt look look a stressed skin or does it looj thick enough sections or enough struts the one on the first page is what it should look like.
But something like the Ciba Geigy M board one looks far cooler.

https://www.kiwibiker.co.nz/forums/showthread.php/145224-Race-chassis?p=1130268943#post1130268943

[Grumph]

I was looking at that and wondering if the engine had to be a stressed member for it to work properly.... but if you think of the long lever attached a the steering head and swingarm even those hefty pipes don't look like enough.

Well, if you think a "normal" tube frame doesn't look stiff enough, don't look at Tony Foale's early spine frames for TZ's....
But they worked. With the tyres of the time.

[husaberg]

Well, if you think a "normal" tube frame doesn't look stiff enough, don't look at Tony Foale's early spine frames for TZ's....
But they worked. With the tyres of the time.

That Spine though is a fully formed box to bend it one side has to stretch the other has to deform.
The plate frame only has to bend inside or outside.
The monocoque has the full box section and a lot of times the skin can also be stressed.

I think of it like a tube 1mm wall thickness
Its a heck of a lot harder to bend that than to bend a 4mm thick plate is of the same weight

[Frits Overmars]

Food for thought, and a great read!
https://www.odd-bike.com/2019/07/guest-post-robert-horns-rohorn-two.html?fbclid=IwAR3QfV3-je6WDttaamUyM4Yg26K3gTeQ4NJffGSLTlS5YSGd_DifUKSqqJ E

[husaberg]

I seen this the other day i had never seen the 500 twin version.
342482
Note the wheels they appear to be fabricated like a comstar or a early marvic/akront.
Pretty sure they only were able to run the 500 twin as a twingle as it rocked too much as a 180 twin.
Also these

342478
Mcmurdos F2 carbonfibre bike based on a ZXR400 chassis with a ZZR600 i think engine.

342477342481


Plus the Bimota split chassis with its coupling which i think was a generic Aircraft fitting design.
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[Grumph]

Food for thought, and a great read!]

Yes, it is. Thanks for posting it.

I was probably too close to events here - but I still cringe when someone quotes John Britten as a reason for doing something.
Most of us now use him as an example for not doing something...

Husa - There seem to have been two versions of the Ossa/Yankee twin. I've got a pic somewhere of the aircooled engine you posted in a dirt bike.
I've also got a road test of the pre-production road bike - with a horizontal, water-cooled engine.

Tony's carbon bike was based on 400 Geometry. He'd had several and liked the handling. First pic I've seen with the downdraft carbs shown. Definitely a ZZR - which at that time weren't sold here.
I believe the engine came through Lawton and Boyle via Kawasaki NZ and may have been a jap market version - or even pre-production.

[husaberg]

Yes, it is. Thanks for posting it.

I was probably too close to events here - but I still cringe when someone quotes John Britten as a reason for doing something.
Most of us now use him as an example for not doing something...

Husa - There seem to have been two versions of the Ossa/Yankee twin. I've got a pic somewhere of the aircooled engine you posted in a dirt bike.
I've also got a road test of the pre-production road bike - with a horizontal, water-cooled engine.

Tony's carbon bike was based on 400 Geometry. He'd had several and liked the handling. First pic I've seen with the downdraft carbs shown. Definitely a ZZR - which at that time weren't sold here.
I believe the engine came through Lawton and Boyle via Kawasaki NZ and may have been a jap market version - or even pre-production.

Are you sure you dont remember the horozontal Cam am twin? rather than the Ossa?
http://www.canned-ham.com/wp-content/uploads/2011/04/1976street500.jpg
I always liked that as it was like a giant MB5
I actually like the look of that OSSA

[Michael Moore]

I think all the 500 Yankees that were production bikes were in tube frames (the dirt models had a frame designed by Dick Mann) and that monocoque racer is probably a later Hererro-tribute bike. The attached Yankee racer photo has a frame that reminds me of an H1R.

I've got a couple of other photos of the 1000cc 4 cylinder racer built for the 1972 Barcelona endurance race that I'll scan and post tomorrow.

