96 F3 wont idle

96F3-Matt · 04-17-2008, 2:06 PM

I left the pecock valve in the on position during the winter by acident or my brother went in the garage and was messing with it. any way i couldent get the bike started so i changed the plugs and oil and sprayed some carb cleaner in to the carbs... now the bike will start at full choke and idle at full choke and i can take the choke off gentaly and some what get the bike to idle... It is still not strong though .... any thoughts >>> i think it might need a new jet because it is cloged some where any ideas on how to clean them out... or get the bike running smooth???

SoCal94F2 · 04-18-2008, 11:41 AM

If you let a bike sit for a log time and fuel in the carbs are allowed to evaporate, then you may have resin clogging up the idle and pilot jets. If you had to crank the idle up from its pervious position, and the bike feels sluggish in the lower rpms but better at higher rpms then this might be the case. It is not too difficult to clean the carbs if you have some basic mechanical aptitude.

To clean the carbs, you need to remove the tank and in some cases remove the right side triangular motor mount plate (depends on how small your hands are). From there you can loosen the carb boots at the engines head (not the carb side), remove a few of the vacuum lines to the airbox (make note of where these connect) and gently rock the airbox and carbs as one unit off the bike (easy trick way). Now flip the airbox over and remove the fuel bowls one at a time.

If this is your first time, it may be easier for you to remove the screws that connect the carbs to the airbox and remove them sepperately. This is also a good time to Jet Kit if you havent done one before

They have easy instructions to follow.

http://www.musclecross.com/jetbox/we...loat-carb5.jpg

There are three copper looking tubes which extend from the carb into the bowls (see link above for picture). The one that only has a hole in it without a flathead slot is the idle jet (far right in the pic). Use the wire from inside a twistie tie to clear that passage of any blockage, the hole is extremely small inside the tube. Next go to the pilot jet which is on the far right in that picture, use a flathead to remove it and clean all the passages on the pilot jet. Finally, since you are already in there, just pull the main jet and make sure it is clear (they almost always are - too big of a hole to clog). Put the bowl back on and you are done. Repeat this for each fuel bowl. Take your time and pay attention to detail. Reverse your disassembly and your done. Be careful not to twist your throttle cables by rotating the airbox all the way over instead of flipping it back the same way you originally turned it over.

96F3-Matt · 04-21-2008, 10:13 AM

awsome thanks for the help i know how to get the bike down to the air box being completly off do you know any where on the net to show me a diagram of pulling the carbs off???

SoCal94F2 · 04-21-2008, 12:38 PM

I keep telling myself I'll make a tutorial on that becuase I've never seen one out there... but I never got around to it.

cbr joe · 04-22-2008, 8:51 AM

i just did the EXACT same thing...my mechanic told me last nite it's my pilot jets!

joe

cbr joe · 05-20-2008, 9:39 AM

just curious, but what ended up happening with this?

joe

17% · 08-09-2008, 3:39 AM

i also want to know

SoCal94F2 · 08-09-2008, 4:07 AM

If it helps, I finally wrote that tutorial:

Musclecross Forum / Carb Cleaning and Tuning Guide - CBR 600 F2 / F3

Corvus · 08-26-2008, 11:24 AM

It really, Really helps! Thanks for taking the time to do this.

I'm trying to revive an F3 that sat for years in someone's basement, and the jets and fuel passages are completely plugged with evaporites (or whatever you'd call them

from old fuel.

cbr joe · 08-26-2008, 11:30 AM

wow!

That is definite STICKY material!

Well done SoCal94F2.

joe

SoCal94F2 · 08-28-2008, 2:27 PM

Thats one of those how-to's that every F2/F3 owner should learn by heart. The dang carb system clogs up so easily and taking it in every time is just a waste of money. Of course moving to Fuel Injection eliminates that need all together now.... glad it helped!

Corvus · 09-03-2008, 4:19 PM

Gotta say Thanks again SoCal! I worked on my terrible F3 carbs for most of the weekend... and now it not only runs but it rips!

The culprit was primarily the idle jet (the non-removable one on the right), so your comments about that being a 'major offender' really sent me in a good direction. Once I got in there, it was clear that no compressed air could be forced through the idle jets... and the 'slow' aka Pilot jets weren't great either.

I removed the diaphrams, etc., then sprayed carb cleaner in each of the idle jets (as well as soaking the removable ones). After a few hours, I then used short pieces of guitar string to unplug the passages, and finished with about 15psi compressed air in all passages.

I also found a couple of small mistakes from when the previous owner installed the DynoJet stage 1 jet kit : Both decel circuit plugs were put into the #4 carb circuit, and the other was left open. Also the floats were a bit high, like about 14 to 14.7 mm instead of 13.7 mm

Now I need to get it to a dyno to check air/fuel ratios... I may yet get this F3 racing (WERA vintage) this year!

D

SoCal94F2 · 09-03-2008, 7:03 PM

Nice!!! Guitar string (high E) is an excellent choice for unclogging the jets. Nice catch on the decel circuit too. Congrats!!!