1979 XS 11 Jetting

[shawn01505]

I need some help with a good starting point for jetting. I have a 79 xs 11 with 13000 miles. It has a 4 into 1 and K&N pod filters aside from that it's stock. Where should I start for needle position, main jet size, fuel screw setting, and pilot jet size. I have no access or finances to spend on exhaust gas analyzers and dyno runs. Through me some ideas.

[pggg]

Shawn, that 79' with K&N and 4-1 should run well with 140 mains and 45 pilots with the needles left at middle position. Also fiddle the idle mixture screws so they're slightly rich for good response and immediate smooth running off idle when cold.

[RiskyBusiness]

Read this post too:

http://www.xs11.com/forum/showthread...=jetting+chart

-RB

[Grimace]

Where can I buy the pilot jets? I found a place that sells the main jets, but bikebandit wants 13+ bucks a piece for pilots, and I am not sure if they are what I need. I googled xs1100 main jets and found a good site, but they didn't seem to have the pilot jets I needed. Thanks,
J

[Hobbit]

jets

I just ordered a set from the very knowledgable Rob at motorcyclecarbs.com

[TopCatGr58]

Hey Shawn,

It will be helpful to you and us in the future for folks to be able to provide pertinent technical info, if you'll edit your profile to include what MODEL your 79 XS11 is, Standard F or Special SF!

Stock mains are 137.5, the jetting guide recommends 3 sizes up for your two mods combined, so 145's would be the about right. They also recommend going up to 45 pilots, but you could try keeping the 42.5's and turn the pilot screws out a bit more!?

MikesXS has both mains and pilots; Pilots are BS30/96 style.
Mains are the large head N100/604 style, $6.00 pair for both!
Just don't tell them you're ordering for an XS11!! SERIOUSLY!!
Don't ask them any questions about whether any parts will fit an XS11!!!! Just be aware of the parts you need!

Bikebandit also sells them!!
T.C.

[Shuriken]

So, at my 6700ft elevation with only the following mod:
- 4-1 exhaust

I am looking at a 2 jet size increase (up from 137.5) across the board or just on the mains?

This applies even at my elevation?
Ben

[shawn01505]

Top Cat, this is the first XS11 I have ever owned.I think it the standard F. How can I tell?

[TopCatGr58]

Hey Shawn,

To be sure, take your VIN# found on the steering head neck, or also on the Engine, right hand side, above the clutch cover, and go to this thread....found in the Tech Tips, MISC and check for your year and model, registrations are known to sometimes be wrong!
Vin# finder

But also, a Standard has the front axle on the END of the forks, the Specials are mounted in FRONT of the lower tubes. Standard has Square headlight and gauges, Specials are ROUND; Standard has the larger gastank with the knee depressions, Special has teardrop.

Once you get it running right, you won't want any other bike!
T.C.

[shawn01505]

TC, thanks for the info. I must have the standard. I have the larger tank, square headlight and gauges, etc. Even with the bike not running perfect I love riding it. I feel it can only get better!!

[Glarusguy]

Just want to make sure I am using the chart right. I came up with a total of 4 sizes with the same two modifications instead of three. I'll be ordering jets soon. Most likely through Mike's (mums the word on the xs11), and of course I'll check plug color.

[TopCatGr58]

Hey Glarusguy,

You must have missed the tip about cutting back 1 size when you COMBINE mods, so you may want to go up 3 (2.5)sizes, not 4!?
T.C.

[Glarusguy]

Shawn said he has the 4 into 1 with K&N pod filters.
The list says: 2 jet sizes for 4 into 1 exhaust + 3 jet sizes for individual filters = 5 then subtract the 1 = 4. Did I do something wrong then? Thanks guys.

[Glarusguy]

Forgot this part....
"Under a mismatch condition, like individual filters and stock exhaust OR 4 into 1 header with stock filter and air box, subtract an additional 1 jet size. "


Thanks again...

[pggg]

I'd say 3 sizes up on stock main jets would be MAXIMUM anyone should go to on these 34mm carbs. Anything more is just too much, and bigger carbs would be a better choice. Going by my own machine at least - it's got 1196 kit, K&N, 4-1, Drilled out airbox, and a ported head - only 2 or 3 sizes up on the main jets is all that's neccassary. Anything over that and the fuel/air ratios lose the plot and fuel economy takes a steep dive.