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The carbs on my sons '82 750k have no means of adjusting the floats.
The entire float assembles are made of plastic.There are no adjustment tabs like shown in the manuals!
i replaced the old float needles with new ones.After assembly,gas was flowing out of the bowl overflow tubes.Upon further inspection,the floats were almost bottomed out with the carbs inverted.The float heights were way below the .610" spec.
The new float needles were replaced with new ones from another kit.After the assembly,the float heights were more within the spec.Tried to start the bike but seems like its not getting fuel.No signs of fuel in the cylinder that I checked,the plug was dry.
I'm stumped,any suggestions?
Thanks.
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Administrator
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Can you post a picture of your floats? It may help someone identify your problem. Get us a pic if you can and we'll see what we can figure out.
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What color are the floats? If brown, there are no adjustments.
One way to also find out if you're getting fuel in the carb is to drain the float bowl. It pulls from the bottom, so you can find out via that if you've got gas in the bowl.
Otherwise, check out the FSM and look in the addendum area, see if there's any adjustments mentioned in that.
Turbos, Hondas, 4-bangers, what could go wrong?
 Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
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Are you sure you have the right manual for the year of your bike?
If you're working off a pre 1979 manual then the carbs are very different. My 1981 CB750 also doesn't have adjustable floats. I believe it is possible to adjust them with shims, but you shouldn't need to.
Did you give the carbs a really good cleaning and polish the float seats really well? If they're stuck open you'll piss fuel out the overflows. If they're stuck closed I imagine you won't get any gas (although I've never heard of them sticking closed).
1981 CB750K with 900 cams
90K KM's, rebuilt head, rebuilt carbs, upgraded valve stem seals
My wife's recipe website that I'm trying to help promote: Strawberries for supper. Yes, I am a lucky man.
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The manual I used also said that if you don't clean the brass tube, then gas can get around the float and make it overflow as well. I cleaned mine with brasso; it's amazing how dirty it was without looking terribly dirty.
But since you're not getting gas, is the passageway blocked? There should be nothing blocking between the carbs, or in the carb's passageways. In one of my carb bodies, I had a blockage so bad it looked as though it was brass and supposed to be there. Needless to say, I had no gas after that blockage. Perhaps you've got the same issue?
Turbos, Hondas, 4-bangers, what could go wrong?
Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
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The floats are a brown colored plastic with no bendable metal tab.
The bowls are getting fuel by checking the drain screws.
The float heights are close to .610 measured from the surface after changing the needles again.
Does having the air box connectied make any difference?
I completely disasembled the carbs,cleaned with carb cleaner,blew out all passages with compressed air,replaced the air vacuum diaphrams and new seals.
Whats strange is that the stock float needles make the floats sit much lower compared to the ones that brought the floats into spec.
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the floats are brown plastic with no metal..thanks
--- On Sun, 5/13/12, shinyribs [via Honda CB750'S] <[hidden email]> wrote:
From: shinyribs [via Honda CB750'S] <[hidden email]>
Subject: Re: '82 750k carb float adjustment
To: "robs750" <[hidden email]>
Date: Sunday, May 13, 2012, 9:26 AM
Can you post a picture of your floats? It may help someone identify your problem. Sorry you haven't gotten a reply yet. Get us a pic if you can and we'll see what we can figure out.
Montvale,Virginia
Piute said it best: "wheres my 10mm?"
Hellbilly-"that is a great way to tell if you have come to your senses, when you start drilling random holes in things... "
LukeM-"Scooters rock, especially when they're in posse formation. "
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
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The rubber on the end of the stock float valves may have been eroding. What you want is the float, as it fills, to push the valve up into the chamber to shut off the gas.
As long as that happens, at the end of the day that's all good. It COULD be that the new valve is shutting off gas going into the bowl and when you speed up, using more gas, it's emptying the bowl before it can fill again.
Turbos, Hondas, 4-bangers, what could go wrong?
Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
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Well after finding out that i did not replace the o-rings on the pilot screws(old ones still inside and one missing)i added those and connected the air box.Still no start.Was getting fuel in carbs.
So i completely disassembled the carbs.What i did find was the 4 replacement air pucks that are on the sides of the bodies were not machined the same as the originals.The dia. of them are .001" larger and the taper is not the same.They felt sticky sliding in and out the bores compared to the old ones.
Could this be a problem?
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The bike still did not start after rechecking carbs again.Accelerator pump was working,jets clear,etc-.
Did a compression test.............40,60,40,120.Should have done this from the get-go!
Think this why a no start.
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Yep, you have some significant compression issues. Squirt a little oil in there and do another compression test to see if its piston rings, valves or something else. Sent from my BlackBerry device on the Rogers Wireless Network
Date: Wed, 16 May 2012 05:23:17 -0700 (PDT) Subject: Re: '82 750k carb float adjustment
The bike still did not start after rechecking carbs again.Accelerator pump was working,jets clear,etc-.
Did a compression test.............40,60,40,120.Should have done this from the get-go!
Think this why a no start.
1981 CB750K with 900 cams
90K KM's, rebuilt head, rebuilt carbs, upgraded valve stem seals
My wife's recipe website that I'm trying to help promote: Strawberries for supper. Yes, I am a lucky man.
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Thanks.We are going to do a leakdown test first.Hopefully its just the valves out of adjustment.
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I did a valve clearance check.....all of the the intakes were about .004".Four of the exhaust valves were .002"-.003".The other four were tight........one in each cyl. did not accept a .0015" gauge.
So I ground all the exhaust shims to get .005" clearance based on my check.Now I just have to put the shims in and do the leakdown test.
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