CL360 Running Poorly with Exhaust

Hi there,

I'm having some odd issues with my CL360, check it out:

I have had my carbs modded by PJ last winter, am running my bike with UNI filters and have an aftermarket 2 into 1 exhaust.
The bike always ran OK, but wanted to get my carbs reworked since that seems like it improve in the performance.
After I had put my carbs on, the bike began to backfire in all directions, through the carb and exhaust.
I had assumed it was timing so I got my bike timed and well sorted, seems like helped so the next thing was to check my valves for the right gaps and that got fixed also. At this point the bike was still backfiring on both ends, so I assumed it was the valves and began working on them again recently since it was my first time working on them and figured I messed up somewhere.

Here's where I am now:

While working on my valves, I decided to take the exhaust off and noticed that the bike runs much better through the headers and stops 'coughing' and backfiring.
Once I put on my Exhaust it begins to cause some back pressure and bike starts to run poorly again. I'm stumped, but to me it appears that the bike is running rich and there's too much gas flowing into the cylinder, causing it to spew on all ends.

Any ideas?

Thank you,

- Gedi

Also forgot to add, this is only doing it on the left side cylinder.

Have you had the engine open?

I have not opened it up, if i don't fix it after one more garage day. I plan to pull it apart and check out the cam and valves.
Last time I checked though I had "ok" compression, had written down someplace but I think it was around 125 - 127 psi.
You think I should pull the head ?

Thanks,

- Gedi

If you can get the engine warm and run another compression check, that would be good. Those numbers are definitely in rebuild territory.

Just found my recent measurements, I was at ~150psi.

That's OK.

Have you checked the ignition timing with a strobe? Both right and left?

Yep, I actually had an old post where you and I discussed this before.
Had gone over timing and valves already, something is just acting up in the left cylinder.
I just don't understand why back pressure is making it run worse and climb in RPMS.
Once I take the exhaust off, it gets back to normal idle and stops backfiring. WEIRD!

http://www.dotheton.com/forum/index.php?topic=61021.0

Sounds like it could be carb related.