MRC Forum- brought to you by www.morini-riders-club.com

Can some one give me a base setting for the VHBz25bs carbs for throttle stop and pilot screws.

Not sure mine were ever set properly and while I can get it to start it falters after a minute or so and wont run without choke, I'm sure there's lots of other variables but I just need a decent start point for the moment.

Around a turn and a half out on the mixture screws, slide stops set so you can just see daylight under the slides.

I'm running 1 1/4 turns out on pilot screws, my float heights are around 14mm as the plugs were always dark/black on inspection and the needles are on the middle clip position.
I am having running/power issues as well. I do have stainless steel exhaust system thou.

What running issues are you having?

A stumble off idle is common (modern fuel - fit leaner idle jets).

A mid range hole can be ignition, atomisers, or silencers.

Black plugs is pretty normal with modern fuel. Unless they're black and sooty, the mixture is probably OK.

Running issues are ignition timing is viewable with strobe lamp but when you get to 2500rpm+ the strobe shows irratic ignition timing +- 15deg approx. not stable & I think this is stopping the bike from going over 60mph.
Got new plugs BP7ES & new CDI coils & hasn't changed a thing, looks like ignition coil is breaking down rather than resistance issue (231 ohms cold).
Ignition coil & rotor being looked at NLM.

TurboRestorer wrote:Running issues are ignition timing is viewable with strobe lamp but when you get to 2500rpm+ the strobe shows irratic ignition timing +- 15deg approx. not stable & I think this is stopping the bike from going over 60mph.
Got new plugs BP7ES & new CDI coils & hasn't changed a thing, looks like ignition coil is breaking down rather than resistance issue (231 ohms cold).
Ignition coil & rotor being looked at NLM.

Is the pickup "known good"?

TurboRestorer wrote: looks like ignition coil is breaking down rather than resistance issue (231 ohms cold).

Low resistance IS the coil breaking down. A value of 230 ohms is actually a little high, I'd normally expect 220 ohm. You might though have one of the less common 300 ohm coils (or a rewind) and if so, having dropped to 230 ohms indicates a problem.

Some jitter in the timing can be caused by excess slack in the cambelt and it's not unheard of for the crankshaft pulley to work loose leading to more slack.

I am suspicious though of the pickup. If it's failing, you can get a number of strange behaviours, even if it checks out fine on NLM's test rig when cold.

With new silencers my Strada needs one or two sizes up on the main jets but strangely
after a few thousand miles it needs the org ones back I suppose they carbon up a little.

The pickups are the only thing left if the rotor re-mag. & ignition coil rewind does not fix the problem. Whatever the issue is it affects the rev. counter regardless of which coil its attached to, so it has to be a global electrical issue on the ignition circuit.