Mikuni

I reckon you're on the money there Lothar. An under performing condenser will definitely affect spark. Always fit new points and condensers at the same time on the service schedule for all the old cars I used to service. My SF2 had a condenser fail, no spark... Rode home on 1 cylinder
 
What are the signs of it, please? black, maybe even wet spark-plug? could be indeed pointing to a spark problem rather than a carb problem maybe...?
Black plug Lothar partly due to oil coming down the guide, the inlet valve is a bit oily. Problem present before and after putting on new carbs.
For a little while now, if run at constant throttle, it hesitates a bit on pick up and then ok.
Black plug has been like that since 1993 but without hesitation resembling plug fouling. That appears after having put new exhaust tubes and banana box on a couple of years back.

I've still managed to put 130 000 km on the bike.

Paul
 
I know it’s not a popular thing to say here, but in my view it doesn’t make sense to mount those over complex carbs that have a hard time with the twin’s vibrations/pulses.
Just look at the exploded view of the and see yourself dealing with issues on the side of the road. I had Mikunis on my CND, and all issues that I had with the bike were inside the carbs with synchronisation nut coming loose and one of the exquisite rubber mounted float needle holders failing.

I made my 250.000+ km white SF2 happy with a fresh set of PHFs.

If you fancy modern technology, then start with electronic ignition.

Marnix
 
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I know it’s not a popular thing to say here, but in my view it doesn’t make sense to mount those over complex carbs that have a hard time with the twin’s vibrations/pulses.
Just look at the exploded view of the and see yourself dealing with issues on the side of the road. I had Mikunis on my CND, and all issues that I had with the bike were inside the carbs with synchronisation nut coming loose and one of the exquisite rubber mounted float needle holders failing.

I made my 250.000+ km happy with a fresh set of PHFs.

If you fancy modern technology, then start with electronic ignition.

Marnix
Thanks for the advice Marnix.
Paul
 
An SU à la Commando would be interesting.
Paul
Yeah, they'd match your ignition points nicely, just as outdated... they were the carb of choice for the Norton mob because they were probably about 6 shillings apiece at a breakers' yard. :rolleyes: But possibly still an improvement over a clapped-out pair of Amal Concentrics.

If you're aiming for economic reliability, go for the budget Mikuni VM. They're still available up to 44mm, loads cheaper and physically smaller, therefore easier to install than the RS, TMR or FCRs, with none of their drawbacks.

piet
 
Yeah, they'd match your ignition points nicely, just as outdated... they were the carb of choice for the Norton mob because they were probably about 6 shillings apiece at a breakers' yard. :rolleyes: But possibly still an improvement over a clapped-out pair of Amal Concentrics.

If you're aiming for economic reliability, go for the budget Mikuni VM. They're still available up to 44mm, loads cheaper and physically smaller, therefore easier to install than the RS, TMR or FCRs, with none of their drawbacks.

piet
A local friend of mine has an SU on his Commando. He did a round the world trip on it and it's still going strong.
It depends what you want a motorcycle for.
Paul
 
Funny thing I got a pair of new 32mm Amal premiers with my 850 Commando and thought they would be better on the bike than the worn out originals, I fittd them and the bike ran terribly, I had to get some inside info from an old brit bike expert then change every single component withing the carbies to suit the Commando engine FFS it runs well now though!!
 
Funny thing I got a pair of new 32mm Amal premiers with my 850 Commando and thought they would be better on the bike than the worn out originals, I fittd them and the bike ran terribly, I had to get some inside info from an old brit bike expert then change every single component withing the carbies to suit the Commando engine FFS it runs well now though!!
The problems with Amals would appear to be that they wear quickly.
Paul
 
I had 4 Commandos - 2 750s and 2 estart 850s. Contrary to what most people seem to believe my starters actually worked. In fact on one the kick starter almost fouled the rearsets I installed so I took off the kick start lever. I may be looking back through rose tinted glasses but the only problems I recall are ones I inflicted on the bikes myself.
 
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