Carb Float Measurement

[Firewall]

Hello,
I'm having an issue where one of my carbs is over flowing for no reason that I can tell.

Could someone tell me if I'm using the correct method for measuring float height based on the picture below? I have a hard time telling what is what based on the black/white photo I usually see in response to this question

This is on a 77 GS750, and I'm shooting for 26mm based on what I've seen on basscliff's website and on the forum (ignore the actual measurement in this photo, this is just with a spare carb).

Thanks,
Matthew

[nickr234]

that looks about right. if your float is a little bit above the tip of the pilot jet you are in the ballpark. and the only reason your carb would be overflowing from a float hight issue is if it is WAYYYYYYY off...

what might be happening is your float is getting stuck open on the bottom of the bowl. take a rubber mallet and tap the carbs (not to hard mind you) and see if that helps. if it does then you know what your problem is.

if that doesn't work what is probably happening is the float needle and float needle housing are not properly sealing up.

Take the carbs apart and take your carb that is giving you trouble and make sure that there is nothing like little bits of rust or varnish that is keeping that needle from sealing with the housing.

Hope this helps,

Nicholas Ryan Rasmussen

[Steve]

No, you are using the wrong end of the caliper.

On the other end, do you have a small "stick" that pokes out the middle of the slide?
That part is used to measure the depth of a hole.

Place the "stick" against the gasket surface and the end of the caliper on the top of the float, read the display.

Not sure if these pictures are what you have already seen, but they go along with the description I just gave.

The overall setup:


A close-up:


Be sure to measure both sides. If they are off by more than 0.5mm, adjust them so they match.

There is a ridge in the gasket surface. Probably doesn't really matter if you measure from the top or the bottom of the ridge, but do it the same for all of them.

If your caliper doesn't have the "stick", you need a new caliper. Harbor Freight usually has them for $20 or less.

.

[nickr234]

By steve: (for some reason i couldn't use the quote thingy

Place the "stick" against the gasket surface and the end of the caliper on the top of the float, read the display.
************************************************** ****************

With the old VM carbs he has the gasket needs to be off.

also i forgot to mention. there are two float arms (the little tangs that bend back and forth). the second one controlles how far your float can be let down. if that is bent incorrectly that can also be catching on your carb assemble, and not allowing the float to go back up to where is should be.

Nicholas Ryan Rasmussen

[azr]

Man that is one clear photo, wow. Steve's right about the "sticky" thing but other than that I think you have the idea. Now someone correct me if I'm wrong (and I'm wrong lots) but if your carb is over flowing doesn't that have something to do with your float needle sticking and not so much your float height (assuming you don't have your floats sooooooo out of wack that it would cause overflow). Clean out the float seat and have a good look at it, andthe float needle, make sure the spring is working properly, you can even gerry rig gas in a clear plastic container and slowly drop the carb body to watch the float and the float needle work. Can't count how many times I've had a carb overflow and to only smack it with something to unstick the float needle and bingo problem solved. Float seats and needles are cheap though.

[Steve]

With the old VM carbs he has the gasket needs to be off.

Actually, you should have the gasket out of ALL versions of the carbs.

.

[nickr234]

sorry

sorry steve, i missunderstood what you were saying. my bad ^_^.

also one last thing i forgot to mention (i am very forgetful). i had this problem with two of my carbs a year and a half ago. and i tried everything to get them to stop overflowing... turned out to be two cracked overflow tubes. if this is the case for you let me know and i send you a bowl, you'll have to clean it and such, but it should work. Let me know what you find.

[Firewall]

Thanks Steve, I think I've seen those pictures before too. This is the first time they've made sense though, the "stick" blends in with the carbs so well I've never noticed it and couldn't figure out what you're measuring.

[Firewall]

what might be happening is your float is getting stuck open on the bottom of the bowl. take a rubber mallet and tap the carbs (not to hard mind you) and see if that helps. if it does then you know what your problem is.

Actually this seems to have fixed it. I hit it with the mallet and since then it has been on prime for about an hour on a almost full tank of gas with nothing coming from the over flow tubes.

Thanks!