Hi,my 3cv started leaking petrol from the carbs, so I got the carbs of and cleaned the floatbowls, couldnt get the pin out from the floats so put it back together and cleaned the tank. Started it up and petrol leaking out worse than before!! Now when turning the key pump runs and petrol leaks from overflow from carbs , any ideas? This is after winter storing....
1) You have varnish or gunk between the float needle and needle seat holding the needle open allowing fuel to flow. Try running some Seafoam thru to see it clears out, if not, gotta get the float pins out to remove the floats and float needles so you can clean out the seat. Look closely at the float pin. It only comes out 1 way. There is a head on one side of the pin.
2) Leaking float needle seat o rings. Gotta get the floats off to get the needle seats out.
Don't store your FJ with ethanol laced gasoline (e10) or you will find yourself getting real real good at cleaning your carbs.
Look thru our carb files : https://fjowners.com/index.php?board=21.0
Cheers
Thanks for the reply, I did store the bike over winter with a full to to the brim tank. E10 is all I can buy around here so I mixed in some stabiliser additive. I started her up every 2weeks to warm up and topped up the e10 petrol mix. Not a great way by the looks of it
I have been a motorcycle mechanic for over 35 years and the best way I found to remove those pins is with a small automatic center punch. Be very careful and don't let it touch the post that's holding the pin. Same goes for reinstalling the pins.
Dave
I cleaned out the floats and i got the pins out with the punch, thanks for the tip. I put it back together and started it but petrol is still leaking, but I couldn't see it running from any of the overflows! It came from the oilsump!!! I got petrol in my cylinders by the looks of it!
TOTM,
Leaking fuel at the carbs can also mean that fuel is getting into the crankcase, which ruins the oil completely.
Sniff at the crankcase oil filler opening. If you smell fuel there,
DO NOT RUN THE ENGINE,
until you have changed the oil with all fresh oil. You may also notice that the oil level is higher now than when you last changed the oil, which is a sure sign of fuel-diluted oil.
Of course, you will need to get the carbs to stop leaking fuel, before installing the new oil.
HTH.
Yep, follow Red's advice...change the oil. Did you replace the float needle seat O rings? Are the float levels adjusted correctly? Check the fuel level in the bowls to see if the floats are over filling the bowls.
Quote from: Pat Conlon on May 31, 2024, 09:02:21 AMYep, follow Red's advice...change the oil. Did you replace the float needle seat O rings? Are the float levels adjusted correctly? Check the fuel level in the bowls to see if the floats are over filling the bowls.
No I haven't replaced the needle seats 0rings, I haven't touched the float levels,how do you check the fuel levels in the bowls? I did dump the oil from the sump!!
Quote from: TopOfTheMorning on June 01, 2024, 10:37:23 AMNo I haven't replaced the needle seats 0rings, how do you check the fuel levels in the bowls?
You need a FJ manual, float heights and fuel levels are much to detailed for me to post, plus pictures in the manuals are great.
Clymer FJ manual see page 212
Haynes FJ manual see page 3-16
Replace your float needle seat o rings.
Not to hijack this thread, but I have a similar issue. I have pulled the carbs, and was considering sending them off for overhall, but have decided to wade in myself.....simply due to cost. I have seen the Yamaha FJ1200 '88-95 3CW/3CV/3XW Keyster carb kit inc.emulsion tube. This seems to be a popular kit. Is there a better kit that's recommended?. Also is there a list on the site anywhere of the required 'o' ring sizes and types. I have access to an ultrasonic bath and intend stripping each carb, keeping the parts seperate, immersing the whole bank, and the replacing the 'o' rings on the link tubes before reassembly. My bike is an '89 3CV.
Thanks
Rob
I do not know if the carb kits mentioned have Allen screws to replace the stock carb screws, but RPM has a complete kit of these screws. Well worth the investment, IMHO.
Thanks, I have ordered all of the correct stainless screws. If I was in the States, I would just pack them off to RPM.