How light can an XS be?

[mouser]

Well I finally have a rolling chassis! At this point I can pick the whole thing up alone. I am a lil old guy and weight 128 lbs. I will be able to touch the ground!! woo hoo. and I won't have to get off to back up! I think it will likely weigh what a stock 650 weighs...with me on it!!!

61 spins around the sun so far and I still don't know what I want to be when I grow up!

 

[scabber]

Nice bike lean and mean. Like the seat and rear frame brace what is it off of ? Thanks for showing

 

[mouser]

Nice bike lean and mean. Like the seat and rear frame brace what is it off of ? Thanks for showing

Thnx! I made the seat pan and used the foam and cover from a recycled Harley softail seat and the brace behind it is the stock rear fender brace widened to fit, and welded into place.
I posted a few pics in this thread of how I made the seat. post #15
http://www.xs650.com/forum/showthread.php?t=14586

 

[jay760]

I bought a Rickman copy frame a while ago to fit an xs engine into, you can pick it up with two fingers, also has a light weight Dresda copy swing arm

 

[Nickyd]

Hey I'm trying to reduce some weight as well. Are there any front ends that bolt on with no modification? If so which ones? I like the idea of the RD400 front end. With a smaller front end will the weight of the bike on the smaller front end be a problem?

Thank you!

 

[Capt_Zoom]

My wife's bratty bobber weighs in at 365lbs wet. Stripped down everything we could and used one of those shorai lipo batteries along with alum rear fender, new seat rails, new electrics, new tree and new front brake.

 

[jdizon]

That's a badass frame! I'd love one of those for a cafe bike. Any ideas where I can find one?

I bought a Rickman copy frame a while ago to fit an xs engine into, you can pick it up with two fingers, also has a light weight Dresda copy swing arm

 

[DaveO]

Previous thread on Rickman / Metisse Frames http://www.xs650.com/forum/showthread.php?t=2546

Pricey though.

Dave

 

[jdizon]

Previous thread on Rickman / Metisse Frames http://www.xs650.com/forum/showthread.php?t=2546

Pricey though.

Dave

Thanks for the info!

 

[DaveO]

Thanks for the info!

No problem.

Dave

 

[Tim of DO THE TON]

I've been meaning to weigh mine for years. Maybe I'll go buy 2 used bathroom scales and see what's what.

I've cut out a lot of the 1972 frame and removed the center stand/brackets
No starter motor
Most electronics gone - starter solenoid deleted, running solid state regulator/rectifier
Pamco 277 ignition
Tiny Shorai battery
Aluminum tank (which I never run more than 1/2 or so full)
Minimal fiberglass seat
Tomaselli aluminum clipons
Deleted the fenders and chainguard
520 chain
Alloy bodied RAM rear shocks

But the 750cc cylinders and Suzuki 4LS front hub probably made up for some of that

 

[jdizon]

Now that is a sexy cafe! love it man

 

[Capt_Zoom]

Here's what my wife's looks like at 365lbs. Cut a ton of weight off the frame. Kinda funny but at this weight and my wife as the rider this little 650 has roughly the same power to weight ratio as my 1900cc Raider with my 200lbs on it.

 

[arcticXS]

Hey I'm trying to reduce some weight as well. Are there any front ends that bolt on with no modification? If so which ones? I like the idea of the RD400 front end. With a smaller front end will the weight of the bike on the smaller front end be a problem?

Thank you!

Richard Pollock of Mule Motorcycles has some good tips on his website, just look around there. As far as I remember, he stated that the FZR600 (or was it FZ600) fork was the lightest he had come across as a reasonably cheap option. I beleive this had 38 mm tubes, so will require different or modified triple trees also. He may also have mentioned using bored out TT 500 triples with this fork on an XS

 

[arcticXS]

Here's what my wife's looks like at 365lbs. Cut a ton of weight off the frame. Kinda funny but at this weight and my wife as the rider this little 650 has roughly the same power to weight ratio as my 1900cc Raider with my 200lbs on it.

I guess you can easily lose 1.5 to 2 kgs. more on your wifes bike by fitting lighter brake discs front and rear, while getting better brakes at the same time. The rear disc should not need to be bigger than maybe 220 mm in diameter and 4 or 5 mm thick, the front 280 to 320 mm, also 4 or 5 mm thick. I got a custom made ISR front disc for my XS, at 320 mm diameter it weighs approx. 1600 g.

 

[gggGary]

I weighed a stock bare frame at 49 pounds.
I have a Cromoly racing frame (- a few engine mounts yet) weighs in at 17 pounds.
Unfortunately it's on project "backburner"

 

[peanut]

this bike has got to be pretty light and I think she built it herself too !

 

[oldbiker]

hi guys,, a few years ago i meet a guy in ringwood that raced a xs650 yamaha,,,,and he used to do very well ,,, he even went out and purchased a chrome moloy xs650 frame to use on his xs650 race bike ,,,,the worst thing was he experienced cracking in the frame ,,, but it didn,t stop him he ended up getting a fully ticketed welder to go over the complete frame ,,, and thats the last time i saw him regards oldbiker

 

[Capt_Zoom]

I guess you can easily lose 1.5 to 2 kgs. more on your wifes bike by fitting lighter brake discs front and rear, while getting better brakes at the same time. The rear disc should not need to be bigger than maybe 220 mm in diameter and 4 or 5 mm thick, the front 280 to 320 mm, also 4 or 5 mm thick. I got a custom made ISR front disc for my XS, at 320 mm diameter it weighs approx. 1600 g.

Yeah I wanted to convert the rear like I did the four piston front (from a yamaha raider) but the money tree was getting thin. I think I could save some more weight on the rear frame as well. Those up-tubes could be replaced with regular tubing. I could have also saved maybe a pound or three by not having signals, stock horn or a security device on the bike. Maybe some more if I went PMA with no starter.

On my next build I'm thinking of getting a custom brat frame made....possibly out of Aluminum rather than steel.

 

[TwoManyXS1Bs]

Capt_Zoom's comment about power/weight ratio reminded me of an old formula published 30 years ago.

For you 1/4 mile dragheads, these were supposed to give you an idea of expected trap speed/time:

ET = 5.825 * cube_root_of( Weight / HP)

MPH = 234 * cube_root_of( HP / Weight )

On a lightweight bike, going on a diet is cheaper than modding the engine...