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ViragoTechForum.com Tech Articles Float level adjusting - simplified

#1: Idea Float level adjusting - simplified Author: lassesand Post Posted: Thu Jun 23, 2005 3:45 am

When adjusting the float levels in the carbs it's quite frustrating to pull the carbs and put them on a number of times. I measured the distance from the floats underside to the main (& pilot) jets with a ruler. When it was too low I read about 16 mm. Added 2-3 mm to rise the level. Got the #1 carb spot on in the first attemt! #2 was done in 4 more "pulls"...
Perhaps this can be of any help - at least to know where to start adjusting an how much.



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+1 mm is the correct level!
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the carb is upside down...
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#2:   Author: raptorredhawk Post Posted: Mon Aug 22, 2005 9:22 pm

Thanks for that bit of expertise. What carbs are those? I have Hitachi HSC40 on an 85 700. Are your measurements still going to work for me? It would be a big help to have that "starting point". JL

#3:   Author: Matthew Post Posted: Tue Aug 23, 2005 11:40 pm

81-85 / 86ish used the same carbs.
thoes are hsc-40 in the pics.

#4:  Re: Float level adjusting - simplified Author: Savager Post Posted: Tue Oct 18, 2005 4:29 pm

To anyone who has ever done this: Might I assume this measurement is taken with the floats pushed down as far as possible (as oriented in the picture), fully closing the float valve? Thanks.

#5:  Re: Float level adjusting - simplified Author: cerm78 Post Posted: Wed Oct 19, 2005 6:41 pm

I'm adjusting my carbfloats by this procedure... I think that the setting is read with the floats just resting into the needle springs and I'll confirm that in a couple of days...

I think that, because my hardest air push trough the carb feed tubes is stopped just by flicking the carbs upside down...

I'll inform when confirmed!

Regards...

#6:  Re: Float level adjusting - simplified Author: Savager Post Posted: Thu Oct 20, 2005 8:09 am

Cerm78 - Yes, please keep us informed. I adjusted mine to that spec with the float pushed all the way down, not just resting on the float spring. I got the carbs installed last night, and it fired up. Only running on one cylinder however, the other just blowing gas out the exhaust. I didn't have time to check float heights with the tubing yet. Maybe tonight. I'll keep you informed here...
Thanks!

#7:  Re: Float level adjusting - simplified Author: cerm78 Post Posted: Fri Oct 21, 2005 6:08 pm

I measured the actual fuel level in my workbench and it was exaclty at the 0mm mark (actually, 1/10th of a mm over it)... So I think that the correct way to adjust the floats is with them just resting over the shutoff needle valve.

Now I have to mount them in the bike and test them in reallity!

Regards!

#8:   Author: Backroads Post Posted: Thu May 11, 2006 6:46 pm

Never put pressure on the floats to close the valve. You can and most liely will damage the valve seat or needle if you do. Measurements are taken with the weight of the float only. This applies to just about all carbs as far as I know.

#9:  Re: Float level adjusting - simplified Author: lassesand Post Posted: Fri May 12, 2006 1:06 pm

No pressure, just gravity!
Good to hear that it worked for you cerm 78! Beers

#10:  Re: Float level adjusting - simplified Author: pachakutek Post Posted: Fri Nov 10, 2006 5:50 am

can somebody explain me the first picture (carb#1)? I don't get what's being mesured there, also what's the tubing for?... the other pic is clear enough.
EDIT: I found the page on clymer (130), where it explains the procedure... now it make sense the 19mm... It must be a pain if they are far off, since bending the tang is very subjective...

#11:  Re: Float level adjusting - simplified Author: lassesand Post Posted: Fri Nov 10, 2006 6:12 am

The tube is attached to the bottom of the carb and is showing the fuel level. It should be 1 mm above the floatbowl-joint. I had the level much to low ( 2-3 mm under) resulting in the engine stoppin if braking hard etc.

#12:   Author: pachakutek Post Posted: Fri Nov 10, 2006 6:18 am

clymer says to measure the level of fuel on the line, and that it should be 1mm (left) and 2mm(rigth) from the bowl partline.. but it's not clear if the fuel level line should be above this partline or below?...

#13:  Re: Float level adjusting - simplified Author: lassesand Post Posted: Fri Nov 10, 2006 6:24 am

It's above. I've read it in the OEM manuals.

#14:   Author: pachakutek Post Posted: Fri Nov 10, 2006 6:31 am

Thanks... that was fast... this thread should be sticky.

