I think I read where some guys hate the vacuum style and changed to a gravity feed system. My 93 has the vacuum feed and it seems like it's very tempremental, starting when cold.......it seems like it floods too easily and fouls out the plugs.

Educate me; does a gravity feed system work better in the fuel delivery and will it eliminate some of my issues??

 

I think you're getting two things confused.

The vacume system refers to the fuel shut-off vs a manual valve on the petcock.

The gravity feed is with/without a fuel pump.

Here's a fiche of the 93 f2 fuel system...

HONDA OF TULSA 1993 Honda Street Bike CBR600F2 SUPER SPORT Parts List

It does show a fuel pump and it looks like a manual petcock shut-off.

I'm betting you have a bad float(s) and/or needle/seat on one (or more) of your carbs.
When's the last time the carbs were cleaned and sync'd and had the idle speed adjusted?
That's my best guess of where to start looking for a solution.

Hope this helps, Ern

 

Thanks MH059, that makes sense, mine doesn't have a fuel pump, it pulls vacuum to the petcock from the block via a small rubber hose. I just did a full rebuild of the carbs. It (seems) to run fine when it starts and warms up, just hard to start at times and floods easy......pops a few times then I know to leave it alone. It might need a tech who knows how to "fine tune" and sync them. I thought I did pretty good for my first time (on a bike) cleaning and rebuilding the carbs, started right up after a few few turns. Just don't like such a tempremental bike. I guess that's what I get for buying one almost 20 years old. Thanks again.

 

Where does your vaccume line hook into the motor... i belive thats my problem i have a f3 but the engine i put in may b out if an f2 ... i have two empty lines off the back of my fuel tank (f3) was told they are a vent ... when cold if i hit the start buton it will Start and idol for about 4 or 5 seconds then die .. if i give it gas itle just die .. not even try... i cleaned carbs ... i dont have a sink tool so i didnt remove any jets or needle and seats

 

Wrecker, you just described what mine did/does at times. Believe me, I went through my carbs pretty thorough.....the PO had jetted it cause of a K & N air filter and slip on Two Bros exhaust. I returned it to stock (135 main jets) but it still seems to have a (few) issues that I'm not pleased with.

The (small rubber) vacuum line is attached to a nipple on the left hand side of the block, just under the end carb (not sure what number that is) and runs to the petcock. I also have two "vent" line coming off the petcock that fits in to two holders on the frame and just hangs there. I don't have a sync tool either so I sort of played with the idle screws until I thought it felt right......probably not the way to do it but it started right up and idle pretty good for winging it.

Did you check the slow idle needles to make sure they are turned out the same amount of times? I have mine turned out 2 turns per this site. Hope this helps.

 

Tort93f2
i will have to check the manual unles you can point me to the screws without checking .. i have a nipple coming off the block low left side but it has a coolent hose on it hooked to the thermo valve.. scratch that that one is coming off the head .. no ports on the block that i can find and and one nipple on the pet **** .. must be a difference between the f2 and f3

 

Check out this thread, it will help a lot...

https://cbrforum.com/forum/f2-tech-9...g-101-a-96888/

on a side note, the two pipes at the bottom of the tank...the smaller one is a tank
vapor vent, the bigger one is a drain for around the recessed rim of the gas-cap.

I believe the F2's use a vacume petcock, powered off the #1 (left-most) carb.
The connection is actually below the carb, poking out from the cylinder-head.

Ern

 

Wrecker, MH059 said it perfectly......the photos in his attachment also shows it as well. I used that thread to help rebuild my carbs......priceless! The f2's have the rubber vacuum hose set up, the f3's have a fuel pump (no hose).

 

Oh, by the way..........as mentioned, mine has been idleing pretty rough so I desided to take it out yesterday for a spin, you know, blow some gas through the carbs to see if I couldn't smooth it out. Well, it ran like crap, missing, no power, sputtered and died! Had to push it home, up hill.....man was I pissed. Got in the garage, ready to shot it or light it on fire.............then realized I ran out of gas. Switched to reserve, drove her to a station, filled it with fresh (premium) gas and drove her for 30 minutes.....ran great! I can't wait to see if she'll start and run tonight.

 

Tort, you mentioned in a previous post that you restored the jets (the mains anyway) to stock - did you also install a stock air filter, or do you still have the K&N?
If you are using stock jetting, you should really ditch the K&N, and go with an OEM type paper filter, for optimized power.