Topic: Dry weights for cb750 based road racers

[simon#42]

you have got a lot of weight off the old girl then , dont agree with your idea of perfect weight distribution though , am working on a moto 2 frame at the moment and that will be
63% front 37% rear .

Dont I only want a little bias to the front? I always thought that 50/50 was ideal and that rider position could change that as needed. Given what it currently is, moving that much weight around on the bike is unlikely.

you would be able to lap much faster with a more forward weight bias but you would have to alter your riding to suit . i would not do it now as you are going well but but i know you like to plan for the future so keep it in mind .  you have used more modern ideas in your engine why not the chassis ?

[slikwilli420]

you have got a lot of weight off the old girl then , dont agree with your idea of perfect weight distribution though , am working on a moto 2 frame at the moment and that will be
63% front 37% rear .

Dont I only want a little bias to the front? I always thought that 50/50 was ideal and that rider position could change that as needed. Given what it currently is, moving that much weight around on the bike is unlikely.

you would be able to lap much faster with a more forward weight bias but you would have to alter your riding to suit . i would not do it now as you are going well but but i know you like to plan for the future so keep it in mind .  you have used more modern ideas in your engine why not the chassis ?

In what way? I'm all ears.

[simon#42]

well if you mean chassis wise you are going to have to get the weight further forward . moving the engine is the best way but you will need a new frame for that .
if you mean riding then you are going to have to learn to push the front , and push it hard . as the engine isnt making much power you can make big gains here
bear in mind though you will crash more often the nearer the limit you get

[slikwilli420]

Chassis changes are out in this class. If I bump then I can move things around in a custom frame. I could lengthen the swingarm but would lose the handling. It may be ideal for endurance racing, but mine are 6-8 lap sprints, so corner handling is more important. Rider position aside, save for moving the oil tank to the front of the engine a la Bimota, I dont see how I could shift much weight around without frame alterations that would be outside of class rules.

[simon#42]

you dont want to lengthen the swinging the bike is already to long  , moving the oil tank is a good idea its a pity you are not allowed a proper fairing you could make a tank to fit in the nose .
most people put longer rear shocks on which does work but it causes more problems than it solves

[slikwilli420]

No room to make it shorter either. Fairing is a no go, unless I bump a class. There isnt much motivation to do so either since there are only a few Formula 750 guys but grids of Sportsman regularly top 10 guys. Lets continue this in my thread. Sorry for the departure regarding weight.

[scottly]

So I ask Willi and Scott... how much do you figure the street legal and charging parts accounts for.
 
 I am guessing 20 to 30ish lbs..

The charging system, including the field, stator, and rotor, plus the starting system, including the motor, gears, clutch and solenoid, plus the muffler, headlight, mirrors, grab-bar, fairing, kick starter and kick-stand add up to about 33 pounds.

[754]

So that is what I was thinking  subtract from yours, and add to his.
 And you should be quite close.
 I think Scott has around 10 lb advantage frame wise.

[slikwilli420]

A lot more than just removing this components got me to where I am now. Every part I replaced is lighter than stock and that's nearly everything.

[scottly]

How much does your oil tank weigh? How much for the hoses from the tank to the engine?
Your wheels might be your biggest single advantage? My Morris front, with no tire or brakes is about 13.5 pounds, and the rear with no tire, but including the sprocket and brake rotor, is 20 pounds.

[slikwilli420]

Oil tank plus longer lines and cooler is probably similar to suck tank and lines but I never did weigh them. The rear is 17.6lb which includes caliper and master cylinder. I can't find the note on the front but lighter than my old wheel with aluminum hoop.