Not firing and backfiring through carbs after electronic ignition installation

[platapuz]

Hey guys, Long time reader of these forum post but this is my first time posting

I have a 73 TX650 that I just finished doing a bunch of upgrades on (mosfet regulator rectifier, battery, xscharge electronic ignition gen II, battery box, counterbalance seat, special tank with new paint, and new handlebars).

The electronic ignition unit was faulty (should have expected this from mikesxs) and I just got a replacement which I installed and I am getting spark now. My problem is that it won't start at all... It was running (rough) before I decided to upgrade it and the left cylinder was running a bit lean (more about that latter)

What happens is when I kick start it, half of the time, the kick starter it comes back and destroys my foot, and the other half of the time it backfires through the carbs and sends a large puff of smoke out of the carbs.

I took apart the carbs and made sure they were getting fuel. I am noticing I am leaking fuel out of my right carb bowl vent thing so I think my floats need to be adjusted even though I set them to 25mm. It also did that before so I don't necessarily think that is the issue. I checked the compression and this is when things get a little weird. The right cylinder reads exactly 130psi using the electric start. When I went to test the left cylinder, I was getting no reading at all from the compression tester. I then tried using the kick starter instead of the electric start and I get 150psi after a few kicks. For what ever reason it only build compression with the kick start.

I think that is a major component to my issue, but I don't know what would cause that? Before I tore into it I adjusted the cam chain tension and valve clearances.

Any suggestions as to what it might be and what to check? Am I screwed and have to rebuild this engine?

Thanks in advance,
Michael

 

[bikefreakjon]

Well it's definitely not a carb problem...

Sounds like your timing is way off, I would say go back to the last known running configuration, but you replaced the ignition. And so there is your answer! Your ignition is installed incorrectly.

 

[GLJ]

For what ever reason it only build compression with the kick start.

You said it's a 73. Does your left exhaust valve look like this. If so is there a cable running from the lever you use to activate the electric start to the lower left side of the cover?

 

[platapuz]

You said it's a 73. Does your left exhaust valve look like this. If so is there a cable running from the lever you use to activate the electric start to the lower left side of the cover?
View attachment 169940

Yes I forgot that I have the compression release valve! that would explain that. I also figured out the issue with the kickback and the not starting. I installed the rotor backwards! Just for reference in case anyone else runs into this issue, the magnetic rotor for xscharge gen-II goes in wit hthe smaller side towards the engine! they don't explain that in the instructions of course and they ship it together backwards. It needs to look like this.

Thanks for the help guys, I still have a sore foot but at least I am back in business