Strangest thing i ever did see. Still having engine problems with a cylinder.

[stoy75]

Ok here is where I am. All started with the bike while cruising at highway speed not settling into a smooth speed. Bike felt surge/boggy. What I mean is the bike felt like it was minorly speeding up and slowing down. Just enough to feel it. Nothing crazy dangerous. So I delve into the bike having bought it used with not much history other than some receipts for oil changes, regulator and rectifier, and stator.

This is what all I have done:
New Plugs - several times
Techron in every tank
Carb cleaning and rebuild
New air filter
Oil change and filter
New plug caps
Tested coils - impedance within tolerances
Tested stator - within tolerances
Coil relay mod
Adjusted valve clearances - almost all of them were 2 sizes too tight
Changed gear and final drive oils
Replaced fuel line and vacuum line
Replaced carb boots
New battery

So after 8 months, a crap load or money, and greasy hands everyday I have not been able
to ride cause of snow but I am sure the same problem exists. And here is why.

Before while having this problem I could pull the plug off of #3 plug with no change while all others would kill bike. Cold #3 pipe. Well warm but not hot like the others.

And now if I pull #2 no change. All others including #3 kill the bike. The limited function cylinder changed!!!

All I can say is WTH!!! I mean come on. This is driving me NUTS!!!

Did I miss something? Can anyone please help?

[Guest]

I had a similar problem... turned out to be fuel delivery to #3...Float stuck closed... The fact that your problem is moving from cylinder to cylinder makes me think coil problem. I had that happen also... 20 year old Dyna coil would go in and out. Then one of my signal pickups went out... again 20 year old Dyna... I wish I had the magic wand. Anyway, I had more trouble with electronics that gas and air. So I would try and isolate it to maybe a coil going bad...
Curt

[chuck hahn]

It was a cold cylinder..just residual heat from 2 and 4 is what you felt in the pipe.

Check the plug for spark.

Recheck the pilot jet and be sure every hole..even the little one in the tip..is cleaned and poked with a fine wire.

Recheck the float hts and visually lift the float with the carbs in you hand to see that the float needle rises and falls and does so maintaining constant contact with the float.

If it doesnt fall all the way, and there is seperation between the float and the plunger on the needle, then check the float seat to be sure it isnt damaged, dirty, or out of round in any way. The needles should go in smoothly and you should be able to rotate it a full 360 and not have it drag or hang up on the seat walls.

If no spark... remove the cap ( unscrew it ) and freshen the end of the wire by clipping a little off the end.

Also you may have a bad resistor in the plug cap. ( If you HAVE resistor caps ) Look inside and youll see the plug connector is slotted. Unscrew the insert and dump out the contents...the grey ceramic thing is the resistor. Cut a piece of 1/8 inch brass or real heavt guage copper wire and make a piece the same length.

Replace the spring, then the resistor replacement, and then the connector gets screwed in. Youll best served to replace all those old antiquated resistors regardless if the cylinder is firing or not. They arent needed and can go bad anywhere...the brass or copper replacement will never fail.

[stoy75]

Chuck carbs were rechecked and checked some more. And I did replace all resistors after you and I spoke on the phone

[stoy75]

And plug appears to have spark

[chuck hahn]

HMMM..Did you open the drain on 3 to see if its got fuel flow? Obviously fuel has to pass thru number 3 to get to 4, so I suspect that there is fuel...but at what level and rate is the bowl refilling would be the questions i ask myself.

And you got spark good on all wires..so you have spark, air, and now we need to figure out why no gas.

What about compression on that cylinder? Refresh me here..valves are done and good to go also?

[stoy75]

Yup good fuel level in bowl. Good healthy compression. And as far as good spark. I dunno about good but it has spark. I just don't get why it changed cylinders? Coil?

[Guest]

OK,
First you pull the plug off of number 3 (I'm assuming you mean plug cap) and no change, cold pipe, etc. But pull any other plug cap and it kills engine,
Now you pull the plug off of number 2 and no change, but if you pull cap on any of the other cylinders it kills engine.
I think you just potentially identified the problem.
Cylinders 2 & 3 are on the same timing circuit, as are 1 & 4.
I think somewhere along the line, you swapped the plug wiring from 3 to 2, and that is why the problem followed.
Now, since the cylinders did swap problems, I'd say your carbs and all your other stuff are good.
What you need to do now is start checking from your not firing plug wire (you can start the bike and remove the cap and see if there's a spark from the wire to the engine block if you hold it close enough), if there's a spark, check the cap, or swap the caps, if no spark follow the wiring back checking for shorts, opens, corrosion, bad connections, frayed, pinched, wiring, etc.)

Follow Chuck Hahns advice on that plug cap! Those resistor plug caps drop alot of voltage through that resistor, that resistor is only there I believe for radio noise suppression.

[chuck hahn]

Well you can switch 2 and 3 around and see if the problem clears in 3 and appears in 2...that will tell you if the coil is about to give up the ghost. I havent had one go out in just one cylinder. They either give it up or are good.


That being said, I suppose one side may be getting weak, the wire itself could have a bad spot and is somewhat shorting on the frame or the top of the engine??

Shot off the lights in the garage, start the bike and use a spray bottle to mist on top of the engine and see if you see the fireworks.

[barnbiketom]

HOW did you clean those carbs.

[chuck hahn]

If he did them and 3 are ok, I would think he would have done them all he same way. I am waiting to see the results of the black out light show test.

[rustybronco]

Were the carbs ever balanced to each other?

[chuck hahn]

Even bench synced only, one would think they would be close enough to fire off...yes ????

[Guest]

Well you can switch 2 and 3 around and see if the problem clears in 3 and appears in 2...

Chuck,
What he said originally in his first post was the problem was with no. 3, and then the problem went to cylinder no. 2.
If he swaps the wiring from 3 to 2 and from 2 to 3 the problem should follow, and if it does it's just a matter of tracing it back. But I do believe he has a ignitor instead of points and that may make it a little more challenging to troubleshoot than an engine with points.

[Guest]

That being said, I suppose one side may be getting weak, the wire itself could have a bad spot and is somewhat shorting on the frame or the top of the engine??

Shot off the lights in the garage, start the bike and use a spray bottle to mist on top of the engine and see if you see the fireworks.

I do remember a thread somewhere where someone had a coil arcing on the frame.