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On my 85 fxst i think my voes switch might not be working. My bike pings more and more as time goes by. It's not the gas, this has been going on all sumer. I know ther's a test you can do to confirm if the voes is bad, I've forgotten how to do the procedure. Any of you evo motorheads out there Know how to check it? Thanks in advance
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__________________ 85 FXST Belts are for Pants...If it said custom when you bought it..it ain't.
I think your problem would be the switch either being shorted or shorting at too low a vacuum setting. Just disconnect the wire and see if your problem goes away. You should also notice a lack of power with it disconnected but no pinging. If that doesn't help I think your timing is off.
In case you aren't familiar with some of the aftermarket ignitions, my 85 has a Dyna200i. It has an indicator light for the VOES that goes out when the bike is running. It also has a light for setting the timing, switches for 4 different timing curves and adjustable rev limit. I mention this because pinging is usually related to timing and adjustable ignitions are great for timing issues.
You could either swap the VOES out with a new one (around $40) or find someone with an adjustable vacuum source like this.
With an ohm meter, the switch will be open with little or no vacuum and shorted (closed) at 3 to 7 inch-pounds of vacuum depending on the weight of the bike. 7 would be heavier I think.
Start the bike romove the hose from rear of carb to VOES Plug the hose fitting on carb This is the point where the timing should retard thus engine speed should decrease If speed doesn't decrease and increase as described above replace the VOES
If your VOES is broken, it probably is NOT advancing the timing, as they tend to break in the "open" position. I doubt that it would cause an increase in pinging, just the opposite a little decrease in acceleration , especially with light roll ons at low rpms. Can a small intake leak lean out the fuel mixture and help cause detonation?
It is interesting, I just changed my VOES last week, for some reason or other I had to replace it twice in the last couple years, maybe about 10,000 miles. I use the setup described in Pilgrims VOES page and have a LED indicator to let me know when it working.
I run a VOES set at 7, which is a bit higher than stock, which causes the timing to retard a little sooner,at a little little less throttle opening. If you are interested in purchasing a new one set at 7 : TwinTec has them:
Jireh and Dennis Kirk have them as well, but only go up to 6 hg -higher compression engines need a higher amount of vacuum before the VOES advances the timing, to help prevent detonation.
You could also try a small bottle of octane booster, they cost about $3.00 at the gas station, empty it in the tank and toss the bottle. I have not had seen positive improvement using SeaFoam, but many say it will clean up the valves ect and reduce detonation. Seafoam comes in a spray can, just warm up the bike and keep it at a fast idle and spray 1/2 can in the carb - it will smoke a lot and suppossedly clean out any carbon build up. It did not do much for mine, but may have helped make the VOES go bad sooner....
Location: NC and across the Mississippi every opportunity
Posts: 1,121
My timing is right on and I've noticed a lot more ping for the past 18 - 24 months for some reason. I know all my stuff is working right. I think they have gotten slack in checking/enforcing minimum octane content in fuel for one thing.
Weird thing is, been out west twice this year and used a lot of ethanol mixed fuel. With it, I seem to do as well with regular vs. premium. Fuel mileage is a lot lower at high speed, but the same a low speed and seems to run a little hotter too.
Your bike came out with about a 3 lb switch. Maybe a higher value switch would help. Mine is so old, I'm afraid to break it open to adjust it.
What the others told you about checking is correct. Problem with adjusting one is that the hand-help vacuum pumps you get aren't accurate enough to really know what you have.
I put a toggle switch on mine so I can disable it if I get hung up in high temps/traffic/town etc.
"Since a VOES is an electromechanical device it can fail (hell, anything more complex than a cannonball can fail - and eventually will). If it does fail it reverts to the retard mode full-time so there's no danger to your engine, but you lose the benefits of an advanced curve. It's my practice to check its function whenever I change my spark plugs. The quick and easy way to do that is to unplug its harness (if that's how yours is wired) or to disconnect the ground wire from the VOES while the engine is idling. If the unit is working the ignition is advanced at idle, but if it's not working it'll be retarded. So disconnect it and see if the idle changes. If it doesn't, it's broke. "
The idle drops lower when the VOES is not working on mine with a Crane HI-4 ignition, a stock ignition may act differently. If I have idle set at about 1000 with the VOES working, when it is not the idle drops down towards 700 rpm.
We have stopped at gas stations where 89 octane was the best they had. As they all seem to sell octane booster these days, we got the cheapest they had and added that to the tank and tossed the empty in the trash can they usually have near the pumps. With gas being around $4.00 a gallon, another $3.00 is not that much - I know, $20.00 fill ups on a bike sucks, and they wonder why people can't make their mortgage payments these days.
I noticed my 89 FXR was pinging this past summer, could not figure this out. I then filled up with 92 octane and no more pings, I went back to 89 the next fill up and it was back. I just started adding 4 oz per 10 gallons of acetone and now I run 89 and no more pinging. 24oz for 1.50 at Walley world.
Voes test anyone?
85 FXST Belts are for Pants...If it said custom when you bought it..it ain't.
