carb float adjustment

haynes manual states 17mm is this measured from carb body to top of float while held upside down ? :wink: :idea:

 

Which is accurate BUT a VERY awkward way of doing Float Heights.

About the easiest way I know to do the Float Heights is to Bring ONE of the FOUR to Specs. Then, measure the Height of the Tang using a Float Height Ruler (Holley: Available at Speed Shops). The Holley Ruler can Measure the Tang Height of the Height of the Floats ... It's nice to be able to Measure BOTH.

You really only need the Tang Height, though. Set the ruler to the side of the Float Tang and read the Measurement on the Scale (In increments of .001ths) and MATCH the correct Float Height's measurement to the other THREE.

This Highly Accurate Measurement will insure you that your Float Heights are the same right across the board.

 

Rick thanks for the quick responce I have carbs off measured fuel level with clear hose to find level low ill get one right and set others Im long time auto tech used to set floats by measureing just got 1982 xj750 am going over it to get it ready for spring. alot the same but alot different than cars thanks again albert 311

 

RickCoMatic, pardon my stupidity but what is the "Tang" and what position should the carbs be in? As they ride on the bike, or inverted?

 

The tiny metal shelf, between the two floats, that engages the bottom of the Float Needle Pin is the Tang.
That's what gets bent up or down, slightly, to regulate the leverage on the Float Needle to close the Float Valve when the Fuel Level is at the right height.

Bending it up or down regulates the Fuel Height in the Fuel Bowl by having it close quicker or later as the Fuel Bowl fills with Gas.

 

Hello...

Best way to I know to acurately adjust floats and KNOW they work the way they should. With carb bank off the bike, make a wood mount that holds them upright and level (use a small vial level). Mount a small lawnmower tank above the bench with a small valve. Run a tygon tube down to the carb fuel intake. At the bowl drain, attach a short tube with a tee that rises up the carb body (kept open at the top) and the other end to a spare gas can on the floor. Put a second valve on just past the tee for ease of use if you want. Depending on what you dissassemble, you may have to make some "plugs" for the other carbs to avoid leakage. DON"T SMOKE.

To operate, close drain plug screw (or valve) and open tank valve. Gas will flood carb bowl rise in sight tube. Close feed valve, drain bowl and repeat till satisfied. Float provides a fluid height which can be easily seen and measured VERY accurately... Shows sticking floats, repeatability of function, leaking seat etc.

Do all carbs and record over/under... flip carbs over, pop bowls, adjust tang and redo tests...

Andy
XJ1100

 

I bought new valve assys. from a hitachi site that had slightly longer needles and the stock specs wouldn't work! What a PIA.
http://www.sudco.com/hitcarpar.html

 

Not sure what you mean - regardless of the needle height the float height will be the same. A longer needle just means the tang is bent a bit more away from the needle to get the float to the right height.

Float Height
http://www.xjbikes.com/Forums/viewtopic ... t+dry.html

 

Tried to set the fuel level in my carbs and I run in to some problems, for 2 carbs the levels was right 3-4 mm from the top of the bowl, but for the other 2 the level is somewhere half a bowl, even though I bent the tang arm down...someone know what could be the problem? Another curios thing for me: when I filled the carbs with fuel, at one point (when they were full) gasoline started to come out through here (see picture) why is that? should the carbs just stop taking fuel when all the floats are up? is true that the auxiliary fuel tank that I used was siting quite high, can that be the problem?

 

So today I tried to fight with the overflow problem, thinking that might by the float needle or the gasket. Started with the first carb, I removed the bowl and filled the carbs with gas (at one point one carb just threw gas out, no. 3), I just hold the float with my finger no gas was coming out, continued with the 2nd one, still nothing, continued with the 3rd one (at one point carb no 1 threw gas out), and so on with the 4th one...not a drop of gas...So my conclusion is that is not the gaskets or the float needle....what do you guys this? My concern is what will happen when the carbs will be on the bike running, if they will threw gas out, I don't what to make a camp fire . Thanks

ps. Sorry for the double posting, I just copied the post from my thread in the modification section, I think it's relevant here, and I will find some help.

 

I had the exact same issue been looking from some solutions. However, i haven't found a definite solution, i'm going to attempt to feed it backwards like you did and see the results. I would like to point out that the fuel is being held back my your own force. this means that the force applied to keep the fuel in may be greater than the float it self cannot provide. You might have a bad float, i suspect this for my own carb. I haven't tried it yet but see if the floats, float. This would tell you if the float can provide the force needed to stop fuel from leaking past.

 

first off you are replying to a 2 1/2 year old thread

floats are solid

here is how to wet set your carbs

Setting the fuel levels

top 2 holes are the fuel overflow holes lower hole is an air jet to asperator tube under main jet and slide needle

 

The floats in both Hitachi and Mikuni carbs of this era are not subject to saturation. They will always float. If you have not yet started a thread for you problem, please do.

 

"Is there any specific length of clear tubing for we setting? Also does it have to be laid out a certain way? I have read the directions,but see no reference to length..etc.
If I understand correctly, I am using an 8-12" piece of clear tubing, and once connected to drain, the tube simply comes out and inch or two and turns up side of carb(some people tape it to carb bowl side), fill carb, then take measurement. . Thanks"


Length doesn't matter, route doesn't matter
Just as long as you can lay the tube vertically against the carb body and get a measurement

 

Thank you.
I took measurements....
carb 1 is great -3,
carb 2 overflowed slightly and showed a level 1 inch higher than spec
carb 3 is -1 ,I guess I should get it to -3
cand 4 overflowed badly
All jets and needle valves are new. I removed the 2 out of spec bowls,recleaning everything.
I built a wall mount and screwed 2 of the old boots to a 2x4, now I can do my testing with the carbs at 5 feet high....makes filling with gas and watching a little easier. The gas obviously was also fowling my oil and plugs...nice.

Question....is that tiny hole in the back of the bowl( somewhat angled) supposed to allow flow to the "taller" hole behind it? Having a bear of a time clearing it.
When I flash a light into this hole on a clean bowl, and peer into the taller hole, I can see a tiny spec of light in the base of "taller " port, very small. Spraying carb cleaner in the one hole on a clean carb bowl results in a small amount of fluid to exit the other hole directly behind it. I t appears to be a great place for crud to collect. Maybe a guitar string is the answer?

 

that's one of the better answers. also, chacal sells a tiny drill bit for that.
it's part of the enrichment circuit (choke)

there's been problems with some brands of those

 

ok so that small hole should allow flow from the tiny hole in lower side of bowl and the choke port.

 

oh boy...brand recommendation?

 

Get your parts from Xj4ever and know you have the right parts the first time. They will get there fast as well