It won’t start! EFNR44B7 (Solved)

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Charles uk
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Re: It won’t start! EFNR44B7

Post by Charles uk »

The keyway in a 40 crank is in a different position to a century/ KF crankshaft.

On a century the keyway is 158 degrees to the left of the centreline of the big end pin, looking from the flywheel end.

On a 40 the keyway is 43 degrees to the left of the centreline of the big end pin, looking from the flywheel end.

So try removing the flywheel & replacing in the 40 key groove.

If that works Rene was right, sorry!

Perhaps it would help if you explained exactly what you've got there.
Make it idiot proof and someone will make a better idiot.
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Nudge
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Re: It won’t start! EFNR44B7

Post by Nudge »

Why not just try putting the key / flywheel in the other slot? you have nothing to lose.
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andrew
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Re: It won’t start! EFNR44B7

Post by andrew »

will try the other key slot next, thanks for the suggestion! Will also take/post some photos of the setup if that doesn't work.

Cheers
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beerjam
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Re: It won’t start! EFNR44B7

Post by beerjam »

If it is suspected that the timing is the issue you could observe the points, with the spark plug out, and check the position of the piston as they start to open. It should be just before TDC.

Cheers, Mark
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beerjam
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Re: It won’t start! EFNR44B7

Post by beerjam »

beerjam wrote: Wed Jul 07, 2021 5:39 pm If it is suspected that the timing is the issue you could observe the points, with the spark plug out, and check the position of the piston as they start to open. It should be just before TDC.

Cheers, Mark
Please ignore my previous, ill considered post. You have CDI ignition - (much blushing)
andrew
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Re: It won’t start! EFNR44B7 (Solved)

Post by andrew »

Solved! Though not my proudest moment to be sure. Hopefully my mistake will be a lesson for others.

I had reassembled with the Wipac MK4 CDI installed the wrong way around (rotated 180 degrees). So it was still producing an excellent spark, just at the perfectly wrong time ie right before Bottom Dead Centre (BDC) instead of Top Dead Centre (TDC). I had wrongly assumed that the HT lead would come out on opposite side as the carb, which is true for forties but not centuries as the carbs are mounted on opposite sides of the cylinder for the two types of motors.

Putting CDI in the right orientation, it started 2nd pull with the Amal 2 Jet 46N carb still installed. I will pop the Amal 416 1A carb back on and take it for a test run in the bay when I next get the chance.

Lesson learned for me: if you have spark, compression and fuel and motor doesn’t fire, double check that the spark is happening at the right time! I think this error is only possible on the MK3 and MK4 CDI units, but not older points ignitions. The CDI can be mounted either side and there is a hole in baseplate that HT lead can go through on either side, which doesn’t make it obvious which way it goes to the layman.

Photos below for future reference on the forum. Note the MK4 CDI is correctly installed on the port side of motor, not starboard as I originally had it.

Thanks all for your support as I went through this process. Just shows that these simple motors can be brought to life by checking each part one at a time and isolating the issue.
633923B6-7F83-40E9-9388-B9D67EF8D4AC.jpeg
CE06B6DC-5423-4CA4-AE63-07A103403A4C.jpeg
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Collector Inspector
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Re: It won’t start! EFNR44B7 (Solved)

Post by Collector Inspector »

Well done Andrew, I will remember this wee quirk of CDI.

I only have one CDI on an 80s 102 which is still not running well.

So many projects and now unlimited time to get them sorted sigh.

Await noise and wake soon.

B

A chicken is one egg's way of becoming others
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