1982 xj1100 sputtering backfire idle!

hey guys I've been following xjbikes and xs11and learning tons on the bike which is my first and going great.


Before yesterday it backfired on deacceleration which could be my valves, sync, fuel / air mixture screw or even carb Jets plugged.

Two weeks ago I cleaned the carb inside out and took looks of grit and scum out of there and took my time. I did this because the bike backfired on deaccelleration and would take multiple turn overs before starting even with choke and because I had gas overfill in my air box so I checked the floats and cleaned them, they were fine. Also replace intake boots from head too carb and replaced fuel lines and filters. After cleaning The bike ran great with no sputter , no backfire, very quick and easy start. Then it started returning within two days and went back too how it was, long start and backfire when releasing throttle but not loud but consistent after another kind of like a growl.

So yesterday I got my yics eleminator which Installed after cleaning the port and spraying cleaner in it and work with what I got, curious if carbon went into carbs?

I also colortuned the plugs too a blue right after yellow and no further apparently older bikes then 85 work better like that.

I then carbtuned them and in the beginning it was a bit fidgety the murcury was still then bounces and my idle was slightly inconsistent not sure why but I finally got them within 1 cmhg of each other and then I adjusted the fuel air and idle and rechecked sync and it went good.

Today I went for a ride, it had a little longer start but stayed running then went on the highway. After about five minutes it started popping while accelerating and deaccelerating andbog when I give it throttle. When I come too a stop it tends too stall and same when I pull clutch plus the idle is very bumpy.

I carried on incase it was odd carbon that got it and two times on my ride the bike started running great wouldn't stall, or backfire or pop or bog and then it starts out of nowhere so it cannot be a carb issue or fuel air. While I ride I can feel it picked up like it should be then stops again and pops etc. Throughout every gear it does this except when I pass 4-4500 rpm it seems too purr but does pop.

I stopped a few times and too even get going I need too get the engine warm then ride the clutch too get moving then dump it too move or else it stalls even while clutching too get into gear or just sitting there.

I get home and decide too check the pips after they went cold. The bike started and idled wonderful but soon enough I touch the pipes . 1 gets warm, 2-3 get boiling and 4 is slightly warm but more so cold.

Bad coil, and I assume this would explain the lack of power and sputter etc. If the cylinder is completely off but why does it work then stop?

Did I break it after tuning? Prior too tuning yesterday I went on a quick ride too warm it up and it ran good with odd popping in deacceleration, thanks.

Doesn't leak gas into air box anymore so far anyways, but curious why it leaked with peacock off and vacuum lines on, could this be the reason why it leaked and why it takes a while too start, I need too hold the start for 10seconds before it catches, vacuum leak?

I do know my peacocks need replacing too, easy way too fix them myself?

One more thing I've had on my mind, when I first got the bike I got 200-250km a tank and before yesterday I was getting 200 a tank, after today it was about 1530-150 a tank, probably because it's running so rough but is there any other issues why it slowly went down on mileage?

Long story I know




Edit 1: replaced a vacuum line from the vacuum splitter (octy) too the #2 intake boot, it looked old and hardened which may have had an air leak. I also checked the spark on all plugs including the #4 cylinder which checked out with spark even though the pipe doesn't get hot like the others, failing plug or coil wire? Should I ohm the coil wires and if so what's the ohm I need in them?

The plugs were all full of black soit carbon buildup . Before yesterday #1 and #2 were brown but today black.

When I turn ignition on , plugs have one spark is that normal?

 

click this link
Read This First


. I also checked the spark on all plugs including the #4 cylinder which checked out with spark even though the pipe doesn't get hot like the others, failing plug or coil wire?
replace or move plug to see if problem of heat follows plug, trim back the spark plug wire to remove corrosion.


Should I ohm the coil wires and if so what's the ohm I need in them?
yes ohm out the ignition system

When I turn ignition on , plugs have one spark is that normal?
yes it is.


XJ1100 models:
Pick-up coils:
120 ohms +/- 20% = 96 ohms to 144 ohms acceptable range
Ignition Coils:

Primary side (input from main wiring harness):
2.5 ohms +/- 10% = 2.25 ohms - 2.75 ohms acceptable range

Secondary side (spark plug wires, without their end caps):
11K ohms +/- 20% = 8,800 ohms - 13,200 ohms acceptable range

Spark plug caps:
5K +/- 20% = 4,000 to 6,000 ohms per cap acceptable range

Spark plugs:
0 ohms per plug

 

Well last night it was dark so I put off doing much diagnostics. This morning I started ohming everything then decided too check the plug it was ohming in at 5.16-5,72 which clearly ended with me taking an old plug I had left and now back too normal. Cylinder fires and idles very good about too go for a drive. Surprised it fouled its only a month old if that. Hoping no gas went in the engine. Il take a peak. Replacing the two vacuum lines seems like it's making the bike start instantly. Hopefully it was an air leak making it loose vacuum pressure.