The 500s were very much doubled up 230/250 dirt engines.

[husaberg]

I think all the 500 Yankees that were production bikes were in tube frames (the dirt models had a frame designed by Dick Mann) and that monocoque racer is probably a later Hererro-tribute bike. The attached Yankee racer photo has a frame that reminds me of an H1R.

I've got a couple of other photos of the 1000cc 4 cylinder racer built for the 1972 Barcelona endurance race that I'll scan and post tomorrow.

The 500s were very much doubled up 230/250 dirt engines.

Looks like the Seely frame thay made of Smarts Kawasaki H2R, but that steering head looks well raked out.

[Grumph]

Just very high steering head IMO. An unfortunate line to the tank top and frame.

Yes, got the Cam-am mixed in. My error.

[husaberg]

Just very high steering head IMO. An unfortunate line to the tank top and frame.

Yes, got the Cam-am mixed in. My error.

that CAM-AM never getting put into production was always a shame.

[Michael Moore]

http://ossa.2y.net/ossa/ossa4.htm

for some photos/info for the 4 cylinder Yankee which was a private project

http://ossa.2y.net/ossa/ossa41.jpg

http://ossa.2y.net/ossa/ossa42.jpg

http://ossa.2y.net/ossa/ossa43.jpg

cheers,
Michael

[guyhockley]

http://ossa.2y.net/ossa/herreroreplica/index.html

[guyhockley]

If you search "Herrero replica", there seem to be a few of varying quality...

[guyhockley]

The 1000/4 may have been a works effort.

[guyhockley]

There was also a Cobas Siroko Ossa, spaceframe chassis with rotary valve engine but possibly not a factory motor. Check out the (lack of) cylinder finning!

[Michael Moore]

I've added some more material from Norman Hossack, mainly some detail photos of his Ducati street bike conversion (the sides of the upright bolt to the center main section and he also has the outer portions of the axle attached to those side members) and a few photos of a big-block Guzzi frame during conversion.

http://www.eurospares.com/hossack.htm

cheers,
Michael

[guyhockley]

I think there is a bit about the Can-Am/Rotax racer in one of the Mick Walker books.

[guyhockley]

This stuff probably ought to be in the Oddball thread...

[guyhockley]

I've added some more material from Norman Hossack, mainly some detail photos of his Ducati street bike conversion (the sides of the upright bolt to the center main section and he also has the outer portions of the axle attached to those side members) and a few photos of a big-block Guzzi frame during conversion.

http://www.eurospares.com/hossack.htm

cheers,
Michael

Some other bits, very poor quality, sorry.

[guyhockley]

Even worse quality!
From Performance Bikes magazine that seems to have gone bust...

[F5 Dave]

They merged with Practical Sportsbikes mag and have an inner section. They were a bit crap for the last ten years but I was buying it out of habit.

[guyhockley]

German TZ250 with wishbone/steered girder front end.

[guyhockley]

Few more of the Hossack TZ :confused:

[guyhockley]

Displayed at the (hipster) Bike Shed Show. Did he like everything about the Tesi, except that funny front end, or what?

[Grumph]

Displayed at the (hipster) Bike Shed Show. Did he like everything about the Tesi, except that funny front end, or what?

Owner/builder must have incredibly long legs - look at the seat height vs footrest position.
If it had high bars you could ride it standing up - like a cycle pacer.

[guyhockley]

I took a phone picture of someone else's magazine and somewhere along the line it's become distorted, the original looked more normal...

[husaberg]

Seen this last night
343274

[Frits Overmars]

Espargarò-KTM front wheel bounce;
at 00:20 it gets interesting:

https://www.facebook.com/pol.espargaro.44/videos/2751560168195785/

[Pursang]

Espargarò-KTM front wheel bounce;
at 00:20 it gets interesting:

https://www.facebook.com/pol.espargaro.44/videos/2751560168195785/

Very interesting. It looks like the rider is watching it happen too!

