Why am I pingin'

[outback2970]

Heres the set-up...
se mcr heads cc'd to 78cc
se flat tops with reliefs cut
se adjustable push rods
zero deck with stock head gaskets
Stock ignition
Stock 40mm CV with 48 slow 200 main and n72s needle
andrews 37g cams with se billet plate and new style pump
I am at sea level buring 91 (highest available) with octane boost (stp or sea foam) and running champion colder plugs.

Big Boyz calc says 9.78-1 static and 9.01-1 corrected with 185 ccp
I believe it is right on because in fact I do have 183-185 ccp. (checked properly of course)
Pings at roll on and when hot it is not hard to do at all.
This is beginning to drive me nuts. I never noticed it with the VH BSS with stock baffles, but when I installed the Quiet baffles, there it was. I have 1500 miles or so on the motor since winter. Many of those miles were in cool temps so I'm hopefull the detonation was minimal in that time. Went to leaner jetting at one tim (experimenting) and when checking plugs noticed some aluminum deposits on the electrode.
I understand my next step should likely be a DTT ign, but should this build be pinging like this in the first place? Mostly rear cyl. for sure. ( I presume cause it runs hotter. ) If there is info I have left out, please ask and I'll post er up.

[rigidthumper]

If you have a bigger motor with increased compression + after market cams and a stock ignition module, would the stock ignition curve be correct for an increased compression non-EPA complient motor?
Me thinks not.
Get thee an ignition module (SE, Dyna, DTT, etc)
Also:
Quiet baffles will increase the retained heat in the heads, which can contribute to detonation.
HTH
Robin

[05FLHTC]

IME too much initial timing & if you are running stock ignition prolly too much advance also for that CR.

The new reformulated gasoline blends are not helping either.

You need to either try a SE -5 fixed ignition module (they can be had new in the box on fleabay) or get a DTT.

The CV carb IME can also produce a lean area right were you don't want it during roll on. Sunny here has more experience with a different needle that helps reduce that without killing you MPG or running so pig rich that you will end up with loads of carbon on your piston tops, maybe he will chime in.

If your bike is 04 or newer you can get the SE race ignition, that's what I'm running now on my 05.

05

[Jeffd]

The stock head gasket (.052) might be part of your problem.  Some times a tighter squish (.030 hg) works better.

[outback2970]

Thanks, sorry, it's a 2003 FXDWG 95"  What SE ign module would be the one I need?

[11.7to1]

Before I spent $300 on an adjustable ignition, I'd spend $30 on a pair of headgaskets. I'm over 225 ccp and no ping. Good luck.

[Geoff1200]

My Keith Black flat tops recommended removing a couple degrees advance...my .02

I'm at 200 ccp, it pinged a bit so added a little more fuel and...Viola!

[Sonny S.]

I've had better luck with the NOKK needle part # 27241-95.

Not going to solve your problem by itself, but it will help.
The 48/200 should work well with it.

If you change head gaskets you still have to address timing.

[george248]

Sonny is right... the NOKK needle did help my roll on ping... still needed an ignition to get rid of it completely (DTT).


Even with the DTT it took some work to get it right.  Turning the dials on the DTT would not completely eliminate the roll on ping.  Had to invest in the cable and tweak the maps in the problem areas.

[05FLHTC]

Before I spent $300 on an adjustable ignition, I'd spend $30 on a pair of headgaskets. I'm over 225 ccp and no ping. Good luck.

So if I read your post correctly, your suggesting you are running 225 CCP with stock ignition? I hope that's not the message you are intending to send, cause if it is I say that's a big bunch of BS!  Either you have access to 108 octane or your gauge you used to check CCP with is chit or your just pulling our chains.

Please don't share information that can mislead folks, that's not what this site is all about...

[L-]

"I understand my next step should likely be a DTT ign,"

Imperative.   78 cc heads, 0 deck and stock gaskets, 183-185 psi. and a richly jetted carb!!   So close to my build.   You will need a tuned timing curve.   Especially in the heat, different gas and with those stock head gaskets...... ugh.  Yep, DTT.

L-

[outback2970]

Thanks for the replies/advice. The only reason for the stock head gaskets was to keep the compression down at the 9.8-1 level for the 37s. .030 puts me a little above 10-1 static and I didn't want to push it where as the 37s (from what I've read) like no more than 9.8-1 max. As for rich carb jetting, it only shows signs of being rich at idle, everywhere else seems great. No dyno/sniffer for a while so my observations are from plugs, friends riding behind me, and my own nose.

[dakota224]

i just sold a -5 se ignition cheap on e-bay..  check around,, you will find one.. put a ad in the swap meet section too..(needed se -5 degree ignition)

[Upswept]

Outback, you need a 31775-01A.  It is a system with a coil and a module for '03 bikes for 1 10 degree retard.  31710-01A for a 5 degree retard.

[Mix01FLHT]

If you're gonna spend the money, you might as well get the adjustable one.  just in case you have to go beyond....

[mayor]

here's another vote for a new ignition module.  unless you know what you're doing with the ignition timing programs using the data link cables (or know someone who does), I'd go with the SE adjustable ignition module for your Dyna since getting to the knobs on an adjustable ignition is a real PITA.  The SE adjustable can be adjusted with a hand wand, and only requires a little bit of bike disassembly to get too (opposed to a whole lot with the knob type ignitions).

[Admiral Akbar]

Heck on a DTT, you can get to the curve and initial switch easy if you cut a hole in the plate the TSSM sits on... All you got to do is pull the cover that fits on the gromets..

Max

[11.7to1]

To 05flhtc,

No I'm not running the stock ignition, sorry for your misinterpretation. I was just saying, before spending 300 on an ignition, I would tighten up the firing ring. As for my CCP, I'm running 15.7 CC dome pistons, 81CC chambers, and 9bg cams, with a 3.875 bore. My squish is set to .024. You do the math. Oh, and my ignition settings (DTT) 4 initial and 7 slope. I run premium fuel which around here is either 91 or 94 octane. I am fully aware of what this site is intended for, as I've been a member here since early 2002.

To OP,

If all you want to do is cover up the problem, then just do as suggested, richen up the AFR and pull out timing. If you actually want to correct the condition, then you must correct squish. The squish band / firing ring should never be compromised for the sake of compression. Do yourself a favour and google squish band and read for yourself.