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V50 mk2 Running on 1 cylinder Please help please

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This might be a dumb question, but I think back 40 years ago to a Yamaha 125 we had on the farm. My Dad put gasohol in it once and it ran OK until it was parked for extended time. It then ran really rich so I took the carburetor apart and found no O-rings. The alcohol completely dissolved all of them (looked like they were never there—not even rubber residue).

Therefore, I am asking did you replace all of the O-rings and any other rubber parts? Look carefully for O-ring grooves on the starter jet, idle jet, needle jet, and main jet or where they screw in. O-ring(s) may have been missing when you first disassembled the carburetors so you may not notice them missing. I am asking this because that Yamaha acted exactly like you describe.
 
This might be a dumb question, but I think back 40 years ago to a Yamaha 125 we had on the farm. My Dad put gasohol in it once and it ran OK until it was parked for extended time. It then ran really rich so I took the carburetor apart and found no O-rings. The alcohol completely dissolved all of them (looked like they were never there—not even rubber residue).

Therefore, I am asking did you replace all of the O-rings and any other rubber parts? Look carefully for O-ring grooves on the starter jet, idle jet, needle jet, and main jet or where they screw in. O-ring(s) may have been missing when you first disassembled the carburetors so you may not notice them missing. I am asking this because that Yamaha acted exactly like you describe.
Not dumb question at all !

So basically when the bike was restored everything was rebuilt/replaced and every time i disassemble the carbs i replace the orings with new ones, yes every time ! I went to go buy a o ring kit exactly for this reason.


Only thing that didn't have o rings on was the chokes but i did fit them a couple of days ago.
 
Hi everyone, hope you are well.

So next weekend im borrowing an exhaust gas analyzer hopefully that will tell me something and be able to tune carbs better then i will try and sync them
 
Hi everyone, hope you are well.

So next weekend im borrowing an exhaust gas analyzer hopefully that will tell me something and be able to tune carbs better then i will try and sync them
Sync first. Then do the tuning. You want them flowing evenly to get good exhaust gas readings.
 
Hi Guys, its been awhile and im still struggling to get my guzzi running on both cylinders... i am pretty sure it is not carb related anymore and leaning towards ignition side.. after i started bike now in atleast 2 months the left cylinder is not running and the right side is. I want to replace ignition pickups for peace of mind as i know carbs are still clean and i have brand new coils.. can someone tell me if these pickups are universal? Will i get them at any motorcycle spare shop?

I got a timing gun but according to my manual i need some sort of timing plate?

Thanks guys and happy new year.
 

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You might try searching on the number on the pickups. As far as I know, not universal, but Guzzi has a history of using common parts to other Italian brands. The part number is 63721600 and appears to be available but it isn't inexpensive. If you have access to an oscilloscope you should be able to tell if it is generating a signal before replacing. If you upgradde you account, you can access the schematics. Have you checked the module between the pickup and the coil? This looks like the one you need;

https://www.guzzitech.com/forums/resources/1977_v50.150/download

 
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If you have a timing light, hook it up, if the cylinder doesn't flash it's not sparking, if it's flashing you have spark.
Looking at that picture, there isn't a timing plate that moves.
Some timing lights hook to coils, others are hooked to just plug wires.
 
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The 'timing plate tool' is just a premarked insert to simultaneously do both the pickup gaps & pick up alignment statically in one; instead of going through the 'manual process' using feeler guages & lining up the flywheel marks/pick up alignments individually (so it isn't critical). BTW You don't use it with the timing light or run engine with it on !

Since you already changed the coils & switched the CDI boxes & connectors without any change, it sounds to me it could well be pick up (I had failed pick up AND CDI box on V65 Florida). Assume you checked the pick up resistance per manual ??; but even then I couldn't 'measure' anything wrong with mine & bought replacement 2nd hand pick up (it's a plate on motoplat system) which worked fine.

Pick up
 
Thanks for the responses everyone. I found the the left cylinder was not firing with the timing gun so i swapped the plugs and the right side stopped firing so the plug had fouled but this is exactly the issue i had like i mentioned earlier on my posts that the bike keeps fouling plugs ive been through 4 or 5 sets so something is causing the plugs to foul and this causes the misfire. I have tried 3 different heat ranges. I will test my pickups resistance soon as the multi meter i have failed on me last week. So if i check the timing with the gun i obviously check it on the flywheel right but its so hard to see the marks on the flywheel as they are very fine. So if the timing need adjustment do i move the pickups sideways to advance/retard assemble everything start bike check again and if not correct take everything apart again 🤔 or can i start the bike with the alternator off ?
 
Oh and another thing guys, my flywheel does not have any letters on as per manual only has like small lines ingraved but no letters.
 
You previously replaced the coils. Did the new coils include new high-voltage leads and spark plug caps? My experience has been that the timing light will still flash with a fouled spark plug if the rest of the ignition system is working properly (pickup, CDI, coil, and high-voltage lead).

An open circuit condition in the high-voltage lead, plug cap, or spark plug (so that no current can flow) will cause the timing light to not flash).

Although unlikely since you have replaced plugs, perhaps the spark plug has an internal open circuit instead of just being fouled by carbon (which causes a short circuit).
 
You previously replaced the coils. Did the new coils include new high-voltage leads and spark plug caps? My experience has been that the timing light will still flash with a fouled spark plug if the rest of the ignition system is working properly (pickup, CDI, coil, and high-voltage lead).

An open circuit condition in the high-voltage lead, plug cap, or spark plug (so that no current can flow) will cause the timing light to not flash).

Although unlikely since you have replaced plugs, perhaps the spark plug has an internal open circuit instead of just being fouled by carbon (which causes a short circuit).
Ok i understand what you're saying but if the plug does not spark properly or weak spark in my case it wont complete the circuit in order for timing light to light up or am i wrong? So basically the plug on the left was very weak intermittent spark and timing light did not light up at all then i swapped it with right side the and it worked but the right side stopped working. I know if i fit new plugs both will fire but till bike heats up and i take it for a 10 min ride same thing happens bike starts loosing power and heavy misfire to the point where i can barely ride it back home. So my plugs only last 10mins average before going bad so something is killing my plugs
 
What is the odds that coil packs or pickups wiring is swapped around? Will the bike still run if this was the case?
 
What is the odds that coil packs or pickups wiring is swapped around? Will the bike still run if this was the case?
I am NOT a mechanic-
but I imagine that would put the timing 360 degrees out of whack - firing at the top of the exhaust stroke…
i don’t think it could generate any power at all… are you burning a LOT or oil , blue smoke out the back, done rings or valves guides could contribute to the fouling plugs , is this bike carburâtes ?
Stuck float, way too much fuel, Does if smell like un burnt gas ?
( NOT A Mechanic )
 
OK. Yes you can take rotor off and run the engine with pickups uncovered. But make sure when adjusting the pickups, not only the angle is important, but the gap too: use the feelers, piece of tin from the can, or just a piece of paper. As flywheel crown has 90 teeth, every tooth counts as 4 degrees. Your markings should be: ignition, then some 9 teeth later the TDC(a point to check valve clearance, invisible when running with lamp), and if you can't see them, use a toothpick, dip it in the thick paint, fill the mark. I might not get it - large reading here by now, but if spark plug dies off so quickly, it is usually a much too rich mixture, quite often caused by partly open choke circuit. Have you got visible play on choke cable? This question applies of course only in situation where dead spark plug occurs on one and only the same side.
 
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