FFFFF... Floats...

[JPaganel]

Set floats, put carbs back on. Got airbox in place.

Start it up.

Gas leaks again.

Guess the floats are still a bit high. Now I have to take it all apart again.



I really, really, really, hate floats.

[oldktmdude]

   If you are one of the patient people  that still uses an airbox, why not start your bike before you fit that piece of shit airbox. Might save a lot of swearing.

[Sparky84]

That's a brilliant idea Pete.

But how am I to become a Master of Zen if I can't practice on refitting my Airbox ?

[X-Ray]

Went through this exact thing recently. Float level could be out ( check first using the clear tube fuel level method to be sure), or the needle valve seat is not seating properly like mine were. He's a bit of a write up of my fun times on the Aussie FB page https://www.facebook.com/groups/2331723123/permalink/10155024412278124/

[JPaganel]

   If you are one of the patient people  that still uses an airbox, why not start your bike before you fit that piece of shit airbox. Might save a lot of swearing.

I did.

It ran fine.

However, it dribbled a bit before running fine. I think the difference is that I didn't start it up right away, so it overfilled instead of sucking excess into the intake. Which would also explain why I needed to open butterflies a bit to have it run - to add enough air to compensate for too much gas.

The airbox isn't really that big a deal to me. FJ is seriously one of the easier bikes in this regard. Try doing it on a solid backbone bike like an XJ, for comparison. And I really don't consider more intake noise to be much of an advantage. I hate the process of removing carbs and fiddling with floats a lot more. If you got some magic trick that will take away that necessity, I'm all ears.

[FjLee]

JPaganel.............

I'm  familiar with my  USA 1984 FJ1100.........less familiar with other "flavors" of FJ........but I think what I'm gonna say applies to other FJ's besides mine.

Setting  _FLOAT_  level measurement can make you crazy, cuz it may not get you to where you want to get!  This especially true of old FJ's.  Let's assume your FJ has "old floats".  If so, they probably vary from one to the other in the degree of bouyancy that they have. 

Also, there's a good chance that at the float pivot point, that there is a variation in the amount of friction from one carb to another.

Remember,  the bottom line  you seek here is the FUEL level in the bowl.  The bottom line is  _NOT_  some physical distance measurement  of the floats.  If everything is/was  perfect, then setting FLOAT level will indeed get you close to correct desired FUEL  level.  But on an old bike, there can be many reasons that all is not perfect. I named only 2 reasons, but I'll bet there's a whole shoppimg list of reasons.

Cut to the chase........set the FUEL LEVEL in a direct fashion by actually measuring the FUEL  level.  Do like the manual sez.

I have the GYSM, plus the Haynes.  I also looked at AVIATIONFRED'S  FJ manual while we were in Ouray at the FJ Rally.  All 3 of those manuals address the procedure of directly  setting FUEL level.  The Haynes manual  seems to explain it best, but all 3 manuals had illustrations.

No , the Genuine Yamaha Fuel Gauge Level  (YM-01312)  is not required.  All ya need is a piece of transparent flexible vinyl hose.

The FUEL LEVEL  can be checked without removing the carb bank.  However, _adjusting_  the level will require removing the carb bank, unless you are adept at removing the float bowls with carbs ON bike!!

Anyway.....This info may or may not help you, but a quick check will indicate whether or not the FUEL level is correct.  Then go from there.

On my FJ, I dicked with fuel level a lot........for a couple of different reasons.  My findings may not apply to any other FJ on this planet, but I found better throttle response and better miles per gallon when I set my fuel level 1 MM lower than what Yamaha tolerance specified.  GYSM sez 3MM plus or minus 1 mm.  MY final and happy setting was 5MM.  (For this paragraph to make much sense, ya need to see the illustration in the manuals)

FJLee...Lee Carkenord....Denver CO....1984 FJ1100....2016 Suzuki 1255 Bandit

[X-Ray]

100% agree, actual fuel level should be the final check when assembling carbs after doing the preliminary float measurement. I always make my level in line with the washer on the float bowl, and this works well (for me).

[FJ1100mjk]

FJLee...2016 Suzuki 1255 Bandit

Howya likin' that Bandit? Nice, huh?

F those floats!

[ribbert]

100% agree......

We can see that from your avatar....

[JPaganel]

Remember,  the bottom line  you seek here is the FUEL level in the bowl.  The bottom line is  _NOT_  some physical distance measurement  of the floats.  If everything is/was  perfect, then setting FLOAT level will indeed get you close to correct desired FUEL  level.  But on an old bike, there can be many reasons that all is not perfect. I named only 2 reasons, but I'll bet there's a whole shoppimg list of reasons.

You are right, and I know it.

The FUEL LEVEL  can be checked without removing the carb bank.  However, _adjusting_  the level will require removing the carb bank, unless you are adept at removing the float bowls with carbs ON bike!!

Anyway.....This info may or may not help you, but a quick check will indicate whether or not the FUEL level is correct.  Then go from there.

