Bike was running great, all of a sudden comming out of a corner, felt like it ran out of gas(boy that was fun). It still had gas, so assumed it was the fuel pump. So got home and tested it and this is what I found. It will start and run with the choke on, but as soon as you load it, it dies. Off choke it slowly just boggs down and dies(under 5 sec). If you attempt any throttle movement it immediatly kills the engine. I am very familiar with cars, but not so familiar with bikes. I've assumed its a lean condition so i've tested to the best of my knowledge the fuel system... the fuel pump is working, (the appropriate flow rate I don't know---no means of measurement) But it seems to be only when demand is needed. If you jump batt power, it runs constant and good flow ( I would guess the 3 1/2 lbs needed). But when on the bike and ignition on, it will sputter intermittantly. Have tested the fuel system using the honda manual and common sense, relay is fine, seems to get the signal from the spark unit/pulse generator (flickering test light), the petcock screen and the fuel filter are not plugged, but yet has lean condition feel. I've seen other posts with similar problems that state the charging system is to blame,... Charging system is fine. Any help on this would be greatly appreciated, this has been driving me crazy for some time, and I don't want to start throwing parts at it or mess with carbs unless needed. THANK YOU

 

This exact thing happened to me last weekend. Tested the fuel pump, it was fine, check the filter and petcock and those were fine. Then i figured i'd check for spark. I pulled 1 plug, had spark so i put the plug back in. Pulled the next, and hit the igntion to test and it wanted to start up. So i put that one back, and didn't start. Went to the next plug and pulled it and it started up. So i put it back and it ran perfectly.
It has been fine since, though thats only 6 days and a couple of rides. I put i new battery in (i had been trying to stretch to its death) it seemed not to hold a good charge. With the new battery, I basically flicked my finger at the ignition and the thing started right up...i was like WOW, amazingly fast start up.
All i could figure was that either something clogged the carb and me pulling the plugs created enough of a pressure difference to clear it....or the spark plug boots had disconnected.
So I guess really the only thing i can say to do is pull the plugs one by one. Thats not the most informed suggestion, but it worked for me with the exact same symptoms.
Good luck.

 

i would make sure the plugs are not fouled and getting spark, i had the same problem *AFTER* i had my carbs cleaned, turns out the #3 carb's main jet had come loose and fallen out and was laying in the bottom of the float bowl. you might also want to lube and adjust the throttle cables.

 

that sounds alot like a spark problem....plugs and wires are always cheaper than fuel system repairs...and it's easier and cheaper to start there...

 

here is a list of things to check as per honda repair manual.

engine idles roughly, runs poorly or stalls.
- improper choke operation
- ignition malfunction
- fuel contaminated
- intake air leak
- incorrect idle speed
- incorrect carb sync
- incorrect pilot screw adjustment
- low cylinder compression
- by-starter valve stuck open
- damaged by-starter valve seat
- rich mixture
- lean mixture
- clogged carb
- faulty purge control valve (ca. model only)
- faulty air vent control valve (ca. model only)
- faulty hoses of the emission control system (ca. model only)

lean mixture
- clogged fuel jets
- faulty float valve
- float level low
- blocked fuel tank cap vent hole
- clogged fuel strainer screen
- restricted fuel line
- clogged air vent tube
- intake air leak
- restricted or faulty fuel pump or relay
- vacuum piston stuck closed

incorrect fast idle speed
- incorrect choke cable free play
- choke valve stuck or damaged
- choke valve not adjusted correctly

 

Hey mate I have the same problem. Any luck yet? I've done pretty much the same things you have. Let me know please.

 

nice digging.......what is the condition of your bike, has it been sitting? have you ridden it lately or did you just purchase it? how long has it been doing this? and have you ever had the carbs apart? there are tons of suggestions above already, what have you tried or not tried?

 

I've got a thread going on this will all my details. Check it out and see if this matched up with you.

https://cbrforum.com/m_340310/tm.htm

Jack Riddley

 

hey bro i read your thread and it sounds like you have eliminated it being a fuel problem. as for my bike i tore apart the carbs and found a stuck needle and some crud in there. also i change the plugs at the same time while i was there, and that took care of my problem. i dont know how much electronics a 93?? has on it, but my guess is its going to be there. if it were ignition related i would think it should happen under the same load no matter what rpm. so if you have a manual find out what sensors arecontrolling the ignitioncircuit, ie crank sensor, cam sensor, thottle pos sensor, etc. but the guys at the shop should know this better than you or i. well dont know if this helps, good luck and happy hunting.

 

so mine was a missing jet, yours was stuck needle and clogged jet, seems like we have a 'carbs not working' scenario for these symptons.