Carburator question on a '91 Honda CBR600F2

Timothy1959 · 07-20-2009, 8:47 PM

Carburator question on a 1991 Honda CBR600F2.
On the bottom (underside) of each vacuum piston, inside each carburator are a pair of small holes. One of each pair of holes is plugged with a small rubber plug.
Can someone tell me what these holes are for?
Should they BOTH (or neither) be plugged?
The factory manual and parts fisch is no help at all.
This seems pretty lame for Honda!

Cbrfrenzie · 07-21-2009, 1:32 PM

When a jet kit is installed they specify that you fill one of these holes up in each slide. This affects the rate at which the slides raise, as the jet kit is designed to be operated in this manner. IF you have a jet kit installed (different needle and longer spring) then leave it as is... if it is stock, then take them out!

Timothy1959 · 07-22-2009, 12:14 AM

Quote:

Originally Posted by Cbrfrenzie

When a jet kit is installed they specify that you fill one of these holes up in each slide. This affects the rate at which the slides raise, as the jet kit is designed to be operated in this manner. IF you have a jet kit installed (different needle and longer spring) then leave it as is... if it is stock, then take them out!

THANK YOU for the advice!

I discovered that I do indeed have a jet kit installed. I got the bike used. Now I know which parts to replace to fix the bike. I am going back to stock.

Cbrfrenzie · 07-22-2009, 10:30 AM

Quote:

Originally Posted by Timothy1959

THANK YOU for the advice!

Now I know which parts to replace to fix the bike. I am going back to stock.

You are quite welcome! May I ask why you are going back to stock? Jetting the F2 does quite a difference, especially if you are 2000+ ft above sea level. If you do stick the stock needle in there, keep the stiffer spring for a quicker throttle return. What altitude are you at, I'll give you the size of jet to use for that range. Also, what mods are on the bike?

Timothy1959 · 07-22-2009, 11:12 AM

Quote:

Originally Posted by Cbrfrenzie

You are quite welcome! May I ask why you are going back to stock? Jetting the F2 does quite a difference, especially if you are 2000+ ft above sea level. If you do stick the stock needle in there, keep the stiffer spring for a quicker throttle return. What altitude are you at, I'll give you the size of jet to use for that range. Also, what mods are on the bike?

Sure, I am going back to stock because the bike has a SEVERE flat spot on the mid range. I am a perfectionist when it comes to engines. They MUST run SMOOTH at ALL SPEEDS, perfect idle, EVEN power band, no stalling, FAST warm up, etc... I am demanding, but I know Honda can do it, because they are very well designed machines. The extra 7 HP is not that important to me. The bike already has PLENTY of power! It is a TRUE CROTCH ROCKET !!! :-)