1947 Indian Chief back firing through the tail pipe.

[FUUN063]

Hello all. I don't really get on the computer much any more, but I have a question for the masses and informed of the forum regarding my Indian Chief. I have owned it for a long time and have been riding it a lot, putting on miles whenever I can. But, today I was riding along and everything was fine. Then, the bike lost power and began popping and cracking through the tail pipe leaving me barely able to get home that last 6 miles or so. Upon my arrival, I went through the usual things to try and diagnose the issue such as checking the points. They had a small spot on them and I touched them up with some emery cloth as usual, then reset them at .020" on the large lobe. I also checked the spark plug wires (good) and their connections (good), coil wire (good) and it's connections (good), carburetor/intake bolts (nice and tight), removed spark plugs and check spark of each one (nice bright blue, snappy spark), checked fuel flow to carburetor and through fuel bowl assembly (nice flow) and have at least 12 volts from battery and at coil. I started the bike back up and it still pops and cracks at any speed and at any timing location of the handle grip. Any ideas, please feel free to post here so that I can get this thing rolling again. Oh yeah, I checked warm engine compression and have around 80 psi on both cylinders. I don't really know what it was before, but it always ran pretty well with good power. Thanks in advance.

Leland

[Oilcan]

Bad condensor. Usually your points get burnt at the same time. Try replacing it.

[FUUN063]

I already have placed an order for both the points and condenser. I usually get a weak spark on the plugs when a condenser is bad, but I've seen odd things happen. I will pull the condenser tomorrow and test it. Thanks for the reply. Just for thought, the condenser and points set are the original ones I put in over 15 years ago and they have never given me any trouble.

Leland

[hairynob24]

did you take the fuel bowl off ? check the big nut on the bottom see if it has water in it so collect what comes out ?

[tfburke3]

Hello all. I don't really get on the computer much any more, but I have a question for the masses and informed of the forum regarding my Indian Chief. I have owned it for a long time and have been riding it a lot, putting on miles whenever I can. But, today I was riding along and everything was fine. Then, the bike lost power and began popping and cracking through the tail pipe leaving me barely able to get home that last 6 miles or so. Upon my arrival, I went through the usual things to try and diagnose the issue such as checking the points. They had a small spot on them and I touched them up with some emery cloth as usual, then reset them at .020" on the large lobe. I also checked the spark plug wires (good) and their connections (good), coil wire (good) and it's connections (good), carburetor/intake bolts (nice and tight), removed spark plugs and check spark of each one (nice bright blue, snappy spark), checked fuel flow to carburetor and through fuel bowl assembly (nice flow) and have at least 12 volts from battery and at coil. I started the bike back up and it still pops and cracks at any speed and at any timing location of the handle grip. Any ideas, please feel free to post here so that I can get this thing rolling again. Oh yeah, I checked warm engine compression and have around 80 psi on both cylinders. I don't really know what it was before, but it always ran pretty well with good power. Thanks in advance.

Leland

When you say riding a lot the first thing that comes to mind, is a burnt exhaust valve.Hows the compression?

Edit : reread,sorry see your compression is ok
Tom

[FUUN063]

Thanks for the replies, fellas. I took the fuel bowl off as one of the first things thinking that I had some bad gas or water in it. No water and clean bowl. I put in more gas just to make sure, same thing. I'll tinker around with it some more today and see what comes of it. New set of points and condenser on the way, too. I also wanted to add another question: Do other Chief owners have the small amount of play in the distributor shaft/oil pump drive? It seems that I have a little so I pulled the distributor and looked down in the oil pump. I then took a flat blade screwdriver and turned the oil pump (remembering where it was located originally to return it there for the timing) and saw that the oil pump gear has a small amount of play in it. Is this normal?

Leland

[Rubone]

Could be a sticking exhaust valve, especially if it has been sitting for long periods. Try a little top lube in the fuel (two stroke oil). If they momentarily stick you will lose power and backfire. They may not show up at all on a compression test.

[T. Cotten]

...carburetor/intake bolts (nice and tight),....

Leland!

With all possible respect, "That don't mean diddly squat".
Although vacuum leaks usually do not report at the exhaust, no two are alike (except those that prevent the machine from starting at all.)

When you have exhausted all other tail-chases, please bubble-test the manifold assembly. Beware that over-tightening causes as many issues as coming loose.
The manifold flange should be arbitrarily ground flat, and the carb lathe-cut, as nearly all are distorted from fastener stress.

If it was cold weather, I would have suggested that it was exhaust leaks, allowing cold air in to expand explosively.
In hot weather, my 'armchair' suspicion suggests that the mixture is over-enrichened to accommodate a vacuum leak, and the un-ignited fuel gets lit on the hot pipes.

Discolored pipes are a clue, and you do not want exhaust leaks either,

Let us know,

....Cotten
PS: Folks, with ethanol fuels, you should never find separated water in the bowl, or bottom of the tanks, as it absorbs it. (Just like methanol "HEET". That's how it prevents gasline freeze in autos.)
Ethanol's affinity for water is why the whole gasahol notion is economic folly: It take more energy to produce and dehydrate ("rectify") the ethanol for mixing with gasoline than we get back.

P4gas has a larger "carbon footprint" than fossil gasoline alone.

[phillie]

I had an ignition switch go bad once.... also a coil.

[FUUN063]

Tested for air leaks and there are none that I am aware of here. Also, ignition switch and coil test great. I was actually kick starting it and the casting for the kick start pin broke off!!!! Just my luck. I got it all cleaned up and found that someone years and years ago tried to braze (poorly, I might add) the broken casting before I got it 16 years ago. Well, I now gotta fix that and install my new points and condenser, then we'll see. Also, it broke the 1/2"-24 tpi nut that holds on the sprocket/kicker gear, too. Great.