watsup guys,

i recently got my first cbr...a 93 f2. it only ran with the choke on so i cleaned the carbs and she ran great. the bike however had a slight issue wen you came to cruising speed. it seemed to not be getting enough fuel and lurched very slightly but enough to make me wonder wat was going on. so i took a buddies advice and threw some seafoam in the oil and in the gas, i put 1/3 the bottle in the oil and the same in a full tank of gas. i rode the bike around town for 5 miles or so and it ran just fine, came home changed the oil, topped off the gas, and off i went to go for a little ride. i got about 2 miles from the house and the bike died while i was at a stop light, i nursed it into a parking lot where it still wouldnt start. i was baffled as to why it wouldnt start so i drained the seafoamed gas and put in fresh. still wont start..so i got some starting fluid and that worked but under throttle it died...and after the starting fluid burned up it wouldnt idle...it would just die......im baffled as to whats wrong and if anyone could steer me in the right direction it would be much appretiated. thanks in advance guys

 

Does fuel come out of the petcock when vacuum is applied to the appropriate port?

 

@buic...

not sure yet...me and a buddy are gonna go get the bike tomorrow and bring it home....that will be the first thing i check tho

 

First, no seafoam in the oil. the oil lubricates the clutch too, so you don't want extra crap in there.

You may need to do an extra carb cleaning as the seafoam may have loosened some crap and plugged the jets. Also, if you took the tank off originally, pull the side panels off and check the vent tubes at the back bottom. they fit through slots in the frame and can be easily kinked, even when it doesn't look like they are. Get on your hands and knees and use a flashlight. That was my damn problem for 2 months, even when I took the tank off and put it back on at least a dozen times. its running near perfect now.

 

@mikeinCtown

i always make sure the vent tubes arent kinked...and all the vac lines are right....i was thinkin that maybe the carbs needed to be cleaned again...just didnt want the headache lol....i guess ill pull em off and take a look....thanks for the advice...well see what happens

 

Since it was running, albeit roughly in spots, before, and now not at all, it would definitely SEEM like some gummed up fuel could be blocking jet passages in your carbs. Even though you cleaned the carbs, and even if what you mean by that is an absolute FULL cleaning where all circuits had their respective jets removed, and passages cleaned and blown out with compressed air - putting Sea Foam in the tank could have dislodged some deposits there or in fuel lines, allowing them to get into your carbs. Sea Foam is awesome, and depending on the concentration you use, it WILL dissolve the carbon deposits created by old still fuel, but it's more of a preventitive maintenance then a quick fix. Once again, it WILL do the job but it will do it S L O W L Y, relative to the concentration you use.
If your tank vent lines are flowing, and your petcock opens up when vaccum is applied, then you might want to give the carb cleaning another go -that is, if you feel at all you that might not have been super thorough. The fact that you had to run it choked at first is definitely an idicator of a lean condition of some sort - after you cleaned the carbs, did you still have to run with the choke on? Is the air filter OEM, or an aftermarket "high-flow" unit?

 

ive taken the carbs off and cleaned them again...so thats not it...and all the fuel lines are clear so thats not it...it would start on ether, but wouldnt get fuel after i got it goin...so im pretty positive the fuel filter or petcock are broke...but the petcock flows fuel when vaccuum is applied to it, and wen you take the petcock out and turn the tank over, it also flows fuel out...im stumped! all i can think of is that wen vaccuum is applied by the bike it sucks a bunch of **** down onto the filter and it wont get fuel, but i cant get the filter outta the tank to clean/replace it...i hear its supposed to come out, but mines stuck!!! idk wat to do at this point lol im baffled

 

o and it has compression so thats not it either...and i reconnected all the vac lines to so thats not it either...fml

 

I don't know your experience with carburetors; so I apologize if what I'm going to say seems rudimentary. Firstly, when I first cleaned my carbs, I thought I understood what it meant to clean them. As it turns out, it took me 3 tries to gain that understanding.

I guess the first question is: After you cleaned the carbs and cranked it a few times, did the bowls on the carbs fill back up? If so, then it's not your petcock, fuel lines or fuel filter. Also you stated that it starts with starter fluid, so that rules out compression and spark (for the most part). So, that leads us back to the carbs.

In the bowl, there are 3 copper stems, 2 of which are removable. Did you remove those 2 fittings? Did you blow carb cleaner through the stems? Did the cleaner spray out of 2 other holes? One on top and one in the venturi? (hopefully you were wearing safety glasses when you did this).

On the third removable stem, there is a hole dead center. This leads into the venturi. It's your idle jet. Without this properly cleaned, it will be VERY painful to get it started. This is the things I discovered the 3rd time around. There was just enough build up in there that I couldn't event tell there was a hole! Easiest way to clean this out: take your wire brush. and pull a set of wires off it. You should have 2. Stick one in from the venturi and stick one in through that hole in the copper fitting. You should be able to get these wires to touch! After you get to that point, spray carb cleaner through it. BTW: Make sure you take the whole thing apart before spraying the carb cleaner. The cleaner and the rubber pieces, a match do not make.

OH...here's a question: before you do any of that, turn your carb screws all the way in (not snug or you'll damage it) and then back them out 2-1/4 turns. That's your starting point! You should be able to get the bike to start at the default setting, assuming you have the stock jets and all of them are clear.

 

You can easily remove the plastics and crack open the float bowl on cylinder one with a flat head screw driver. If fuel leaks out, then you're good. If not, you've got a fuel delivery issue up until that point.