[husaberg]

Espargarò-KTM front wheel bounce;
at 00:20 it gets interesting:

https://www.facebook.com/pol.espargaro.44/videos/2751560168195785/


Very interesting. It looks like the rider is watching it happen too!

Really really bad chatter isnt it.
here is a less dramitic version
https://twitter.com/motogp/status/1056244321823924224?lang=en

i cant believe the saves thee guys grind out day in day out, fricken aliens the lot of them.

i have a theory its like like riding ruts in Mx
i think some riders dont seem to get front chatter as they dont grip the bars and bike as tight?
you watch the best rider they are always loose on the bike they go with the bike a fair bit.
Given a few million dollars a few years a bevy of women and a small Labrador i could dial that out for him. If only he asked.

[Pursang]

i have a theory its like like riding ruts in Mx
i think some riders dont seem to get front chatter as they dont grip the bars and bike as tight?
you watch the best rider they are always loose on the bike they go with the bike a fair bit.
Given a few million dollars a few years a bevy of women and a small Labrador i could dial that out for him. If only he asked.

Not sure about the rut theory?? Front wheel will tend to track around the rut, so long as you don't get the front wheel too light and climb out of it!
But I agree you need to let the front end have its way. This looks more like a front knobby walking around on a hard, oiled, dirt track surface. Basically bouncing from knob to knob.

There is a LOT of different things happening before and around 20s. (The whole system, Bike & Rider, is a Quivering Mass, not derogatory, just an observation):eek5:
I would expect that the mechanics/technicians know enough about suspension to have the springs and damping pretty close.
Looks to me that the front tyre is oscillating on very edge of grip and side slip, producing weight transfer effects in the tyre itself, that the forks cant really monitor or keep up with.

Here's Mr. H looking for similar, in the days before HD SloMo Video.
http://www.motorcyclemuseum.org/halloffame/hofimages/Soichiro_Honda_04_l.jpg

Cheers, Daryl.

[husaberg]

Not sure about the rut theory?? Front wheel will tend to track around the rut, so long as you don't get the front wheel too light and climb out of it!
But I agree you need to let the front end have its way. This looks more like a front knobby walking around on a hard, oiled, dirt track surface. Basically bouncing from knob to knob.

There is a LOT of different things happening before and around 20s. (The whole system, Bike & Rider, is a Quivering Mass, not derogatory, just an observation):eek5:
I would expect that the mechanics/technicians know enough about suspension to have the springs and damping pretty close.
Looks to me that the front tyre is oscillating on very edge of grip and side slip, producing weight transfer effects in the tyre itself, that the forks cant really monitor or keep up with.

Here's Mr. H looking for similar, in the days before HD SloMo Video.
http://www.motorcyclemuseum.org/halloffame/hofimages/Soichiro_Honda_04_l.jpg

Cheers, Daryl.

You must really want that Lab:lol:
the reason i think that the grip on the bike (and it is just a theory)makes a deference to chatter is when you have it the harder you try the worse it gets and others with the exact same set up can go just as fast as the guy suffering from chatter.
I feel tensing up alters the spring rates and the damping and chatter is a mismatch in the total suspension damper spring and tyre and surface.you end up with a them almost resonating (likely wrong word)like the narrows bridge
or if you have ever had a trailer get away from you.
the more you fight the faster you go worse it gets.
http://i.imgur.com/vZhXOGV.gif
if we only knew a physicist.........
https://thumbs.gfycat.com/ElegantSickFoxhound-size_restricted.gifhttps://i.imgur.com/RbQqmAT.gif

[Pursang]

You must really want that Lab:lol:
the reason i think that the grip on the bike (and it is just a theory)makes a deference to chatter is when you have it the harder you try the worse it gets and others with the exact same set up can go just as fast as the guy suffering from chatter.
I feel tensing up alters the spring rates and the damping and chatter is a mismatch in the total suspension damper spring and tyre and surface.you end up with a them almost resonating (likely wrong word)like the narrows bridge
or if you have ever had a trailer get away from you. The more you fight, the faster you go worse it gets.

