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Indian Four 1932 - problem with 3rd cylinder

3K views 31 replies 12 participants last post by  Bikesofbrads 
#1 ·
Hello,

My name is Tomas and I live in Czech Republic in Central Europe. And of course sorry for my bad English.

I am contacting all of you for advice when I am finding a solution for my specific problem. I believe that there are skilled mechanics among you with many years of experience can help.

I recently bought an Indian Four motorcycle from 1932.
The bike is after a complete renovation, including the engine.
And just when the engine was running in, a fault appeared that I can't handle.
The third cylinder burns the mixture imperfectly, it works at about 30%, the spark plug is after disassembly wet and unburned.
The other cylinders work without problems.
I was able to rule out a fault on ignition, including another cables and spark plugs (I use NGK AB-6).
This indicates me a problem in the mechanical part.
The compression on all cylinders is about 4.6 atm (67.601 PSI). Valve clearances are: intake valve=0.15 mm (0.59 in), exhaust valve=0.25 mm (0.98 in).
The engine willingly starts and responds quickly to the accelerating of throttle.
That the cylinder does not work properly, despite the spark plug spark gives, I detected using a thermal camera (see attached, heat difference between 3rd (70.73°C=159.31 F) and 4th cylinder (127.15°C=260.87 F) .
I want to ask you for advice if someone would give me the answer where to look for a problem solving.
I've heard that third cylinders have always had a problem, but I can't believe it's been over 1 hour engine run-in.

Thank You for all your advices and responses.
 

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#13 ·
The problem is that timing is OK, twice chcecked. I disassembled the engine and found that cylinder no. 3 is nice clean. It shows no fuel soot in there but I know that fuel is in cylinder because spark plug is wet. Intakte manifold and exhaust are not clogged. The spar plug throws a spark when it is outside. But it seems that not inside.
 
#7 ·
Welcome from DownUnder
Great to have a real Indian in here!
Post up some pics of the bike please?
Have you tried a new spark plug?
Or as mentioned swapped leads around?
 
#8 · (Edited)
I Newtown Ct. there is an owner of the antique news paper there. “Antiques and the arts weekly” His name is David. Any who he is a motorcycle mechanic / enthusiast stemming from models way back and he has an Indian I believe early1940’s ! All original ! He knows a lot about them. Maybe you can reach out to him for information and sources.
 
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#9 ·
I Newtown Ct. there is an owner of the antique news paper there. "Antiques and the arts weekly" His name is David. Any who he is a motorcycle mechanic / enthusiast stemming from models way back and he has an Indian I believe early1940's ! All original ! He knows a lot about them. Maybe you can reach out to him for information and sources.
There ya go, much more helpful than your first response :buttkick::huepfenicon111:
 
#10 · (Edited)
Anyone else notice the date at bottom left for the thermal camera is Dec 10, 2010, it is besides the point but I too would switch plug wires with another cylinder & see if changes anything. What’s that other lead go to on the colder cylinder, right where the temp of 70.73 is printed on the image, I don’t see that lead on other cylinder but appears to be on 2 outta the 4. Love those old bikes so hope ya get it sorted out.
 
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#19 ·
Anyone else notice the date at bottom left for the thermal camera is Dec 10, 2010, it is besides the point but I too would switch plug wires with another cylinder & see if changes anything. What's that other lead go to on the colder cylinder, right where the temp of 70.73 is printed on the image, I don't see that lead on other cylinder but appears to be on 2 outta the 4. Love those old bikes so hope ya get it sorted out.
I did not have set right date for the camera. Anyway, that wire what you see on pics which is not plugged is another free wire for testing wires. Yeah I am starting to love old bikes (irony) :)
 
#23 ·
Sounds like the motor was completely rebuilt. Is it possible the camshaft was re-ground improperly? Take the spark plug and distributor cap off. Mark the distributor at the aproziment point rotor is in third cylinder fire position. Stick your finger in the spark plug hole. Crank and see if compression and timing are close. Those valve gaps seem excessive.
 
#26 · (Edited)
@Heldy So #3 does the same thing even with a different spark plug & wire? Does it have a set of points for each cylinder or 1 set inside the distributor for all four cylinders? If is a timing issue you may have to go completely back and double check all the alignment marks on cams/ wheels/ gears and then make sure the distributor gear/ cap/ points are good and then of course the plugs/ wires. Remember that sometimes even brand new parts are defected & are no good. Best of luck & sometimes you just got to step away for awhile and clear your mind.
 
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#29 ·
It's hard to understand Heldy. First you said after a complete renovation upon firing up the bike the 3rd cylinder is firing about 30% of the time. Why is the bike now disassembled in your garage? Why did you take it all apart? The plug you say throws off good spark outside the cylinder but is wet upon removal? This would indicate a plugged jet or something in the carburetor for that cylinder that is affecting the fuel mixture. Consistent spark and compression means only fuel delivery is the remaining issue.
When I wrote first time here I think the 3rd valve firing about 30%, I saw that on thermal cam and of course I didn't want to disassemble the engine after the GR. But I had to. Fortunately I think I found solve that. I will write it below.
 
#30 ·
Hey,

I probably solved the problem. After reading your advices and checking everything over and over, I came up with the following:
1. My original magneto had a weak magnets. This caused the spark to be weak and unable to ignite the mixture inside the cylinder.
Questions: How is it possible that three cylinders work and one does not. Why the spark from 3rd cylinder is always wet? The answer: Rich mixture.
2. That led me to the second problem. Carburetor.
The carburetor is not a complicated part. Unfortunately, during the general renovation, someone folded one of the needles (idle) incorrectly. Above the needle there should be a spring which allows to control the richness of the mixture. Someone put that goddamn spring on the needle from below. This ignorance caused the needle was open and a rich mixture to fly into the cylinders. Such a rich mixture could not be ignited at idle in cylinder no. 3 and in cylinder no. 4 there were insufficient explosions as well, although it was not heard. Now I will want to fine-tune it and I believe that we will only have pleasant moments with the new motorcycle for future.

Let me to thank you for your advices, contacts and support. The sun is coming. When I pull out my Indian from the garage, take a few photos and put them here.
 
#32 ·
@Heldy Thank you for keeping us informed of the progress, nice classic machine and am very happy that you are giving it more life.
 
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