There must be someone who has had this problem, so here goes; 900ss 1996 (Carb). CA Cycleworks coils. With new leads, caps and plugs. The bike starts up great and idles lovely. Pick up the throttle a bit and the back cylinder cuts out and runs on the front only, even when the revs are increased to over 6,000. No popping and banging or mis-firing on idle, but stutters a little as the throttle is just off idle then cuts out completely on further opening. Swapped ignition boxes around - no difference. Swapped the new coils around - no difference. Put the old coils back on and even swapped them around. Checked the ignition pickups for resistance - both at 107-108 Ohms. Always missing on the vertical cylinder, which would lead to the pickup for that plug. So the question is; 'Do the pickups breakdown as the revs increase?'. I seem to remember that these pickups either work or not. Am I missing something here? My next task is to replace the pickups, but I thought I would spin it to you technical chaps out there first.
I also need to say that sonically cleaned the carbs and swapped the jets around. Although the bike has been stood for a few years, there wasn't too much crud. And because the motor doesn't chime in or even pop and bang as the revs build I've ruled out carbs,....for now!
I think you have it - a pick-up can break down in many ways but the consistent one that I remember is when engine has warmed up. When you examine the pick-up look for tiny cracks in the plastic body surface - they are not that obvious but chances are the good one doesn't have any (and if it does, then replace that one as well). If they are original units then it makes sense to swap them anyway tbh. it's worth checking for shorting out/open circuit of leads and running gap before you remove the unit.
just been trying to find a UK supplier for the Kokusan (BB1105) connectors that I last used but so far can only find them at Carmo Electronics. You may not even need them of course but (plastic) plug refs are:- 2MK-110 and 3MK-110 https://www.carmo.nl/index.php?main_page=product_info&products_id=2296&language=en http://utf8.cyterminal.com.tw/site/...mpany_SN=19147&Product_Site_Classify_SN=13802
Sounds like a problem i had with a 900ss recently except it was cutting out on both cylinders. It turned out that the pickup wires were the wrong way round at the connectors. Try reversing the two wires of the vertical pickup connector.
Worth checking the air gaps on the pickups whilst you're in there. At low rpm the signal might just register. As rpm climbs, less so.
This morning, before I removed the cover to look at the pickups, I thought that I would just have another look at the cabling to the ignition boxes and coils. So, with it running and wiggling the cables it chimed in on both cylinders. The upshot is that I found a cable break where the loom splits into two. I quick scalpel, solder and heat shrink and we're running beautifully. Nice result! Just MOT and we're ready for spring.
Nice one, perhaps the replies to your post made you re-focus on the possible cause of the fault. Steve
Absolutely! Sometime you have to step away from the problem to see it. Thanks to all you guys who responded.
Maybe I should have emphasized it more but I did include this in post #3. The whole loom run from exciter to pick-up can get very straggly and can get snagged just after crankcase entry point or adjacent to loom clamp between pick-ups plus the joints can lose their insulation and short or become loose or partial/full open circuit. Have had experience of all 4 different failures, and even when lead(s) shorted out you normally get away without any further damage if you catch it early.
