I have a 2000 CBR 600 F4 that I got two years ago. This poor bastard has been in and out of garages and storage units and on trailers probably more miles than it's been driven. When I got it, it needed a Time-Sert to repair one of the spark plug threads that had blown out. Success! Well sort of. As the video shows after some fresh spark plugs and new gas it was idling. BUT it would only idle when it was cold and on full choke. If I tried to adjust the choke or touch the throttle it would immediately die. Once warm, it would refuse to start again. No problem I thought, It's just the carbs being gummed up. So two years and a baby later I'm at a cross roads with this bike. I'm either going to figure out this one last problem and get it running or I'm going to drag it to a sand pit and shoot it with my new AR-15 because that's what us NH people do (kidding). Bare with me on this next part;

I'm pretty handy with a wrench but I'm completely stumped with the bike not running now. Here's where I am now.

1. Pulled the carbs off and cleaned everything and replaced the pilot jets, main jets, cleaned every opening even under the mixture screws, careful reinstalled them.

2.Installed the carbs. Not even a sputter or hope of life with starting fluid, choke on, choke off, airbox on, airbox off.

3. Tested the coils with in inline light and grounded the plug. All spark plugs are getting power.

4. After lots of research on this forum I thought it might be my 16 year old regulator rectifier. Ordered a brand new one, installed, and still nothing.

5. Fuel pump is brand new and getting voltage and priming the carb bowls. I can't tell if it's pumping while cranking the engine over.

6. Tested the stator and it looks nice and healthy. Decided to throw more money at the bike out of frustration. Purchased and installed a brand new pick up coil, fuel relay, and starter relay.

7. Tested everything electrical again to see if I have a ground in my wire harness. Tested the TPS, brake stand lever, ignition switch, and kill switch.


Spark plugs are wet from gas

I tested the pink wire for the security system. I've read that it's suppose to be 9.7V if I remember right. Mine is 10.8v. Could this be my problem? I thought resistors either worked or broke, not kinda worked like this.

I need to confess something... When I put the bike away last summer it was idling. I though I would clean the carbs and it would be good to go. So while I had the the carbs out I put a jet kit in it from carbjetkits.com I know my needles have three shims, my pilots are actually smaller than stock and I forget what my main jets are. Even if I messed up my jetting shouldn't I get some kind if sputter or rough running at all?

Next step will be pulling the carbs, getting the jetting back to stock, and buying some 5.56 ammo just in case.

 

So it only ran with the choke on only at idle. Even after you installed the jet kit. Its getting too much air from so where. When you choke it you richening it up. Vacuum leak somewhere, carb boots not tight or dry rotted/cracked. Synchronising ports not blocked off. Air box not down all the way letting air sneak past the filter.

 

I've never had it running with the new jets. I've been trying to start it with the air box off, sync ports open. I'll try it tonight with everything hooked up. It's getting so much fuel that the plugs are wet and I can see fuel vapor coming out of the PCV line. I've been trying to combat that with more air. Do you know what the pink wire voltage is suppose to be? Thanks for all the help.

 

Tried starting it last night with the air box and hoses all attached. I got a massive fireball out of the exhaust in the first 5 seconds of cranking the motor. No sign of life at all while trying to start it. Any ideas?

 

Anyone??? The carbs are now back to stock jetting, perfectly clean, all the hose lines are connected and I'm still getting nothing. I sprayed starting fluid in the air box and nothing... I know I have spark.