"Ruby" - 1980 SR250 bobber.

One of two projects im working on at the moment here in Australia.

"Ruby" is a 1980 yahama SR250 single



She was offered from a friend, who was unable to finish her due to uni commitments, so rather than leave her to live a slow life in the corner of a garage, I parted with a fist full of notes and stepped in to finish the build, I was quite impressed by the quality of workmanship already done, but there's a whole lot more to go...

In all honesty I didn't like the way she was going, so I decide to restyle, opting for a classic tank and sprung seat setup, with a low down riding position, to smooth out the harsh lines, and present a homage to vintage chopper styling.



For the next update, Ill start going into tank modification to overcome the factory backbone design.

aside from Ruby im also working on another project bike, a 1985 suzuki GSX250 called Daniella, which will be styled as a café racer.
check the link in my signature.

wow looking good...I want to hard tail my sr250 after seeing this one....

thanks, but an XS would be a nicer candidate than an SR to make a bobber.

itd probably be the same amount of work for frame modding, but tank mounting would be much easier...

the SR frame has a backbone that divides into 2, as you can see in this picture.



this makes it much wider and more difficult to fit a tank...

most off the shelf chopper style tanks only come with a small tunnel, so some cutting and welding will be required.

Ive started to mod the tank, to try and get it to sit right, so far ive cut a bit out of the rear section, I still need to hammer the gaps shut.



but because the bungs for the petcocks are down the end, its making it difficult to remove enough material to make the tank sit right down on the backbone.



you can still see the rear needs to come down probably another inch. I could probably get away with it as it is, and mount the seat hing away from the frame a little to keep the lines flowing, but Id much prefer it lower.

I'm going to cut some more out, and I'm even considering moving the bungs to new position, maybe 1/4 of the way along the tank, but patching the holes would be a pain in the ass.

As for mounting, I plan on having a 1/8" neoprene rubber strip between the tank and the frame, but even now the gap is too small fit that thickness, due to the factory gusset having a pressed lip on the edge of it.. I'll try beating the tunnel of the tank out a bit with a hammer.. as I don't really want to mess with the factory gusset, the lip is obviously there for strength.

XS would be a better hard tail gotta start somewhere tho....probably gonna leave my frame mostly stock it just looks weird with the springs on top of each other (seat springs and suspension)... Is the Tank your using a copy of a 60's wassel tank? Looks like the one i have only not rust....I was having the same problem fitting the tank so i switched it for a much uglier suzuki dirt bike tank ( not the way to go) but i won't have to mod the frame or the tank, or buy a pet cock & gas cap....(trying to use up all these extra parts kicking around)....Anyways looking good so far tank mods should be a bit easier than frame mods

Yeah its just a generic wassell style tank, bought it on ebay, I was hoping it would be a lot closer to fitting but the seller had the incorrect measurments listed.

I bought a new one so it would be somewhat safer to cut and weld, but I still purge it when cutting and welding.

im thinking of maybe just cutting out the whole tunnel and making a new one with a larger width, it might be the easiest way.

Looks greats, just wondering how you plan to get this rego's for aus roads?

The hard tail was actually done by a bike fabricator/builder, who registers bikes, (and is also a friend of a friend) so when its running i'm going to take it in and just have a walk through of what needs to be done to make it pass. I'm assuming it will be no hassles for him to certify his own work.
I'm making sure i'm following ADRs for fenders / lights / mirrors etc, using all E marked items and since the wheel base has not been lengthened or rake angle changed, I'm not expecting too much of a headache.

This is wicked. Small metric bikes going hard tail is always good. Motivation for me to get my cb360 hardtailed

any way you could let me know what spark plug size u have?...mine is missing one...I could also use a picture of the clutch return spring ....also missing....Thx

spark plug is BP7ES

pic of the clutch return spring

where abouts are you located mate?

have you got yourself onto caferaceraustralia.com? and heard of sydney cafe racers?

thanks man huge help!

This thing is awsome...

Nice work

Thanks for all the kind words / comments, I appreciate it.



So I wasnt real happy with how I was modifying the tank. So I decided to take a different approach and replace the tunnel completely. which should be a bit better and easier.

So I got a peice of large OD pipe, and some steel sheet.

Tack welded it to the pipe and bent it around...



This is normally a two man job, or in my case, having no one around, a "one man and one beer" job.
The best way to describe the effort required to bend the plate around the tube is the aussie slang "almost busted a nut" which roughly translates to "almost ruptured a testicle."
It helps if you bend the corners a little first.

finished product.



and the reward.



after the Beer had worn off, (safety first), I got the grinder out and rough cut the old tunnel out, to the approximate size of the new tunnel.



as you can see its pretty rough,



this particular tank had two bushings for the petcocks at the rear, so I had to chop those out, i will be relocating them underneath at a later stage.



yep its pretty hacked up but nothing a grinder and welder cant fix.



I test fitted the new tunnel, not bad for not measuring and just free cutting!

now Ive just got to start smoothing out the high points, and reducing the gap as small as possible for welding.

reduced the gap and fired up the TIG

Very cool. Good to see some serious fab work happening.

Thanks.

So I continued to work on the tank today,

trimmed the tunnel.



in progress patching the holes.. just cut some steel out to fit the holes, welded it up then smoothed it out...
should hold up but ill pressure test it none the less, might put another layer of weld on it and smooth it some more.



and test fitting on the bike!

Great job...lets see a pic of the whole bike with the tank on it

Nice job....U got me looking for a TIG set up now