solved the backfiring (popping) issue...

[LowRider94]

My bike (1994 FXDL) had been backfiring on decel for quite a while, and it seemed to be getting worse.

It's always been a bit cold natured, and I usually have to pull the choke (enricher) to get it to start and run.

I asked around quite a bit, and got various answers as to what the problem might be (exhaust manifold gaskets, carb issues, bad plugs, wires/and or coil)...

But no one mentioned intake gaskets until I spoke yesterday with a mechanic at the Lynchburg, VA Harley dealership. The guy's name was Don Keifer, and when I told him the bike was giving trouble backfiring a lot on decel, he asked me if it was also cold natured, and did it want to hesitate at times when I rolled the throttle. I said yes...and he said check the intake seals.

I bought a set, and installed them today. The old seals were pretty well trashed. The bike's got nearly 60K on it now, and it had never had these replaced.

The problem went away totally... and the bike's running better than I recall in quite a long time.

I wanted to post this in case someone searches the archives here with the same backfiring issue, as they might need the intake seals.

The problem starts out sort of small, and might even go away and come back (when the seal moves around and seals, then unseals, depending on engine heat). Then the issue gets progressively worse, with the bike getting more and more cold natured. If your bike ever acts this way, suspect the intake seals. Replace the carb base seal while you've got it apart... it's not hard, and requires no special tools...

Dan

[elliottharley]

seen it time and time again, damn seals....my bike did the same thing.

/e

[Horse]

Good post LowRider94

EVO intake seals are often overlooked and it pays to replace them.
The chemical mixtures of gasoline is hard on them, especially methanol blends.

[Old_Evo]

This sounds like what's happen on my EVO. It's funny that you brought this up as the backfiring has gotten worse but very, very slowly over this summer. I have 89k and can only assume they didn't need to replace them on the 1st 20K when I bought her. I'll get the seals and do this when I have to give up riding when the snow flies.

With 89K on the carb should I do anything with that since I'll be in there? Seems to work fine, just asking our Harley Guru's here.

[Horse]

With 89K on the carb should I do anything with that since I'll be in there? Seems to work fine, just asking our Harley Guru's here.

Great time to rebuild the carb but a couple of questions first.

When was the last time the carb was rebuilt, have you done this before and have you changed anything in the fuel / exhaust system since that time.

Carb rebuilding is not complicated especially if you have the maintenance manual and a parts catalog. If your happy with the present performance keep the same jet size but replace them.
An easy way to set the float is on a tilt table and I use my band saw for this, setting the angle of the table first.

Check the HCG Technical FAQ's for CV tech info,, some great advice there.

[Old_Evo]

When was the last time the carb was rebuilt, have you done this before and have you changed anything in the fuel / exhaust system since that time.

Carb rebuilding is not complicated especially if you have the maintenance manual and a parts catalog. If your happy with the present performance keep the same jet size but replace them.
An easy way to set the float is on a tilt table and I use my band saw for this, setting the angle of the table first.

Check the HCG Technical FAQ's for CV tech info,, some great advice there.

I believe the carb to be original, but still working just fine. We did re-jet when changing out pipes.
I have both maintenance and a parts catalog (thanks to Kagan.)
I don't have a tilt table but my brother or neighbor may have one.
I'll check the tech FAQ's section.
Thanks Horse, right now there is a bit of fear of the unknown but I'll guess that once I get into it I'll say "hey this is simple and easy" just like the first time I ripped into my clutch.

[Horse]

Hey Old_Evo let us know what's up.

[LostLake]

I thought we said to spray a little WD40 or starter fluid around the head and intake to check for a leak... Must have been another thread....

[Old_Evo]

Right now I'm just gathering up parts, cause it's going to be in the 60's this weekend so I'll ride. Once the snow falls and the roads are full of salt I'll start tearing into the intake, carb, new handle bars, and oil pump.

[Horse]

Old Evo.,,,, how you doing?