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Old 09-29-2009, 10:10 AM   #224
LukasM OP
Beastly Adventurer
Joined: Nov 2006
Location: On a RTW ride - currently SE Asia on the way to OZ
Oddometer: 5,427
Somehow my subscription got messed up when the thread was moved, but I'm back now! Hopefully with some progress this weekend, supposedly the Versys engine is in transit to Austria once again. I'll believe it when I hold it in my hands...

Originally Posted by Arch
This is well beyond off into twins territory, so it's time for a thread punt.
Now you've done it Arch... but it's all good, I have secretly started calling this thing "The Beast" a while ago anyway (even though it's really just a bare frame at this point ).

Originally Posted by Roadracer_Al
Lukas, don't encourage me. I have in mind a complete frame. It's probably only a little more work than a heavily mod'd stock frame.
You might want to get in touch with the Webers. I remember reading in a post somewhere how many hours it takes them to make the frame, was it 600? That's why they put a $50k+ tag on the Rally twin.

Coming from the kit car world I can definitely see the point of a donor bike concept, though. Sign me up if you make one that will accept KTM parts!

Originally Posted by tonymorr
LC4 frame questions....

Does anyone know what changes KTM made over the years to the 640/620 frame and suspension? I have a buddy that will give me a good deal on a 1999 640E but I haven't really looked into wether that would be the best choice yet. If anyone watching here could save me some time it would be greatly appreciated.

I like idea of the KTM LC4 chassis because of it's dirt prowess and accesories avaialable but as I rode the Mutant to work today I was thinking about a few things....

1.What to use for an airbox and how would it effect perfomance?
2.What to use for a fuel pump?
3.Will the KTM radiator work? (is there an electric fan or one available)

The LC4 frame is basically the same for all the years, just some smaller details as pointed out above. The SC and SXC version came without frame in the oil, but that tube will likely have to be removed anyway since it's in the same place as the 650 oil filter. I am looking into an oil filter relocation kit, though, in case that is the only thing in the way. For our purposes go with whatever is cheapest, or where you can recover money from selling the engine.

Forks will also interchange between most KTM models, I have a set of revalved and resprung 48mm WP forks off an 03 SX for my 97 frame.

For your other questions:

1. We'll know more about the clearances once one of us actually puts the twin into the chassis. The throttle bodies might require more room than the carb but I think the engine is not as high. With some luck we could just make a bigger airbox in the stock location. For my bike I am also considering putting on the split front tanks which would allow me to run the airbox in between, just like on the KTM 950/990 and Rally bikes.

2. The fuel pump is something I have looked into quite a bit as well. We need 45psi at the injectors, which means most automotive and motorcycle EFI pumps will work. The easiest would probably be to have an inline external pump and regulator hooked up to the stock fuel tap. The Adventure tank would even give you another tap which you could hook up to the return line of the regulator. With the 4 Rally tanks it gets much more complicated of course, i.e. how do you assure fuel gets drawn from each tank equally, where do you hook the return line up to etc. Might require a complex solution with a surge tank...

3. All LC4s have two radiators, with the Adventure ones being a bit bigger (or so I read). Comparing the surface area, together they are about equal to the single Kawi one. You can put one or two fans on them as well, so I am not expecting any problems in this regard.

Originally Posted by BeeDub
Cool build idea Lukas! I'll be keeping track. I just wanted to let you know that I got curious about this motor, and ended up finding a free download for the workshop manual on the 650r. You can find that here. There are several other cool things on that site too, happy hunting.
Thanks for the link, that site was very helpful.

Originally Posted by Fuzznuts
I wonder if the XR L has the tach and standard ignition switch. I've heard on some cars, the engine won't run if it's not in the circuit. I thought I'd leave the KTM cluster and not use the tach. I'd learn pretty quick not to bounce it off the limiter and besides, I want low end grunt most of the time. Very curious about the radiator, too. One KTM looks the same size as the Versys. Mine came with fan. Could move it over to the right one with the filler and make room. Still looking for an engine...
The 650 engine will run without the instrument cluster hooked up. However it provides a lot of useful info, so I might just keep it. Since you will likely throw all of the KTM wiring out it's definitely a better option than the KTM cluster.
Currently going RTW on a KTM 690 Rally, trip blog:

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