#15:  Re: Float level adjusting - simplified Author: lassesand Post Posted: Fri Nov 10, 2006 6:57 am

OK. Here in Sweden the clock is 12 (noon), isn't it in the middel of the night in Canada??

#16:  Re: Float level adjusting - simplified Author: pachakutek Post Posted: Fri Nov 10, 2006 2:02 pm

Yes.. it was about 2:30am (PT)when I went to bed Rolling Eyes I got carried away with the carbs info .... I'm in California-USA and the flag on my profile is Peruvian though... :grin: They look similar, but Peru's has the national shield in the middle instead of the Maple Leaf.


Thanks again for the great info, I'll let you know how it goes.

#17: Idea Re: Float level adjusting - simplified Author: MDawdy Post Posted: Fri Dec 29, 2006 10:43 pm

lassesand wrote (View Post): ... I measured the distance from the floats underside to the main (& pilot) jets with a ruler ...


Precisely, did you measure to the top of the main jet, or to the top of the main jet boss [the tall thing that the m jet is screwed into]? In the pic it looks like you measured to the boss. Thanx.

Mick

#18:   Author: steven s. wardlaw Post Posted: Sun Dec 31, 2006 11:14 am

hello! just wanted to tell my side of the carb story.my 82 920 had all kinds of carb trouble when purchased. after buying a couple of manuals and carb kits i went to work. i have rebuilt hundreds auto carbs(quadrojets). these virago carbs are as touchy as any of them. i set my carbs float height measured off the gasket surface. i used the 19mm height i read off another web sight. one carb was spot on the other had to be moved slightly. to make adjustments easy i replaced the float bowl screws with allen head screws and use a ball ended allen wrench to remove screws. you want have to remove crbs to make fine adjustments. i also cut off an allen wrench to make a short reach for a couple of the screws. you can now do all your adjusting without removing carbs. happy new year!

#19:  Re: Float level adjusting - simplified Author: guest Post Posted: Thu Apr 26, 2007 1:28 pm

Here try this


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#20: Idea Re: Float level adjusting - simplified Author: lassesand Post Posted: Thu Apr 26, 2007 2:49 pm

MDawdy wrote (View Post):
lassesand wrote (View Post): ... I measured the distance from the floats underside to the main (& pilot) jets with a ruler ...


Precisely, did you measure to the top of the main jet, or to the top of the main jet boss [the tall thing that the m jet is screwed into]? In the pic it looks like you measured to the boss. Thanx.

Mick


The main jet boss. X-scuse for a late answer.
I'll probably tear down my carbs this weekend. Seems like there is something blocking one of the pilot jets from time to time. Today was a lovely day (summer 20 deg Celcius and sunny) for being in the end of April (in Sweden). Had a very nice trip driving my TR1. home from work! :grin:

#21:  Re: Float level adjusting - simplified Author: pachakutek Post Posted: Thu Apr 26, 2007 6:25 pm

guest wrote (View Post): Here try this


What?!!!..
I thought this thread was "Float level adjusting - simplified"

JK.. good info. :)

#22:   Author: vroomvroom Post Posted: Thu Apr 26, 2007 11:48 pm

the haynes manual says: "...measure the distance between the top of one float and the mating surface of the carburettor body. If the float height is correct, then this measurement should be 15.8 +/- 0.5 mm (0.62 +/- 0.02 in)

I've got mine set to this. I haven't check the fuel level with the tube on the bike yet with it completely warmed up, but before it was warmed up it was sitting a little low.

#23:  Re: Float level adjusting - simplified Author: xanabella Post Posted: Thu May 10, 2007 12:02 am

I thought I'd add my 2 cents.

The first image on this thread was extremely helpful in giving me a starting point on which to base my adjustments, so, thanks!

Since I had already refurbed my carbs and didn't want to remove them again, and since I had reinstalled the floats with allen head bolts I thought I'd attempt the adjustment on-cycle.

With a rounded allen and a cut off straight allen at about 2 inches, it was fairly simple to remove the bowl. Once removed I simply used a pre-cut piece of plexi-glass cut to 19mm and held it against the tube that runs between the floats, I removed the float and after bending the tang a couple times got it right-on (simply push up the float till it stops lightly, but don't push in the plunger). This procedure was only necessary on the front cylinder and now all that remains is adjusting my mixture and syncing my carbs. I'll be adjusting the mixture with a Colortune plug and will be syncing with a vacuum gauge set-up (saving up for a Morgan Carbtune).

#24:   Author: Fingerpick Post Posted: Thu Aug 16, 2007 5:38 pm

I did the Allen screw thing to my bowls too but used slightly longer ones with nuts on the inside to get the bolt heads down where they'd be easier to get at. Don't want to get them too long or they won't clear the cylinder barrel fins.

