# 4 cylinder

[RadioHowie]

Since the FJR uses a "wasted spark" ignition, has anyone suggested swapping #1 and #4 spark plug leads?

If you moved an injector but the problem didn't move, then swapping out the plug leads could at least point to an ignition problem, either in the plug wires or at the coil.

Trying to eliminate "external" influences before pointing blame at a combustion chamber/intake/exhaust valve problem.

 

[Mihalis fjr]

Steve said when he went on the road with 100 and over miles per hour..No problem!the spark is grey normal..The problem is in the low speed riding when the buterflies are much closer..!I believe something going wrong with the fuel mixture at the low speed..and at the high speed when the buterflies are much opening and plenty of air comming from air box..the mixture close to normal...But i am not very sure about it...if the problem comes from faulty electricals i think the problem would continues to remain at low and high speed...

 

[wfooshee]

You'd have to take the coil apart to do that, wouldn't you? As is, the #4 wire can't reach the #1 plug, and the coil end is not removable, is it?

 

[Mihalis fjr]

I believe the problem is a blocking air passage in the throttle body No4..Just the same be came and to me in my other bike a XTZ750 Two cylinder bike,two carburetors..when i was driving in low speed in the city the one spark plug when i pull it off was realy black and the engine was working very rough in low speed..The other plug was grey normal..I pulled off the carburetors,blow all the passages with compressed air and thats it!

 

[RadioHowie]

You'd have to take the coil apart to do that, wouldn't you? As is, the #4 wire can't reach the #1 plug, and the coil end is not removable, is it?

I thought about that, but I've read posts with conflicting reports...that the wires COULD be removed from the coil, and other posts saying they couldn't. Be worth a try, though.

 

[Bungie]

Let's try to look at this logically. There are a whole lot of things that can't be causing the problem, like any of the FI system sensors because the ECU modifies all of the cylinders fueling the same amount based on their inputs and you are only having the problem in one cylinder. You've already ruled out the fuel injector since you swapped with an adjacent cylinder and the problem didn't move.

This is the FJRForum. Logic, and more specifically, troubleshooting skills have absolutely no business here.

 

[Mihalis fjr]

Let's try to look at this logically. There are a whole lot of things that can't be causing the problem, like any of the FI system sensors because the ECU modifies all of the cylinders fueling the same amount based on their inputs and you are only having the problem in one cylinder. You've already ruled out the fuel injector since you swapped with an adjacent cylinder and the problem didn't move.

This is the FJRForum. Logic, and more specifically, troubleshooting skills have absolutely no business here.

:lol: :good:

 

[steve'o']

I guess to clarify the situation, before leaving for my trip, I switched out injector 3 with 4 and vice versa. It did appear that #4 did have a slight amount of sludge, crud, whatever you would call it. I blew it out with compressed air, put 4 brand new plugs in, drove for 2 hours straight, at approx 60mph, ended up at home and checked all 4 plugs, and all 4 were absolutely fine, no fouling on # 4. Later that night I went for another ride, but during that ride there was some slower, and lower rpm riding. Pulled the plugs and #4 was fouled a bit but not as bad. I did my trip, had 1500 kms under my belt, most highway, but did get caught in some heavy stop and go traffic, that's when I could tell it was starting to run slightly rough, but I had 45 mins of interstste rididng after the stop and go. Pulled the plugs when I arrived at the condo, and # 1,2,3 were all fine, # 4 did have some grey on the tip, but there was evidence of some fouling on the bottom 2-3 threads. I swapped #3 for # 4 and finished my trip. I am far from a mechanic, but I have also learned a fair bit over the last 2-3 weeks about my bike. As I stated earlier I am getting a "leak down test" done and a valve check. Other than that maybe swap out the coils, possibly do something with the plug wires. I have not attempted the barbarian mod yet, and will not until something gets resolved. If this doesn't work, well, Scott looks like I'll be hooking up with you for a ride, to see your german dude so he can wave his magic wand and fix it!lol

 

[Mihalis fjr]

I believe again for a cloged passage air in the throttle body 4#..When it stops in traffic in the idle,the engine worked roughly,because the 4#throttle body was given a very,very rich mixture with buterflies closed..Just the same was doing and to my bike...

 

[SkooterG]

I believe again for a cloged passage air in the throttle body 4#..When it stops in traffic in the idle,the engine worked roughly,because the 4#throttle body was given a very,very rich mixture with buterflies closed..Just the same was doing and to my bike...

Along those lines, the 'Air screws' (used for TB sync adjusting) have been known to get 'gunked' up and cause issues. I can't remember specifics but it has been reported before around here. In fact, I believe my local dealer once told me Yammie had issued a Tech Bulletin about them.

Might be worth a look-see.