I don't need a dog, Thanks!

I did have a trailer get away, once. Tandem with a 1947 Desoto on it. Deflated a rear trailer tyre at 100kph..shook my Charger like a handkerchief.
I suspect the deflated tyre shifted the COG rearward and off centre.
Spinning the steering wheel lock to lock just to keep it somewhere in the centre of the highway. (No power steering). Girlfriend Squealing!
Over-ride brake on the trailer coupling eventually bit and pulled it back in line.
Not an experience I would like to repeat.

https://www.youtube.com/watch?v=6mW_gzdh6to

I think 'resonating' is a good word, there are a lot of things happening that added up to produce the 'incident'.
Thank God for knee sliders!!

Cheers Daryl.

[F5 Dave]

The thing I can't get over is the camera car following the trailer sees it happening and doesn't brake like fuk to avoid the fallout which could have been a car in the face.

[Pursang]

The thing I can't get over is the camera car following the trailer sees it happening and doesn't brake like fuk to avoid the fallout which could have been a car in the face.

1: Old NASCAR trick! Aim for the crashing car, cos it won't be in that same spot when you get there! (Usually):dodge:

2: Never let your Personal Safety interrupt capturing a potential YouTube post. .:bleh:

Cheers, Daryl.

[husaberg]

I don't need a dog, Thanks!

I did have a trailer get away, once. Tandem with a 1947 Desoto on it. Deflated a rear trailer tyre at 100kph..shook my Charger like a handkerchief.
I suspect the deflated tyre shifted the COG rearward and off centre.
Spinning the steering wheel lock to lock just to keep it somewhere in the centre of the highway. (No power steering). Girlfriend Squealing!
Over-ride brake on the trailer coupling eventually bit and pulled it back in line.
Not an experience I would like to repeat.

https://www.youtube.com/watch?v=6mW_gzdh6to

I think 'resonating' is a good word, there are a lot of things happening that added up to produce the 'incident'.
Thank God for knee sliders!!

Cheers Daryl.
with the trailers is normally to heavier a trailer or weight to far back the trick i understand is to ease off the throttle fighting it makes it worse as its sort of a pendulum effect
i was using it as an example as the forces co-incide and amplify which is what i think happens with the chatter
i could describe it better with the million dollars and the pitlane girls

[F5 Dave]

1: Old NASCAR trick! Aim for the crashing car, cos it won't be in that same spot when you get there! (Usually):dodge:

2: Never let your Personal Safety interrupt capturing a potential YouTube post. .:bleh:

Cheers, Daryl.
There was an article on Kilfies the other day which is apparently the name for people who got killed taking selfies. People are odd. And vain.

[Pursang]

i could describe it better with the million dollars and the pitlane girls

When you secure the contract, the budget, and the girls, I will happily act as Consulting Devil's Advocate!
Or, If you pay me enough, I think I could agree with (and technically justify) just about anything!:shifty:

Cheers Daryl.

p.s. F5 Dave - "Kilfies":lol:

[husaberg]

When you secure the contract, the budget, and the girls, I will happily act as Consulting Devil's Advocate!
Or, If you pay me enough, I think I could agree with (and technically justify) just about anything!:shifty:

Cheers Daryl.

p.s. F5 Dave - "Kilfies":lol:

there is one where a shot shot himself in the head taking a selfie with a gun and a phone.
.......
google there has been heaps who have done that.......

[el chupacabra]

So I've got a dilema or at least i might have a dilema. . . here is my RGV with a Banshee engine swapped into it. So my question is, will the angle of the engine adversely effect the handling of the bike or will it be fine? (it will definitley effect the oil level).
If its going to make the bike handle like a pig i guess I'll just have to cut out the mounts and re weld them.
343384343385343380343381343382343383

[jato]

The most important thing is the front sprocket position in relation to the swingarm pivot - with a powerful engine it can have quite an effect. safe bet would be to copy the std rgv as close as possible. your dog looks like it needs a few decent feeds...

