I have a pinging issue that I cannot seem to solve. I've don't know what else to try.

First let me run down the bike and the situation and how it came about:

The bike:
1990 FLHTCU Ultra Classic. Picked it up last fall off one of my dad's riding buddies who bought it new off the showroom floor in 1990. So he has records of EVERYTHING that has been done to it.

It has 70K miles on it now. 20K miles ago, he had a Weisco 10:1 piston kit and a Crane 300 cam put in to keep up with all his buddies buying newer bikes. Re-jetted the carb to a 185 pilot, and 45 slow. Stock ignition with dual fire coil. It idled smooth, and had plenty of power. This thing ran great. Very strong. You could roll on the throttle at any speed and it would just pick up and go. Great when climbing hills in 5th gear while all the other guys are downshifting. And it got around 42 mpg even when loaded down.

The situation:
2 months ago, I loaded up the bike and took a 3500 mile round trip from Spokane, WA to Vegas, to LA, up the coast of California to Portland and then back home. 14 days of amazingness. But thats a whole different story.

For the first half of the trip down to Vegas, the old girl ran amazing. Fully loaded and getting 42MPG with out skipping a beat. However one of the days on the road, we went from Vegas to LA in the scorching heat. It was reading 110+ in the shade and thanks to one of the guys I was riding with, we had to stop every 45 miles. (he had a sporty with a frisco'd tank that had a range of about 60 miles). It gave us time to cool down and drink some fluids. Basically made the 4 hour trip into about 7 hours. It was miserable hot. Found out later that it had reached 122 degrees that day while we passed through the California desert.

So we finally make it to LA and get stuck in traffic where it is still in the mid 90's. I noticed a heavy pinging coming from my Evo. Like a couple of Krylon spray cans being shook by a hyperactive kid. It was noticeable in every gear. Any time the bike was under load it would ping. Being my first Evo, I chalked it up to it being overly hot and needed a break. I made it to where I was going out in Long Beach and let the bike sleep for the night.

Woke up the next day and she fired right up. But was very noisy at idle and still pinged under load. So I decide to change the oil. Well, the fresh oil I put in before I left on the trip had lost all of its viscosity and poured out like water. So I put a new filter and fresh 20w-50. It quieted down and ran pretty good, but the idle was all over the place and it still had the ping. Not as bad as before but if I really rolled hard on the throttle, it was there. So for the rest of the trip, I took it easy and never really hammered on it. I made it home and she was still running, but rough and was pinging and backfiring through the carb.

I started doing my research into the causes of pinging in an old EVO. Lean conditions, timing, etc. Basically anything that could cause the detonation. It wouldn't stay timed. It backfired through the CV carb while holding throttle. It pinged under load all the time. So I decided to replace and upgrade some things.

So here is what I have tried:
I took apart the CV carb and cleaned the jets, checked all the gaskets and diaphragms, checked the float, put new fuel lines and set the mixture. New carb to manifold gasket. Sprayed around and checked the manifold to head gaskets and they were solid. No leaks. It started great and idled smooth, but still pinged and backfired through the carb when holding speed. Seemed like a timing thing now.

Pulled the plugs and noticed that although they had a perfect color to them, the front was gapped at 0.15 and the rear was at 0.50. I have no idea how that happened, and I definitely didn't do that because I never had the plugs out since I purchased the bike. So I put in a new set of Harley plugs and set off checking the ignition.

Checked the stock ignition module and found it soft and melting. So i tore it out and put an Ultima programmable unit in. Made sure to be at TDC on the correct stroke, checked the TDC mark in the inspection port, installed the unit and set the static timing like the instructions said. I wired it with the VOES, but turned it off with the programming selectors also as per the instructions. I tried all 4 curves in the unit. Settings 1 & 2 were just as bad as stock, setting 3 was better, and setting 4 is very close. It no longer does it through the first 2-3 gears under load. Plenty of power too. However when in 3rd, 4th or 5th and rolling hard on the throttle (like to get away from an idiot cager) the ping comes back. Not as heavy as before, but noticeable for a few hundred RPMs… then once you get above about 3000 RPM, it goes away. No more backfiring through the carb and can hold speed.

