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Author Topic: RS1 magneto change rotation  (Read 327 times)

JD84

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RS1 magneto change rotation
« on: June 29, 2019, 05:24:57 PM »
Hi all,

Had to source another mag for the Lister D as the coil went. Managed to pick up one cheep which saved on a coil rewind and it offers a great spark. Problem is its set to anti clockwise rotation... Does anyone know how I would go about changing it to clockwise? Any help would be much appreciated

Many all thanks in advance!

Johndoh

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Re: RS1 magneto change rotation
« Reply #1 on: June 29, 2019, 09:11:09 PM »
I would have thought it would make a spark no matter which direction it was turned. Wiser heads than mine will clarify this
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cobbadog

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Re: RS1 magneto change rotation
« Reply #2 on: June 30, 2019, 07:04:09 AM »
The Lucas RS1 and SR1 can be made work in reverse rotation but there is a trick to it. There are a couple of things to try first.

Would it be easier for you to swap the coils over as the steps for reversing rotation are a little bit tricky?

If you want to reverse it you have to understand what the magnetic flux is in your magneto. this is the resistance as you rotate the armature. As the flux gets it its highest point this is where the cam starts to open and to alter the timing on the cam is one of those jobs you need 3 hands for. The cam would need to be loosened and pulled away off the taper it sits on so you can move it to be at the best position for reverse rotation. Once you have found the best flux point you have to hold the armature in that exact spot and then rotate the cam lobe so that the points are just breaking.

My best advise is swap the coils over, simplest fix or go to a magneto bloke and get him to do it or there are books on how to do this on Lucas magnetos or research YouTube.  Let us know what you decide to do.
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JD84

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Re: RS1 magneto change rotation
« Reply #3 on: June 30, 2019, 11:31:55 AM »
Thanks for the responses, it was very informative, thankyou.

I totally see your point with regards to the simplicity of changing the coils over, and to be honest I didn't think of that.

However, I would like to try the second more fiddly option of cam positioning.

Reason being I can use the new magneto, which is in an overall better condition, less corrosion, better bearings etc. Additionally being able to set it to the best available point of flux would be great and a good skill to learn.

I understand its just as the magnetic field begins to collapse that spark is produced. I have seen some information online but not solely for the this magneto.

Any further help on the stages of the process, disassembly etc along with ideas of cam removal would be much appreciated.



cobbadog

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Re: RS1 magneto change rotation
« Reply #4 on: July 01, 2019, 07:41:40 AM »
I just thought of something else and that is you MIGHT need the other ignition plate to be fitted when reversing the rotation s that the cam opens the points from the right direction. Sounds silly I know but it does make a difference I believe.
Another option for you is to swap the coil to the magneto with the right rotation but put the complete workings into the better body, this is a straight forward swap and again easier than altering the cam position.
If going for the cam re-positioning mark it before you move it so that you can put it back if needed. Test the flux on it before moving anything so that you get the feel of what it is you need to find when changing it.
Sorry for my late thoughts
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JD84

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Re: RS1 magneto change rotation
« Reply #5 on: July 01, 2019, 09:47:44 AM »
Many thanks its much appreciated I will be having a go this weekend so will be sure to post how I get on. I have sourced the workshop instructions to aid me, pdf copy availble to others if needed (see other thread)

sirpedrosa

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Re: RS1 magneto change rotation
« Reply #6 on: July 01, 2019, 12:08:26 PM »
Hi Jd

Do you see any inconvenience in making the manuals available in my thread here: http://listerengine.com/smf/index.php?topic=8395.msg100104#msg100104.

BR
VP
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JD84

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Re: RS1 magneto change rotation
« Reply #7 on: July 01, 2019, 05:18:00 PM »
Hi VP,

No problem, but cant seem to upload them. Message me your details and I will send them over and you can load them on your thred?

Hope that helps,

James

JD84

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Re: RS1 magneto change rotation
« Reply #8 on: July 03, 2019, 10:17:27 AM »
Last night I finaly got round to changing the direction on the RS1 magneto.

I must say its a simple process but I can see why it can often cause problems.

I started by removing the points cover and the locating screw on the cam. Using a small screwdriver either side of the cam and nudged it free from the shaft.

Note the cam its hardened so go easy on it to prevent damage. I did have a puller as back up, but got lucky! If you do use a small puller put the screw back in a few turns so the puller has somthing to push against until it starts to move. That way no risk to shaft or threads.

I then rotated the magneto in my chosen rotation (clockwise) and found the point at which the magnets pull and the most resistance is felt.

Continue to rotate just to the point the resistance started to drop away. Hold it steady and install the cam in a postion so the points are just open, screw only tight enough so the cam wont slip from postion.

I then rotated and checked for spark and carried on repeating the process with slight adjustment of the cam postion until a really good spark was seen. When happy lock down the screw and add a bit of thin oil to the felt washer/pad so to replace the lubricate on the cam removed through handling.

Hope this helps someone - thanks all.


cobbadog

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Re: RS1 magneto change rotation
« Reply #9 on: July 04, 2019, 07:33:26 AM »
Very well done mate. On some magnetos there is a place to put a small pin or nail in a hole to hold the armature in place while you adjust the cam. Also some you have to replace the points plate for the points to open correctly. So many variables with magnetos and they can really test you at times. A popular make and model magneto on stationary engines is the Wico EK magneto. SO many people talk them up but reading about magnetos on a specialty magneto forum, Smokstak in the US and they have a separate area to discuss magnetos the most commonly talked about magneto is the EK with so many problems and they have the hide to call Lucas "The Prince of Darkness". I keep reminding them that there doesn't seem to be hardly any issues discussed here on here but Wico is the most common one having trouble.
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