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Engine Mechanical TopicsDiscussion for motor builds, cams, head work, stripped bolts and other engine related issues. The good and the bad. If it goes round and around or up and down, post it here.
Myself, I'm running 216 psi. It does help in making power. Also running the PV2b w/Target Tune. I used to get a lot of false knock counts because of the plugs I was running, NGK's. I went back to OEM 6r12 plugs without issues. The resistance in the OEM is only 105 ohms compared to the 5,000-ohm NGK's. If your electronics has the spark knock ION sensing coil it's very possible you're getting False knocks. The 6r12's will help a lot to correct that.
Myself, I'm running 216 psi. It does help in making power. Also running the PV2b w/Target Tune. I used to get a lot of false knock counts because of the plugs I was running, NGK's. I went back to OEM 6r12 plugs without issues. The resistance in the OEM is only 105 ohms compared to the 5,000-ohm NGK's. If your electronics has the spark knock ION sensing coil it's very possible you're getting False knocks. The 6r12's will help a lot to correct that.
Ok, good to know your bike runs fine on that compression. I run stock plugs beacause of the ION system. However, I am not sure about the plug wires. One of them has very high resistance (short one 26 kohm) although they are stock. Could this generate false knockounts perhaps?
Ok, good to know your bike runs fine on that compression. I run stock plugs beacause of the ION system. However, I am not sure about the plug wires. One of them has very high resistance (short one 26 kohm) although they are stock. Could this generate false knockounts perhaps?
Yeah that's way too high. Short@2k ohm and long @4k. Do not use spiral wound steel. Use only carbon core..
Here are the spark tables I have used. One before the big bore, and one after where timing is pulled 18 %. There are minor differences from a mathematical decrease of 18 %. I think I might have used the smoothing function in WinPV, so it is not exact 18 % everywhere.
Last edited by OakMountainRider; Dec 9, 2024 at 04:17 PM.
I had a bad experience with MMO in my Shovelhead. It ate up the tank liner. This was with just a cap full for a few fill ups. Could have been a coincidence….Not saying it will affect your liner but that is the experience I had.
Last edited by garystaven88; Dec 9, 2024 at 04:15 PM.
Thanks Max, it is always great to get opinions, experiences and knowledge through this forum.
I have actually scratched my head more than twice wondering why my Cold Cranking Compression is so high. I even sent my manometer to be checked, as I thought it showed too much. It did, but not that much.
Been thinking of Andrews 37, or even 54, to bring the compression down, but have not decided yet. Maybe I just seafoam it this spring.
Anyway, bike runs fine and does not ping anymore, in as the ECM does not count any knocks - this after I Autotuned it several times and pulled timing 18 % from the tune (received from Dynojet when I changed to Andrews 26). Especially it stopped pinging after I removed the DK Custom torque plates in my baffles, which made it ping as soon as I twisted the throttle.
(When I say pinging I refer to knockcounts seen on the Power Vision. I have not heard any sound as my hearing is not so good.)
If you like the power you are getting I wouldn't change a thing..
Too many think that retarding the timing is only going to lose power.. When you have higher cylinder pressures before ignition and the spark occurs, the air/fuel mixture is going to burn faster. Faster burn requires that the timing be retarded over the previous build because the peak is happening to close to TDC and energy is wasted. I forget the ideal peak pressure location but it's somewhere between 10-20 degrees after TDC. With nice thing about digital map based timing, you can set the timing more precisely and it won't change once set.
As far as the baffle causing the ping goes, that simply means the cylinder fill was truly higher in those locations and if corrected in that area, the motor will make more power. Timing curves are not all the same. They do not have the same general curves across different builds. You should be able to reinstall the baffle, find where ping events are recorded and remove timing from there..
