Building... something.

[Spider John]

Building... MX XS WTF

Ok, I admit to the cowardly practice of not starting a build thread until the project is complete. I realize, however, that I'm denying myself a lot of input, inspiration, and sometimes a much-needed kick in the ass. So here goes.

You know how those back-burner projects go, sometimes it takes years to accumulate the parts, time, budget, and inspiration to jump into it. And sometimes you get tired of looking at it and make someone who's wiling to take over and see it through a hell of a deal. For once I was on the recieving end of said deal.

Enter a canibalized '79 Special frame and engine, and a complete basket case 2001 KX125. Maybe an odd starting point , but so far I've gotten a good start AND recovered most of my initial investment by selling off unused parts.

Day 1 involved yanking the forks and swingarm off the KX, test fitting, and figuring out what bearings, bushings, spacers etc. I'll need. A few issues to address, but looks like it's a go.

 

[Spider John]

Now I should mention that the previous owner of this pile of parts is the shop owner, and that he had grand plans to open up the middle of the KX frame and cram the 650 engine in. The dude's got some fabrication skills and could have pulled off something crazy like that. Me, I'm picturing a twisted abomination covered in my globulous farm welds. Not happening. Some tabs on the swingarm for some nice long lay-down shocks and I'm rolling. "C'mon," he bemoans, "You at LEAST have to do the monoshock!" Man, I'll be glad to get this thing to my house where I can work in solitude.

 

[Jbinnington]

MX xs650, now that's interesting!

Are there any "vintage" MX classes such a creation could compete in? Like a dirt bike version of BOTT...

 

[Spider John]

Alright, so I AM trying to keep this from being just another Yamabobber. Much work, frustration, head scratching, and a litle have I gotten myself into, but the monoshock is finally in and fuctioning and well worth the effort. Ended up using a much shorter shock.

 

[tonyc]

Great work work Spider.

 

[Spider John]

MX xs650, now that's interesting!

Are there any "vintage" MX classes such a creation could compete in? Like a dirt bike version of BOTT...

If not there should be. Personally I'm partial to '70s enduros. I'd love to see some restored scramblers duking it out on a modern motocross course. No high-flying 12+ inches of travel antics, just old farts on old bikes .

I was originally hoping for something like this, but without relocating the swingarm pivot it ain't happening.

 

[Spider John]

Great work work Spider.

Thanks! I'm not exactly a master fabricator, just a struggling musician and part-time mechanic who loves tinkering with bikes.

 

[Spider John]

The rear height is necessarily a fuction of the trajectory of the countershaft sprocket through the swingarm pivot coupled with the smallish rear sprocket required to at least get close to the stock gearing, so now the forks are WAY too long.

 

[Spider John]

Using a ratchet trap to eyeball it, I'm looking at lowering the forks around 4" or so.


Though it's sorely tempting to just go with the long fork look, epecially since i don't need the upper shock mounts and could hang a low solo saddle off the back of the seat post. Plus, I have lots of chopper crap lying about.


But I build bikes to ride. I like to dive into corners fast and I HATE low speed copper-flop.

 

[Spider John]

Idunno. The damned long forks are kind of growing on me.



Going with this for the frame color. still a lot of work to do first.

 

[JayR]

....Me, I'm picturing a twisted abomination covered in my globulous farm welds. Not happening.

That's funny. Looking good, I'm in the MX / XS WTF camp too. Keep up the vision.

 

[Spider John]

Yeah, nice, I like the front and rear 17's with the Shinko 705's.

 

[Spider John]

How much did those wheels set you back if you don't mind me asking? I'd really like some supermoto wheels but I'm not likely to shell out a thousand bucks for two wheels that are made in China no matter how cool and practical they seem.

 

[Spider John]

Shake down run around the block. Carbs are smoothing out but still need to up-jet because of the Uni filters. Power-to-weight ratio is impressive, but it's hard to really tell on dirt roads. Can't tell much about the front end geometry either until I can get it tagged and take it on the highway. Suspension feels great! Stock exhaust sounds like arse.

 

[Spider John]

Damn, right carb is flooding. Hopefully just trash in the needle and seat.

Clutch is still feeling kind of funky. Took it apart to unstick it and couldn't remember which way the bevel on the plates went. Tried them facing in at first, but the consensus here seems to be facing out. Didn't help really. I suppose a closer look at the worm gear is in order.

I've noticed a few bikes with hydraulic clutches from other bikes retrofitted. Has anyone tried the aftermarket kind that has a cable that connects to the worm gear instead of replacing it with the slave cylinder? Seems like it would be a noticeable improvement, assuming that the worm gear was in good working order.

 

[Spider John]

Got the clutch and carbs sorted out. Got it inspected, tagged, and insured. Time for a few good long shakedown runs. Stick a fork in it, it's done for now. I'll tear it down and finish all the cosmetic details when I get bored with it, but it's time to do some riding.

 

[Spider John]

Need to come up with some kind of side covers. Thinking about something vaguely reminiscent of number plates, only not.

 

[gggGary]

A great journey down the road less traveled! For side covers, fab something that reflects the the tank shape, and shows off the mono shock, hmm, like this?

 

[Spider John]

Wow, like it! I was thinking of some kind of parallelogram, but I like the organic curve much better, definitely ties in with the tank.

I'm all about the road less travelled. Why go through all the time and effort of a hand-built motorcycle if it's not going to be one of a kind?

 

[gggGary]

As long as I'm remodeling YOUR bike.



The big swing arm is great but it might help to break up the look of that flat slab of aluminum.