That's the part I really hate. The whole thing where you measure/drain/adjust/fill/measure/drain/adjust/lather/rinse/repeat/

[FjLee]

That's the part I really hate. The whole thing where you measure/drain/adjust/fill/measure/drain/adjust/lather/rinse/repeat/
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

It can be a hassle, yes.  However, I have found  on my FJ that once FUEL level is set directly, using the hose in the correct manner,  that the fuel level doesn't much change over the miles and years.

Please be aware that getting the FUEL level set correctly may not solve the problems that you're currently having.  However, having the FUEL level set correctly should be part of normal maintenance the same as clean air filter, tire pressure, and periodic oil changes, etc.

Here's some more bits of info that I have in my maint. log that may help:

The Haynes manual sez if  _checking_  the FUEL  level with the carbs ON the bike,  "with bike on centerstand,  use a floor  jack under the engine and raise it just enough so carbs are vertical."
An exact quote.  That's simple enough, and I do that for  _CHECKING_  the Fuel level.  A note here...I pop the fuel filler cap "open"  during FUEL level check, and I have the engine running at idle.  Sometimes, it seems like the observed FUEL level in the hose is erratic and unsettled.  Tap the carb and wiggle/shake the hose.
Don't be tempted to blow into the test hose to "settle down" the reading.  That'll  introduce some kinda confused reading.  I already tried it!

For adjusting the FUEL level, I get the carbs/carb bank  "vertical" at the bench, using a vise and a spirit level plus eyeball to "get the carbs vertical".  I use an auxiliary gas tank, hanging above the carbs so the fuel level in the aux. tank is abt. equal to what it would be with the FJ tank.

With the carb bank in a vise, it's not a real big mechanical deal to pop off the float bowls and set the float tabs so the FUEL level in your vinyl hose is where you want it.

FJLee...Denver,CO.....1984 Yamaha FJ1100....2016 Suzuki  76.6 cubic inch  Bandit

[Firehawk068]

This is all excellent info (Thank you Lee)!
It is something that I've had in my mind to check and adjust the next time I had to get into the carbs (which happens to be Now).
One thing that I'm going to have to experiment with, is exactly HOW to take this measurement?

With the procedures that you have described, this would work perfectly for a gravity-fed FJ. With mine being a fuel-pump model, I'm going to have to introduce the output pressure of the pump into the mix as I attempt to get fuel level set properly..............................

[Pat Conlon]

Re: Carbs vertical for fuel level reading: As DavidR pointed out several times, if you place the measuring tube on the edge of the middle of the float bowl the reading should be the same. If you are reading the tube off the front of the bowl, then yes, the carbs should be vertical.

Alan, you could always run a long fuel hose from your FJ fuel pump to the carb rack on your bench.

I've often wondered on FJ's with the back end raised, how that tilt affects the fuel level and the pick up of fuel within the bowl.
For example: With the back end raised, the fuel level is now higher in the front (forward) section of the fuel bowl. I have heard that this can block a vent in the fuel bowl area which can lead to a siphoning action of fuel and fuel leaking out the choke vent hoses.

Lee, this is what I mentioned to you in Ouray last year.

Drilling a 1mm relief vent higher in the bowl (above the fuel level) prevents this siphoning action. Here is the discussion:

Having tried all the usual tricks/adjustments/replacements, and a few more besides, to stop the carb fuel gusher I figgured out the cause was syphoning through the choke vent pipe. Once the OEM carbs get to 40 odd thousand miles the wear in the choke assembly can set up a fuel lock in the choke fuel pick-up tube when the motor is on over-run - ie when there is a vacuum in the inlet tract - and this then creates the syphon which drains the float bowl. (So the gusher only occurs after you have run the bike on the road).

The simple fix is to drill a 1.0mm hole in the vent pipe casting within the float bowl chamber. This breaks the syphon and prevents the gusher from starting. The location of the hole ensures it is well above normal fuel level in the float bowl.

This is a breeze to do and costs nothing assuming basic mechanical skills.  

I have attached 3 photos:

1st shows the underside of the carb body with float bowl and float removed. "A" is the dip tube for the choke assembly fuel pick-up. "B" is the choke vent pipe stub.

2nd shows a 1.0mm drill bit showing the location of the hole and angle of drill.

3rd shows the hole when finished.

This is done for all 4 carbs.

This mod does not adversely affect performance (both sides of the hole are normally open to atmosphere in any event) but during a test run of 1500 miles last week (Stornoway and back) the bike ran without a hitch and carbs were dry as a bone - no leaks. (Compared to months of leaks/gushers over the years/months before I did the mod).

Usual T & Cs apply - I'll accept no responsibility if you do this to your carbs and stuff up etc etc - if you don't know what you are doing - ask an adult to help.....

Additional discussion: http://www.fjowners.com/index.php?topic=7056.0

[aj52]

I also need to do my carbs,but with all the problems one can get,I will rather send it to someone that knows what to do. Never done something like this on motorcycles. Machinical stuff not a problem,but think carbs is above my knowledge.

Hannes

[JMR]

 Recently ran into a float related problem on a vintage roadracing bike using Mikuni smoothbore 29's. Long story short placing the floats in a small pail of fuel revealed that the floats had different buoyancy......much different. The cure was new floats. There wasn't so much of the gushing just an inability to get the tune correct. Who knows exactly what long term exposure to ethanol is doing?