Hi Kasper, I have fitted a 650 motor to a 500 custom frame. I have used 650 front motor mounts and fabricated brackets to take them to the frame, the radiator is 650 with electric fan. i have converted the ignition system to transistor using coil and spark unit wiring from a 650 wiring loom. the water expansion bottle has been moved into the r/hand side panel, but if you can get one from a late 500 Cc model or GL400 it will fit behind the engine. The carbs are difficult, I have used 500 carbs with 650 jetting but all brackets, throttle spindles, choke, and fuel feeds are lengthened by 15mm for the wider motor, as you found out 650 carbs foul the frame. The drive output shaft is 500. It was quite a lot of work, but it was something I wanted to try. I am sorry that I cannot speak your language but maybe Wouter or Floris could translate if it is difficult for you. I will be going to Sint Jankslooster and maybe meet you there?

Hi Trevor, good to hear from you. I've seen your bike at Vechta and I was quite impressed. Especially the carbs are IMHO a job well done.

Yo Trevor,
thanks for your posting on this forum.
In part I did the same things as you did. I converted the engine to CDi ignition as the main 'cable tree' was a 500custom one. I hope this works out.
The engine runs now, but seems to have some irregularity. I haven't hit the road with it yet. Probably it's caused by the carbs, the ignition, or (god forbid) the stator which is second hand and might fail. Also synchronising should still be done.
What I can hear while having the engine running, it sounds like good old 500 with the 500 custom exhausts, only a tiny bit 'funkier'. Probably I should fit the Euro exhausts.
I'm not quite sure if I can go the SJK, in either case I'm going to inform this forum of the proceedings.
Cheerio.
Kaspar