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Author Topic: 1983 XV500 Cafe Racer  (Read 37113 times)

Offline wynand2000

  • Posts: 100
Re: 1983 XV500 Cafe Racer
« Reply #75 on: Oct 20, 2013, 11:45:27 »
This looks great! Maybe you can even copy the system Ducati`s have....they have some sort of adjustable headstock trick whereby they can adjust the degrees wished for an that certain track.

Keep up the good work

Offline Karlloss

  • Posts: 197
Re: 1983 XV500 Cafe Racer
« Reply #76 on: Oct 20, 2013, 16:34:14 »
This looks great! Maybe you can even copy the system Ducati`s have....they have some sort of adjustable headstock trick whereby they can adjust the degrees wished for an that certain track.

Keep up the good work

Thanks, I think an adjustable headstock may be a bit much for my fabricating skills, although I'm thinking of reducing the rake to 24 degrees.

Offline xb33bsa

  • Posts: 7727
Re: 1983 XV500 Cafe Racer
« Reply #77 on: Oct 20, 2013, 17:22:22 »
your work looks good but the upper mounts should have not been welded with a plate across the tube and the gusset on centerline is wrong
not that you totally failed i am just sying now you should add some outer gussets
2 plates running alongside the outer edge of the tube is the better way
same thing with your headstock run your gussets on the outside
dont run a single gusset on the inside centerline ;)

Offline Karlloss

  • Posts: 197
Re: 1983 XV500 Cafe Racer
« Reply #78 on: Oct 21, 2013, 15:25:15 »
the upper mounts should have not been welded with a plate across the tube and the gusset on centerline is wrong
not that you totally failed i am just sying now you should add some outer gussets
2 plates running alongside the outer edge of the tube is the better way
same thing with your headstock run your gussets on the outside
dont run a single gusset on the inside centerline ;)

I'm curious, why do you say this??

Offline xb33bsa

  • Posts: 7727
Re: 1983 XV500 Cafe Racer
« Reply #79 on: Oct 21, 2013, 17:27:29 »
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

Offline Karlloss

  • Posts: 197
Re: 1983 XV500 Cafe Racer
« Reply #80 on: Oct 22, 2013, 10:10:04 »
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.

Offline johnu

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  • Posts: 1427
Re: 1983 XV500 Cafe Racer
« Reply #81 on: Oct 22, 2013, 14:31:12 »
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!

Offline Karlloss

  • Posts: 197
Re: 1983 XV500 Cafe Racer
« Reply #82 on: Oct 22, 2013, 16:38:53 »
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.

Offline Karlloss

  • Posts: 197
Re: 1983 XV500 Cafe Racer
« Reply #83 on: Oct 22, 2013, 16:54:29 »
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??
« Last Edit: Oct 22, 2013, 16:56:06 by Karlloss »

Offline xb33bsa

  • Posts: 7727
Re: 1983 XV500 Cafe Racer
« Reply #84 on: Oct 22, 2013, 17:34:41 »
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

Offline johnu

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  • Posts: 1427
Re: 1983 XV500 Cafe Racer
« Reply #85 on: Oct 22, 2013, 20:05:50 »
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 :)

Offline xb33bsa

  • Posts: 7727
Re: 1983 XV500 Cafe Racer
« Reply #86 on: Oct 22, 2013, 22:11:39 »
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

Offline Karlloss

  • Posts: 197
Re: 1983 XV500 Cafe Racer
« Reply #87 on: Oct 23, 2013, 08:26:45 »
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. 

Offline Karlloss

  • Posts: 197
Re: 1983 XV500 Cafe Racer
« Reply #88 on: Nov 10, 2013, 16:16:22 »
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!!!!

Offline Karlloss

  • Posts: 197
Re: 1983 XV500 Cafe Racer
« Reply #89 on: Nov 30, 2013, 08:56:27 »
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.