Need help only one cylinder firing

[bigo]

Greetings!!!

I have a 277 rephased 78 that I "rebuilt" and am having trouble with her. FYI the "rebuild" took me roughly 5 years =).
277 Electronic ignition Kit
Electronic Ignition Plate & Rotor
High Output Ultima Coil
HHB CDI kit

I got the bike started and idling for a few days at 1100 rpm but couldn't get it working just right. It took a while to get it started and had to have the throttle wide open when cold. It started easily when "warm"

I noticed an oil leak coming from the left side valve cover (intake side? the one closest to carb side). I removed the cover and then put it back on and tightened it up. The bike no longer idled and started only firing on the right cylinder (non leaking side). I think the oil leak meant I had an air leak and thats why it was hard to get here "tuned"?
Before i realized an oil leak it was kinda too lean so I upped the jet sizes which helped get it to idle. Now that the leak is "fixed" it seems way to rich but now only fires on one cylinder now
I cleaned carbs and played with different jets etc. These are new vm34 carbs from tcbros.
Here is what got it idling (even before noticing the oil leak)
Mikuni VM 34 2.0 slides
180 main
P6 needle jet
6F9 needle in #4 position
17.5 pilot jet

Ya mama pipes
uni pods

I really thought I holed a piston but I did a compression test (expecting 0 on right side), cold, roughly 10 kicks =). Left side (non firing cylinder) is at 125-130 same as the right side at 125-130. 5 kicks gave me 125 on both sides, 10 kicks 130 all tested cold with open throttle when kicked.
I grabbed an inline spark tester and I have spark on both sides.

I tried switching the carb to the other cylinder to test and still does not fire.

I tried swapping plugs and tried swapping plug cables from left to right (even though confirmed spark on non firing cylinder). Still only right side fires and left side does not.

One other thing I want to mention is that the bike idled good for a few days then I noticed a hanging idle. The advancer springs wouldn't snap back and my dumbass shortened the stock springs. I thought they were mikes springs but now I think they were the stock springs. Its really tight now but it did run. I lubed the advanced rod which I should have done first before shortening the springs. It snaps back super quickly now but its not as easy to turn. I have to use a bit of force. Keep in mind it ran good after this as well.

Can any pros please help point me in the right direction as to what to troubleshoot next.

I'm assuming timing is good as the bike used to start good. It will try to turn on but only right side is firing now.

After 5 long years I'm starting to get impatient and sad HAHAHA

 

[drgonzo]

Perhaps the timing is off on the left cylinder. I've never owned a rephrased 650 so I am not clear on how the timing is set across the two cylinders.
More knowledgeable folks will weigh in on this.

 

[BluzPlayer]

Hello Bigo,
Well you have compression and spark.
With the carb swap, fuel doesn't seem to be the issue. That leaves timing.
I wouldn't assume, I would check it.
With a HHB twisted crank I believe it is timed from the left cylinder as normal.
Hope you get it dialed in. Sounds like it could be a fun to ride. Keep us updated.

 

[gggGary]

To check timing you need both TDCs marked on the rotor Might want to plainly ID them as left, right.
Now manage to keep it running while looking with a timing light to see where spark is occurring in relation to TDC.
this system?
https://www.hughshandbuilt.com/product/pandemonium-277-xs650-re-phased-electronic-ignition-kit/

 

[gggGary]

Is the pipe staying cold on that "dead" cylinder?
A quick this or that? with it running, spray a bit of carb cleaner in the dead side carb inlet.

 

[bigo]

Thanks all! Yeah that's the right setup I have: https://www.hughshandbuilt.com/product/pandemonium-277-xs650-re-phased-electronic-ignition-kit/

You're right I should definitely check timing. Hugh even says it at the end in the guide I followed initially:
https://www.hughshandbuilt.com/2012/05/30/pamcopete-277-ignition-install/

I went out today and bought some new plugs and a timing light. As I was checking for TDC (eyeballing it looking through the spark plug hole with an led light, no stopper) I noticed its on right on point where I marked it during installation of the new rotor.

I pulled the advance rod out again to inspect and noticed one of the magnets was really dirty. This must have happened when I was adjusting the springs and lubing it.

Not sure if this affected my #1 left cylinder not firing?? I cleaned it and reinstalled it.

I'll report back when I try to fire it up again and check where I am at with the timing. My battery died so I have it on the trickle charger right now.

I forgot to get some carb cleaner so I will try squirting some of that as well.

Thanks again

 

[bigo]

Hope everyone had a nice memorial day weekend! I bring good news! Both cylinders are now firing.

Thank you everyone for your input! After troubleshooting this further it results that I killed my coil. I do remember now prior to having issues, I tried to turn on the bike without the left plug wire connected. I read this could have killed my ignition as well.

I wasn’t getting light from timing gun on the left cylinder but I was from the right cylinder.

I sat and waited for a new coil and after install both cylinders fire!

I now have to mess around with the carbs and timing to make sure its dialed in right since I now have the tools. I had the bike idling and then swapped jets during my troubleshooting this issue. I’m starting to get faster tearing these down haha

Cheers!

 

[BluzPlayer]

Great news Bigo!!
Some great information tuning those carbs in the tech section.
A little study will take you a long way.
Several experts here available to aid and are usually very happy to do so.
But most info is already in those pages.
It helps them help you as well as helping yourself become more familiar with your machine if you study them.

 

[bigo]

Found the pdf in the tech section thanks! Couldnt get this thing to idle but runs with throttle. Turns out I swapped slides when I was switching jets haha shaking my damn head. The CA was facing inwards. Now I have to start from baseline 2.0 slide jet settings again you live and you learn.

 

[bigo]

For my notes and to help others if and when I get this right. Slides are now in correct spot
Starting with
Mikuni VM 34 2.0 slides
175 main jet
P6 needle jet
6F9 needle in #4 position
12.5 pilot jet
Air jet removed
Synced up by finger tip feeling

Bikes starts a lot easier now but cant get it to idle. Boggy at less than a quarter throttle so and I didnt try going hire than 2k rpm

Bike seems to start and speed up when I pushed the idle screw outwards thus causing the slide to drop. So with that setup idle screw was out 3.5 turns. The little air screw is 1 1/4 turned out

Sudco specs im going to up the main to 185 and focusing on the pilot jet specifically for idle. Going to try 20 since I tried 17.5 a while back.

Adding a pic of the plug with that above setup. Per pic its dark so im running rich?

Note to self
the pilot mix on VM carbs gets leaner as the screw is turned out. The screw should never be turned out past 3 turns