Float level/Carb adjustment question

Orion61

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I have looked around for an answer to my Float level question, but haven't quite gotten my answer. I know the float level should be about 27mm (+ or - ,1mm), from the inner ledge without the gasket.
But it doesn't say if that level is just sitting on the springy tip of the needle valve or with the float tang pressing it down? The Float itself isn't very heavy but I don't know if that little bit of fuel in the bowel is enough to press the needle tip in to regulate the fuel level..
Also I am having a bit of a hesitation, so if I move the clip on the long needle that runs inside the slide
down one setting which will lift the position enriching the mix, will that help with the bit of hesitation?
Thanks so much,
Orion
 
Let the float just rest on it to take your measurement. The "springy" pin is free? Not gummy and doesn't stick?
Raising the needle will make the transition happen quicker and may help with the hesitation.
But to make the mixture richer you would change the main jet to a larger size.
 
The tang of the float should rest lightly on the needle. Lower the float as gently as possible. As to needle adjustment and hesitation, there's not enough information to say if that would help; where is the hesitation occurring? If you have breaker point ignition, off-idle hesitation can be caused by advance issues. If your pilot mixture is lean, secondary effects from raising the needle may clear up off-idle hesitation. If you're jetted rich on the mains to tune for relieved exhaust and/or intake, however, you may need to use a leaner needle position, and richer pilot jets may be called for to relieve the hesitation. Reread the Carb Guide section on tuning for modifications.

Dan, installing a bigger main to fix off-idle hesitation would be an error. You have to know where the mixture imbalance is happening before trying to tune it out.
 
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Float level spec will depend on the year of your carb set. 27mm is almost right for one year only, the brass floats in the 1980 BS34s (actual spec is 27.3mm ± .5mm). If you're dealing with the older BS38s, the spec would be 24 or 25mm, again depending on the year. If you've got them set at 27mm, that would give you too low of a fuel level and could be the cause of your hesitation.
 
They are B38s It is a 1975. The hesitation is right off of idle. The float question has been answered thanks. I just cleaned the carbs and to be quite honest I am surprised it runs at all as bad as they were! I am also getting a bit of popping from the exhaust at times as well so it may be a "lean mix" from the residue not removed after cleaning. I actually purchased another set of carbs for it and I am just waiting for O-rings for the jet.
It is too cold to ride it (16 degrees F) I think I will buy a couple of buckets of carb cleaner and just pull the original carbs apart and soak them for the whole Winter. You never know when you will need a good set of carbs!
Who makes good kits that include the jets?
The bike other wise ran perfectly before it set for 13 years lol... and yes it still has the points and it starts OK off the electric starter and charges fine. so the magnets are still good.
 
If you dunk and soak the whole carb body, you will ruin the butterfly shaft seals, unless of course, you remove them first. Carb cleaner is very strong. Soak the bodies long enough and the aluminum will melt. If you check them in a month or so you may find nothing but dark gray carb cleaner, lol.

If your carbs are a 1975 set, the float level spec is 24 ± 1mm.
 
I use brake cleaner. Its alot stronger. Carb cleaner leaves a residue. 1 can per carb.
If i soak anything, i use berrymans chem dip.and rinse with brake cleaner.
 
I don't really have a preference. They all seem to work OK for me. But this is combined with compressed air. Just soaking doesn't always do the trick. You need to blow the passageways clear as well. I also flush afterwards with something mild like WD40 to get any carb cleaner residue out.
 
OP, save yourself further grief and read the Carb Guide that 5twins and I took the trouble to write for XS650 Garage USA. We gave float level specs and cautions on soaking carburetors there, so it's clear you didn't bother to use the resources already provided. Click on "Tech" at the top of the page and follow the menus to the link. I'm done here.
 
Someone above hinted that the tiny little spring in the float valve can be an issue, on any bike you intend to be a reliable runner, new float valves are a wise investment. Carb kits not so much.
 
OP, save yourself further grief and read the Carb Guide that 5twins and I took the trouble to write for XS650 Garage USA. We gave float level specs and cautions on soaking carburetors there, so it's clear you didn't bother to use the resources already provided. Click on "Tech" at the top of the page and follow the menus to the link. I'm done here.

UM yes I did, I spent about an hour looking through different posts, I did not happen to see your post. There are a ton of threads out there, so thank you for your help and on the other hand...screw you!
Everybody here has been very helpful and I appreciate it, I have had a great many questions answered by searching her archives here. Sometimes you guys don't realize just how much time you can spend going through old threads, and sometimes certain key words used in a search doesn't match up to past threads. Nobody appreciates your help and the vast effort people put into this site, But I will NOT be chastised like that by anybody!
 
These carbs with a few variations were used on many bikes. Carb kits that come with any brass parts are generic parts. These parts may work in many applications. Just not an XS650. Gaskets are sometimes usable.
Best to follow the steps in the carb guide, Can be found following grizld1's instructions or go to www.amckayltd.com/carbguide.pdf Once you have them apart and inspected you can buy the parts you actually need.
The carb guide explains how to ID your carbs, tear down, clean, inspect, reassemble and adjust.
On adjusting the floats, have the carbs set on the end, now tip them so the floats tip away from the needles. Tip back till the floats just touch the needle. This will be at about a 15 degree angle. I cut a wedge out of wood at 15 degrees and set the carbs on this wedge. Measure, bend tang as needed.
Check both floats, the bridge between them can get bent. One side can be right, the other off. Set both sides.
Leo
 
Another thing, are you using the stock air box? If not the K&N type pleated pods are a poor choice. The shorter and more tapered the worse they are. These type pods cause air turbulence through the carb. This disrupts the vacuum signal for the slides. This slows the lift, causing the off idle flat spot.
Straight foam pods are a better choice. A lot of us use Uni filters.
Leo
 
Thank you Leo, I am using the stock air boxes.. I did wrap a thin foam around the outside of the filter and seal it with silicone (it was there and the bike ran great, It is surprising how much dust it caught but was rotted out. the OP had removed the paper filter and made these. I am keeping this bike as original as possible There are thousands of dirt bag rust buckets to chop up or whatever ride you want out there. The decent ones are getting harder to find.. Thank you for the link to the carb guide it is well done and I have saved it for further reference. After I am done with this I am going to find a TX750. I have a lead on a pair and I have a clean title and frame neck. Most people hated them but if you know how to work on them and maintain the CB system, they have a beautiful ride and feel to them. They honestly have a better ride than bikes MUCH bigger and carry my 220 lbs plus momma at 75 mph all day long.. I believe I am going to sell my Boulevard V twin to fund this project.
I am still fairly new here and don't have all of the site memorized, I hate it when people fail to realize just how many threads there are out there, let alone finding the post that has a link to what you are looking for. I have seen the kinds of replies like griz gave me and all it does is alienate people and cause hard feelings.
Chiding remarks do no good at all, and as you see don't float with me. 5T has been very helpful and I think he is a great guy. I am almost afraid to ask where to get GOOD carb parts for my B38's.
Thanks again Leo.
 
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