f4i doesn't like to rev
 

hello lads, today my f4i tought it was a good idea to start messing with me.

problem: rev it above 8,000 and it cuts off. no matter if riding or not. it will not turn completely off but it goes down to 500rpm and then resumes idling and works completely fine again until you hit 8k+ rpm.

and then the strange part, with the lights + fan off (manual fan) it will sometimes rev happily to redline but not guaranteed.

lights + fan back on and same problem will never rev above 8k.

anyone know what it could be?

bike was working fine yesterday and the days before, this problem came out of nowhere.

Oh and also the lights dim when revving it

I'm not particularly adept with electrical issues but I'd say to start with your rectifier and/or checking your ground wires. Here is a good overview on the charging system and how to test the components (it's on a RR, not a F4i, but close enough) -
Hope that helps!

Thanks. Battery voltage is 12.9 with engine off, 14.5 with engine on.
But as soon as i flick the fan on battery voltage drops to around 13.2

Sounds like the fan might not be hooked up correctly but there is clearly something else going as well. My expertise in this area is extremely limited so hopefully one of the more knowledgeable folks will chime in!

That could be, however the fan has been working fine for the last 3 months and I have not changed anything electrical other than a LED headlight instead of Halogen.
My new fairing set will arrive next week so I really would hope to get the bike running properly until then :/

Dang it bought a new battery today since the old one has been in the bike for ages however that didn't help at all either. Also when revving it to 8,000 it sounds now like a slow rev-limiter, battery voltage drops to 5-7volts for a millisecond everytime it bounces off the 8k 'rev limiter'

New spark plugs did not help either, any help would be appreciated!!

Was checkkg voltage at fuel pump, as soon as it hits 8k rpm fuel pump gets 0 voltage, now the bike doesnt even want to prime everytime.. Sometimes it will get the 12volts to pump to prime it but some times nothing

Alright what the hell this is the weirdest problem ive ever had, i flip the ecu upside down and it works like a dream as soon as i flip the ecu to its original position its not working properly anymore