V35 Imola - Bosch electronic ignition info

I’m trying to get some views from people with experience of bikes with the Bosch electronic ignition system as fitted to early V35. The bike, which is new to me, is running like a pig (hesitating, won’t pull away cleanly or from from 3-6K RPM but sings from 6K up. There are various possible causes so I’m trying to rule out a few. It has K&N and Busso silencers (loud!) so I thought it might be lean but think there’s more to it, The right hand cylinder is particularly lumpy. I’ve adjusted the carbs, replaced various gaskets and the choke plungers and mesh screens and the carbs seem pretty good with minimal wear. I also balanced them. I’ve also tried with a richer main jet to no avail and also moved the needle up a notch but it just smoked.

So. is it ignition (because the system is crap) or carbs, or even something mechanical (broken valve spring, bent pushrod etc). I doubt it’s mechanical TBH as thething really pulls at 6K+ RPM. I’ve set the valve clearances and also gapped the Bosch sensors on the crank. One of the sensors was ground to a semicircle on the crank - it must have been too close, so I have filed it flat and reg-gapped. I have some second-hand sensors coming which I will bench test for resistance and then fit. I have also stripped the fuel taps and checked for flow - no issues.

At this stage it would be really useful to know if the Bosch system can be made to work well or is it a lost cause that should be replaced with a modern electronic system? I can’t find much information about the Bosch system except I think it was known for a flat spot (or was this the Marelli?).

Thanks for any insight.

Is that effectively the same trigger boxes as for the V50 II ? If so they have a steep advance ‘curve’ (more of a cliff really) somewhere around 2.5 - 3 k rpm which can give a flat spot around there. Shouldn’t make any difference above that though.

Thanks, I don’t know - two cubes the size of big sugar lumps, one either side of the crank end behind the alternator rotor. Parts arrived to day and the pick ups look good so fingers crossed.

Got the used pick ups and wiring loom today from TLM in the Netherlands - fitted this evening, set the ignition timing and gapped them - it’s like chalk and cheese, finally the bike is pulling like it should! Phew, that was a slog…:wink: