First motorcycle and a cylinder not firing.

jpdevol

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If the slide on the RH carb was in bad shape, I'm wondering about its diaphragm - perhaps test it when you revisit (drop test, etc.)

So on the clanging: a pic of the current chain adjuster position with cap removed may help. If it is bad, it means a top-end rebuild anyway. The most likely worst outcome of running as-is is that it would jump time, resulting in perhaps a bent valve - not a major difference.

Nobody has questioned, yet, your ability to grab the right spark plug cap while running without apparently getting shocked - tells me it ain't sparking on the right side
 

5twins

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Yes, the 4200ST is just a plain 4200 with the extra sleeve on it. Yes, you can take it off but I'm not sure it will make things any leaner. The main mostly comes into play at higher speeds and large throttle openings so trouble shooting at idle and lower RPMs should be OK with it being too big.
 

Raymond

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Just watched the video and I'm with JP - your r/h spark plug might not be, uhm, sparking. Try running the engine with the r/h plug removed and laid along the cylinder head - hold it with dry leather gloves.

If it doesn't spark, could be a fault in the wiring to that coil or a dodgy coil.
 

Jan_P

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Not read through But I cannot see the Words " New Points " " New Battery " " Alternator Brushes Inspected "
It is obviously not running on one side
Points can be tricky if not experienced. And even if experienced it can be tricky. There can be oil and dirt in there. Insulating washers missing and small wires broken .Can try to clean with a solvent But the normal approach is replacement.
I can hear the clanging and it is not good A bit High :but it is difficult to localize it can be a loose bracket vibrating
It can also sound terrible with the wrong mixture or timing / spark
My first assumption is ignition related
This is a case of the method " Simplest Cheapest First "
I have never had a big carburetor problem ( more or less ) in 40 years ( Unless I created them Myself ) I dont know anything about carburetors
because they have always worked
Again not read through but if this was me .The battery the charging the points would be a first More or less Normal Maintenance / Service

You have compression so no holes or so . I would be surprised it that does not do the trick getting it to fire both sides .. Then listen on the clanging
I guess it is gone but it is a bit high.
 

Thursty

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Not read through But I cannot see the Words " New Points " " New Battery " " Alternator Brushes Inspected "
It is obviously not running on one side
Points can be tricky if not experienced. And even if experienced it can be tricky. There can be oil and dirt in there. Insulating washers missing and small wires broken .Can try to clean with a solvent But the normal approach is replacement.
I can hear the clanging and it is not good A bit High :but it is difficult to localize it can be a loose bracket vibrating
It can also sound terrible with the wrong mixture or timing / spark
My first assumption is ignition related
This is a case of the method " Simplest Cheapest First "
I have never had a big carburetor problem ( more or less ) in 40 years ( Unless I created them Myself ) I dont know anything about carburetors
because they have always worked
Again not read through but if this was me .The battery the charging the points would be a first More or less Normal Maintenance / Service

You have compression so no holes or so . I would be surprised it that does not do the trick getting it to fire both sides .. Then listen on the clanging
I guess it is gone but it is a bit high.
I did mention that I have new points installed, and set them with clean feeler gauges. I also did replace the battery, however, did not mention that. Alternator brushes, as far as I know, have not been inspected. Unless those are the little pads/brushes/whatever that run along the cam lobe in the points assembly? Not sure if I'm using proper terminology, but that's how my limited experience would describe it haha! I also did check the plugs for spark (one of the first things I did), and they do spark consistently. How good they spark however? I'm not exactly sure. Looks like a blue spark to me. But I'm inexperienced. Going to clean the carbs again today. Before reinstalling them, I'm going to go over everything again. Cam chain tension, valves, points, timing, carbs. Ill take a picture of the cam chain adjuster too while I'm at it. Could be a wiring thing related to the right spark plug wire. I wouldn't be surprised if it was a carb issue too tho, as mentioned before, the right carb was seized when I got the bike, and the right carb doesn't seem to be using fuel.
 

Thursty

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I completely went through the carbs again, and honestly didn't see anything peculiar or alarming. I was actually quite impressed, but nonetheless, did a thorough cleaning through again anyways. I did a quick bench sync, reinstalled, and then moved onto cam chain tension in order to set the stage for valve clearance, points gap, and timing. I'm confused about setting the cam tension. this is my third time doing it, and took my time a little more than previously, as it seemed as though every time i set the tension, it would be out of whack again. I hope this video portrays my findings clearly. It seemed as though no matter how far in, or out i set the adjuster flush with the rod, when i would turn the engine over counterclockwise, the rod would still protrude from the face of the adjuster about 1/16 - 1/8. Im trying to get the rod flush with the adjuster at its outermost position arent I? Am i doing something wrong? This video was taken at the adjusters outermost position, before i got nervous and screwed it back in... Seems different from every other description ive read, either from other people, or from manuals. Thanks. If i can get pointed in the right direction, id like to hopefully set the valves, points gap, and timing again...
 

jpdevol

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At 0:54 & 0:58, it appears the adjuster bolt "wobbles" up & down - I've not seen that happen before?

