One more thing guys.... I'm going to remove the fuel screw and clean that area as well..... however, I have one question regarding the settings when putting back the screw (sprint, washer, rubber grommet):

The 2000 Honda CBR F4 is stock:
How many turns should the fuel screw be screwed in to be set back to OEM specs?
Are there different turns settings for the different carbs (1 - 4)?

Post #267 shows the settings for an F2 with OEM paper filter. Can someone provide the settings for a 2000 F4 with OEM air filter?

Thanks again.

-Nelson

 

Bear in mind, this is the "F2 Tech" section, so all that is referenced here is the F2 carbs - I don't have any knowledge of the OEM settings for an F4, but I do have an F4 manual somewhere - in the meantime, I would pose those questions in the F4 section of the forum... if you do have a manual for the bike, the information will be in it.

 

OK, located the F4 manual:

US 49 state & Canadian bikes - 3 1/8 turns out
California bikes - 2 3/8 turns out

 

Thanks much for the information.
Any info you could share on my previous post #270 regarding the orifice that was not labeled in the walk through?
Thanks.

 

Hello nepelsopon,
I have a 90 hurricane and the carb looks the same as yours but I cannot say it works the same. I couldn't remove that piece (label 4) when I did mine so what I did was I used an air can and spray in it then you can see where the air leaves or of it's return back at you.

I don't know if yours has this but once you take the valve out underneath it there is another screw if you remove it you will see a filter in there, mine wasn't clogged up but I also put them in carb cleaner and brushed them a bit.


One suggestion though, you may want to submerge your carbs bank in carb cleaner. When I did mine it was a pain to put the carbs on the bike then remove them to clean them again. I did this three time as the diaphragm would get stuck and do not slide up and down smoothly, but once I submerge them I also use a nylon brush to clean the area where the diaphragm seat and problem solved.

Good luck

 

hi guys,

i have cleaned my carbs and fitted a dyno jet stage 1 kit. the idle is much better now and upto 4k revs its nice and smooth. around 8k> higher it is like a scalded rat and damn excellent but it has quite bad hesitation when trying to cruise or work within the 5.5k (ish) to 8k (ish) range and if i open the throttle quickly nothing really happens until the revs creep up to 8k. the bike also vibrates quite badly throughout this range.

so with my basic understanding the mains are fine and mixture screw is good at 2.5 turns out (this doesn't impact anything over 3k right ?) so i need to adjust the needle but i am not sure if i need to move it up or down,, it is currently in the second position with the small washer underneath.

any ideas would be great

 

You're right on the money regarding the need to adjust your jet needles, but without riding it or hearing it myself, it would be hard to say if it's lean or rich - what you're describing sounds like it might be rich, but once again, that's not easy to tell from here.

What I would recommend is getting to that 5000RPM area, in 4th gear, and going WOT - when the hesitation begins, try rolling off the throttle a smidge... if it picks up speed when you roll off a touch, you are most likely lean. Do this in 5th and 6th as well, as the more load you have, the easier this little test will be to perform accurately.

If you are lean, then you want to raise the needle one clip position, and remove the shims, for the smallest step up, if this makes it run better in that RPM range, but you think it could be a little better still, then leave that clip position, and then put the shim back in, for another slight step richer.
If you feel you're running rich, then you could start by simply removing the shims, for the smallest step down (leaner), and once again, if it is improved, but still could be better, add the shims back in, and lower the needle one position.

Worse case scenario is that if you are unsure of you're rich vs. lean diagnosis, you can just pick one way to go, and see if it worsens, or gets better, and work from there... it can be tedious, but that's just how it goes with carbs!

 

thanks buddy i will try the little test.

I did throw in the stock paper air filter and it seemed to improve the issue and pulls much better and smoother but it now gets better the warmer it is so I am starting to think its now a little rich.

like you say worst case change it one way and see what happens right :-).

I'll give it a whirl over the weekend and let you know how I get on.

 

Acutally, if the situation improves when it's warmer, then you're probably lean.

Also, if you were previously running a hi-flow filter of some sort, went to an OEM air filter, and it's running better, then that is another indication that you were/are running lean... in this situation, you're restricting air flow, meaning you're richening the overall mixture, so if that change brought an improvement, then that further confirms the lean condition.

 

well it turned out to be rich ?. i dropped the washer out from under the clip and its running much, much better. no hesitation and pulls cleanly through the rev range which is just excellent and tranformed the way it feels. it is still much stronger after 8k revs so I do wonder if dropping the needle down one more position with a washer might improve it even further but i havent got the time to try it for a while and it rides great so i will leave it for now.

thanks for your help