WET SETTING FLOAT HIEGHTS

There is a school of thought that says wet setting floats should be done with the carbs on the bike & the motor running at idle speed, which does make sense, as you would be 'maintaining' a level. Thoughts ?

 

Which is why when doing them on the bench, it's best practice to drain/fill/drain/fill a few times before taking a reading; and then repeat and take another reading.

I never "read" the initial fill.

You could do it the way you described, but the need for any adjustment would make the process cumbersome at best. Plus there's the whole safety factor with loose fuel and a hot bike.

 

I have beeen trying to find float levels for a 1981 XJ750 but can't find anything on it other than, between 2-4mm. Is that close enough? Is there another place I can find the specs?

thank you.

Steve

 

It's not a matter of close enough it's with in specs.

Here u go...

http://www.xj4ever.com/setting%20fuel%20levels.pdf

This should get you going.

Start a new post and let everyone know if there are any other questions.

 

Interesting question. Checking the floats with the engine running would not only highlight issues with static level, but would also highlight problems with supply capacity like a clogged tank filter, beanie screen, or swelled needle valve tip or even a petcock issue.

Couple thoughts... The fuel consumption at idle is surprisingly low. I haven't actually measured it, but it's on the order of a half cup per minute? Maybe less? Point is that it doesn't take a lot of supply side capacity to get the engine to idle. Also, the fuel consumption at idle is much lower than it is under load, so you could still have a supply capacity issue but it might not show up until you're using more fuel. It might me a mild enough issue that you're OK at idle, but starve at WOT.

So I guess the bottom line for me would be that I wouldn't bother, and here's why:

When you're setting the bowl level, start with the bowls empty and when you fill the bowls, simply watch to see how fast the fuel fills each bowl. Again, something that I haven't actually timed with a stopwatch, but maybe five seconds or less to fill a bowl from empty to full? And if all of your bowls fill that fast, you know you don't have a capacity issue.

So having tested the supply capacity already, you can put that to rest and then do the level portion of the testing static.

However, if it takes thirty seconds for one or more bowls to fill up, you might want to start looking for a clog somewhere? You can also test tank capacity separate from the rest if you're using an aux fuel supply to check the levels.

On a somewhat related note, I've seen automotive carburetors with sight glasses built right into the sides of the carb bodies and they want you to check the sight glass level with the engine running. Too bad we don't have built in sight glasses. That would be awesome!

 

Mike Schindler ( list member) made a bowl out of Pyrex so he can visually check rack carb .... He did write-up on it ----you can search for it.

 

Oh yea, clear Pyrex or something similar!! Sounds like a project for someone with a 3D modeling platform.

Soooo - it's necessary for float bowls to be level. Without hanging your bike from the rafters while running --- I think I'll pass but would be interesting u-tube clip. At least on my XJ level and running is tough.