Float height and other adjustments

[kebabs]

Yes mostly back together. I bought a carb kit from Mike XS. It provided new float needles, main jets, pilot jets and carb gaskets. When I took the jets out I discovered a #120 on the right side and a #127.5 on the left. From what I read the XS400J (maxim) stock should be 115 and 125. That was 2 of the options in the rebuild kit from Mike XS, so I changed them to stock. The float needles did not have a little basket on the end like the old ones but do have a screen at the bottom. I tried to put the old baskets on the bottom of the new float needles but they did not seem to want to go on. The new float needles do have a small screen on the bottom so I figured that was a replacement for the “baskets”. Now I have encountered a problem. The floats are WAY, WAY off. Apparently 28mm is the measurement (from the carb without the gasket to the top of the float. My floats measure 24mm. I am surprised they are so far off. And the tab is already bent down I’d have to bend it even further. Since this is my first time rebuilding things like this are “red flags” to me. I’ve read the original tabs were almost level with their metal bracket.

I'd take one of the orings off and check size.id think u would be able to get replacements.
bend the tab and make it level.
I see you have plastic floats ,are you able to bend the arm that they attach to ,to get the height needed

 

[GuyS]

My dilemma is the measurement of the float level…..32mm or 28mm? The information I’ve read so far is non conclusive. Mine is an xs400J, a Maxim. Is there a difference between a XS400 and a XS 400J in float height? Or, some have said a “brass or a plastic/rubber float” makes the difference. If I bend the float tab level won’t it increase the required measure? It’s already bent from level.

 

[kebabs]

My dilemma is the measurement of the float level…..32mm or 28mm? The information I’ve read so far is non conclusive. Mine is an xs400J, a Maxim. Is there a difference between a XS400 and a XS 400J in float height? Or, some have said a “brass or a plastic/rubber float” makes the difference. If I bend the float tab level won’t it increase the required measure? It’s already bent from level.

try the 28mm first.theres going to be some trial and error before you get it right. the important thing here is having the float needle opening and closing at the correct intervals. with the floats attached and needle in its housing and float bowl off hold the carbs up in the position they would be on your bike look to see how much the needle is out its housing .it should only be out a couple of mm.this pic is an example

 

[kebabs]

ment to say .CaptChrome on this website gave me lots of help when doing my carbs .he is the man

 

[kebabs]

also there is 2 tangs on the floats .one for setting the height and one for adjustment of the float needle .the brass floats have them .
After adjustment of your float height. flip the carbs over ,the floats will be hanging. push the float up with your finger .Once the float stops the needle should be in its closed position, if the needle is still open at this point adjust the tang in the centre of the floats so it's in its closed position. if not in the closed position fuel will flow into the cylinders and air filter. I hope this makes sense .
I had the carbs on and off a few times before I got it right quite frustrating

 

[GuyS]

Hey thanks kebabs! The more I understand the better.
Getting it back to the original factory specs is the only way to have a reasonable starting point. Since its only got 21,850km on it, I suspect it has not been running very well for a very long time. Over the last 43 years there’s been some tinkering for sure. Maybe some of the tinkering to compensate for things that absolutely had to have been fixed first. Like my damaged/poorly repaired “carb holder” (I managed to find a new one to replace that). It’s been very hard to find a local mechanic too. Most of them are only familiar with the newer technology.

 

[kebabs]

Hey thanks kebabs! The more I understand the better.
Getting it back to the original factory specs is the only way to have a reasonable starting point. Since its only got 21,850km on it, I suspect it has not been running very well for a very long time. Over the last 43 years there’s been some tinkering for sure. Maybe some of the tinkering to compensate for things that absolutely had to have been fixed first. Like my damaged/poorly repaired “carb holder” (I managed to find a new one to replace that). It’s been very hard to find a local mechanic too. Most of them are only familiar with the newer technology.

keep going with it you'll get there. I was going round the bend with mine was going to take a shotgun to it.im sure it's been tinkered with lots over the year's .
another thing I did was blow through the fuel entry on the carb with my mouth while raising the floats to see exactly when the needle was shutting off .
there is a good mechanic where I live. he knows his stuff with the older bikes but I grudge paying so always give things a bash myself.
my bike is running great now I had been chasing an oil leak and eventually found it.so pleased with this.keep me posted.