Do I need to jet my carbs? Or anything else?!

[CaseySmithersxs]

Im in the process of setting my carbs, but im also going to be running air pods and straight pipes((just unbolting the stock exhaust at the swell by the peg mounts)). So I was just going to put on the pods and take the exhaust off before I set my carbs for the mixture change with the pods and pipes. But would I have to rejet my carbs or anything because of the exhaust and pods? Thanks in advance guys!

 

[XSLeo]

Lets start with a good solid maybe. You might get lucky and not rejet but the odds are that you will have to.
This question or one very much like it gets asked every few days. A bit of research on your part will find the answer.
You can start by scrolling down this page till you find a heading of Simular Threads.
Then try the XS650 Tech section.
Leo

 

[Gene]

found this in another thread

Yes, definitely rejet for these mods. I would start with #140 main jet (which is 3 sizes up from stock), and #45 pilot jet (1 size up from stock). You may need to replace the rubber plugs that go over the pilot jets also. They need to have a good seal, and the originals are usually in bad shape due to age.

 

[Gene]

maybe someone can chime in, but where would a good place to purchase jets?

 

[CaseySmithersxs]

Mikesxs has alot of carb parts... I mean will it hurt to over kill it? Like jet the carbs anyway? Or will it hurt to do these things and then see if it needs to be jetted?

 

[Gene]

Mikesxs has alot of carb parts... I mean will it hurt to over kill it? Like jet the carbs anyway? Or will it hurt to do these things and then see if it needs to be jetted?

I'm running pods and just running headers. It seems to start up and idle fine, and has good snap to it off of idle, but i have really yet to ride my bike. I don't trust the stock jetting to really run the bike. You may be able to change the clip on your needle and get away with that. I just ordered some larger main/pilot jets to mess around and see where I end up. I

 

[CaseySmithersxs]

What do you mean you dont trust them enough to ride?

 

[Gene]

What do you mean you dont trust them enough to ride?

I figured that the carbs air/fuel ratio was set up with a baffled exhaust and restrictive airfilters/box. I don't think that with my new set up, the fuel demands won't be able to keep up. I am not worried about fuel mileage or performance, just want a bike that runs right. I will eventually go back to a nice muffled exhuast, but what came on my bike was some thrashed up oem pipes that just had to go.

 

[CaseySmithersxs]

I plan on running mufflers... Maybe baffles...

 

[CaseySmithersxs]

So what size main jet abd pilot jet would i need, i have a 77. and if other parts are needed.

 

[weekendrider]

Until you have the exhaust and intake settled it is hard to say.
But more importantly than how long the pipes are, whether you use a brillo pad or stock air filters is what carb set are you working with?
You need a bit more background for us to work with until then it does matter if the pipes are baffled, cause we are.

Keep in mind ALL these are a bit worn out so what absolutely works for one, doesn't for another. Like people, everyone of these are a little different.
You might consider getting what you got running well enough to harass Harleys (and a stock 650 will make them work for it) then start the testosterone treatments.

 

[CaseySmithersxs]

Until you have the exhaust and intake settled it is hard to say.
But more importantly than how long the pipes are, whether you use a brillo pad or stock air filters is what carb set are you working with?
You need a bit more background for us to work with until then it does matter if the pipes are baffled, cause we are.

Keep in mind ALL these are a bit worn out so what absolutely works for one, doesn't for another. Like people, everyone of these are a little different.
You might consider getting what you got running well enough to harass Harleys (and a stock 650 will make them work for it) then start the testosterone treatments.

I was thinking about just getting it to run better like it is, but then i figured i would just have to do it all over again once i run exhaust and pods. So why not all in one lick ya know. For now i plan on just unbolting the stock pipes where they start to swell by the foot pegs.

 

[CaseySmithersxs]

And would i need to do anything besides main/pilot/and adjust needle? My bad about sll the questions, im new to all of this haha.

 

[weekendrider]

If they are stock carbs that would be all.
3 sizes over stock on the pilot and 5 over on the mains.
Shim washers if the needles aren't adjustable.

 

[wherearewe]

Also worth noting that not all the jet parts Mikes sells are OEM. With something like carbs, OEM is probably a good thing. You can tell the Mikuni stuff because it will be stamped with a little logo. The needles and needle jets seem to be OEM, but not the jets. Try 650 central or niche cycle for those.

 

[CaseySmithersxs]

Weekendrider, that seems kind of extreme... Ive messed with jetted 350s and never had to jet that much, i know its a totally diff set up. But hey who knows.
And @Wherearewe thanks for that info man! I never knew!

 

[5twins]

You probably only need one up on the pilots, that's what most of these 650 carb sets require, sometimes 2 at the most. If you really do have a '76-'77 carb set then mains in the low to mid 130s should do. If you don't have this carb set, those mains would probably be too small. But then, you don't know what carb set you have and without knowing that, trying to help you is a waste of time.

 

[XSLeo]

www.amckayltd.com/carbguide.pdf has a tuning guide. You might want to read it.
www.xs650.fi/pohja_files/fi/XS650carbs.htm is a bit tough to read but is a good guide to ID your carbs.
Leo

 

[CaseySmithersxs]

Thanks, Ive got it to idle decent off choke, but not on chock the rpms rise without me being on the throttle. and cant figure out why. And I have original 77 carbs.

 

[angus67]

niche cycle, cheap cycle parts, dealer. get genie mikuni jets.
Have you read the carb guide?
Nice restraint, 5twins, as I was reading, I was thinking, "oh, just wait till 5t finds this"
Back on the wagon?