Topic: What is everyone stripping off to save weight?

[scottly]

There are tons of things that can be done to make these better and the detractors have no place here.

10+
As far as retaining a "stock" look, my bike is far removed from the way it left Japan, but only last Monday a fellow driving past my shop spotted my bike out in front, fresh from a test of the new front brake, and commented "Nice bike! Honda 750?".

[slikwilli420]

Slikwilli, I think that you’ll find that everyone diving down the rabbit hole of weight reduction will need to decide for themselves where their limits are.  And not just in time and money, but also aesthetics.

If you are thinking of maximum weight reduction only, the temptation is to install very modern components where possible.  Such as Supermotard type rear spoked wheels or super light modern cast, spun, or forged wheels(carbon anyone?).  Modern front ends, etc.  Many here embrace the modern on classic look. 

Then there are those like what Patrick Bodden did when building his cb750 based formula 750 racer.  He was determined to use period OEM Honda parts, combining all manor of Honda only/70s only parts along with some clearly hand made parts(as could have been made 40 years ago), to build his racer. 

You are racing a bike under a specific set of rules for AHRMA Sportsman 750 class, so your options are more narrowed down.  And you have more significant need for high performance parts that can stand up to the rigors of road racing.

But even within the racing rules, you can skew toward one direction or the other.  More “period correct” vintage in appearance or more modern looking in the details.

Just something to consider.

I'm with you George. While I didn't go so far as to use the heavy OEM Honda components I have kept the very vast majority of my bike period as a personal goal and as part of the rules which are about the spirit of the period. Save a few parts you could build my bike from catalogs available in the early 70s. I have started dabbling in titanium fasteners because they are both light and high performance. I plan to have one of the very lightest 750 bikes known and am getting to a great spot with more fat to trim. With recent changes I am under 390 with 4 gallons of fuel. That's 365 dry.

[scottly]

With recent changes I am under 390 with 4 gallons of fuel. That's 365 dry.

Well done, sir!!!!

[754]

I figure 1 or 2 gallons of fuel is fair for stating wet weight..

[slikwilli420]

I should probably use whatever I need for a race. That's a practical amount for my purpose. Realistically it's about 2-2.5 gallons.

[TwoTired]

Where are the races for these bikes?

[slikwilli420]

AHRMA is across the country with races in Michigan, Wisconsin, New Jersey, Georgia, North Carolina, Oklahoma, California and Utah.

[Yamahawk]

AHRMA is across the country with races in Michigan, Wisconsin, New Jersey, Georgia, North Carolina, Oklahoma, California and Utah.

I hope AHRMA will consider Nelson Ledges Race Course as a possible venue for racing. They just did a full repaving last June, and the track is phenomenal... 2 miles and 13 turns. It is easily one of the fastest, if not THE fastest course in the country. Its is also the track where Nicky Hayden got his start in road racing!
The new owners have a plan to start bringing back the endurance racing next year, and there are plans for improving the facilities as well. Nelson used to be the hot spot for this back in the 70's and 80's. They are planning a 250 class also, they are a blast out on the track, and can pass the larger bike s in the turns!

Slikwilli, I think that you’ll find that everyone diving down the rabbit hole of weight reduction will need to decide for themselves where their limits are.  And not just in time and money, but also aesthetics.

If you are thinking of maximum weight reduction only, the temptation is to install very modern components where possible.  Such as Supermotard type rear spoked wheels or super light modern cast, spun, or forged wheels(carbon anyone?).  Modern front ends, etc.  Many here embrace the modern on classic look. 

Then there are those like what Patrick Bodden did when building his cb750 based formula 750 racer.  He was determined to use period OEM Honda parts, combining all manor of Honda only/70s only parts along with some clearly hand made parts(as could have been made 40 years ago), to build his racer. 

You are racing a bike under a specific set of rules for AHRMA Sportsman 750 class, so your options are more narrowed down.  And you have more significant need for high performance parts that can stand up to the rigors of road racing.

But even within the racing rules, you can skew toward one direction or the other.  More “period correct” vintage in appearance or more modern looking in the details.