Good video BTW
 

Jim

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I think y'all know me well enough by now to know that I'm all about checking ignition first.... but did y'all miss this little clue....

"I made this observation when shutting off the fuel to both carburetors while the bike was running, and keeping an eye on the fuel levels in the fuel lines. The right fuel line hardly dropped at all by the time the left fuel line was empty. Not sure if thats any help or not?"

I'm all about "sparks before carbs" but (lack of) sparks don't cause little to no fuel flow. :er:
 

jpdevol

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I think y'all know me well enough by now to know that I'm all about checking ignition first.... but did y'all miss this little clue....

"I made this observation when shutting off the fuel to both carburetors while the bike was running, and keeping an eye on the fuel levels in the fuel lines. The right fuel line hardly dropped at all by the time the left fuel line was empty. Not sure if thats any help or not?"

I'm all about "sparks before carbs" but (lack of) sparks don't cause little to no fuel flow. :er:
I reckon it could be a clogged float valve (esp if not removed). I read that, but deemed inconclusive given other happenings:)

What's your take on the tensioner bolt?

What's your take on being able to grab R spark plug cap while running? :umm:
 

Jim

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What's your take on being able to grab R spark plug cap while running?
Path of least resistance? Dunno. Don't recall ever gettin' bit by a properly functioning cap/plug/wire. Only time I've been bit was when something wasn't right. Fwiw... just ran the SG and touched both caps. No shock from either.
I'm not saying the iggy system is OK... there very well may be problems, but... fuel not feeding through the right carb is a known fault we can see. Let's fix that first?
Haven't watched the last video yet....
 

jpdevol

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LOL - IDK - it's been many years ago (and maybe it was raining), but I recall getting a helluva jolt that way. Haven't had the guts to try it since;):laugh2:
 

Jan_P

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I think y'all know me well enough by now to know that I'm all about checking ignition first.... but did y'all miss this little clue....

"I made this observation when shutting off the fuel to both carburetors while the bike was running, and keeping an eye on the fuel levels in the fuel lines. The right fuel line hardly dropped at all by the time the left fuel line was empty. Not sure if thats any help or not?"

I'm all about "sparks before carbs" but (lack of) sparks don't cause little to no fuel flow. :er:

I dont know much about carburetors thinking out loud here
Is there not a bottom drain plug on these BS38 also
How does it sound loosen that right side drain .
Petcock in pri position se if it opens Petrol flowing
Perhaps can se in the fuel line what happens doing it.
Closing and opening the drain.
 

Jim

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I dont know much about carburetors thinking out loud here
Is there not a bottom drain plug on these BS38 also
How does it sound loosen that right side drain .
Petcock in pri position se if it opens Petrol flowing
Perhaps can se in the fuel line what happens doing it.
Closing and opening the drain.
Good idea Jan. I'm thinking either the float valve is stuck closed or clogged.... or the pilot circuit is clogged and not feeding the cylinder. If we get good flow out the float bowel drain, it means the float valve is OK and it's likely the pilot circuit. If there's little to no flow out the drain, it's a float problem.
 

Jim

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What's your take on the tensioner bolt?
Watched the video. Not sure what to make of it. The other end of the tensioner rod sits in a round pocket. If it wasn't perfectly centered (and it doesn't need to be) it might be putting a side load on it as tension loads and unloads. I don't think it's really hurting anything.... but I never noticed one doing that before so.... dunno. :umm:
 

Thursty

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As soon as I saw the suggestion to remove the right carb plug, and see if fuel drains through it, I went and gave it a go. I have some very interesting findings in a video that im going to post... I'm sure you guys would have a better idea pinpointing the issue than i would. It looks to me as though ill have to take apart the carb again. Im just happy to be moving forward.
 

Jim

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Well you may have some petcock issues goin' on there, but that proves the float valve isn't stuck or clogged. The bowl is filling. So that kinda points to the right pilot circuit being clogged.
 

Thursty

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But why does my petcock flow fuel without the line hooked up? its as if there is an air block in the fuel line.
 
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