GSXS650R Abomination special

Wacajawaka

XS650 Enthusiast
Messages
54
Reaction score
158
Points
33
Location
London UK
I wrote a whole monologue on this and the draft vanished so once again...
Hello, new to forum and in London UK. I had a 1990 750 slingshot from which I removed the engine and stuck it in a short stroke frame for road racing in the early 90's, this one had an 1100 transplant which blew up and has been redundant for 30 years+. I also had an xs650 motor that was going in a featherbed frame one day until I saw pound notes and sold it a Norton enthusiast. I won't insult members intelligence by listing modifications, this is more welding on than cutting off, yes it's measured out although this pic shows screwdrivers the 10M bolt is being machined at 330mm 12.9 steel, the mounting points on the frame lengthened the lower rear mount is a monster as the gixxer's sit so much lower, the top rear is a cut out section of a Kawasaki swingarm which will be welded to the shock mount spar which in turn will be strengthened. I'll leave it there for now, constructive criticism and mockery welcome, abuse of a classic engine/frame accusations happily accepted. "You'll never get that to work" but as they say in Belfast "god loves a chancer"
 

Attachments

  • IMG_20240606_154503.jpg
    IMG_20240606_154503.jpg
    371.5 KB · Views: 109
  • IMG_20240606_154524.jpg
    IMG_20240606_154524.jpg
    261.4 KB · Views: 113
  • IMG_20240606_155031.jpg
    IMG_20240606_155031.jpg
    455.8 KB · Views: 107
The XS dosent look too lost in there it fills in the space nicely. The removable sections of frame will make installing the engine easier.
How does the exhaust down tube clearance look?
Watching with interest.
Hello
The head can come down a few millimetres more from where it sits now, as for the exhaust headers it'll be a case of pinching in or pushing out! I'll get some Flexi exhaust on there to have a look at the bends soon, head and barrels are being worked on as cracked liner (then rebore) and the valves etc to replace so it's going slow. Thanks for responding.
 
Interesting. How many miles before the aluminium frame cracks with the vibration?
I crashed the Gixxer years ago so the xs650 lump can only exploit the damage already present! I will fit a top mount "headsteady" even if it raises the tank profile a bit but I need to work it out as in side to side or back to front bracing. If I get worried I'll use a z750 twin instead.......there is no vibration at speed.....50mph??
 
I crashed the Gixxer years ago so the xs650 lump can only exploit the damage already present! I will fit a top mount "headsteady" even if it raises the tank profile a bit but I need to work it out as in side to side or back to front bracing. If I get worried I'll use a z750 twin instead.......there is no vibration at speed.....50mph??
It's an interesting project for sure.

On an XS650 there's always vibration. The old Z750 motor had balance shaft(s) and I'm not certain, might have been a 180 degree twin. Resulting in considerably less vibration from the motor compared to a conventional 360 degree parallel twin like the XS650.
 
True, but the engine looks like a four that's lost 2 friends and purely on aesthetics you'd say no to the Kawasaki wouldn't you? I rode a friend's z750b in 1996 and it didn't have linear power or peaky top end or huge midrange, it was just.....there. I will try to isolate the motor as much as possible but let it have a little free reign.
e.g - during a party a mate of mine thought it would be funny to take his wife's vibrator out and turn it on and let it dance across the work top, I noticed that when he picked it up I could only hear it, he told me that when she used it you couldn't hear it at all!! I'm trying to work out how I can use this info......
 
True, but the engine looks like a four that's lost 2 friends and purely on aesthetics you'd say no to the Kawasaki wouldn't you? I rode a friend's z750b in 1996 and it didn't have linear power or peaky top end or huge midrange, it was just.....there. I will try to isolate the motor as much as possible but let it have a little free reign.
e.g - during a party a mate of mine thought it would be funny to take his wife's vibrator out and turn it on and let it dance across the work top, I noticed that when he picked it up I could only hear it, he told me that when she used it you couldn't hear it at all!! I'm trying to work out how I can use this info......
My take would be that Kawasaki would rather forget the Z750 twin ever happened. Like Yamaha and the TX750. Both of them were dreadful things.
 
