CBR600-FW 1998 - 8,000 miles. I've had this problem twice now. Engine starts fine from cold, and then allowed to warm up. Then engine won't rev over 4000 - 5000rpm. Sounds and feels like like fuel starvation. Eventually engine died, and the 1st time it started after a few mins and was fine. The 2nd time it would not re-start. Removed fuel tank and fuel seems to be clean and flowing ok from tap. I see a few things it could be: in line fuel filter, fuel pump, or solenoid valve. Also someone else had problems with fuel tap vacuum diaphragm. Any ideas? or anyone had same problems? thanks

 

stuck at 5000rpm makes me wonder about the main jets in the carbs....isnt that when they are supposed to kick, somewhere around there?

Besides that, yeah fuel starvation....

I'd start by pulling the fuel line off between the carbs and the fuel filter. Turn the key and see if the fuel pump is pushing fuel through. If not, start working backwards...

 

I had a simular problem. It wasn't the air solenoid but close. Since this is carb'ed the bowls need to be equalized be cause of the direct air (I call it RAM Air). This is done with the D.A.I. or Direct Air Intake system. You have two lines that feed the air solenoid. Make sure the one (split into two)sticking out under your head light are connected to the air solenoid. This ram air is what creates equal pressure in your carbs so the bowls can refill with gas. That is why you are only able to get to so many rpms and a certain speed. Once the bowls are depleted it's basically a trickle of gas untill there is no more and the bike starves out. Send me an email if you have further question. Also, I posted all of my trouble shooting while I had this problem so look it up. It might help. Cheers Mate!

Jack Riddley

 

Many thanks guys. Jack - thesymptomsareexactly likeyou describe it. Was your problem only intermittent like mine tho? This has only happened twice since I've had bike (a couple of months)
Tank venting seems ok. Fuel pump is pumping ok.
I'll have to remove tank again to check the DAI hoses like you said, although I couldn't see any disconnected before.And its running fine at the mo.
If the hoses all look connected up ok, and no blockages, what else could it be?Maybe the solenoid valve. How can i checkthis is working correctly and what activates this solenoid valve?
Also does it make sense to you thatI had this problem one day but the next day it was fine? (when starting up from cold) What was your problem in the end?

 

Jack: I just read all your previous troubleshooting on this problem and I should also say that my problem (of restricted revving and straining to rev freely) happenswhen the bike is stood still, as well as when its moving. Your problemseems to only be when bike is moving (due to RAM air) Does this still sound like the same cause? My problem also seems to occur from cold, and when bike hasn't been run for a week or so. Cheers Tim

 

I had a similar problem....turned out that my fuel tank vent line was crimped. If it happens again, open the gas tank immediately. If you hear a whoosh sound of air sucking in, it's a blocked or crimped vent line.