buzzbomb
Resident Lurker
One thing to add, tho I'd guess you know this already; the Sync screws control air volume only. So every time the CO is messed with, it impacts the idle AFR.
zap!
Ok, I spent a few hours working on the bike over the weekend, fired the bike up with the vacuum gauges hooked up, and tried different CO and IAC screw adjustments, and got it running pretty evenly, without any wubwub, and a steady 1260rpm idle. I spent a while trawling through posts on this site learning how the CO and IAC screws interact, which helped a lot.
The vibes were still there, so I thought I'd start looking at the engine and exhaust bolts. I took off the front 3 engine mount bolts (M10) and checked the alignment, they're pretty well centred, so it wasn't resting on the mounts.
On with the exhaust... I started with the headers and took them off, all good, then the cat pipe. After that was out I moved the muffler pipe and noticed it had a lot of side by side movement. After stripping the tail section off I found a 10mm bolt on the bottom right hand side of the muffler (muffler to indicator bolt, tucked up right next to the silver plastic exhaust cover) was loose. Everything else was tight, but this 10mm bolt was letting the muffler pipe move from left to right, and after it was tightened up it seemed much firmer. Still a bit flexible, but firmer.
Could this be the cause of my vibe problem? When the cat pipe and headers are bolted up this might have allowed the muffler to resonate/vibrate, but I won't be sure until it's all back together.
While I've got the headers off I'm going to touch them up with a bit of Hi Temp paint, as it was a few years since they were last painted. Once this is done and it's all back together I'll know for sure if this has helped or not.
I'll call back once it's back together to let you all know how I went! :thumbup: