Hey guys, new to the CBR world. I have an 87 cbr600. I just got it from a guy and tried to pass emissions to get it registered to no avail. Idle standard i need to meet for HC is 1800 PPM, i was at 2654 PPM. The bike is currently idling at about 1500-1600 RPM. Any assistance would be great guys thank you.

 

Doug is the choke returning all the way home - she's not idling this high because
the choke is partially stuck ? That would dump extra gas in and make it read high

 

Check for a vacuum leak, carb boots and stuff. High HC means its lean.

 

Hey guys. So i turned the idle up a bit more to about 1600-1800 rpms. Still failed but down from 2654 to 2301. Tried one mroe time after double checking all vacuum lines and boots and everything and turned my idle down to about 1100 and failed even worse at almost 2900 PPM for HC. I did notice however that my bike likes to fluctuate at idle by about 300 rpms or so. So could it be i have a misfiring cylinder due to bad wires or plugs maybe. I know that would cause me to fail cuz if its not firing right its not burning all the fuel right. Let me know if you guys can come up with anything else thanks

 

Is it running poorly?

 

Keep failing and they'll require you to call in and get permission to run again. Do some real work, IE replace plugs, sync and adjust carb settings, replace air filter, THEN go back.

 

Agreed; do an actual tune-up first, THEN re-check. New plugs and air filter, and a carburetor clean and balance is a good place to start. Check for cracked or broken hoses and other rubber parts during the process. If you can't or don't want to do it yourself, I've had good service from Sportbike Solutions (Jody) before.

A good-shape and decently-tuned (meaning totally factory-stock, with proper and even compression, but simply with a relatively fresh tune-up and carb balance/synch) F4 will pass emissions here so easily it's not even funny. It'll show half or even 1/4 the allowable emissions limits. I don't see any good reason for any of the Fs to be particularly worse.

 

Something that may help with borderline results that I've seen with cars is to be sure that the bike/car is fully warmed up, not just up to temp after a cold start and idle. A decent 15-20 minute or so drive just prior to testing will allow temps to fully stabilize and usually produce the best results. As mentioned previously, a tune up is a great place to start.

 

Ok so I did a little test a buddy told me about.... I started the bike and pulled the wires off one at a time to ensure I was even getting spark to all cylinders first and sure enough I am running on 3... So I pulled the plug from the cylinder that wasn't firing and the spark plug still looked brand new so I am pretty sure I found my problem...

 

Ok guys so after that happened a little bit ago I replaced the wire and took the carbs off and cleaned em... Still only running on 3 cylinders... Plug was wet with fuel still so that's not an issue and there is pressure in all cylinders... What I wanna know is what might allow it to run perfectly fine on 3 cylinders and totally bypass the 4th...