Unholy unions - XV750 with 1290 SuperDuke running gear

When it comes to building bikes for myself, I am a bit of a traditionalist. Also, I am cheap and old and tatty bits are a lot cheaper than new and shiny stuff. That being said, my mate Andi, well he prefers to go down a different route.  And as a result, he got himself "da good" stuff. KTM/WP 1290 suspension all the way and asked me to make it fit. 

We started off with the rear shock, which was pretty straight forward and just needed a few bushings to reduce the internal diameters and to locate the shock properly in the bike. 

Front forks are dead easy, press out the stem out of a set of XV750SE triples, turn it to size and press it back in, into the SuperDuke triples. 

So what was in it for me you ask? Well there's this little 790/890 Duke shock, which looks like it could turn out be a VERY good replacement for the current XT600 1VJ rearshock I currently run in my TR1...

The XV sidecar - connecting the dots (part 7)

So last time we left off with the lathe work being done on the front mount, but still some milling to be done.

Testfitting the strut to see if it fits nice and tight.

And fitted in place. The little stub will be the holder for the right downtube of the subframe. But for fabrication reasons, this has not been fitted yet. 

The rear mount followed the same basic principle, but inverted. I turned a M16x2 bung that would be a press-fit inside one of the tubes...

And then turned and milled the male clevis-mount part to screw into the tube to give me a bit of extra adjustment.

Next was to make a rear subframe that would bolt to the main frame, but not to the detachable (stock) rear subframe. 

Then I found out that I had to shorten the rear strut. (Why cut it out in the middle you may ask? That's got to do with the fact that it is now sleeved on the inside and this would have been more difficult, if I did it at the bottom of the strut. Mainly because I would very likely have terribly escalated and re-engineered the bottom clevis mount...)

The next challenge was to make a proper rear subframe.

 

Only to find out that the strut had to be shortened once more.

But then it was time to put the old girl on her wheels and roll her out of the garage.

Looks terribly crooked and incredibly flimsy, but she's on her wheels and now stored in the garage next door, because I really have to fix up the broken XT600 engine of Dre-XT-Stück in the coming days.

The XV side - it's a sidecar, sort of... (part 7)

Last time we left off with having cut a huge gaping gash into the rear frame tube to finally make the rear mount adjustable again. So at first this had to be welded up again and then the inside ground flat again.

The amount of loose rust that came out was more than impressive though.

A 40mm flap wheel was the perfect tool in the end to get rid of the weld slag that had built up on the backside and remove a bit more rust on the inside.

In order to work out, how everything will be going together, I had to weld on the final bends, which gave me the opportunity to finally do some thin-wall stainless TIG-welding again. 

By the way did I mention that it was a bit fresh in the workshop?

After all of this it was well about time to lay out and make the mounting hardware for the rear sidecar mount.

Stuff that makes the engineer happy: when you hit that number WAY closer than planned.

As the tube in the frame I was going to use, was 14.odd mm in diameter, I made two bushes to get it down to spot-on 12mm.

Obviously I needed a long enough bolt, which started out as a bit of all-thread with a nut welded on.

Then (for the umpteenth time) the sidecar step fell out of its box and I decided to get the snapped stud out and fit it up to the sidecar-frame

After this very welcome intermission, I started again on making that rear mount. First of all it needed an M10 thread in the back, so I could take it off during the numerous mockups. (So I thought - never had to take it off even once.)

The turned parts were done to a light interference fit, to limit the number of hands needed to make everything line up.

Nice... this sits right next to the rear wheel and with this amount of leverage it'll twist the lower subframe into a pretzel in no time. 

"All the amps" were applied and the rear mount lengthened by about 130mm. Bonus: it now can sit a bit higher as well as it doesn't have to clear the muffler anymore, but only the exhaust pipe. Which is another few milimeters gained. 

Shortened and welded the rear mounting tube and "pinned" the mount (for future-welding) with an M8-bolt to the backplate.

It will do for rolling it around in the workshop, but not much more without welding, but it will definitely make triangulating it a lot easier.

The last bit that I turned my attention to this time was the front top mounting point. Now I had a lovely clevis mount, but unfortunately it was male (externally threaded) and I wanted to use the long bolt connecting both top-mounts and as such, needed the female version of it. A nut with a clevis, if you would like to see it this way. 

Unfortunately I didn't manage to get it milled in time for this post.

So, the next step is to turn the old girl into a roller and maybe (while we're at it anyway) make the upper rear mount and then find out how to do the exhaust routing, fit the footpeg-backplates and work out how to run the front downtubes.