Losing 1 cylinder at idle...

LukeMacPU wrote:

Breaker19 wrote: You're still running lean on the pilot circuit, sounds like. What pilot jet numbers are installed? That slow-to-drop idle and sluggish type rise at idle sounds like when the pilot needle is opened too many turns; but if you have to open it 3.5+ turns, that also suggests some intrinsic lean problem. Again, what's those jet numbers? With stock everything, they were 37.5 on my 1100 and that ran perfectly smooth, like a sewing machine at idle.

Pretty sure, the pilot jets were marked 17.5. That's sounds small compared to your 37.5's.

My pilot air screws are set roughly out 1 turn. Started at 1.5 per the manual, ended up with best idle around 1 out for most all the carbs.

It'll drop to idle fine, and won't creep up except for when the bike is warming up. Once warm, it stays where I set it. That same idle setting won't keep it running when the bike is cold so I have to adjust it up until the engine is warm.

Breaker19 wrote:
This is an 1100 motor? No way they're 17.5 with Mikuni carbs... the rebuild kits come with 37.5 and 40 pilot jets, I stuck with stock 37.5. Heck, the mains are 120's... if you have 17.5 -- which I doubt (it wouldn't idle at all, hardly) -- then there's your lean issue if indeed they're the wrong jets. You need to look at them closely, record the numbers off the pilot and main jets.

LukeMacPU wrote:

Breaker19 wrote:
This is an 1100 motor? No way they're 17.5 with Mikuni carbs... the rebuild kits come with 37.5 and 40 pilot jets, I stuck with stock 37.5. Heck, the mains are 120's... if you have 17.5 -- which I doubt (it wouldn't idle at all, hardly) -- then there's your lean issue if indeed they're the wrong jets. You need to look at them closely, record the numbers off the pilot and main jets.

Sorry for any confusion, my bike is a '75 Z1-B (903cc). 17.5 is the stock pilot jet.