Just something to consider.

George, great article on the CB750! And, I agree with what you are saying here. I am a racer, and weight is very important. But for the street not everyone is concerned with it at the bottom line. I prefer a good looking bike with period looks, myself.
Charlie

[gschuld]

Slikwilli,

365lbs dry for a proper cb750 racer is fantastic.  You should be proud.  Sounds like you are starting to get into diminishing returns regarding the weight lost to time/money spent ratio. 

The major items obviously give you the best bang for the buck(time/money spent per weight lost). Wheels, brakes, exhaust, frame bits, engine weight reduction(starter, alternator, battery, crank, etc), neutered wiring, lighter seat and fuel tank, etc.

Once you start getting down to titanium bolts level (defcon 4 , you are now generally  going after ounces each rather than pounds.  That’s serious dedication, and I applaud you.  That’s about two full levels beyond my interest level, but I have different goals and priorities.

Please keep updating your thread, I enjoy experiencing your efforts from a safe distance(can’t afford to have any of that rub off on me)

George

[slikwilli420]

Slikwilli,

365lbs dry for a proper cb750 racer is fantastic.  You should be proud.  Sounds like you are starting to get into diminishing returns regarding the weight lost to time/money spent ratio. 

The major items obviously give you the best bang for the buck(time/money spent per weight lost). Wheels, brakes, exhaust, frame bits, engine weight reduction(starter, alternator, battery, crank, etc), neutered wiring, lighter seat and fuel tank, etc.

Once you start getting down to titanium bolts level (defcon 4 , you are now generally  going after ounces each rather than pounds.  That’s serious dedication, and I applaud you.  That’s about two full levels beyond my interest level, but I have different goals and priorities.

Please keep updating your thread, I enjoy experiencing your efforts from a safe distance(can’t afford to have any of that rub off on me)

George

Thanks for that George. Even at that weight, I have not done my wheels yet, and am still on a stock internals engine with stock cases. Still a lot of fat to trim yet. I look at everything on the bike and want to make it a little better and lighter, but never sacrifice safety or performance. I think there is still 20 pounds to be had. Time will tell.

[754]

Where are the races for these bikes?

Used to be at many traffic  lights and the dragstrip for me..

[gschuld]

Slikwilli,

365lbs dry for a proper cb750 racer is fantastic.  You should be proud.  Sounds like you are starting to get into diminishing returns regarding the weight lost to time/money spent ratio. 

The major items obviously give you the best bang for the buck(time/money spent per weight lost). Wheels, brakes, exhaust, frame bits, engine weight reduction(starter, alternator, battery, crank, etc), neutered wiring, lighter seat and fuel tank, etc.

Once you start getting down to titanium bolts level (defcon 4 , you are now generally  going after ounces each rather than pounds.  That’s serious dedication, and I applaud you.  That’s about two full levels beyond my interest level, but I have different goals and priorities.

Please keep updating your thread, I enjoy experiencing your efforts from a safe distance(can’t afford to have any of that rub off on me)

George

Thanks for that George. Even at that weight, I have not done my wheels yet, and am still on a stock internals engine with stock cases. Still a lot of fat to trim yet. I look at everything on the bike and want to make it a little better and lighter, but never sacrifice safety or performance. I think there is still 20 pounds to be had. Time will tell.

Well, your rear wheel is certainly a worthwhile target.  It looks like you are currently running a factory cb750 drum hub laced to an alloy rim with SS spokes.  The cb750 drum rear is quite heavy, though about the same weight as the FACTORY rear disc wheel/brake combo.  If I remember correctly, a complete rear drum hub wheel laced to an Akront 3.5x18 rim with Buchanan spokes and with aBT45 130/18 tire with tube is in the mid 40s.  (I can check when I get home). I’ve got a spare front/rear set on the shelf.

