Sportbike Racing Forum banner

CBR600F3 fuel or ignition problem?

7K views 15 replies 5 participants last post by  JDog 
#1 ·
Been a long time since I have been on here.. Anyway, my 1995 CBR600F3 sat outside for about a year. I started it earlier this month ran fine, rode down the street and no problems. I took it out two days ago for a 5 minute ride shut it off and when I went to start it again the battery was all but depleted so I get it charged. Next day I go to start it and starts fine, but can't get the RPMs high without it bogging down and stalling( i can get the RPMs a little higher with choke on). Eventually I guess I flooded it out completely because I can't get it to fire and killed the battery again. Time for a new battery, I guess.

So I start taking the fairing off to check the plugs, check for spark and the limited stuff I kinda know how to do, but the spark seems fine on all cylinders (just a visible spark no accurate measurement). So I fiddle around with it a little while and end up getting it started with no tank on it (runs now but still with same problem and some back firing when I rev it higher). So i put the tank on and turn the gas on, but no go. Turn the gas off and try after a few seconds it starts; so as its running I turn the gas on and it almost instantly cuts the engine off.

Am I dealing with a gunk build in the carbs from untreated gas sitting in the tank? Is there anyway to treat without removing the carbs (or a shot in the dark). Am I even thinking in the right direction? The only other odd thing is there is a slight exhaust leak out of one of one cylinder from the exhaust manifold.

Anyway, thanks for the help in advance. :)
 
See less See more
#9 ·
Drained carbs and fuel seemed to come out, difficult to tell about the water. I poured some seafoam in there (bad choice?) to let it sit for a little and hopefully work some magic to save me from pulling the carbs. I've got everything pretty much stripped down, but my carb experience is about as much as a single Carb on an 1986 XL100S; really simple on that.

Now if I end up having to pull the carbs, I thought I remember hearing something about you have to vacuum sync them? Is it difficult?

Thanks again
 
#10 ·
If you don't separate them into the individual carbs, you might be able to not sync them. I've had multiple racks off and never re-synched them. YMMV simply because you're working with a higher stung bike than the GS1150 and the CB550 I constantly had the carbs off of ~

JM
 
#11 ·
Got the carbs off the bike, they were stuck on pretty good too; don't know if theyve ever been removed. Funny thing though, as I was taking all the tubes off, where the air vent solenoid valve is, it was entirely filled with gas almost to the front of the bike. Not a good sign I assume.

I'm pulling it apart (not all the way or I will never get it back together) tonight and we'll see how clogged the jets are. I'm hoping they are since i've got it this far apart. While I have everything apart is there anything I should do? Any replacement gaskets? Or could I get by, since I'm just taking the float bowls off , with just using the old ones?
 
#12 ·
I've re-used float bowl gaskets on several occasions. I put a thin layer of grease on them to help them seal. One of the biggest concerns is the pilot jet, they clog easily, so give it a good look ~

JM
 
#13 ·
I've got the carbs out finally after a bunch of prying because they were stuck to the cylinder head side. I took the bowls off of each and might I say, those things were dirty. Jets weren't significantly clogged but still some debris in them. As for the pilot jet, the service guide recommends not remove them unless doing an overhaul, should I remove them to clean them or is compressed air and carb cleaner sufficient. The floats seem to have no deteriation at alland everything else seems good, as far as I can tell.
 
#14 ·
There's lots of openings in most pilot jets I've seen. The compressed air likely helped get the carb cleaner in there.

Why the manual recommends not removing them is beyond me, someone else will have chime on that. I just pull carbs apart with reckless abandon and I've had no problems with pilot jets from removing them ~

JM
 
#15 ·
Definitely remove pilot jets. When you spray carb cleaner into passageway you should see it come out the small holes next to the butterfly. You should also be able to spray in through the air jet at the inlet of the carb and get fluid to spray out where the pilot screws in.

Hold the pilots up to a light. The hole should appear round and not restricted.

Keep in mind, carb cleaner (and gas) has a tendency to swell the slide diaphrams so its easier to remove them before playing too much with the carbs. This is unless you plan on leaving them in.
 
#16 ·
Got everything back together, seems to run ok now. I was wondering why there was so much smoke and than I remember that there was one gas tank that had a Two-cycle mix in it.. Haha.. Now I just need a new battery, this one won't hold a charge anymore.

Thanks for all the feedback and help fellas
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top