Higher mileage - knocking

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May 12, 2008 | 10:17 AM

Weavr99FLHT

Thread Starter

Outstanding HDF Member

Joined: Mar 2008

Posts: 2,306

Likes: 39

From: Everywhere

Higher mileage - knocking

Hi all -

Question for the more mechanically inclined amongst us. Bike in question:
99 FLHT (EG Standard) Carburated. 60,165 miles (all mine)

Mechanical Mods: SE Air cleaner, SE Performance Mufflers, SE 203 Cams, SE/Mikuni 42mm Carb, Adj Pushrods, Stock compression.

All the above mod's were done either when the bike was new (mufflers, a/c) or at20,000 miles (cams, carb). Bike has been great, reliable, the envy of all my friends (basically all it ever needs is to change fluids, tires, brake pads, plugs). Ridden from Maine to California, Maine to Oregon, Maine to Alabama, and everywhere in between.

Question is... at about 50,000 miles, it started knocking and pinging usually when below 3200 rpm and under load (pull out to pass without downshifting at 50-55mph). more so when loaded with gear and/or a passenger. Doesn't have to be "hot" outside either - does it when it is 50 degrees.

I use the highest octane gas I can find at every fill-up (usually 91 where I live (highest in my part of the country, 93 when I travel). I have started using Harely's additive about every other tankfull - the one that says "Reduces octane requirement increase that normally occurs with mileage" and doesn't seem to help at all.

A friend suggested a new SE Ignition module.

figured I'd see what you guys and gals think....

Thanks in advance - ride safe!

May 12, 2008 | 10:40 AM

Ugly Troll

Road Master

Joined: Mar 2006

Posts: 828

Likes: 8

From: western Mass

RE: Higher mileage - knocking

My 05 stock EGC has started pinging more lately.......it was explained to me that it's most likely the **** gas we get here in the northeast.........not much we can do about it. I did learn a few days ago about "tier one" gasoline though, and started looking for those brands..........it SEEMS to help some. also told to try Nippendenzo plugs as they seem to be better in the Harleys..........gonna try those also. Waiting on them at my local indy shop. Seems our gas in new england is MORE than the 10% ethanol it claims to be and that's the problem. The HD motors do not like it at all! Octane booster should help; indy says just a splash each fill up, not the whole can. May take a few tanks to notice a difference. I've been using Shell the last couple times (one of the tier one gasolines) and I noticed a huge improvement in my milage also! Bike is back to 47+ mpg! That's what it used to get when it was new. About 30k now and the mileage was off about the same time as the pinging started. Hope any of this helps! At least gives you some ideas. Good luck

Troll

May 12, 2008 | 10:55 AM

Lopoetve

Road Master

Joined: Apr 2008

Posts: 1,195

Likes: 2

From: Denver, Colorado

RE: Higher mileage - knocking

run a can of seafoam through to see if its carbon.

May 12, 2008 | 10:57 AM

Zimbob

Stellar HDF Member

Joined: Dec 2006

Posts: 2,906

Likes: 11

From: Grottoes Va.

RE: Higher mileage - knocking

Pinging and/or knocking can also be caused by carbon buildup, or so my wrench tells me. I use a tank of fuel cleaner every third tank just to help out.

Just a thought.

May 12, 2008 | 02:10 PM

fordhd2005

Road Master

Joined: Apr 2006

Posts: 863

Likes: 166

From: Athens, AL

RE: Higher mileage - knocking

I have used nothing but the cheapest gas I can find since the new wore off of it. I've used the ethanol type and never any octane booster, cleaner, etc, and never had an issue. It sounds to me like you have a timing problem. It just takes a couple of degrees off to get the knocking and pinging. It might not hurt to retune the carb or even go up to the next size on your jets.

May 12, 2008 | 05:59 PM

PFD232

Cruiser

Joined: Jan 2008

Posts: 140

Likes: 0

From: Illinios

RE: Higher mileage - knocking

Try seafoam after motor is warm spray some in carb while you throttle up. Keep spraying till you kill the motor and let sit for 15-20 min. start up bike and run the sht out of it. Use 93 or higher feul and and a cap full of seafoam every tank. If you are starting to carbon up it will take care of it!! If that don't work try differnet jets. Is the temp ariound you alot colder than normal? That will have some to do with the jets and feul mixture. If not prob timing.