So I've got 2000 cbr 600 f4 and it had bad gas left in it and wouldn't start so here's what I've done so far...... This is my first bike and pretty well no nothing about it but I wrench on anything all the time so I've done the usual and took off tank got new gas, change out new lines, and had to finally pull the carbs off which was very terrible! And had to change the o rings on the two tees that connect to fuel lines they were leaking.. so I've took carbs all apart checked over everything and clean it all out everything back on fixed leaking gas and changed spark plugs as well .... It will start right off the back no problem now after I've done all this in the past week, here's the thing it only will stay running with choke switch all the way pulled down but when it gets warm and I push it back up bike falls on its face every time, I've driven it and still can't get it idle with out choke so I'm just curious if I need to check the jets on carbs cause I thought I cleaned them well but I'm new at this and I've been reading slot of advice on here and videos that's has gotten me this far so any and all info for this new rider would be greatly appreciated cause I'm ready to ride. Thanks

 

How did you clean the jets?

 

Intake leak or carbs not cleaned and adjusted properly would be my guess.

 

Pulled everything apart and just went through it with carb clean... My step dad left gas in it and it got pretty bad

 

Yeah, you should really clean the carbs. Just going through them with a spray carb clean isn't enough for your slow jets. Also make sure you're getting a good seal on the CV slide

 

Ok got ya what's best to clean jets

 

I like a carb dip on all the jets, emulsion tubes, etc. - anything metal. I've also boiled carb parts before in water. That worked well, but when I'm not in a hurry to get something done, I'll just let the carb dip do it's thing overnight.

Some people buy ultrasonic cleaners, get great results with them, but I've never used one, so I can't really comment on it.

 

I have a Harbor Freight Ultrasonic Cleaner. I use it with Krud Kutter and it works very well.
I've also used the methods Conrice recommends and they also work great. When I boiled mine, I used some lemon juice in the water also.

 

Well I will give these things a shot trying to avoid shop work at all cost I got it this far before it wasn't running now it will but only with choke so I will try these ideas thanks much freinds

 

You don't need a shop! Just remember, much smaller jets than on a car. This means they clog easier... My guess is you can't see through your slow jets.