I pulled the carb on my '93 FLHTP because the idle circuit was all messed up. It would start with starting fluid, but would not stay running at idle. It would run okay at any setting above idle. I don't know how it runs when riding because I recently acquired this bike in it's current non-running state. With the carb rebuild, I found the idle mixture adjust screw was missing the o-ring under the washer. In addition to a good cleanup and new parts, it should run great.

With the carb off, I was looking around and noticed the VOES had been connected to the carb via a vacuum line, but the positive lead was not connected to anything. Looking at the wiring diagram, I see that it should connect to a violet wire...which happens to be connected to a home-made ground! The PO had bypassed the VOES and had it in running in a simulated VOES closed state!

Reading up on the VOES here, I see that the VOES failsafe mode is in the open position (or ignition retarded). The PO bypassed it, in closed mode (or ignition advanced). While he may have been doing this to get some more "umph" out of the engine, the cost was possible detonation and potentially lower fuel economy at cruise speeds.

I'm sure some will say that the VOES is there only to keep the tree-hugging, motorcycle hating, EPA at bay. That may be the case. But I think having better fuel economy, and little to no pining/detonation is a positive benefit of the VOES. What do y'all think?

I did a bench test on my VOES, as described in the link above. I found it was closing/engaging at 4.5 in.Hg. This is at the top end for an FXR (3.5-4.5 in.Hg). For a bagger such as mine, the range should be around 5-6 in.Hg. So, I opened it up by removing the rubber cap on the tower. With my multimeter and my Mityvac, I adjusted it to 5.5 in.Hg. This was about 1/2 to 3/4 clockwise turn to reach that setting. I have new black RTV over the top and will let it rest overnight. I placed a thin coat of oil over the screw so that I can easily remove the "cap" later if more adjustments are required.

What are your thoughts on this? Run without the VOES (like the PO), or reinstall it and run it (correctly), changing the setting if need be.

 

If it's set up for it why not run it. Your ignition system looks for that input

 

What ignition module is on the bike?

 

Indeed! Some aftermarket systems do not use the VOES, so don't spend too much time on this until you can confirm what system you have.

 

I am possibly also having a voes problem since putting Andrews 23 cam I am getting some detonation under load, give it more throttle and it stops, I have voes off the bike , I checked electric connections are good. I am gonna replace because it seems to come and go. Then check timing , is the clear plug the best way or mark rotor in primary ?

 

Every thing on my bike is stock , except for cam

 

Although the VOES "failsafe" mode is "open", I had one fail "closed" (full advance). Made the bike ping like crazy.

i don't understand The animosity toward the VOES. It simply allows more spark advance when operating conditions permit it. Vacuum advance/retard has been used on automobiles since before I was born, long before the EPA ever existed.

 

My bad...that's relevant info. I have stock ignition.

 

Read the info in the link I provided in the OP. It's super easy to adjust the VOES up. From what I've read, it sounds like you need to adjust it a bit higher.

 

As Uncle G. says, the VOES is functionally the same as a vacuum advance on a typical car motor pre-EFI. With a stock ignition module, you need that. No tree-hugging EPA crap is involved in it.

The proper way to set the timing is with a timing light. You can use the clear plug, or just set the bike upright and use no plug at all. A bit messy, but it's just oil vapor.