Recently I'm having issues with my Ultra spark knocking when I'm at 2k- 2400 rpm and I get on the throttle....Would hotter plugs possibly help with spark knock??

 

You need to find why it is doing it first. If your plugs have been in there a while, change them for the correct grade and check the gaps are spot on. If you have a carb check the float bowl is clean, gas tank filter is clean, simple stuff like that. Could be you have a slight fuel starvation that becomes obvious when you accelerate and demand more gas.

 

Could be the VOES is not working properly.

 

Hotter plugs could make it worse. When plugs get a lot of miles they can cause it also, if the engine is run on lean side anyway... The common major causes are: fuel, timing, excessive heat and without typing a very long explaination, I'd say replace them and see what happens, go from there.

 

My only experience of a VOES problem was very erratic running indeed, much worst than brino describes.

 

What's your setup, and has anything changed recently? What cam are you running, and what ignition? If everything's stock, you could have just gotten a bad tank of gas... that's happened to me several times, and Bertha runs like crap for awhile until I burn it all out. I always run premium, too.

The reason I ask is because I installed a V-Thunder EVL-3010 cam last Christmas, and a Daytona Twin-Tec single-fire ignition. The Daytona instructions said to set the ignition module advance to 7 (out of 10) initially for premium gas, so I did - but she knocked like hell at that setting when I got on the throttle under 3000 RPM. So I dialed it back to 5 and no more knocking. The combo of the EVL-3010 cam, which apparently likes a bit higher revs, and the initial timing advance didn't work very well together. I learned quickly that with too much advance, I had to downshift and run above 3000 RPM before I really got on it, which was a hassle...

 

retard the timing until it stops . check your timing.

 

How about a little more info on the bike like year, ignition, carb, jets, exhaust, miles, any work done on it, and gas that you are running. Do you ride solo or two up??

 

The VOES switch WILL do this if it quits working all together. In a low vacuum situation, such as rolling on the throttle, the VOES retards the timing to keep the motor from knocking. Check the switch with a vacuum pump and an OHM meter. If it doesn't switch with about 3 to 4 inches of vacuum, replace it. While you're at it, get one that is set up for 6 or 7 inches of vacuum. It will give a heavy bike more gitty up when you roll the throttle. If the VOES checks out, it could be the ignition itself. Just some things to check... Good call Jim Kraft

 

A VOES enabled ignition module will have two curves, an advance curve that will reach full advance at about 1500 rpms and a more gradual curve that will reach full advance around 2500- 3000 rpms, depending on settings. The advanced curve is not much of a curve, basically full advance all the time.

The slow curve on an ignition on a stock 80" may go to full advance around 2500 rpms whereas a 140" may need go to full advance around 3000 rpms.

When the VOES switch is "on",the switch is closed it allows the control signal to go to ground which tells the ignition module to use the fully advanced curve (full advance 1500 rpms) , so it it more accurate to say the VOES advances the timing, not the other way any more than you would say turning off a light makes darkness. Using a ohm meter you can see when the switch closes, but keep in mind when the switch closes the current flows to ground to tell the ignition module to "advance" the timing. If the switch stays open, the signal does not go to ground and the timing is not fully advanced ( well , not until 2500-300 rpms).

The VOES is designed to fail in the open or "off" position using the slower advance curve. A big exception would be if the VOES wire was bare and grounded somewhere,as this would actually bypass the VOES and the timing would be fully advanced all the time. The switch on the VOES is controlled by vacuum, if you lose vacuum the switch opens and stops the signal from going to ground which tells the ignition module to stop using the fully advanced curve.

You can check the VOES by unhooking the wire from ground at idle , if the VOES circuit is working the idle should get slower because the timing is no longer being advanced. When you ground the wire, the idle will go faster, if neither happens, you can bypass the VOES and ground the wire before it gets to the VOES, when the wire touches ground the timing advances, when it does not touch ground the timing drops back (retarded). You can tape up the wire at this point to keep it from going to ground and ride the bike and see if there is any detonation problems, if there are NO detonation problems with the VOES out of the circuit ( wire taped up) then the detonation problem is associated with the VOES advancing the timing. BTW: You will probably have to adjust the idle up a little if you unhook the VOES. On the other hand if it still has detonation problems without the VOES ( wire taped up) it is something else, as stated earlier, just retard the timing a small amount until the detonation problem is gone, then hook up the VOES up again. If the detonation problem returns after you hook up the VOES again you know it is now being caused by the VOES advancing the timing too soon.

Eliminating the VOES will only affect the engine performance at low rpms, you will not loose any peak horsepower/torque on the dyno. Once the engine hits that magical 2500 - 3000 rpms ( depending on advance curve being used) the ignition is at full advance regardless of what the VOES is doing. I know, many guys insist it retards the timing, but it advances the timing, removing the VOES and taping up the wire so it can not touch ground will use the slower advance curve. You would not install a VOES to "retard" the timing, but removing it will. A VOES that is set up to advance the timing too soon will cause detonation problems, in that case, removing it will eliminate any detonation problems. Many big inch motors do not use a VOES to help prevent detonation problems caused by a VOES set up wrong.