Even checked the tci box for the solder which checked out perfectly and checked the coil wires in end caps for corrosion. All good. 35 years later and still going hard, love the xj even though she's a finicky girl

Thanks xj550, good information for the future, fingers crossed I didn't jinks it

 

Hey , so went for a ride, the bike started quick, ran fine for the first 15 minutes then it started backfiring while holding a rpm in low range but at high range it was good but idle was rough. Only one time after fielding did it stall while idling and it had trouble starting everywhere (longer start had too give throttle when I pushed start) but no choke was needed even when cold.

But it went on and off running good, starts backfiring while holding low rpm and hesitates but then it starts running good but I hear it miss odd times. I get home and I check all resistance of caps, the same cylinder that had a bad plug #4 ended up the cap was ohming in at 312k which right away I knew it was bad. It's dark again so tomorrow il ohm the secondary wire for the plugs but why did the plug foul and the cap died could this mean the wire is fouled and the module is dead for #4?

I went and bought e3-46 plugs and new cap so there installed.


Also my mileage is better but still missing 20-50km at end of tank.


I checked all the plugs and there all carbon filled even though I colortuned them too a blue right as soon as it stopped firing yellow. How is it still too rich??

Ps the e3 plugs are resistor plugs with the new cap which is also resistored hopefully not an issue. All caps came in at (4.3-4.8k ohm)

Battery running has 12.5volts

 

12.5 volts at what rpm?


For all XJ-series models, the maximum available charging output VOLTAGE should be as follows (all values are approximate):

* approximately 500-2000 rpms: 1.8 volts gradually increasing to 14.2 volts
* 2000+ rpms: 14.2 volts up to about 14.8 volts, with a maximum of 14.8 volts (all models except XJ700-X and XJ750-X)

could be your charging system is causing you problem

read about it in this link way down at the bottom
The Ultimate Relay, Switch, Sensor, and Diodes Guide

 

I don't want to be "that guy", but like a lottt of threads on here, you should check your valve shims first. Tight exhaust valves will give you hard starting when hot, and tight intake valves can give you an inappropriate mixture. If the problem keeps on coming back, it clearly wasn't solved the first time.

 

Thanks xj550hvil follow up with this thread after and pilot no worries any advice is good advice. I'm doing valves Sunday. Just odd how I had no issue before tuning and suddenly it's the plugs that are shit and caps.

Wonder if the yics being plugged showed all the symptoms hidden


Xj550 it's 12.5 at idle 1100rpm

 

does the voltage rise to 14+volts and what about at 2k rpm?

 

just remember, it could be worse
https://pittsburgh.craigslist.org/mcy/6123850340.html

 

Wanted too test this however I decided I wanted too checks the valves.

All Intake valves checked out wonderfully

3/4 exhaust valves failed.

1 .011.
2 .011
4 .013 (all in inches)

Ordering shims. I'm heading out of town so il have too put this on standby , two weeks il be back. Also noticed while I was checking the shims, the camshaft dots are slightly less then a quarter inch too ccw of the cam cap alignment mark, also on the intake sprocket the alignment mark is 180degrees out, last person rebuilt this installed the sproket wrong.

When I get back il do the shims, do a cam chain and camshaft alignment if I figure it out .


Where exactly would I align the sprocket alignment mark too? Dead centre of the cam cap mark with the camshaft dot?

Then il check the battery running and do a vacuum sync and colortune and il get back here.

Curious if anyone has the valve cover bolt torque specs, cannot find it online or the manual for some odd reason. Thank you



Also I topped battery up with diluted water, charge s it and battery holding at 12.75 with everything off.

I also ohmed the pickup line and primary which are all in spec. The secondary is have to offer cut open so il have too get some wires first although I think there fine.

 

Home tomorrow anyone able too enlighten me with a few answers if possible, much appreciated.

Those valve cover torque specs is a priority and exactly where do I line everything up so my engine is properly timed?

As stated, one of the two cam chain sprockets is I believe the wrong way, the dot is facing the clutch side of bike while the other is towards the coil.

Both have too be facing the coil?

And do I line the marks up with the cam shaft cap dot and camshaft dot all while being between the markings on the coil?


http://www.xs11.com/forum/showthread.php?t=35129

This is the link where I am getting this cam sprocket dot lineup, does it all have too be dead center or just anywhere, couldn't be just anywhere on that rotation could it?

Thank you gentlemen! Looking forward too a reply!

 

Dude, you're Canadian. Whatchyoo doooin measuring in inches for?
Even us backwards Yanks measure Japanese valve clearnaces in metrique.

All procedures having to do with the valves can be found here (the XS engine isn't enough different from the XJ in this regard):
AIRHEAD VALVE ADJUSTMENT with Pics

As long as the dots are close you're golden. It dosen't matte which way the cam sprockets are on the cams, though it is more convenient if they both have the dots facing the cam caps with the arrrows.

 

I may have missed it but did you make sure the vacuum line from the #2 carb to the electronic advance is hooked up?

If this was an XS I would suggest checking the pick-up coil wires to see if they are broken.

 

Inchs because where I work they do inchs majority of the time aha.

Good too know wasn't too sure, as long as timing is in I'm fine.

I will need too line up timing on everything however, it's all out an 1/8th I'd say

Yup sure is, I ohmed the pickup we are fantastic! Just need those darn torque specs now

 

Post up a pic. It's probably good as-is. If not, then you may need a new chain.