[el chupacabra]

the poor old girl, she struggles to hold any weight now days she gets feed quite a bit, she's a 12 year old greyhound cross.

The front sprocket position is the same as the original RGV as i just took measurements off of my VJ21. I'm just being a bit pedantic before i carry on and start fabricating pipes.

[F5 Dave]

I was going to say the front sprocket looks low. If it's the same height but further forward it will be too low.

I'd run a chain on that and spin it. It should only just skim. Tie down compress to rider sag and it must be clear. That's a starting point and not the be all of squat induced effects. You can buy 17T, which may help. The RGV range of rear sprockets are quite limited. Actually I gave my offset 17 to someone using a VJ21 with a 421 RZ.

A VJ21 produces about 52 rwhp, but a banshee, maybe 45? A YPVS, 49 . 70 awaits with a serious tune of all those options but some considerably more peaky than others.

And watch those carbs have the solenoid controlled airjets are blocked off though think some jap models had them, nz 21s may not have.

[el chupacabra]

I have a 17 tooth 10mm offset sprocket to put on it. I also have some 38mm air strikers there I just don’t have manifolds for them yet, I’m going to knock some together for the final thing.
It’s has a 4mm crank, v force 4 reeds, cool heads with 18mm domes, 130 transfer and 192 exhaust timing, a zeeltronic ecu and a banshee first gear with the rest rz350. So I’m aiming for something more like 75-80hp
I am just using the free mota software to design the pipes, not sure how good it is but I have done a few two stroke exhausts for other bikes.

[F5 Dave]

I just got some Chariot manifolds off Ebay, it was easier and they come with mikuni rubbers, think they do them for banshee as well (mine has CPU barrels which is CR250 reed). The kit rubber ones UPD or something both split.

Sounds like a fun project.

[el chupacabra]

In this case fun and expensive are interchangeable. I’ve seen the Mikuni oz website have manifold rubbers and all that kind of stuff so I might make my own so the carbs sit level.

The cylinders are a Chinese pair that were $200 new. I brought them to practice porting, although the cheetah cylinders look good but for $2000 to upgrade the ported Chinese will do for now.

[F5 Dave]

Athena are the other choice people seem to go for. My 496 Cheetah kit with PVs crank etc was circa $5k a decade ago. Pre kids of course. The Cheetah Cubs are cheaper option. There is the Serval which is similar but not so biased on drag racing which is what these quad guys in 'murcia seem obsessed with.

[el chupacabra]

What did you end up doing for your exhausts?
I think I’m in it about 4K including the bike . . . So far

[F5 Dave]

I had a forum mate in souf affrika hydraulic some headers and send pipes in kit form. Actually he did 2 headers, the 2nd set were made into the VJ21 RZ 421. Actually I think his engine was level so he must have made new rear mounts. . . . getting back to chassis for a small moment.

[el chupacabra]

Decided to go ahead and re-do the engine mounts after looking at how every other Banshee swap had the engine sitting pretty much level so i made up a frame jig during the week. It'll probably come in handy for a few of my other projects I've got coming up.


343433343434

[Frits Overmars]

Just stumbled across this Feet-First discourse.
http://www.oesten-creasey.eu/hightech/feetfirs.htm?fbclid=IwAR1DkuGhnAJqLjvx4HCpY-qH4XHBSLOBBcnYu9Xhhl_RpfNM3-qaqI1p2QI
Feeling fairly positive about FF-twowheelers myself, I agree with about 50% of the contents.
In other words: food for thought.

[F5 Dave]

As I lie here in bed in the approximate position propped up a bit I can't think of anything more unnatural than lining up a corner and deciding to roll into it. Can't move any weight and unlike luge tracks, race tracks are severely banked on every corner. Long wheelbase and you'd have to lean further to achieve the same effect, again with minimal weight redistribution.

