I’m trying to get my MC21 back on the road after a good few years of it sitting in the back garden under a bike cover.

It runs fine in neutral, rev’s fully, servos work, no smoke, but when I try to ride it its barely able to do 10mph – seriously - it has nothing to give and very smokey.

Thought it was running rich but carb set up does not help at all, its still dead.

Has to be ignition related but the fact the engine rev’s fine and the servos work makes me think the PGM is ok.

Any ideas other than try a new PGM?

has it got new spark plugs in?? is it running on both cylinders on tick over? check if the smoke from the pipes is warm on both ?

Could be a case of weak spark being blown out once you load the motor up.
Get some new plugs. Check coil connections for corrosion.

Double check both cylinders are firing. The engine will still rev out in neutral on one cylinder (trust me i know) But once you try and ride it, is very lazy.

Like was said earlier, exh should be warm, and should pulse. If one pot is out, it will still push air our, but it will be cool, and wont pulse.
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Check your side stand switch.

give the contacts a good clean, maybe swap them over for a test run, just to see if theres any difference
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Good to see another NSR back on the Irish roads ,how fresh is the battery?

thanks for the feedback, to answer some questions,

both pipes are hot, so i'm assuming both cylinders are firing, plugs are new as is the battery, we have stripped everything down [carbs etc].

side stand is ok [netural with stand up runs fine].

will investigate spark strength further.

do you think i can take it that the pgm is ok [its the only bit that would concern me, so it would be good to be able to park it as not a problem]

Check the centre crank seal could be stuffed after sitting around

Have you done a compression test?rings may be goosed.

compression test was fine

i had a similar problem with my mc18 which had been stood for years.

the problem with my bike was that the carbs were not seated properly and the float breather pipes on the carbs were blocked.

what compression test results did you get?

my mc18 has 130 psi on both cylinders and runs well.

hope you get your bike sorted.

we have improvement!

cleaned out carbs again and got rid of a good bit more crap. looks like it was drawing air too, new seals fitted.

it revs cleanly to 9k now on the road.

power valves are working so i think i will go for more carb cleaning to see if this is whats is limiting the top end.

could PGM problem limit the top end? i would recon PGM's either work or dont, but thats not based on anything other than being male and thinking i know everything.

thanks for the feedback to date, its got me 9000 revs more than i had

m

forgot to say compression was 120psi