I’m having trouble getting my MC21 to run well. It was off the road for years, and has not run well since then.
Compression is ok, new airbox seals fitted, all the usual things have been checked / replaced. Power valve is fine.

It starts on the first kick and will rev out perfectly on the side stand. On the road its not running well at all

Initially it was reving up to about 7-8 pretty weakly [there was a small bit of power there] It would run badly above these revs and would not rev any higher.

Carbs were properly cleaned several more times and set up to correct spec.

Now in lower gears it sometimes pulls reasonable well at higher revs, but the next minute it runs badly again. When its hot it gets worse and the choke makes no difference to hot running.

The rest of the time it runs badly.

Any ideas what the problem is?

Is there any way I can test the PGM? I would like to exclude it from the potential problems list.

Thanks

Spec -

It an R but has an SP engine, nothing other than the engines was swapped over. I cant see this being the problem as I ran it for years with this configuration and it ran fine.

Its got the wire spice de-restriction.