Building a race bike

"Somebody else is running a single chain on this engine, from memory a race bike."
That?d be me Andy. I am still waiting for the next time I need to open the motor. Bloody twins just keep on keeping on, I must have touched wood good and proper. Next time the lid comes off the single row goes in. The same goes for the roadbike.
Piet, how did this motor you know of do the tensioning bit? I had thought of just using one side of the crank and corresponding side of cam sprockets with it working on one side of the (SFC type needle roller) camchain tensioner, does that sound ok?
Cheers Lee
 
andychain said:
Somebody else is running a single chain on this engine, from memory a race bike.

Dont forget to put the "big pin" singles in.

Good luck

Andy
Click to expand...

You will be supplying the chains Andy so it'll be your fault  :D :D :D

I will use a manual chain adjuster without a spring etc. I don't want things jumping around when using some silly RPM.

J
 
Yep, the 73 works machines had a single row cam chain. One is running again.
Didn't Andy Wagner propose the conversion?
Paul

PS: lovely looking Julian.
 
Tippie said:
"Somebody else is running a single chain on this engine, from memory a race bike."
That?d be me Andy. I am still waiting for the next time I need to open the motor. Bloody twins just keep on keeping on, I must have touched wood good and proper. Next time the lid comes off the single row goes in. The same goes for the roadbike.
Piet, how did this motor you know of do the tensioning bit? I had thought of just using one side of the crank and corresponding side of cam sprockets with it working on one side of the (SFC type needle roller) camchain tensioner, does that sound ok?
Cheers Lee
Click to expand...

Exactly. :D  Been working fine for years.

Julian, the tensioner is actually fixed, no spring in action once the tensioner is buttoned up.  The spring is only to feed the tensioner roller to the chain.  A bit of "springing" through the rubber bumper though.

Paul, a second one will be running again soon! :D

piet
 
Love reading about the tricked up Laverdas being put onto the tracks of the world. Fun project, Julian. Sounds like you'll be building a crank from scratch? Don't suppose the inner crank webs of a 500-based Lav crank would offer the stroke you're after ... or whether it's adaptable to SF cases? Some rad headwork on the way too! Keep up the postings!

As for drum brakes, IMHO you're sacrificing a load of potential for aesthetics; the rules allow discs and they are a proven quantity. I raced on a TZ 350 4LS set up by guys in W Australia who really knew their stuff in drum brakes on racetracks. It was fantastic on one track (Wanneroo) but faded very badly on a street circuit that demanded too much of it. I'd never build a dedicated race bike with a front drum.

Steve B's Breganzane 917 looks absolutely 'classic', has discs (and a square profile swingarm  ;)) ... and goes like the proverbial.
 
Hi,

Obviously discs are better than drums, no one disputes that, however this bike is going to be made as light as is physically possible, going to work really hard here.
It will also be used at tracks where we think it will work best (after testing of course) and the rider is a really top guy,  just won the best newcomer at the TT so really knows his stuff.  (unlike me who would crash at the first corner)  I just feel that a classic bike should have a drum!  Most of my collection are drummers for that reason and the only ones with discs are there because they were always childhood (or teenhood) dreams of mine to own.  I think I will get it to stop OK,  may not be the king on the brakes but it should be ok.  Will see if we can add / remove some bits to help cooling.

It's got to be a drummer I'm afraid  :D

Will try to do some pics soon although not much is happening as I'm a bit busy with work.

Julian
 
Shit pic but here is a pic of the first mockup from Sunday,

Regards,
Julian
 

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Bloody ripper, Julian! Gonna be one hell of a spesh there. From the pics I'm guessing you've gone from the std 28 deg rake down to about 24! Should lighten up the steering a tad ;-) And a loong swingarm!
 
Hi
Thanks guys
The rake will be around 26/7 degrees but easy to play around a degree or so with ride heights etc.
The drum is a TZ Yamaha unit but will be modified before finished.  Tyre on the front is too big at the moment 110/90 but will be a 100 shortly.  Race tyres of course.  Avondale just for the build.

Looking forward to getting stuck into the build again.
J
 
interesting to note from the frame builders progress pictures on their website that the first part that is added to the top tube is the headstock, because at Mr Eglis Swiss workshop, when I was there a few years ago, all frames were 99% complete before even the top tube was cut to suit the headstock, and this was definitely the last component installed and welded not the first. I did ask the question as to why it was always  last? and was told that once all other pipework and fixings were in place, the most critical part can be added without any fear of distortion or movement of the whole, so is always the procedure used.

Fritz's son Ensio, I think, did like my first attempt ever at TIG welding , and was very complementary saying that I could easily get a job there and would be "up to speed" with TIG in hours not days.
However, since then my son has become very proficient at it, so I have hardly done any since, I just wait for him to get the TIG kit out and pass him the job I am waiting to get welded, Me? I will stick with the Oxy/Acet and rutile or cellulosic stick for now. He had some 40mm plates to weld onto 20mm thick box section (sign legs) and the tool for that was my Lister driven DC (or AC) welder made in 1954, bloody noisy, hand cranked and started first swing after about 4 years of non use, 350 amps sir?, 5mm rods? my pleasure, wont even make me sweat.
CLEM
 
Hi Clem,
In my working life I have learn that it's the end result that counts not how you get there.  Good is good and bad is bad.  What works for one is not necessarily what works for another, specially with different materials and welding techniques.  I certainly can't see any advantage in starting away from the headstock, if someone can't fabricate and weld a fairly simple bike frame without it warping then they perhaps shouldn't be making a frame. 
I must say that the work done by JLM on my frame is really top notch and you will notice quite a few changes to Egli"s basic design. (Mostly asked for by me)
We are not trying to make an Egli but just using the basic design to stay inside the classic racing rules. 
Interesting comments though Clem and always good to hear people's ideas and reasoning.

Thanks
Julian
 
Extruded tubing is always going to move when welded, the trick is to find a welding sequence which minimises it...
When I was doing the Aermacchi replica frames, I always attatched the steering head tube to the spine as the first weld.
The last weld was finishing the attatchment of the rear subframe to the spine. Part way up a fairly long tube so it was always going to cause some distortion. Once that weld was done, it was check for alignment and if necessary heat quietly and let the tube cooling pull it back into alignment.
 
Latest pic of the bike in general "start build from here" setup.

23 degree head angle
Raked back on fork yokes -1 degree giving me 94mm of trail which i'm very happy with,  This will hopefully give me a sharp steering bike while still keeping it reasonable stable at high speed.  (we will see)
Wheel base is about 1450mm depending on chain tension of course.

Tyres are Avon 110/80 front and 130/70 rear for setup etc,  Obviously race rubber will go on later but the same size etc.  Looks and sits much better now than with the other profile tyres.

Tank outer shell is on it's way to me for making the mockup of the inner before sending back for finishing.
Realy looking forward to getting to grips with the build.

Engine will come apart shortly for more measuring and chopping bits off.  It's really going to be as light as possible.
Will have a set of SFC spec Carillo rods for sale eventually as I am having a new set of Ti rods made, these need to be quite a bit longer as it will have only a 63mm stroke.

Hope you like the pic.




 
agree entirely Julian, I can see the some of the changes from Egli spec including the swing arm mount and top engine mount, interestingly though that top mount is very similar to my own "Egli" which was instigated by G Binnion when he roughed out the frame (the first he built after rescinding the license from Egli)

CLEM
 
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