Hi guys, just wondering if anyone can help. I recently bought a 2001 cbrf4j sport as my daily commute to work. I love the bike- but in cold mornings when I start it I revs at around 300rpm till the temp registers on the clock. Is this fixable? Thanks a lot.

 

Every F4i does that. It's the automatic choke at work. A wax operated unit is designed such that the starter valves(tiny valves on your throttle bodies which feed air at idle when the butterflies are closed) are wide open when it's cold and then expands to push the starter valves cold and drop the revs to the usual idle rpm. The was unit is warmed by coolant btw! On very cold winter nights the was unit contracts much more than during summer so the starter valves are more open in the morning when you crank it up, plus the coolant takes longer to heat up, so this is more noticeable in winter.

 

Thanks for the reply. I might have to change the Micron end can then as I leave for work about 6 and I don’t want to pee the neighbours off!

 

Hmm. I'd suggest you try this out till spring time-
Sit on the bike, slot it into first, then start the bike with clutch lever pulled and let it warm for 30 secs. For most modern engines 30 sec warm up is fine provided you don't go berserk with the throttle immediately after that. Then pull away and let the bike warm up as you make your way through traffic.
The reason I ask you to slot it into 1st before starting the bike is that if you do it when the autochoke is still doing its thing(revs are high)then it'd make a huge clunk and is not good for the gearbox in general.

 

I think the idea of letting a bike idle for 3-4 minutes on the stand is a fallacy.

As in the previous post, ride gently until the bike is warmed up, this will help warm up the whole bike, not just the oil/coolant.