Confusion on bench testing carburetor floats.

[Chaharly]

Hey guys, over the winter I had a set of rebuilt carbs sent to me from a member on a facebook group and ever since then I have been dealing with a bad rich fuel condition. When i first got the set, it came with aftermarket needle jet slides and the bike would barely carry its own butt down the road. I replaced them with the OEM ones from my set and it ran better. My brother in law told me he could smell fuel when riding behind me and the bike starts to cut out and fall flat at wide open throttle.

 

I installed a set of thinner needle shims that I purchased @skydoc_17, (great dude by the way. Would do business with him any time) and adjusted the pilot jets to what I think isn't terribly too rich.  My pilot jets are only turn about 1/4 turn out, and unless they're totally closed the bike will idle perfectly and really never needs to be choked (rich condition). On a good day, with a tail wind, doing 55mph, I'm lucky to get 36-37mpg.  Before switching to these carbs I would have easily pulled over 40.  

 

So that leads me to my question. I want to take the carbs off the bike and adjust the float height. Looking at my old set of carbs, it looks like i need to dissasemble them from the rack to get the bowl covers off. Do I have to re-assemble them, then level them upside down as an assembly, or do I do one at a time? Also in this thread, the OP says that you don't let the float compress the needle all the way? How do you prevent that while the carbs are upside down?

 

Here's the link to the thread I was reading.

 

Also what size of clear hose are you guys using for the wet test?

 

Thanks so much in advance guys! Good riding!

[cimmer]

Here is a little cheat sheet on setting the floats with the float bowls off.  Also check and make sure the rubber plugs in the bottom of the jet block are nice and tight so no gas gets by them when running. They should be very tight in the jet block. 

I hope that helps

Rick F.

[Marcarl]

25 minutes ago, cimmer said:

Here is a little cheat sheet on setting the floats with the float bowls off.  Also check and make sure the rubber plugs in the bottom of the jet block are nice and tight so no gas gets by them when running. They should be very tight in the jet block. 

I hope that helps

Rick F.

Yep, works perfect.

[saddlebum]

Here is a set up I threw together in a pinch to wet set my carbs on the bench any variation of this would work. The key factors are a pressurized fuel source at a steady 3.5 psi (an air tight container with a tube going to the bottom which supply's gas to the carb and a metal tubeless tire valve secured to the top to add pressure ) the clear plastic tubes installed on the drain holes. I have since Used a different set up much more compact and simplified but I have no pics. however the attachment should give you the jest of it.

Home made set up for wet setting floats on the bench.pdf

Edited June 30, 2023 by saddlebum

[Chaharly]

Just an update, got everything put back together. Did very minor adjustments on the float height but had two of those rubber plugs on the jet blocks almost totally pushed out. Thanks to cimmer for mentioning that, need to synch the carbs and take it for a run to see if I find any improvement!

[Bob K.]

On 6/27/2023 at 4:26 PM, Chaharly said:

Also in this thread, the OP says that you don't let the float compress the needle all the way? How do you prevent that while the carbs are upside down?

 

Sorry for the confusion, Chaharly.  In that photo, I was trying to explain a problem I was experiencing, not making an imperative statement about how the needles should be positioned.  When properly adjusted, the needles will close off the fuel supply during wet bench testing.