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1990 FLTCU. Service manual says set height of top of float to the flange at 0.725 inches. Seems I was way off at original setting, but had no issues in running except it was time for removing 30 years of gunk. I used a tire depth guage to measure, it only has 32nd and ml so I used 18.5 ml to get close to the 0.725 inches. Difficult to measure. Seems my original was around 15 ml. I find it hard to believe it was that far off. You tube says measure with carb at 30 degree angle, I saw none of that in service manual. Is something amiss?
1990 FLTCU. Service manual says set height of top of float to the flange at 0.725 inches. Seems I was way off at original setting, but had no issues in running except it was time for removing 30 years of gunk. I used a tire depth guage to measure, it only has 32nd and ml so I used 18.5 ml to get close to the 0.725 inches. Difficult to measure. Seems my original was around 15 ml. I find it hard to believe it was that far off. You tube says measure with carb at 30 degree angle, I saw none of that in service manual. Is something amiss?
I'm gonna go out on limb here and guess you are working on a Keihin CV carb.
IIRC all you have to do is flip the bowl upside down and make sure the float is level in the bowl.
Then again I'm not a fan of the CV carb.
The float level is fairly critical in a way, in another way not so much as the metric Keihin versions. You really need a dial caliper, but if all you've done is clean and assuming the needle is identical and you've not "adjusted" anything, put it together and use the clear tube method of checking the float level. (Not all Harley CVs have a drain type bowl)
You want the level to be within 1.5mm of the seam where the bowl meets the body. Be sure you have no air bubbles in the tube, else you'll get a radically false reading. If you raise the tube after you open the petcock, drain and re-start. If you lower the open end of the tube, the fuel level will always return to the same reading. Gravity is a wonderful thing
The float level is fairly critical in a way, in another way not so much as the metric Keihin versions. You really need a dial caliper, but if all you've done is clean and assuming the needle is identical and you've not "adjusted" anything, put it together and use the clear tube method of checking the float level. (Not all Harley CVs have a drain type bowl)
You want the level to be within 1.5mm of the seam where the bowl meets the body. Be sure you have no air bubbles in the tube, else you'll get a radically false reading. If you raise the tube after you open the petcock, drain and re-start. If you lower the open end of the tube, the fuel level will always return to the same reading. Gravity is a wonderful thing
This looks different than my carb, my float is orange and round and I do not have drain in bottom for this clear tube method.
No. LOL. My bowl has drain. From diagram it seemed that I needed drain on center of bottom of bowl. Mine is on side of bowl, exactly like this pic. So I stick a tube In the drain hole, mark on tube where seam is between bowl and cap, put cap on and fill bowl with fluid until level on tube where I marked isthe same?
Well, I learned this trick by accident, long before YouTube existed. It's just a good check method.
Carb has to be assembled and level and you have to have a gas source so, on the bike is the most convenient but bike needs to be standing up straight.
Put a clear hose on the drain/overflow pipe. Loop it up well above the bowl and hook it to something. A clothes pin clamped on the air inlet works good. Open the petcock, let the bowl fill. Open the drain screw and the clear tube will fill and show exactly where the gas is in the bowl. Remember, if there is any air bubble in the tube, it will give a false reading so tap it and let the bubbles clear. Turning on the petcock before opening the drain screw usually eliminates this issue.
Here's a video. Don't listen just watch it at about the 1 minute mark for a visual of what I'm trying to say. Different carbs, but the method is the same.
I will do this on off the bike on level bench. I can fill carb bowl through fuel line hose into carb and see what level the gas in the line from float bowl drain hits.
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Float bowl adjustment question