I tried backing off the timing a few degrees, and it did help slightly, but the Krylon can is still being shook at me under heavy throttle. Tried a few different set of plugs gapped at different settings. Tried stock Harley plugs, cheap plugs, and iridium plugs. Right now as we speak it has a set of NGK's at 1 step colder range gapped to 0.38 and seems to be the best I've been able to get it. But the ping is still there.

It is not a hot day here, maybe in the mid 70's and it really doesn't show itself heavily until after I've ridden a few miles. But it is still there, loud and clear when I roll-on hard in 3rd, 4th, or 5th. Goes away if I back off the throttle slightly.

So, any other ideas? This thing starts good (though some high compression kick-back every now and then), idles smooth, has plenty of power even through the pinging, and doesn't backfire through the carb at all. The plugs are all perfectly colored and she doesn't burn any oil, and hardly even leaks any. The only other thing I can think of is that the VOES is bad, but I have the ignition set to not use it by having switch #1 OFF. Am I correct in thinking that?

Sorry for the long-winded post, but I figured if you are reading this, I might as well answer any questions beforehand so you can get an idea of what I'm dealing with.

Thanks for your time and help!

 

Check compression. All this could happened when it maybe at 215 psi+ per cyl.

Carbon build-up! Or use 100 octane, not easy to find.

 

I was thinking of doing a compression check and maybe a leak down. I've never done that before so I'll have to find the equipment and learn how.

And I ran some seafoam through it over a few tanks of gas, but don't know if that did any good for carbon buildup. And I know I can't find 100 octane here. Or else I'd have tried that too.

As far as compression check goes, how would I go about doing that, and what's a good number to be at?

 

In all of this did you check the VOES for proper operation? The rubber diaphragm in that switch doesn't last forever.

My bike began pinging this year, and I blamed jetting, carbon build-up, bad gas, and finally, on a whim, I put a vacuum gage on the VOES, and found it not only leaking, but stuck closed, so I was always on the "full advance" curve. A new switch fixed my bike.

 

The VOES is the one thing I havent fully checked yet (besides compression). I thought by having the Ultima ignition and selecting the VOES to "off" it would bypass that. Does it still play a part?

I seem to get different answers on that depending on who I ask or what posts I read.

 

In high temps you need a thicker oil.

Your bike will thank you for it.

 

Hey Tex I agree if I was in those south areas more. But I live in the upper Midwest right now and we don't see those triple digit temps very often. I run a good HD 20w-50 in it.

 

I don't know enough about the Ultima ignition to be able to answer that.

 

Uncle thank you for your input though. Tomorrow I am gonna hit up harbor freight and get a vacuum pump to check the VOES.

The indy guy I bought the ignition from runs it in all his builds and claimed that it bypasses the VOES by switching it off. But on these forums I have read it both ways that it's needed and isn't needed.

I'm also going to try to run a compression check and maybe a leak down. But like I said, it's only 20k miles since the HC pistons and cam had been put in. And before my trip it ran like a trained pit bull!

 

im having a similiar problem with my RKC. blowing through quite a bit of oil on the highway tho in my case (seems extended 80mph runs (1hr+) and it'll carry over a LOT.

mine was tuned by a pro, and never pinged a bit on the dyno....now she's running hotter and hotter as we're rolling, and pinging worse and worse as she gets hotter.


double check your timing. not with the status lights on the ignition module...but with an inductive timing light (borrow one like i'm doing). if I get it fixed first, i'll let ya know what fixed mine. Ive already tried adding some fuel, and while it did help a bit, it didnt do enough. she'll run like a raped ape for the first hour or two, then gradually lose power...yours seems a bit more constant than mine