Surging problem?

Hi all,

Hope someone can help, this is for a friend with a 2010 blade..

Problem is; on the motorway, constant throttle at around 70mph, the bike will start surging, like the fule is being cut off for a split second then coming back!?

Mods:

Pcv
O2 eliminator
Running a base map for his setup

He's tried putting in fresh petrol, same problem!

Any ideas?

 

Does he have an aftermarket exhaust fitted?

 

Yeah and Akro slip on

 

Sounds more like an intermittent misfire to me, try load the engine up in a high gear ie just off labouring the engine, and see if does it then.

 

Does it for about 3-5 seconds! :-/ thinking it may be running a little lean, but want more peoples opinions!

Thanks