I spent months trying to track down what I thought was a carb problem on my XBR, which sounded quite similar to yours. I broke down a few miles from home and had to be recovered. When I told the recovery driver about the problem, he said "ECU". And he was right. I tried 2 different ones: an expensive one from Holland which turned out to need rewiring and whose supplier was very rude when I told them that, and a cheapo from ebay that worked perfectly.
The expensive one was from Carmo Electronics (
https://www.carmoelectronics.co.uk/) - I attach below the email I sent to them. The cheapo one was from ebay:
https://www.ebay.co.uk/itm/404753268868"I have to say I’ve been disappointed with my experience with your company. First of all, the unit arrived with no instructions whatever and was described as “plug and play” on your website. It was far from this. When connected via the small harness you supplied I had no spark. This turned out to be because pins 1 and 4 were swapped in the link harness. I did try connecting without the harness and this immediately blew a fuse on the bike when I operated the starter – I now realise bacause the XBR CDI has a +12 feed on pin 5 which you have broken in the link harness. When I cut this wire and instead fed a direct earth to the CDI, connecting without the link harness, I had success.
I understand that this positive feed may have a function in retarding the ignition when the starter is operated, however cannot find any documentation to this effect. I would have hoped that you would incorporate this feature, or at least point out to the user that it existed.
I have in no way been helped by you other than your providing a link to an information sheet which you should have given me at the outset. You should also have provided details of the advance curve and other characteristics. I have spent hours in my garage checking other components (entirely unnecessarily) but have been greatly helped by members of an online forum who have made many helpful suggestions. I should not have needed to do any of this. The only positive aspect is that I have now learned a great deal about CDI systems.
It has become plain to me that the unit which you sell as specific to the XBR500 is instead a generic unit. This raises questions in my mind as to what the advance curve is and whether this has been tailored to the motorcycle or – as I suspect – you have merely used a standard curve which may or may not suit the engine characteristics. I cannot believe that you have actually supplied any of these units to an XBR500 owner and that they have fitted it without problems.
It may interest you to know that in desperaion I bought a generic “pit bike” CDI unit complete with coil from ebay at a cost of less than £12. This was delivered to me today and I find that it replaces your unit directly and seems to give similar performance. It’s interesting that the pinouts on this unit are identical to those on your unit WITHOUT the link harness ie with B/W to pin 1 and red/black to pin 6. I accept that its internal components may be inferior but am left with the feeling that I could have saved myself £100 or so by purchasing this in the first place."
