Need help here

[Aussie]

Hi there, recently bought an xs650 bobber and after searching have found out my engine is a 1972 and my carbs are '76 - '79. Question is it dies on idle so should I re-jet as for a '72 (45 pilot) or just find new carbs of that year. At present I have 27.5 pilot and 155 mains. Am going to try a 30 and 40 pilot but would welcome suggestions.

 

[XSLeo]

You tune cabs by the year of the carbs. The 76-77 carb set is very different from the 78-79 carb set, both are very different from the 72 carb set.
Have you read www.amckayltd.com/carbguide.pdf ? This will help you id the carbs you have and how to tune them.
If using a 27.5 pilot then my guess would be they are 78-79 carbs. They used a 27.5 as a stock pilot size, the mains were 135. I think the 155 is way to big. Even with velocity stacks and open pipes.
Leo

 

[XSNate]

Nice paint!

I assume it was running when you bought it? If so, I would check battery/voltage. I've learned these bikes REALLY don't like low voltage. The coil can't make enough spark to keep the bike running.

 

[Aussie]

Hi thanks Guys, yes the bike is gorgeous and was running when I got it but not running for long. So I reckon I shall just up the Pilot jet to 40 - 45 and drop the main to 130 - 140. The electrics are SHIT really and am going to re-wire in a modern Reg/Rec . Has a boyer bransden fitted. Might go for the permanent magnet charging system in time but seeing we only have several weeks left until winter kicks in I am impatient and want to get a bit of riding in on her. But question is if I will get away with using these carbs but re-jetted or am I just wasting my time. I have baffled the pipes slightly as it was way way too loud . Still damn throaty though

 

[itrguy]

nice scoot!

 

[Aussie]

Thanks

 

[5twins]

As mentioned, you really need to positively I.D. your carb set year or you'll be just wasting your time and taking shots in the dark if trying to re-jet it. I will tell you that 40 to 45 pilots are way, way too big for any of the '76 to '79 carbs. They may be fine in a '72 carb set but you don't have those now do you. The type of pilot used also matters. For the '76 to '79 carbs, you need the VM22/210 type .....

 

[Aussie]

Yeah I checked that and have a rake of jets on order and will do trial and error. Probably mostly error ha ha ha

 

[Aussie]

Lowered main jet to 130 and raised pilot to 30. Put on new Boyer Bransden brain and running sweet as a nut

 

[5twins]

130s are way too small now. I hate to say it but you're going to have that bike all fucked up in no time. Get a carb jetting education before you seize the thing, lol.

 

[Aussie]

You reckon ? Will try the 140's and compare. I am new to xs650's so will take your comment on board. Many thanks

 

[TwoManyXS1Bs]

Aussie, no no no, don't just experiment first. ID your carbs first, look in the Tech section under carburation, become very familiar. If you can, post some crisp close-ups of the carbs, especially the sides (inner and outer), the inlets, top of the bowls, bottom (looking up) of the bowless carb body.

You've got a full-on custom there, and some non-`72 engine parts. We've seen many part combo bikes here (frankenbikes), and strange 'previous owner' creativity.

To save yourself possible future frustration, should get to know the variations and identify what you have first...

 

[XSLeo]

www.xs650.fi/pohja_files/fi/XS650carbs.htm
Is a very good guide to id your carbs. Some of the wording is a bit difficult because it was written in Dutch, translated to German then English.
Even with that it describes the carbs and the changes from year to year.
Leo

 

[Aussie]

I have the '78-'79 carbs ( 2FO ) so what do you reckon, just leave the 130's in them or take it to 140
Will get some photo's tomorrow in the light and post them up to be sure though

 

[XSLeo]

78-79 carbs had a 27.5 pilot, 135 main. With the stacks and an open exhaust I might try one up on the pilots and two up on the mains.
From there I would follow the testing procedures in the carb guide. Make just one change, test, make one change, test.
By following the procedure of change and test you will find out what your bike tells you. By learning what the bike has to tell you, you will know what you need to change.
It can be a long process or a quick process, depends on how fast you learn.
Leo

 

[peanut]

welcome Aussie I'm in the same boat as you at the moment sorting my carbs out. I'm also hoping to get a few rides in on mine before winter sets in, although judging by this morning I'm too late lol.

Check out customxs.com a UK based forum with a good bunch a lads on there many of whom are also on here.

If you think you have problems ....check out Anlafs thread . He's just rebuilt his engine 6x times ! He can do it with his eyes closed now

 

[Aussie]

Thanks for that Peanut. Tried customxs.com and was coming up as not known

 

[Aussie]

These are my carbs I am running on my bike I believe them to be '78-'79 2FO.
Correct me please if I am wrong

 

[Aussie]

Carby update. Tried the 140's and no different really from 130's. Ran okay. Just tried it with the 155's back in and BOOM she runs like a trooper. Fuckin' awesome ride. So that's it as far as I'm concerned then. 155's it is.

 

[Maurice]

'78-'79 yes.

They're missing the top brace. Some of the screws are mixed up they stick out too far, probably due to the missing bridge: