yet another update.

[Alan1982XJ]

A week or so ago I asked everyone for advice on a cylinder issue. Here is all I have done to figure out why #3 was still cold.

*carb complete tear down and cleaned.
*compression test. All 4 85-90 psi
*new plugs
*tested plug wire swap from two to three.
*cleaned fuel lines ensuring no delivery issues.
*tore down octy and cleaned for good measure.

After all that, 3 is still cold compared to the other three. After 1 minute of running 1,2,4 are at running temperture and in good order. 3 however is still touchabley warm.

After some thought I decided to play with how the fuel lines feed from the petcock to the carbs. Is there an all inclusive diagram I can find to ensure it is right? I did some fiddling and 3 began to fire again but later having to clean the tank out forgot that sweet spot as it were.

I am hoping this is it. Or who knows...

[bikerphil]

Octy fuel line diagram in this thread....

http://www.xs11.com/forum/showthread...t=octy+diagram

JAT, possibly a loose pilot jet in #3 carb?

[TopCatGr58]

Hey Alan,

Hate to ask it, but just how much of a complete tear down do you mean?

Do your carbs have the brass cap on the TOP of the front of the carb bodies, or can you see into the tunnels to the PILOT JET Screws?

Have you checked the vacuum caps on the intake boots for looseness/cracks, folks have had a small vacuum leak there that wreaked havoc in their tuning till they found and fixed it. Also, bolts securing boots to engine are tight?

Did you pull the Float needle seats completely out, there is a screen under/ on the bottom that can get clogged. Did you ensure that fuel/air can flow thru the fuel INLET T's, not all gunked up? #3 should get fed the same time #4 does, but could be something clogging it at the carb body?

Still sounds like a Pilot circuit problem not providing enough fuel!?
T.C.

[b.walker5]

Compression seems low, should be in vicinity of 130 to 140, but if all four are the same then it's simply telling you that there may be ring (or cylinder) wear but should still be running on all four. Apart from that, I tend to agree with the others and lean towards pilot circuit problems.

Next time you do a compression test, do two. On the second one give a couple of squirts from an oil can down the plug holes and see if the second reading is higher than the first. If it is then it's telling you the rings are worn. Not nessecarily a problem, but can tell you if a new set of rings should be in your budget.

[11Rider]

Regarding the compression test, make sure you have the throttle opened.

[DenyP]

And you are performing the compression test with a warm engine???

Deny

[Ken Talbot]

Here is all I have done ...

*carb complete tear down and cleaned.
*compression test. All 4 85-90 psi
*new plugs
*tested plug wire swap from two to three.
*cleaned fuel lines ensuring no delivery issues.
*tore down octy and cleaned for good measure.

All good stuff, and bonus points for tackling the octopus! So, now what about syncing and 'colortuning' the carbs? IIRC, your XJ will have the YICS system so you need either the special tool or the eliminator to isolate the cylinders so you can sync it properly.

[Alan1982XJ]

Re did compression test while motor was warmed, they were much higher and in the range someone had posted earlier they should be. Off the list, and good.

Why are the spark plugs (NGK) with a narrow screw down type tip to them? seems weird but thought I'd ask.

On a side note, headers and exhaust pipes are fully painted! no more ugly rusty chrome! muwahahaha, poor man's fix

TopCat - Carbs were torn down to the extent there were designated cups with letters and soaking bins... very torn down.

Phil - Thanks for the diagram! Fixed a delivery issue I was having.

On a side note, EBAY looks like someone tore down a XJ entirely and tossed every part up ready to sell for understandable prices. I've already bought a few of his things...



Cleans up nice with soft wool and some degreaser! I also coated the carb boots in Liquid Electrician's Tape

A bit streaky ugly from the strokes but doesn't look like aged, cracked rubber anymore and I feel MUCH more comfortable with them the way they are now.

No, I didn't paint that one part of the motor black. The jackass before me did and he didn't cover it correctly... over-spray for the win.