Hello again members, as this is an XS650 forum I don't want to write about other "brands" too much but knowing that xs riders are a broad church, stock,chop and cafe' etc I thought I'd comment on other frames if someone is trying to deviate from stock and doesn't mind butchering stuff to get the 650 lump in. First thing, obviously the xs650 doesn't go in any other frame other than the one it was designed for (and many of you will totally agree that it should stay that way)
In the attached picture you'll see a Honda cbx750 frame I have (as you may know, the cbx750 never saw light of day in America) it has a "shallow draft" sump as the oil circulates in the frame, however unlike the cb750 frame which has 3 spines so to speak the single tube bracing can be cut to a point where the measurements allow the xs650 to fit canted forward slightly without robbing the Brit looking chopper. Did I do it? no, I was undecided on where to brace it and started the gsxr job instead. If you got the 1994 cb750 in the U.S, it's the same frame except for being a twin shock, I don't think the oil is in frame on this one, dimensions may be different. The kwak gpx600/750 frame always reminded me of a deformed Norton featherbed! The engine was water cooled so major chopping, but the frame spaces seem huge compared to modern water cooled stuff. In my pictures, the alloy frame is a slab side Gixxer, the xs motor is canted forward and overall it doesn't work, this frame was my 1985 750 and the frame has no detachable section, the following year's 1100 might work. The 3rd picture is cbx with a cbr600rr swingarm, maybe that'll fit an xs650 frame..... ;)
Right, no more talk of other manufacturers.
 

Attachments

  • Screenshot_20240213-172405.png
    Screenshot_20240213-172405.png
    1.5 MB · Views: 73
  • PXL_20240205_090846076.jpg
    PXL_20240205_090846076.jpg
    231.5 KB · Views: 79
  • original_7b508554-927f-4ed4-be3e-28f84a3ef71e_20230429_151959.jpg
    original_7b508554-927f-4ed4-be3e-28f84a3ef71e_20230429_151959.jpg
    706.8 KB · Views: 77
Looks like you have a fertile imagination and like to keep busy. Often fun to try things just for the hell of it, with whatever is lying around. Personally I'm fine with the xs motor in an xs frame, maybee a Norton or Metisse. But we've all seen that. Hope you'll continue to post here.
 
Going off to work for a 3 weeks so there'll be a pause on the build, I stuck the clutch cover on to check the clearance (or lack of..) we've got a little there at the back and on the front I can squeeze another few millimetres. I'm cheating a bit because I'm taking the crankcases and frame to to an engineer before I leave to devise a lower solid bottom mount and a rubber mounted upper rear mount. He's got better machining skills then me, and he understands the issues of securing an engine while letting it jiggle around a bit, he's also f####g expensive.
IMG_20240610_161640~2.jpg
 

Attachments

  • IMG_20240610_161630~2.jpg
    IMG_20240610_161630~2.jpg
    190.7 KB · Views: 37
  • IMG_20240610_161556~2.jpg
    IMG_20240610_161556~2.jpg
    171.4 KB · Views: 40
  • IMG_20240610_161712.jpg
    IMG_20240610_161712.jpg
    136.2 KB · Views: 39
Right, I'm off to work for approximately 3 weeks work in two different countries, not major long haul this time so not more than a month.
The actual parts to build the bike are laying about. So telescopic forks/yokes from Triumph 955i rs, Daytona 955i front wheel/calipers, swingarm is "banana" gsxr slingshot with matching wheel, standard linkages and shock for now. Tank is late model gsxr 400, this will require repositioned fuel outlet so I'll use external fuel pump and move it forward.
Various rubber mount/bearing combos and a few Buell anti vibration arms possibility for head , connection points to be accessed . The cost is with the physics of that engine and making it work. Engine is stock though as I'm not thinking about total performance, if the engine functions, great, it'll stay fitted! On many occasions I did 165mph+ on this frame, occasionally sliding in cow shit and sucking rabbits out of hedges, now I'll probably ride it to the home depot....... Goodbye for now🖐️
 
Back
Top