You could lose several pounds by just swapping in a cb500/550 drum hub assembly.  But ideal would be a lightweight non Cush drive hub with a heavily lightened or modern disc.  With a lightweight caliper and bracket setup, it’s possible to reduce over 10 lbs on the wheel/brake package back there, using Sportsman class compliant parts.  Several more pounds if you are able to adapt much more modern hub designs like the supermotard hubbed spoke wheels.  JohnN went from racing with a factory drum rear to a modern hub disc rear wheel and was very happy he did.  Not sure what your class will really tolerate when it comes to modern stuff(AHRMA rules tend to be rather vague and subjective at times)

With some serious dedication and killing machine time, one can get a measurable amount of rotating mass off the factory brake rotors as well.  Brent Waller’s efforts are a good example.

You can drop another 4 lbs with a lightened crank, 10 plus from the rear wheel/brake combo.  A little more here and there and sure another 20 lbs seems well within reach.

George

[slikwilli420]

The plan for wheels is a Barnes style hub up front with a custom carrier on my lightened cast iron rotor.

The rear is where the magic happens. I will be using a quick change Barnes style hub, with custom adapters for both sprocket and rotor. Braking at the rear will be a Brembo P32 caliper and 11mm master cylinder, a 9.5" Ducati Monster rotor, and all the associated attachments for said braking made as light as possible. I will stick with rain gutter rims both back and front and upgrade the stock spokes to SS units from Buchannan. I think 10lbs is well within reach, having already lost a pound up front by making new damping rods and shaving the caliper lugs off the unused side.

[cb_n00b]

I'm knocking off my center stand this weekend. That thing is just dead weight on my bike.

I have a MotoGP Werks pipe on my bike, which doesn't allow the center stand to sweep down anyway, so off it goes! I have lifts I can use at the local community garage so I don't need it for maintenance anyway...

[BobR]

Slikwilli, I think that you’ll find that everyone diving down the rabbit hole of weight reduction will need to decide for themselves where their limits are.  And not just in time and money, but also aesthetics.

  Indeed! My weight reduction was really aesthetics/ practicality for me -at least at first. That said I like the idea of reducing its weight - within my vision of what I want the bike to look like. For instance a lighter battery or lightened rotor would be great but too stripped isnt for me. Bob

[pjlogue]

The ex.   

-P.

[BobR]

 A instance of aesthetic weight reduction done today. Shaved 2lb 11oz off the bike while getting the look I want. Removed the grab handle and cut down the fender. Going to replace the light with one that is probably lighter too. Bob

[Gene]

I'm a stocker guy but now am thinking about going lighter weight since we bought an '80s bike for my wife. Marking this thread for that reason. Might be time to rethink - I really like that light bike with aluminum wheels etc.

[przjohn]

I am going to try and loose 20 lbs from all my bikes, by loosing it the hard, but cheap way, diet and exercise this Winter. Coming off a broken ankle injury on my KTM 990ADV in August and just back at the gym so hopes are high. I know the thread is about what how to lighten the ride but, as any off-roader knows, it ain't just the bike that's at work here.

[Gene]

I am going to try and loose 20 lbs from all my bikes, by loosing it the hard, but cheap way, diet and exercise this Winter. Coming off a broken ankle injury on my KTM 990ADV in August and just back at the gym so hopes are high. I know the thread is about what how to lighten the ride but, as any off-roader knows, it ain't just the bike that's at work here.

THIS is always the first, best way to take weight off the bike Doing the same thing.

[754]

First thing us usually pipes, the 4 into 4 are heavy.

[Powderman]

I'd be surprised if the chrome steel headlight bucket didn't weigh less than a thicker walled plastic one.

[Gene]

I'd be surprised if the chrome steel headlight bucket didn't weigh less than a thicker walled plastic one.

Interesting - but I would think the density of steel would still outweigh the plastic. Who's got a scale and test subjects?

[seanbarney41]

The stock plastic bucket is full of metal parts.  I could easily weigh up a Kawi chromed steel bucket vs. a CB750 plastic...have not noticed any big difference while working on my various bikes.

[Gene]

The stock plastic bucket is full of metal parts.  I could easily weigh up a Kawi chromed steel bucket vs. a CB750 plastic...have not noticed any big difference while working on my various bikes.

Right? It's gotta be within a couple ounces.

*can't believe I'm actually thinking of taking off my center stand*