Hi, I have a slight problem with my 247. It developed a fault recently. It starts no problem but will not rev out. It will pull fine on low throttle openings but when under load it just dies out. I have cleaned out the carburettor and replaced the jets and the float. It has electrex ignition and I was wondering if it may be the spark breaking down at higher revs. If so, is it possible to check for this ? 

Very hard to diagnose over the internet using words.

Can you post a video on youtube of it misbehaving?

 

Change plug, cap and ht (if possible)  Have you checked timing ?

As above plus, check the fuel tank vent is not blocked, check fuel tap filter is not blocked also the filter on the carb, if it has one. Try running the bike down hill and wind open the throttle to get it to cut out and do a plug check to see if it is wet, if so then the problem is very likely ignition. Have you checked the ground on the ignition system? Bye, Peter B.

Done all of the above, wanting to know if it is possible to check the CDI unit. I may revert to the standard system meantime and see if the fault recurs

Also check to make sure the exhaust isn't partially plugged with carbon somewhere. That could cause the symptom you describe also and seem to run ok at low throttle.

Losing power, or gaining weight ?