Building a race bike

Modern bushed forks. Beautiful stuff he makes and for actually very reasonable prices! Pair of 38s on your triple, Vince - would save you endless searching for the best of what can be had from a std Marzo  :-* :-*

I wonder if his Yamaha replica 4LS brakes are sturdier than the original - I went through two, and the cast drum liners separated on both. Spokes pulling the alloy away from the iron part ... heat no doubt  helping hasten the separation.
 
Agree about the prices,  this is one of the reasons for going this route,  If I remove the resale value (I don't intend to sell though) of the original 38mm Cerianis then the GPs are mega cheap!!  Adjustable for bump and rebound  Mmmmm Lovely.

Will see how the Yam brake manages,  I am really trying hard to get the bike to be as light as possible to help the brakes as much as anything else.  If the linings come loose, Ill make new ones and screw them in.  We make drums regularly and usually have no trouble,  We will see, but they do look good  8)

Can't wait to unwrap them,

Doing the foot-peg mounts last Saturday,  it seems like a comfortable position (for a race bike) 
Left or right hand change, this is the Q now?

Regards and all keep well,
Jules
 
It is coming along well Julian, fits and starts but progressing. A huge job, admirable.
"Left or right hand change, this is the Q now?", best to ask the bloke or lady who will get to race it. RH is most direct.
 
Vince said:
I had a look through that fork site and it looked like the only 38mm forks were for disc brakes. Do they come with bushes, that would be interesting? Chris is that pic Julians bike, looks like tubeless type spoked rims?
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Don't think so, reckon Julian just added some lightness! :D

piet
 
You right, on close look the spokes are in the standard position. Speed holes in the rim flanges, never seen that before. Looks pretty sexy. I thought they were outer style spokes, there are rims that do this for tubeless use. Apparently, despite plenty that think it, spoked wheels are usually heavier than cast, especially lightweight cast race wheels. Maybe this adress it, I wonder how much weight it saves compared to std. I once saw a prototype Dymag wheel they made with a carbon fibre rim, that was before Dymag went broke and then came back from the dead. Don't think they made any more.
 
My Yamaha 4LS front wheel was very light. Never weighed it but very light and immediately noticeable.

You want fancy wheels? Check these out - and the weights! Wonder how sturdy they'd be on a touring bike! Only come in massive 6 inch rears.

https://www.motomillion.com/products/bst-carbon-fiber-wheel-set-for-yamaha-r1-r1s-r1m-fz10?variant=44696789134

They have loads of different ones. Some are even lighter I think.
 
Jury is still out for me on carbon wheels.

fc08kfojivmy.jpg


 
chrisk said:
Jury is still out for me on carbon wheels.
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Gotta hand it to them... they got the periperal weight right down! :)

Back to spokies, Jerry Kooistra - who made those indecently fast pre-72 Honda twins ridden by Levi Day and others - told me he made an elaborate jig to hold the rims so he could machine them down in strategic locations.  And I think that was when starting with Excel Takasago rims which are already very light.  Those bikes were rapid, and reliable too, they won almost every time out.
 
Vince said:
You right, on close look the spokes are in the standard position. Speed holes in the rim flanges, never seen that before. Looks pretty sexy. I thought they were outer style spokes, there are rims that do this for tubeless use. Apparently, despite plenty that think it, spoked wheels are usually heavier than cast, especially lightweight cast race wheels. Maybe this adress it, I wonder how much weight it saves compared to std. I once saw a prototype Dymag wheel they made with a carbon fibre rim, that was before Dymag went broke and then came back from the dead. Don't think they made any more.
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Every little bit counts, Vince.  Especially placed so far out on the diametre of the wheel, reduces gyroscopic effects and lets the bike be flicked around easier.  Not like that bike will end up very heavy anyway...

piet
 
Yes I remember seeing an example on The Don Lane TV show decades ago. They had a Science thing where they demonstrated the effects of a wheel spinning at speed on an axel. Some crazy unexpected Physics effects were demonstrated.
 
The first time I remember this happening was at Kyalami in South Africa to Freddie Spencer. If the Honda GP team has failiers what does that tell you?
 
Vince said:
The first time I remember this happening was at Kyalami in South Africa to Freddie Spencer. If the Honda GP team has failiers what does that tell you?
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Those were the then-new Comstar wheels.  The race items were quite a bit different to what was shown on the showroom floor, but they broke nevertheless.

Yeah, even HRC has their bad days...

piet
 
carbon can brake. Remember watching the John Britten Story where his testrider tried to keep the bike on the backwheel only as he recognized that the front-fork was broken... He had to drop the bike as he wasn't able to ride around the course with a broken fork...
 
Laverdalothar said:
carbon can brake. Remember watching the John Britten Story where his testrider tried to keep the bike on the backwheel only as he recognized that the front-fork was broken... He had to drop the bike as he wasn't able to ride around the course with a broken fork...
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You can see on some Pics how tiny and small that pice was....
 
Looks like the aftermath of a stack to me. Could be wrong. But ... carbon today is not what carbon used to be. The technology of weave and use of special fibres (my bicycle forks and rear end had titanium wires woven through it!). The stuff on that carbon wheel website seems to have been made in Germany, where very rigorous testing has been done - no way they could sell something as integral to safety as wheels without knowing they wouldn't have their arses sued due to failures. F1 cars are full of the stuff.

There must be several billion carbon framed bicycles frames on the roads these days, most made in Taiwan (the best at it - manufacturing for all the big names, including the Italians) for massive companies - who don't want to be bankrupted by lawsuits ... so if done right, carbon is fine. Would I use wheels like that on my SFQ? Maybe ... but would look bizarre anyway ... and I could never afford them!

Biggest prob is, when carbon fails, it fails catastrophically ... no warning and whammo! If it's been in a collision or suffered a severe impact it has to either be X-rayed or tossed.
 
Piranha Brother 2 said:
Biggest prob is, when carbon fails, it fails catastrophically ... no warning and whammo!
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There was a guy in my yacht club who busted a carbon fibre spinnaker pole on his 52' yacht. It didn't just snap in half, it exploded into a million bits. It cost him over $4,000 to replace it. That was about 10 years ago. Dunno whether it's got cheaper or more expensive since then.

Boba's carbon fibre fuel tanks have a layer of Kevlar in them so they won't disintegrate in a crash. The carbon might break but the Kevlar will hold the tank together, and hopefully keep the fuel inside.
 
The carbon tanks I made I used 2 layers of carbon, then a layer of pure kevlar cloth and then another layer of carbon. I found carbon to be brittle when impregnated with resin. It'll just snap but add a layer of kevlar it'll still snap but the kevlar will hold it together. Pretty sure Boba uses a carbon/kevlar cloth to reinforce his tanks, carbon weave one way kevlar the other.
He does beautiful work and was a big help with advice when I was thinking about making my tanks. Working with kevlar is a pain. It'll fuck anything you try and cut it with.
 
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