KMX 125 big flat spot and serious mis-fire at highish revs

[boing]

Hi All, new to the forum but not to biking... Have an R1 for Summer riding but have just got my old KMX 125 back on the road for the winter.

However, although the bike starts pretty much first time it really suffers from mis-fires at higher revs, and feels like it has a big flat-spot.

The carb has been rebuilt with new jets, the original expansion chamber is still fitted, but with a "Big One" silencer. I'm pretty sure the fuelling is OK but the ignition seems to cut out, sometimes for 2 to 3 seconds at a time, great when there is a HGV behind you!!

I'm going to splash out on a new coil to see if that resolves the issue but thought you guys might have some words of wisdom...

[pjg351]

you can test the coil before you replace it with a multimeter, might save yourself some $$$, if it's not it.