All, I'm not sure if this request should go here or DIY, please forgive me if this is the wrong forum.

I recently acquired a 1994 CBR1000f and need some help. The bike sat a year or so and I was concerned that I may need to rebuild the carbs but when I picked it up it idled and ran just fine. I was told that a sign of the carbs needing work would be that you would need to have the choke on to get it to idle...... Anyway, it does seem to idle just fine without the choke.

The problem is the bike doesn't want to start when cold. It appears as if the choke isn't doing its job. Once I get it running and it's warmed up and I put the choke on it does seem to make a little bit of a difference. I also notice the choke cable runs on the outside of the fork tube instead of between the tube and the frame like the rest of the cables which makes me think the prior owner may have been playing around with the carbs/choke before I bought the bike.

Question:

First I assume the choke works with an enrichment device as apposed to a butterfly.

Second, assuming the first is correct is it likely that the idle jets have clogged from fuel sitting in the carbs?

Third, does the choke cable control all four carbs? Ok, I 'm pretty sure the answer to that is yes, I guess what I meant is are all four carbs tied together and perhaps the choke cable is only working one carb?


Any suggestions from those out there that have BTDT...


Thanks,
Michael

 

Right forum. It would peobably be ignored up above.
The first thing to do is lift the tank and look and see if the choke slider is working correctly. Just take the two bolts that hold the tank off from under the steering stem and lift the tank up. There is a prop rod to hold tank up. Move the choke lever and see if the slider is moving all four choke circuits. I've seen the little fingers that move the plunger not attached on one or more of the plungers so look carefully. If they are all moving, then it will be something else. Possibly a bad choke ciruit or gunked up jets.
FYI My bike doesn't start on just the choke. I need to give it a little throttle, then it starts and idles on teh choke just fine.

 

(1) Yes
(2) Maybe
(3) Yes

I have a '94
My cable runs in front of the left fork turns 90 to the inside of forks and passes thru the rectangle piece welded to the frame just in front of the left side of the tank. You can remove the seat and then remove the two small bolts in front of the tank, you can lift the front of the tank and prop it up with the prop rod under the tank. This give a view if the carbs and cable routing.

Your bike has an auto fuel shutoff that works by engine vaccume. I don't care for this feature. I may find a way to by-pass it on mine. Sometimes I have to crank a while to get it started. The first start of the day is the hardest.

When the bike is clod, here's what I do. I sit on the bike to get it upright. I roll the throttle about 1/2 to 3/4 turn only once. This pumps fuel into the carbs. Too much floods it.
At this point I turn the key to on and start cranking. If it doesn't start I barely crack the throttle a hair. If no starting I back off the throttle and it fires up. Some days it likes a hair open and other days it likes full closed. It stalls about 1/2 of the time but fires back up and stays running.

I don't know, maybe it's me. I don't care either. I am uses to how I start mine and I have a system. I have seen EFI that are harder to start that my bike????????

If you think the carbs are gummy, add some fuel injector cleaner to the tank and ride it.

 

Thanks guys....

Tim (buc two), it sounds like the cable is routed incorrectly on mine. I'll pull the tank up and take a peek underneath over the weekend. Hopefully I won't have to take the whole bike apart to correct this.

In the mean time I plan on running some injector cleaner as you suggested. Am I correct that the only way to get it through the choke system is to drive with the choke on slightly to get "clean" fuel into that circuit?


Michael

 

just drive the bike normal and the jets will clean.