Fuel petcock on or off when you turn off engine?


12 replies to this topic
  • jcbikes

Posted April 02, 2010 - 07:25 PM

#1

I have a 2002 WR426 that I purchased used 7 months ago. Bike runs great and was re-jeted for the Colorado altitude before I got the bike. When I turn off the engine and the bike sits for 15 or 20 minutes, it will start to discharge some gas from the fuel carb. overflow line if I do not turn the petcock to off. I noticed in the manual that it says to do this when you turn off the engine. I never had to do this with other bikes. I adjusted the float level but it still does this. Is this normal and should I just get used to turning the gas off when I always stop the motor for any length of time? Wondering if all the WR's do this too. The rubber shut off thing that is moved by the float looks perfect.
Thanks.

  • WR_Dave

Posted April 02, 2010 - 08:42 PM

#2

On that bike the carb has an o-ring around the fitting that the float needle seats into. Remove the float, the small screw, remove the needle seat and replace the o-ring around it. They dry up after a while and start to leak past the outside of the fitting. Oh BTW, it's always good insurance to close the fuel petcock when not riding, as well as setting the engine to TDC when it sits between rides. It's good for the valves. :thumbsup: WR Dave

  • jcbikes

Posted April 03, 2010 - 07:04 AM

#3

Thanks for the info Dave. I will check out the o-ring. I always put the bike to the compression stroke when the bike is off to release the tension on the valve springs.

  • jcbikes

Posted April 04, 2010 - 10:48 AM

#4

The Yamaha parts book doesnt show the o-ring to be sold separately. Must buy the needle assembly. Do you know, Dave what size 0-ring that is?
Thanks.

  • WR_Dave

Posted April 04, 2010 - 06:10 PM

#5

I don't recall the size of the o-ring. I just used one from our shop's o-ring kit. Most auto parts stores will have what you need. Just make sure it's gasoline compatable. WR Dave

  • jcbikes

Posted April 04, 2010 - 07:28 PM

#6

Dave, the needle valve assembly is $70 and all I need is the o-ring so I will give that a try. Again, thanks for your help.
JC

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  • William1

Posted April 05, 2010 - 03:05 AM

#7

8F2-14147-00 float needle seat oring

  • adem188

Posted April 05, 2010 - 03:33 AM

#8

as well as setting the engine to TDC when it sits between rides. It's good for the valves. :thumbsup: WR Dave



hey just wondering, how do you set the engine to TDC (top dead centre)?

  • WR_Dave

Posted April 05, 2010 - 04:44 AM

#9

On the old 426, I just used the kick start to move the engine to the "hard spot" . On the '07 I do the same thing, but I move the kicker by hand so I can feel where the "hard spot" is now. The engine should always be left in this position when the bike sits for more than an hour or two. Doing this will allow all the valves to be closed and in the most relaxed position. On the older bikes the valves used to stick in the open position and then the bike wouldn't start or worse yet the open valve would get tagged by the piston. Setting the engine to TDC is still the cheapest insurance against this happenning. WR Dave

  • jcbikes

Posted April 05, 2010 - 02:41 PM

#10

WR Dave,
You were right! Took the needle jet assembly out and the o-ring was shot. Found a new o-ring at the local Checker auto parts store. Fixed the problem and the bike pulls cleaner at lower RPM's.
Thanks so much!
JC

  • adem188

Posted April 07, 2010 - 01:59 AM

#11

On the old 426, I just used the kick start to move the engine to the "hard spot" . On the '07 I do the same thing, but I move the kicker by hand so I can feel where the "hard spot" is now. The engine should always be left in this position when the bike sits for more than an hour or two. Doing this will allow all the valves to be closed and in the most relaxed position. On the older bikes the valves used to stick in the open position and then the bike wouldn't start or worse yet the open valve would get tagged by the piston. Setting the engine to TDC is still the cheapest insurance against this happenning. WR Dave



now im not saying your right or wrong but that hard spot which is where you should kick from i don't think that is TDC cause from when you aren't touching the kick start lever at all until you reach that hard spot there is no resistance at all and how could it all ways find TDC it just doesn't seem to make sense, do you know what i mean?

  • WR_Dave

Posted April 07, 2010 - 09:42 AM

#12

now im not saying your right or wrong but that hard spot which is where you should kick from i don't think that is TDC cause from when you aren't touching the kick start lever at all until you reach that hard spot there is no resistance at all and how could it all ways find TDC it just doesn't seem to make sense, do you know what i mean?


You can say whatever you want. The fact thereis a "hard Spot" in the stroke is because you have created pressure above the piston against closed valves. This pressure creates the hard spot and is very near TDC when the spark would normally ignite the fuel mixture in the cylinder and drive the piston down on the power stroke. Any other time one of the valves would be open and nocompression could be built to createa hard spot. Also you don't kick from the hard spot ,but just past it slightly so you get the maximum amount of crank rotation before you get to the next "hard spot" when if your bike is tuned correctly it wil fire and be running. It always finds TDC because it is a single cylinder engine so it isn't confused by any other pistons trying to be #1. So in this hemisphere it does make sense, so .... no,I don't know what you mean. :thumbsup: WR Dave

  • adem188

Posted April 07, 2010 - 02:22 PM

#13

You can say whatever you want. The fact thereis a "hard Spot" in the stroke is because you have created pressure above the piston against closed valves. This pressure creates the hard spot and is very near TDC when the spark would normally ignite the fuel mixture in the cylinder and drive the piston down on the power stroke. Any other time one of the valves would be open and nocompression could be built to createa hard spot. Also you don't kick from the hard spot ,but just past it slightly so you get the maximum amount of crank rotation before you get to the next "hard spot" when if your bike is tuned correctly it wil fire and be running. It always finds TDC because it is a single cylinder engine so it isn't confused by any other pistons trying to be #1. So in this hemisphere it does make sense, so .... no,I don't know what you mean. :lol: WR Dave



ok, no need to be a :thumbsup: :) about it!!




 
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