OT CBR600 Running BAD!

[Good]

Guys, I know this doesn't belong on this forum, but the only other forum I belong to that is motorcycle oriented is www.pashnit.com and they don't have a tech section and there are so many really intelligent tech guys here I thought you might know what I'm up against.

I have a '98 CBR600 F3 Smokin' Joe edition with just over 6000 miles on the odometer that I picked up from a buddy last year with around 3000 miles on it.  He owned it since new.  Well, we've been getting our monsoon storms here in AZ so I haven't been able to ride street much, so it's sat under it's tarp-like cover for about a month.  When I parked it it ran fine.

Problem:  I started it the other day and it would start with the choke on, but as soon as you turn the choke off, it immediately dies.  If you try to give it any gas, it immediately bogs and will immediately die if you don't let off the throttle.  It will, however, idle indefinitely (although very poorly) with the choke on.  I started it on two different days with the same results both times.  Do you think it could be in the bike's intake not getting air or something?  I tried changing the fuel petcock to reserve and back to on and it remains the same...

I cannot state it enough, I'm not a mechanic and the nearest H**** dealer is 120 miles away.  I don't know where to look first.  Please help!  Thanx,


Tim.

[KXcam22]

Good,
There are two possible culprits.  One is that you have gotten a lot of water in the fuel.  The second is that your pilot jets are likely plugged with deposits.  The choke circuit opens a bypass to enriched the mixture, which is what keeps the bike running.  I would check for water first since it has been raining there a lot(and is the easiest).  Hope this helps. Cam.

[BDI]

I would have to agree with cam. I would drain out all the fuel and clean and synchronize the carbs. What ever you do don't flush the tank with water it will flash rust and you will never get rid of it. Once it starts it will continue to get worse and worse. The symptoms you give are pluged pilot jets all the way.

[Good]

THANK YOU GUYS!!!  I messed with it all afternoon yesterday to no avail.  I'll drain the tank today and see if that's it!  thanks again.

[BDI]

Your just beating your head against the wall and wearing out your starter. you need to drain the tank and clean the carbs too. Any time you pull and clean carbs on a street bike they should be synchronized after you put them back on. If I was you I would buy a carb synchronizer and a shop manual for the bike or load it in your truck and take it to the shop. Good luck

[Danger4u2]

Pull the tank and dump the gas into a white bucket to check for crud in the gas. I would pull the petcock and clean the screen.  Blow it out with low pressure air.  Blow out the tank also.  Of course do this outside away from the compressor.  They can make a spark when they kick on.    I would pull the carb bowls and look at them, if if the bowls look clean you might not need to tear them apart.  If you don't want to tear into the carbs at least turn the little screw that drains them.    Most tarps made in this day and age (China) are not water proof.  It just keeps the sun off the bike.  When the sun comes out after a rain the tarp creates condensation on/in the bike.  Like the others it sounds like a fuel problem.  I would also pull the ignition cover and take a look.  Might be moisture in there.  Check the air filter.  Check all the easy stuff first.  Pull the spark plug caps, blow in them with air.  Put them back on, pull them off again then stick them back on, to make sure it has a good connection.

[KXcam22]

Also remember that gasline antifreeze (methyl hydrate) helps any water get dispersed into the gas where it will get burnt (within reason).  On the 600 (like my 900) the floatbowl drains are easy to get at.  I like to drain them onto a piece of white paper towel as it acts like a filter and you can easily see if any crud is left behind.  If you need to pull the float bowls off it is far far easier (an faster) to remove the whole carb bank, flip it upside down, and do it on the bench.  Cam.

[Good]

Thanx guys.  I drained the tank and put fresh gas and it seemed to help, but it still runs bad below about 4000RPM (13,500 redline).  I can give it throttle now with the choke on though.  Once the RPMs are up I can turn off the choke and keep it running with the throttle above 2000RPMs, although it pops a bunch and alltogether runs poorly.

Should I drain my bowls to look for debris?

[KXcam22]

Yes.  There is lots of room to put an inline fuel filter in as well to prevent future problems.  Cam

[gowen]

I'm with everybody saying your pilots are clogged, it is possible to ignore the pilots and they MAY clean themselves out over time, but as BDI said, with the pilots clogged, the carbs are out of sync. Removing them will help getting them out of sync. My old d**ned R1 had issues with the carb and it ran like s**t until I sync'd the carbs. Good luck, sportbike carbs are a pain in the ass. I was so glad when they released FI bikes.

[demographic]

Yet another vote for blocked pilot jets, I have had a few bikes over the years with those symptoms and its always been blocked pilots thats caused it.

Generally if the bikes been sitting for a long time without being used.

[BDI]

I'm with everybody saying your pilots are clogged, it is possible to ignore the pilots and they MAY clean themselves out over time, but as BDI said, with the pilots clogged, the carbs are out of sync. Removing them will help getting them out of sync. My old d**ned R1 had issues with the carb and it ran like s**t until I sync'd the carbs. Good luck, sportbike carbs are a pain in the ass. I was so glad when they released FI bikes.

    I spent years learning about street bike carbs and untold dollars on carb tools,books, exhaust analisers and the like. I even have this really cool pyrex spark plug that lets you see the fire in the combustion chamber so you can set the pilot screw by the color of the flame front. After all this, the thing I learned is that carbs suck, fuel injection is the way to go. The bike I have now is an FI bike and I have never been happier. The cool thing about all of this was that when the thumper dirt bikes came out I already had a very strong grasp on what was going on and all the tools to work on them and they are one fourth of a pain in my ass to tune. I cant wait to tune my bike dirt bike with a lap top

[Good]

Thanx for all the help guys, I really appreciate it.  I drained the fuel added new and it's running a lot better, but still not great.  It will run without the choke on and I even went for a ride the other day.  Rideable, but not perfect.  I dunno what happened as it only sat for about a month, but whatever happened, it clogged the carbs.  I need to have a mechanic with all the tools clean/sync/jet the carbs.  Now, where to find such as he...