1983 XV500 Cafe Racer

Karlloss · Oct 22, 2013

xb33bsa said:
its not stucturally good to weld across a tube it can bend/weaken the tube as well as creating a stress concentration in the excact wrong direction
it is pretty much common knowledge of frame building what I have said, not something I made up
you do good work but design wise it would behoove you to look at some existing frames and see the themes on gussets and mounts etc

Thanks for your observations, I did consider to use gussets on the outside of the mounts. I haven't got around to designing the gussets for the headstock yet, I see what you are saying. The original frame used the engine as a semi stressed member, I am considering adding a down tube from the headstock to the engine casing as there is a un-used mounting point just above the starter motor. Additionally I have been considering welding a gusset/rip along the top of the main frame tube from the headstock towards the rear of the frame.

johnu · Oct 22, 2013

xb33bsa said:
its not stucturally good to weld across a tube it can bend/weaken the tube as well as creating a stress concentration in the excact wrong direction
it is pretty much common knowledge of frame building what I have said, not something I made up
you do good work but design wise it would behoove you to look at some existing frames and see the themes on gussets and mounts etc

This is what I was saying in my earlier post Karlloss. Sounds like you have it handled though!

Karlloss · Oct 22, 2013

johnu said:
This is what I was saying in my earlier post Karlloss. Sounds like you have it handled though!

I was thinking the single longitudinal gusset would have sufficed, hence I welded one in, this was always the plan if you look back to my mock-up with cardboard, as the headstock will cause flex the along the length of the frame tube. I am wondering if I need two flat gussets either side of the mount and headstock or whether a single gusset longitudinal gusset will be ok.

Karlloss · Oct 22, 2013

Some basic mock-ups, not sure what is the best solution yet!

Although I've only shown the gusset going onto the front mount, I will incorporate both, just need to decide on which solution. Any suggestions??

xb33bsa · Oct 22, 2013

bottom one, one on each side cut a few 1" longs slots along where it lays on the centerline of the backbone tube for some skip-welds

johnu · Oct 22, 2013

Yes bottom one. I am sure you are aware of this but you have to get that headstock tube set spot on as far as the rake angle and being perpendicular to the frame. If you are just a tad off at the joint it will be way off at the bottom of the fork. just saying

xb33bsa · Oct 22, 2013

you pretty much want to have that in your jig locked up solid,with minimal gaps at your welds will minimize pulling out of line
preheat a bit get it all over pretty darn warm before you start welding
dont make any long time heat soak welds in one place switch around do opposites in a similar time

Karlloss · Oct 23, 2013

Yep, definitely aware of the need to have the headstock perfectly aligned, the pulling of the welds was something I hadn't considered when I welded the gusset between the mouts, the outcome being the tubes/spigots for the bolts pulled in a bit but still within tolerance, just!

I don't have a jig, I intend to scribe a centre line along the headstock and align this to the centre line I have scribed on the frame tube, which was a pain to achieve, I did this by leveling the motor/swing arm mount using a spirit level and then marking out the centre line using another level, set squares etc.

I had considered warming of the tubes before welding, mostly to allow good pentration of the welds.

Karlloss · Nov 10, 2013

Today I was supposed to be in the garage working on the project, instead went out for a lazy lunch. I need to find some motivation!!!!

Karlloss · Nov 30, 2013

Managed to get into the garage this weekend, making bearing cups which will fit into the headstock tube and be TIG welded in place, well that's the idea.

wynand2000 · Jan 2, 2014

Any bit further yet? Love to see progress on this unique build!

rundown · Jan 2, 2014

Ditto, this is a remarkably ambitious build and very interesting. Your frame is being watched by quite a few I should think. Happy new year, now get back to work your audience waits with bated breath.

Karlloss · Jan 3, 2014

Thanks for the support, yes a two steps forward three back. I machined the new bearing caps and pressed them into the tube I was using as the headstock, all good until I welded the joints, I even took care to alternate the welds, but the heat transfer caused them to come out of alignment. Having said that I built up the headstock with new bearings and it rotated ok on the headstock shaft, as the misalignment is only slight, but I am not happy with it so I am trying to source some 55mm round bar/stock to machine a one piece headstock. So now I have a scrap piece of metal that looks like a headstock and cost £40 (approx $60) and more experience. I'll post some pictures this week end. This project is certainly a learning curve for sure.

wynand2000 · Jan 3, 2014

Sorry to hear about the bad luck on this piece, guess I would have done it the same way.

Curious for the pics!

Karlloss · Jan 4, 2014

Here are the pics. Before I welded the headstock I thought I'd have a practice run as it was only my second time TIG welding. The practice run went great, really neat weld, however when I went onto weld the finished piece it all went wrong, the welds are bloody awful. I'm not impressed with my work on this occasion. The 1st and 2nd pictures are the practice, the 3rd the finished piece.

xb33bsa · Jan 4, 2014

are you getting comfortable ? resting your arms and or elbows right on the bench when possible helps a lot
what kind of technique are you using?

xb33bsa · Jan 4, 2014

on the headstock piece yaeh they are always machined out of one piece, if not, machined AFTER the weld together
you could build yours up inside and re-machine,

Karlloss · Jan 23, 2016

Well, after a break of two years, which included a house move and remodeling, a change of job and all the other things that get in the way, I have finally got back to my build. I've now machined up a new headstock. What I have also found out is that my lathe is quite worn, as you would expect from a machine built in 1956, so machining parts to fine tolerances is extremely difficult, but on the plus side at least I have a lathe and can turn components.

kiwiguy · Jan 23, 2016

Nice! Is this 1 piece or is this from your first idea and is the three piece weld together you have turned down to finish?

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Karlloss · Jan 24, 2016

I machined it from a new piece of round stock. Boring it out was quite difficult on a small ML7 lathe, very slow and time consuming. The internal bore isn't as smooth as I'd like, but as no one will ever see it, its not an issue. The bearing seats are good though.

One thing I did find out, I have two sets of the same bearings from the same supplier, however one outer race is slightly smaller, which means that it in future if bearing replacements are needed, bearing fit adhesive might need to be applied as I machined the bearing seats to the larger size. Not an issue for me, but does highlight the difference in tolerances even on 'precision' items.

1983 XV500 Cafe Racer

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