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Quality carb rebuild kit for 1975 XS650B.
- Thread starter Rickv
- Start date
I just don't know how to respond to this request so I WILL be as polite as possible. The consensus is that there is no "kit" useable for XS 650 carbs because the change every 2 years. There is a very good tech section on carbs on this forum. These carbs are surprisingly easy IF you spend only a modest amount of time in that carb section. I will post a link to that section and a page that show all of the jet configuration used over the production run and you will understand that one kit cannot cover all those permutations. The carb section has incredible info and step by step guide to help you through any carb work you may need. Search nichecycle.com for jets or other parts if you need them after you inspected the carbs. https://www.xs650.com/threads/carbs-carburetors.43/
Welcome the forum, post pics
Welcome the forum, post pics
Thanks Kevin for answering my question. I have downloaded a carb. rebuilding report provided by this forum and it looks very comprehensive. Thank you for being patient with people like me who don't have a lot of experience working on motorcycles or navigating forums.
Choosing one, navigating this forum is more important. Until a few years ago my experience working on bikes was oil changes and making exhausts louder. This forum and a bunch of members guided and inspired me. Choosing to rebuild a garb set suggests that they have some problem or other. When you describe the problem, a member might have a suggestion (guess) on a repair action. a running issue might be an incorrect needle height, air screw adjust, diaphragm failure, dirty or clogged jets and/or passages. Each can be addressed with the carbs still in the bike.
Pics?
Sounds like an air leak, possibly intake boots.
As @Wingedwheel suggests check the intake boots (carb to cylinder head manifolds). Spraying carb cleaner or WD40 around those helps identify intake leaks. Know too that the XS650 is a rather cold blooded beast and you sometimes have to nurse it up to operating temp before setting the idle speed to the ~1200 rpm spec. Then follow the standard procedures, sync the carbs, reset the idle , adjust the air mix, reset the idle. Every step is going to change your idle speed a little. I ride ~1/2 mile gently after a brief warm up before I remove the choke/enricher. Then the idle is almost good. A gentle mile further and my idle settles in
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Carb cleaner, yes.
WD40, no. WD40 leaves an oily residue all over everything (it's messy).
Carb cleaner, brake cleaner and elec contact cleaner all evaporate quickly, leaving no messy residue and all are flammable.
Soon as the cleaner finds a leak, engine vacuum sucks it in and you'll get an increase in rpm.
Use the provided straw and you can be very precise at finding leaks... without leaving a mess.
@Rickv please expand on why you feel the need for carb parts. I don't remember 75s needing alot of carb rejetting. In a very basic way. if an XS650 has the requisite cam chain adjustment and valve clearances set, the first troubleshooting is often a thorough check of spark, charging and battery condition. Forgive me if I am going too basic. Cheers.
Please make sure you are charging at roughly 13.8v-14.4v at the battery when the revs are at 2000-2200 rpm. If you are seeing only 12.2v -12.4v you need to back track and check alternator brushes and magnets, regulator adjustment etc.
See this https://www.xs650.com/threads/expanded-charging-system-guide-in-progress.10561/ from the tech section.
You can see @gggGary put alot of organizational thought into that post. A weak charging system can cause all sorts of gremlins. I do not know what our ignition coils are step up count is. If they are 100:1, an uncharged battery reading 11.7v ( and degrading, weak or dead charge system) is a spark of under 12k volts where a charging system delivering 14.2v is a spark more than 2kv hotter. These are 50 year old bikes. I have a little DVM wired into my head light shell and velcro taped on my bar centers, on both my bike (brown wire, ignition switch hot) that gives me a good relative check of what the charging system is doing. Because there is switch loss to that wire it is NOT battery voltage but ~0.5v less. A relative indicator . Less than $10 for piece of mind,
Those 24 ga or 26 ga sensor wires are pretty easy to tuck into BROWN and BLACK bullet connectors in the headlight shell for easy instsllation.. Side effect is you can compare BROWN/BLACK voltage to battery +/- volt to determine voltage drop across your ignition switch. Those contacts do get dirty. IIRC the BROWN is sense voltage to the regulator and if you have too much voltage drop the regulator will have an artificially low reference and try to overcharge your battery leading to short battery life, @650Skull posted the various schematics for all the XS650s in the tech section/electrical. Blow it up and print it in color, 2 pages taped together. Thank me later... 
https://www.xs650.com/threads/some-wiring-diagrams.61/
https://www.xs650.com/threads/some-wiring-diagrams.61/
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I would also check for vacuum leaks at the throttle shaft seals. On 50 year old carbs they most likely leak...