 

[Fred W]

That should be readily evident just by hooking up a TBS tool of some kind and comparing the vacuum to the other cylinders.

 

[Bustanut joker]

I believe again for a cloged passage air in the throttle body 4#..When it stops in traffic in the idle,the engine worked roughly,because the 4#throttle body was given a very,very rich mixture with buterflies closed..Just the same was doing and to my bike...

Along those lines, the 'Air screws' (used for TB sync adjusting) have been known to get 'gunked' up and cause issues. I can't remember specifics but it has been reported before around here. In fact, I believe my local dealer once told me Yammie had issued a Tech Bulletin about them.

Might be worth a look-see.

FUZZY BALLS..

Couple years back I was having similar issues. Changed plugs, cleaned anything I thought might be related to it, and still it persisted. :huh:

Hmm lets try a TBS... Well I'll be! the number 3 cyl adjusting screw doesn't do squat no matter how far it turn it in or out..

Pulled it out and gave the passageway a few liberal squirts of carb cleaner and some PB Blaster,shot compressed air into it. Well what do ya know

After reassembly that screw was up to the task again. and we all lived happily ever after..

Till the sidestand switch fiasco :dribble:

 

[steve'o']

F#^&^%$#G #4 mixture screw was way out, 1 1/2 rotations more than the other three, 4 1/2 total turns out, with hardly any thread left to hang on too, plus the washer and "O" ring were not even on the screw, and the end of the screw was even fouled! Will be checking the plugs in the AM, and if there is no fouling, then that was the culprit! Fingers crossed! :blink:

 

[dcarver]

Gotta LOVE an EZ fix..

Good luck doode!

 

[Canadian FJR]

Great news, be sure to report back.

Canadian FJR

 

[Mihalis fjr]

Have a very good clean there with a very little carb cleaner and if it is necessary because the carb cleaner is very caustic!And lot of compressed air!Turn the screw in sligtly in the end of it way in the hole and turn out about 1 turn and do a TBS again with throttle body 3 as standard and if it is in the (220-280 mm Hg)..I believe you have solve your problem..!!

I hope you will inform us with good news..!!

Good luck!!

 

[Bungie]

Just a little backstory. I've paid my local dealer to do a carb sync about 3 or 4 times over the years. It always ran slightly smoother at idle so I never thought to ***** about it.

Then last year a local FJR owner was selling his bike along with a bunch of other stuff, one of which was a Morgan Carbtune that I managed to snap up.

Long story short, my vacuum levels were WAY WAY off. I'm guessing Mr. Now Out of Business 5 Star Yammie dealer was doing it by ear.

It idled and ran significantly better after I got it dialed in from scratch. Speaking of which, it's time for plugs and an air cleaner.

 

[Mihalis fjr]

My realy story..if you will listen it you don't believe it..!When i bought my bike and after many miles an abnormaly sound starts from the right side and was the faulty CCT..The bike was in the warranty and the topic big dealer here he listen it and talld me the sound came from the clutch housing..!!He replaced the clutch housing and when he was put the new he dont alignment the rear balancer tooths with the clutch housing tooths corectly and the balancer was many tooths out of alignment!!When he starts on the bike it was shake from the vibes!!The stupid man talld me..No problem!!the clutch housing is brand new and after some miles it closing to normal..(He is a 5 stars mechanic!!!unbelievable..!!!)After about 300 miles with extremely vibes..and some burnt bulbs i was came back to the '5 stars dealer' with my new service manual and saw to him his realy big unbelievable fault!!After some realy strong screams from me..he was align correctly the tooths and replace too and the CCT....From then i never leave nobody to touch again my bike...I am doing by my self anything in the bike.....

 

[Afast03nNJ]

F#^&^%$#G #4 mixture screw was way out, 1 1/2 rotations more than the other three, 4 1/2 total turns out,

If the idle air screw was "out" more then the others, then one might conclude more air giving a leaner a/f ratio would have been seen at that cylinder.

You have the opposite going on. Did you blow the passage out with throttle body cleaner and compressed air? I'd do an "unauthorized TB sync" after that. Hope you figure it out, I think your on to something here.

 

[Fred W]

F#^&^%$#G #4 mixture screw was way out, 1 1/2 rotations more than the other three, 4 1/2 total turns out,

If the idle air screw was "out" more then the others, then one might conclude more air giving a leaner a/f ratio would have been seen at that cylinder.

You have the opposite going on. Did you blow the passage out with throttle body cleaner and compressed air? I'd do an "unauthorized TB sync" after that. Hope you figure it out, I think your on to something here.

I'll bet the screw was way out because the last jamoke that tried to do a TBS couldn't match that cyl to the others because it was occluded with spooge, so he just cranked it way out and then left it there.