Well,
my nc35 is currently only making 46bhp on the dyno and taking a very long time to make it ,the bike is derestricted, it's running with a full tyga system(jetted to suit), carbs balanced, valve clearances done.The guy in the shop reckons that it's an electrical problem .They have tried 2 other cdi on the bike and it made no difference so that is ruled out. Is there any other possible causes for this or has anyone ever come across this problem before?.

First things to check;
vacume hose and fuel line
reg/rec
battery

the bike has no problem starting and is getting fuel.

Yes these bike are prone to the vacume tube collapsing when they get warm (when the vacume tube is old and worn) and this causes fuel starvation. The bike will tick over fine but when you give some throttle it can struggle. What charge are you getting across the battery?

Both are fine thanks anyway!

Does it idle okay?
Is the issue in each gear after a certain amount of revs?
Did you have this issue before the exhaust was fitted and jetted?

jetted to suit... with what jets?

Can you show us the dyno graph please?

It has 110's all round . I'll try and get the graph's of the shop and get them up for ya.

what airbox and filter?

all standard