Setting float height

[Sgriger534]

when you check float height by floating the tubes and checking the height with clear tubing where to you set the fuel level at. I have been aiming to set them at the top of the fuel bowl near the gasket surface.

[GLoweVA]

The Manual only tells about the fuel height check for the 81. (it's the only carb set that has the drain ports on the bottom of the bowls)
Here's what it says for that:
"Check the fuel level in the tube. It should be 0.12 +/- 0.04 in. (3 +/- 1mm) below the top surface of the float bowl"

This of course is the newer carbs with the plastic floats where the float height is set to 0.906 +/·0.020 in. (23.0 +/- 0.5mm)

Now the float height on the older carbs (brass floats) are set to 1.012 ± 0.04in. (25.7 ± 1.0mm).

I did the tube level check in my carbs on my 80G and while I wasn't looking for an exact height, I did want to check for consistancy across all 4.
So, If you've set you float heights according to the spec (for a 78) and all your levels are the same, then you should be good go.
Remember, the higher the level, the more rich you may be, and too high may cause a little overfilling/spillage.

Just my 2cents. Hope that helps.

[Sgriger534]

That does help thanks,

I had set all of my floats to 25.7 mm and when i checked the level all of them were close but seemed really low, about half way down the bowl. so i think i will set them just below the top surface of the fuel bowl and see where that gets me

[GLoweVA]

I guess your floats are a really bouyant.
Maybe someone here who has the earlier carbs and has done this level test can chime in and give you a bit more guidance.
The worst thing that can happen if you set them too high is the performance might be a bit 'off'.
At least you'll know why and can go back and drop you heights down a little and see if it gets better.
A little trial and error, so to speak.

[JeffH]

That does help thanks,

I had set all of my floats to 25.7 mm and when i checked the level all of them were close but seemed really low, about half way down the bowl. so i think i will set them just below the top surface of the fuel bowl and see where that gets me

If you make that adjustment as you indicated above, please share the result with us.

I have been experimenting with the 11E. Here are two pics of floats taking a swim. You can see the variation in buoyancy. One float had been dented by PO and one float had very weak bellow. Didn't leak, but outer bellow would collapse if you touched it.

So, from the Float Pic you can see what variation in Bowl Petrol Level I was getting with the set of floats (pictured) set at 25.7mm. Note the lower bowl marking on #2 and #4. Those were the dented and weak floats. #1 and #3 were in better shape and you can see how the 25.7mm setting resulted in actual bowl height. BTW, had just put in new OEM Needle & Seats (+ r&r petcocks to resolve the gas in crankcase problem).

So, here are a few meaningless pics that might be of interest. At least is shows the bowl petrol level marks Before (lower marks) on #2 and #4 and After putting in new OEM Brass Floats in #2 and #4.

After the testing 25.7mm and viewing the results with the 2 new floats I decided on 24mm setting. That resulted in a fuel level approx. 13mm below the rim of the bowl. How does it 78' 11E run with that setup?? GREAT ! Excellent Roll-On power, No Popping or Backfire, 38 MPG. Guess it is a bit O' Science, bit O' Art with a bit 'O luck. Good experiment for the next time my carbs are off would be to try 23mm float height setting to try and get the bowl fuel up +2mm or +3 mm higher. However, bike is starting & running so great right now I hate to mess it up.

Next time I will isolate the floats individually then see how many grams of weight it takes to bring the float top to the surface of the water.
Anyway, got a couple riding low and one riding high:


Low mark on #2 & #4 are the floats I ended up replacing:


Jeff

[Sgriger534]

Well it actually left the floats set at 25.7mm. I realized my homemade carb stand was not perfectly level. After doing some tweaking to my bench and getting my carbs level. the fuel level was just under the mounting surface.