carb jetting ???????

[mitch]

ok now i got this 1982 xj , i found a 4 into 1 exhaust cheap,me very happy ,i also ordered 4 single air filters some hard to get the carbs off with the stock box. my question is how much hp will i gain and what should i do to my pilot jets and main jets will 140s do the trick with 1 size up on the pilots ??any help will be much appreciated thanxs ; doug

[chopper]

hi.......older xs11's have 132.5 main jets...rejet to 122.5........1.1s(possiblly xj's) have 110 main jets...rejet to 107.5 the xs runs without an airbox or rejetting(not to well,but safely) i use ledar air corrector kit ack2 easy to fit and perfect running...also motad 4 into 2 into 1 exhausts available in l/h or r/h exit! will run fine without can (add your own) and is cheap ...you may need to raise needles one notch..........hope this helps.....yes you do go down in size on the jets its not a mistake

[Mike Hart]

Hi Mitch. If you want to really know how much hp you will gain, dyno before and after. It's like 'a few', maybe even 5 or 6.

Did you get that 140 nr from my adventures in rejetting my xj? Did you get the Emgo cone filters? Some other kinds have an airway restriction. This long thread would be worth skimming if you haven't already.

I'm not done yet, I'm going to have to go bigger on the pilots by yet another size or three as I'm still lean at cruise.

[Mike Hart]

Originally posted by chopper
i use ledar air corrector kit ack2 easy to fit and perfect running (snip)....yes you do go down in size on the jets its not a mistake

Chopper, what the heck is ledar air corrector kit ack2?

If you had to jet down, then you are getting less air.

[chopper]

ledar is a tuning company in uk(highly respected) ack2 is the product no. i am a mechanic and can assure you the xs11 runs fine with my specs i also use a xj650 ignitor and kawasaki 12v coils honda cb250n reg/rec my bike is fast and reliable and i get 40m.p.g(uk gallon) ave unless thrashing it (20 ish mpg)

[tiel]

Jetting

Forgive me if this sounds stupid!

I understand the need to re-jet, but isn't jetting kinda like timing? what I mean is, someone in Kansas wouldn't use the same jetting as someone in Colorado!

Doesn't the altitude factor into the air/feul mixture? Thus affecting the number of jet sizes you would need to increase or decrease whichever the case may be?

Example:

My 80 XS1100 G has one step up jets, I am running 4 into 2 exhaust with open headers and individual filters. My plugs
are in the tan/gray range (maybe just a hint of white) Thus the reason for my question.

[chopper]

hi mark, extremely high alltittudes will weaken your mixture.......some of you guys dont seem to understand the basic principall of plug chopping.....you should test your jetting on a dyno or failing that ride totally flat out up an incline (to load the motor) in second or third gear. switch the motor off WHILST the throttle is fully open! VERY important then check your plugs instantly or all you will be reading is your idle mixture.

[strom]

OK, since the topic is open...

The engine gets too much fuel... how to adjust... other than changing jets. Float level is OK at factory specs.

Some other weird stuff...

checked ignition timing today with a strobe light... seems that when (after 50m) rpm fall to 500-1000 and won't rev beyond at full throttle and die if 1/2 or less throttle is applied... it has intermitted spark on 3&4 cyls. On 1&2 spark is constant and at regular intervals.

HELP?

LP

[nashville_bill]

Sounds like you need to pull the spark plugs and check color. It would be hard for you to loose spark on 3 & 4 but anything is possible. Take the spark plug wires from 1 & 4 and reverse them; put 1 on 4 and 4 on 1 and see if you still have no spark on 3 & 4. You could also do this with 2 & 3 if you would like.

I think the spark plug color will give you a good idea as to what is going on.

[strom]

Originally posted by nashville_bill
Sounds like you need to pull the spark plugs and check color. It would be hard for you to loose spark on 3 & 4 but anything is possible. Take the spark plug wires from 1 & 4 and reverse them; put 1 on 4 and 4 on 1 and see if you still have no spark on 3 & 4. You could also do this with 2 & 3 if you would like.

I think the spark plug color will give you a good idea as to what is going on.

The spark on 3 and 4 is present, but not constant... it misses sometimes (30-50%).
The plug color is black. I cannot depend on the color info, since I cannot ride it more than 50m at a time...

BTW: How do I adjust fuel/air mixture othen than changing the jets? I think it needs more air/less fuel...

LP

[Jerry]

1. Be sure your carbs are *absolutely clean* before changing jetting. These carbs are now 20+ years old and need some TLC.

2. Make sure the diaphragms are not leaking or sticking.

3. Set float height per factory spec on all 4 carbs. Make sure the inlet needle valves are shutting off fuel OK.

4. Check carb to head manifolds (those rubber boots) for leaks and tight clamps. Cracks in the boots can be sealed with black RTV.

5. Be sure the exhaust manifold gaskets are not leaking and your exhaust system is free from broken baffles, plates, and other restrictions. Exhaust system problems sometimes show up as carb problems.

6. Clean air filter(s) as needed.

7. Finally, do a cam chain adjustment before anything else.

The XJ is jetted a bit leaner than some other bikes, using 112 main jets across the board. A few XS models used 110s in 1 and 4 and 120s in 2 and 3. The early E model ('78) used 137.5s, I think. Note there are small changes in the head design of the later bikes, including the XJ's YICS induction system, which includes an extra small port in the head, designed to swirl the fuel mixture. (I don't know how effective this is, but it is mentioned in the literature.)

If all this seems a bit basic, I apologize. However, have learned from experience that unless the basics are covered and you have a good baseline to work from, tuning carbs can be a frustrating experience.

[dntemp_ca]

Originally posted by chopper
"i also use a xj650 ignitor and kawasaki 12v coils honda cb250n reg/rec my bike is fast and reliable ....[/B]

Chopper: It's inspiring to see that you have discovered parts from other makes & models are compatible. Also saw another post recently that the 850 triple's middle gear bolts right on to the XS11. Might be an idea to start a compatible / substitute parts list for XS11's. Anyone up to it?

Back in the '70's I upgraded my Ducati 750GT with KMart auto coils, Accel wires & gold pladium plugs to heat things up. Also pressed some new Sylvania diodes into the reg/rectifier and replaced the Lucas switches. All were recommendations of the Int'l Owners Club and were excellent upgrades. (Yeh, I know....shoulda never sold it! Hindsight!)

[strom]

Thanx for the info, Jerry. I'm trying to get the XS to work, not work well... yet. I have to fix a few oil leaks first and adjust the valve clearancies. I have one exhaust gasket leaking, but since I'm gonna replace the exhaust I'm not that worried.

I have a partially burnt XJ650 TCI, but can borrow a working one from a friend.
Do you still have the pinout for it? XS has a few more connections. I have a 78E.

Ignition coils from 198? GSX (750 I think) work with the XS11, they bolt right on, not sure bout the connectors. I made my own. A simple job and it works.

BTW: Any of you guys have a spare TCI that could part with, and located near europe or canada?


LP

[chopper]

ignitor

hi, i made my own loom....used xs fittings for ignitor tho.so it may plug n play? i'll check to see if i have any spare 1100 ignitors at the weekend

[Jerry]

I have a partially burnt XJ650 TCI, but can borrow a working one from a friend.
Do you still have the pinout for it? XS has a few more connections. I have a 78E.

Sorry, I have never tinkered with the TCI boxes on the XS11 or the XJ. Had one go bad on my XS 400, turned out is was a bad solder joint and fixable. Other gurus on the list will have to chip in here.