How to measure and change float height? (AKA re-jet part II) **Update**

[skoebl]

Well...after a good couple of hours tinkering...I found out that my float levels won't stay put. I set both at 15mm, put the tank back on and whatnot, perfect....5 minutes later, bike won't start; I look down and there's gas everywhere; check the float levels, well over an inch above the gasket....Did this about 3 times so far.

But I must say, I had it working for a little bit (then I had to take the tank off to put everything back on 'cause i thought I was done) and it ran soooooo well.

So, when the float levels are right, the rejet works splendiferically.

Any idea as to what would cause my levels to jump so sporatically?

If I can't fix it I'll probably just end up taking to a local shop and letting them fiddle with it....

[Wrecent_Wryder]

7f

[skoebl]

Seems to be a lot of this going around right now.

If the float bowl level won't stabilize, and it's leaking gas, what could it be besides sticky floats, or the needle valve/seat?

Did you have to drill out the float bowl screws to rejet? Were there shavings?

I didn't have to drill anything.

How can you tell if the problem is with the needle valve/seat? (is it if it leaks gas and the levels wont stabilize?  )

[Wrecent_Wryder]

r5

[scratch]

Unless there's a hole in one of the floats, then it wont float to shut the valve needle.  Test in a bowl of gasoline.

[Wrecent_Wryder]

[5

[Wrecent_Wryder]

[rd

[scratch]

Oh an '01, now I understand.  Good info.    The needle float sounds plausible. 

[joedude]

Make sure that your needle seat is properly seated in your carb. There's an O-ring in there and it can get squared off, or just crack after long exposure to gasoline. That's what happened to mine and it was letting gas thru asthough the float was set improperly.

[skoebl]

Alright....I bought new floats...I THOUGHT I was buying new float needles too...but bikebandit's fiche is hard to read and I ended up buying the needle jet....


Aaaanyway....Still no luck. When I put it in prime gas comes out of the air intake part of the carbs (where the airbox goes)....
I know the needles work, I was experimenting with them on the carbs....and I set the float heights time and time again....


I'm just confused now....   Everything seems to be doign what it's supposed to do..........except running....

[Wrecent_Wryder]

[4

[skoebl]

Took this picture when I was putting in the new floats....thought it was kind of amusing (new vs old)

[skoebl]

Ok, got the right parts now. Put them in....same thing happened; but only for a few seconds (still odd). After the few seconds of fuel leaking out, the levels stabilized. No matter how much I adjust one side, it's about 1/8 - 1/4 inch higher than the gasket; the other is spot on.

Buuuuut, still won't run 

So, any ideas? Would the level being just a little high on one side make it not run?

[Kerry]

Thought I would dust off my image archive.  (After reading the whole thread I couldn't tell whether you have seen them already.  Sorry if they're repeats.)

First, the PartsNMore carb rebuild kit.  This might be helpful while discussing various parts.

[/list]



A page from the ('89 to '97) Haynes manual.  The float height adjustment process is described in sections 6 & 7.

http://www.bbburma.net/Scans/Haynes_FloatHeight_FullPage.jpg[/list]



The most important image from that page.  The measurement should be 14.6mm (+/- 1.0mm)

An illustration from the Clymer manual that might apply here.

[/list]



Since you're draining fuel from the airbox, it sure sounds like either:

1) Your float(s) aren't "floating" for some reason (stuck in a too-low position)

2) The tang used to adjust the float height is way out of position (the floats may rise, but not far enough to push the float needle up against the fuel inlet hole in the needle seat and form a good seal)

3) Fuel is getting past the float needle(s) even when everything is in position and moving correctly.  This is the possibility addressed by the Clymer illustration above.  Another possibility is that there is some kind of crud on the rubber tip of the float needle or the fuel inlet hole that prevents the float needle from forming a complete seal.

4) Fuel is getting past the O-ring on the brass part (the needle seat) in the photo above.

* Remove the O-ring from the needle seat
* Make sure the O-ring is nice and round like a doughnut (not squared-off like a washer, from sitting in pinched quarters for 9 years)
* Make sure the surfaces on the needle seat that touch the O-ring are

clean, as well as the socket into which the needle seat is pressed[/list][/list]

[skoebl]

Well, seeing as how the needle seat, and needle are both brand new (and have no visible signs of wear or damage)...The problem is most likely #2.

It seems as though when I bend the tang to set the height, I have to bend it a significant amount downwards for the floats to move up (I am simulating the bowl being attached by pressign on the float 'cage').  When I look at the tang from the side it goes out horizontally (err...allllmost horizontal) over the needle, then makes a sharp turn downward. Am I right to guess that it shouldn't be bent like this; but more like a straight line pointing downward?

[Kerry]

When we say "tang" we're talking about the small metal part visible in both the old and new "float cages" in your photo above, right?  I would NOT try to reshape that tang; it should work "as is".

What did you think of the instructions in section 7 of the full Haynes page that I linked to?  Does that sound like the way you do the adjustment?  The most important text on the page is:

...hold the carburettor so the float hangs down, then tilt it back until the needle valve is just seated, but

not so far that the needle's spring-loaded tip is compressed.[/list]

It can be tricky to do the tilting with your "fine motor control" muscles, check that the needle valve is in JUST the right position, AND measure the height above the gasket surface all by yourself.  (Maybe this is why some folks turn the carb on its side...?)  Getting a (meticulous) friend to help can be beneficial, or using a bean bag or something that will hold the carb in position and allow tiny position changes -- and free you up to concentrate on the measurement part.

[skoebl]

Yeah, that's how I've been doing it. Before I rejetted there was a float problem and I got them spot on  .....buuuut, no such luck this time. 




**Edit: On a much happier note; I got my new tires today. Metzeler Lazertec 110/80/17 front and 150/70/17 rear. Now if I were just able to put them to use lol