Probs with CBR600fx..

ok...wondered if anyone had any advice on the problem i am experiencing with my CBR..

The bike rides fine, however if when i first start it up and ride off..as soon as I hit about 25/30 mph the acceleration dies (almost like a fuelling issue) and then all of a sudden will kick back in at normal speed....then it dies again.....it does this for a couple of mins or so and then the bike is fine to ride.

In addition, the speedo needle drops to 0 at the same time....as soon as the bike kicks back into life the speedo returns to the speed it should be at...

The rest of my dials remain ok...

The bike does ride along when this happens, albeit at a reduced speed....

quite hard to explain online but it seems odd that it doesnt do it all the time, only when he's started up ..

I have tried letting him warm up for quite a bit before i take him out but that doesnt make a huge amount of difference...

:DHELP!

does sound like a fuel issue iam thinking choke, bike hasnt warmed up as its only on start up,but as you have been allowing the bike to warm up before setting off counts this out,as the speedo is dropping to zero at the same time iam thinking you must have an electronic speedo fitted in wich case maybe you have electrical short effecting the ignition system.

the bike still stays 'alive' when it happens...the lights etc stay on just the speedo dies and the power drops...

could this still be an electrical prob?

hi iam not that hot on modern bikes as i ride and restore vintage bikes but it is possible you have an electrical fualt as the ignition and charging/lighting will be on seperate circuits,is the engine still running when it cuts out or does it just lack power?

The weather has been crap lately freezing cold and damp seems like you could have a short somewhere either on Plug caps/HT leads or coils.So it might even be firing on only 3 cylinders at some point.Spray WD40 or similar on the plug ,HT leads and around the coils see if that makes a difference

I have had the prob since i got the bike in July..

TB - the engine does still run...just on reduced power...almost feels like the fuel isnt getting through but im not sure why it doesnt happen when the bike is warmed up and how its linked to the speedo... >:(

HS it does sought of throw a spanner in the works if you have had the problem since you bought the bike ie its been doing it in wet and dry conditions,i thought alans sound advice would have you soughted and was thinking along the same lines myself,it is worth checking for loose connections around the coils and the ht leads and caps and spraying with wd as a process of elimination.the reason iam thinking it is an electrical problem is because the speedo is dropping to zero it may be wired in to the low tension circuit?if you had a mechanical speedo it would still register a speed.if you still have the problem after checking the above i would have a look at the fuel pump check its got a good earth and all the connections are good make sure the ignition is turned off beforehand sparks/fuel not a good idea :o do you have a workshop manual allways worth buying if you intend to do your own maintanance.did you buy from a dealer they should help you if the problems been there since you bought the bike.best of luck let us know how you get on. steve :)

thanks for all the advice ! will let you know how i get on! I have 2 weeks off over crimbo so it should keep me busy! ;D

afterthought when was the last time the carbs were balanced they might need doing but depends on mileage you have done since getting the bike.if its about 4K get them balanced then aleast you know that the carbs are ok then.Its a start!
Though it still seems its electrical

the speedo is telling you whats wrong, if you ring a helpful honda dealer they may diagnose this...
is the FX the first fuel injected model?
if it is i would suspect a throttle position sensor (but then again im just guessing)............

It could be the TPS as JD says there is a sequence on how to check it if its in the right position, on the TDM there is a sequence but cant remember off hand but i have to line the Tacho needle up with the 4Krpm,Also if the speedo goes up to a cartain rev limit or down for cerain number of seconds that tells you where the fault is .If it hasnt got fuel injection you could still have a TPS my TDM is only carbs.
Best bet is to buy the Haynes manual for your bike it should tell you about it in there .