#25:   Author: grazingazer Post Posted: Mon Jan 12, 2009 7:45 pm

set to 15 mm-1.5 cm

#26:  Re: Float level adjusting - simplified Author: RusVirago Post Posted: Mon Jan 12, 2009 8:22 pm

I cant tell by the picture where the bottom of the ruler should be??

#27:  Re: Float level adjusting - simplified Author: grazingazer Post Posted: Mon Jan 12, 2009 8:41 pm

Here's your sign
count the marks on the ruler...it's on the surface of the float

#28:   Author: RusVirago Post Posted: Mon Jan 12, 2009 8:49 pm

grazingazer wrote (View Post):
Here's your sign
count the marks on the ruler...it's on the surface of the float


HOnestly I am sorry call me stupid but what does that mean??

What surface I am confused???? I figured out this much if you bend the tang down it lowers the fuel supply correct?? that is if the carbs are upside down?

#29:  Re: Float level adjusting - simplified Author: RusVirago Post Posted: Mon Jan 12, 2009 8:52 pm

Thats a bad picture I cant tell where you put the ruler and where should the float be measured on the highest or lowest point?

I am sorry its frustrating...

#30:   Author: grazingazer Post Posted: Mon Jan 12, 2009 8:57 pm

i never called you stupid but it's pretty obvious where that ruler is on an excellent picture...if you emulate that picture with your own ruler you'll have your measurement...what more do you want

#31:  Re: Float level adjusting - simplified Author: RusVirago Post Posted: Mon Jan 12, 2009 8:59 pm

Ok I guess I am a total noob when it comes ti setting the float....

I searched the web anda guy said you measure it from where the bowl mates up so from the crack??

And also I though its when its open???? But I guess its when its closed??? thats where the 15-16mm mark should be>?

#32:   Author: grazingazer Post Posted: Mon Jan 12, 2009 9:06 pm

the end of the ruler sits [ever so lightly] on the float with the needle valve in the closed position...i'm done

#33:   Author: ss350z Post Posted: Mon Jan 12, 2009 10:30 pm

Graz, your plenty clear. For me, I read about it, go and mess with it, and then come back and read it again. Only then do I really understand it and can fix it again, if necessary.

So, your recommending initially setting it at 15 not 19 mm?

#34:   Author: grazingazer Post Posted: Mon Jan 12, 2009 10:34 pm

yes

#35:   Author: ss350z Post Posted: Mon Jan 12, 2009 10:48 pm

Thanks, one more thing to do before I put the carbs back on. Good thing we have about a foot of snow and I'm not going anywhere soon.

#36:  Re: Float level adjusting - simplified Author: lassesand Post Posted: Tue Jan 13, 2009 6:04 am

OK, as seen on the picture, 15 mm if you measure from the mating surface to the top of the float (actually bottom since it's reversed).


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#37:  Re: Float level adjusting - simplified Author: Vyrus Post Posted: Sun Feb 01, 2009 12:29 am

grazingazer wrote (View Post): set to 15 mm-1.5 cm


hahaha GG, I was good with understanding this whole post until you chimed in! j/k

15 mm from the mating surface to the top of the float, or 19mm from the top of the float to the main jet boss, all done while the carbs are off the bike and upside down on the table, or workbench or whatever you use.

Is this exactly what you are saying?? lol

#38:   Author: funkamongus Post Posted: Sun Feb 01, 2009 12:44 am

yes

#39:   Author: RusVirago Post Posted: Sun Feb 01, 2009 3:38 pm

Vyrus wrote (View Post):
grazingazer wrote (View Post): set to 15 mm-1.5 cm


hahaha GG, I was good with understanding this whole post until you chimed in! j/k

15 mm from the mating surface to the top of the float, or 19mm from the top of the float to the main jet boss, all done while the carbs are off the bike and upside down on the table, or workbench or whatever you use.

Is this exactly what you are saying?? lol


LOL that is how I felt when GG chimed in but realy he made sense we just did not understand because we dont have anywhere near the experience that GG and others here have, at this point I can set these carbs perfect no problem!

Anyway to answer your question Yes its 15mm from the mating surface which is called the crack of the bowl to the top of the float if the carbs are upside down ( this also means you realy are going to the bottom of the float because they are flipped to make it more complicated :) ) and yes it is 19mm from the same point you measure to from the crack, only you put the ruler on top of the float very gently dont push, to the top of the Main Jet. Good luck!

Dont forget to bench test, bench test, and bench test! Also use the clear tube method!
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