[mr bucketracer]

Decided to go ahead and re-do the engine mounts after looking at how every other Banshee swap had the engine sitting pretty much level so i made up a frame jig during the week. It'll probably come in handy for a few of my other projects I've got coming up.


343433343434nice . Should go well . May need to steping the fork angle a bit

[Michael Moore]

Frits, there's more of Royce's (and other FF enthusiasts) writing and photos at

http://www.bikeweb.com/

Dave, NSU was planning to use the short (compared to the LSR bikes) Baumm road race FF on fast/open tracks and the conventional GP racers on tight stuff, in a "horses for courses" concept. But they pulled out of GP racing before doing more than testing.

http://www.eurospares.com/graphics/NSU/image-php-html_2.jpg

I think FFs have a lot to offer in certain cases. Rossi etc are probably not going to want them in the high-end road race case because that (to me) is so specialized it hardly qualifies as a regular motorcycle activity (much like watching Bau defy physics on a trials bike). For a public roads bike they have a lot to offer, and I suspect that if they help a rider to feel more confident (as has been reported by owners of Gurney Alligators and some of the few track FFs) they might actually help slow/low fear threshold racers like me go a bit faster in club racing. I was going to build a track FF to address some ergo issues I have (stiff neck that makes it hard to look around corners with clip-ons, hands that go numb from pressure) but I'm now a former racer so that project has lost a lot of what little momentum it had.

Some FF proponents are very much in "evangelist" mode and I think there are some claims made for them that seem unlikely to hold up. But on the other hand there seems to be a lot of riders of conventional HF bikes with very closed minds who won't consider anything that doesn't look like what everyone has been riding for the last century+. A Gurney owner told me he likes to park his bike at a gathering spot and hang around to listen to the (often uninformed) comments. When he finds a likely suspect who pontificates on "must be crap, can't work" he'll offer them the keys for a quick test ride. He said he never had anyone come back who hadn't changed their opinion.

cheers,
Michael

[el chupacabra]

What is the usual process for changing the steering head angle in this situation on an RGV?

[Frits Overmars]

What is the usual process for changing the steering head angle in this situation on an RGV?Heading for a brick wall might help...

[jato]

What is the usual process for changing the steering head angle in this situation on an RGV?

I'm not sure what others do but the last one i did i set up the chassis on a fairly large milling machine and machined away the old headstock leaving an accurate void at the new angle. you have to go 8 or so mm bigger diameter for the new headstock - depending on how much change of angle you are going for. being ali i'd be inclined to finish the last mm or so of the bearing seats after you've welded the new head stock in. if you don't have a pet machinist send me a pm if you like

[F5 Dave]

Lot of work and an RGV is probably fine for a track day bike as is.

[el chupacabra]

sounds like a lot of hassle. Probably almost as much hassle to make a steel tube chassis from scratch.

[TZ350]

I'm not sure what others do but the last one i did i set up the chassis on a fairly large milling machine and machined away the old headstock leaving an accurate void at the new angle.

I did something similar but just used a good hole cutter in a mill drill.

Left an old bearing in the new alloy housing so it would hold its shape when it was welded. Pretty crude but it worked.

343986343987343988343989

[Michael Moore]

Kosman Racing here in NorCal had a fixture that mounted on the table of a Bridgeport mill to hold frames (typically KZ1000) to have the steering heads cut out. They used a hole saw on a custom arbor. Since the hole saw was not deep enough to do the entire cut at once they'd stop now and then and trim out the sections that were free of the main frame. The new larger OD steering heads would be both reangled as well as moved over onto the center line (it sounds like there was often a bit off lateral offset from the factory).

My Cagiva Allazurra was easier to do. Since the swing arm was mounted off the engine I was able to remove the original motor mounts from the frame, reposition it with a steeper rake angle, and then make new (boxed sheet metal) motor mounts. I also removed some of the original bracing tubes and added new ones that did a better job of triangulating the structure, and moved the engine forward in the frame too:

http://www.eurospares.com/graphics/Ducati/cagiva650006a2.jpg

cheers,
Michael