K2F Magneto

pierodn

Joined
Nov 10, 2012
Messages
3,154
Country flag
Hi All.
When you must change the LUCAS K2F MAGNETO PICK BRUSHes and SPRINGs?
Thank you.
Piero
 
You are asking a question that is answered in the manual.

It says the wide part of the brush should be a minimum 1/8” length.

Replace the springs if they’re rusty or not pushing the brushes out.

Don’t replace the brushes if they’re not worn out. There are soft ones on sale nowadays, that cover the slip ring with carbon and cause misfiring.
 
Triton Thrasher said:
You are asking a question that is answered in the manual.

It says the wide part of the brush should be a minimum 1/8” length.

Replace the springs if they’re rusty or not pushing the brushes out.

Don’t replace the brushes if they’re not worn out. There are soft ones on sale nowadays, that cover the slip ring with carbon and cause misfiring.
Click to expand...
Thank you so much.
Piero
 
Triton Thrasher said:
There are soft ones on sale nowadays, that cover the slip ring with carbon and cause misfiring.
Click to expand...

To add to Triton's information: The soft brushes can leave a. carbon track around the entire, or nearly entire, slip ring. This will electrically short the two sides of the slip ring into one, causing the magneto to TRY to fire both cylinders simultaneously. As two spark plugs in parallel will never BOTH fire, but ONE will preferentially fire, it creates a "one side firing" situation.

I have been told that even Wassel made brushes can be soft. How does one go about getting good ones?

Slick
 
Triton Thrasher said:
If the surface of the slip ring conducts, then a spark will occur at the plug which is not under compression.
Click to expand...

This is exactly what one would expect with both plugs installed, and the engine kicked over, in which case the engine will not start as both plugs will be, in turn, delivering wasted spark.

However, when an ignition problem occurs, most diagnosticians pull the plugs, and in turn, short the earth electrode of each plug to the cylinder head. In this instance, both plugs are not under compression, and only ONE will preferentially fire. This leads to the claim "My magneto only fires on the right(or left) side!"

The brush/carbon smeared slip ring condition is well worth remembering when a K2F is sparking only on one side.

We digress from the OP's topic, but it is related to brushes.

Slick
 
norton bob said:
This is a very helpful thread as I am looking at a 650 with exactly that problem.
Click to expand...

its easy enough to clean the slip ring a
rag moistened with petrol or other solvent carefully inserted in the ht pick up hole on a bit wood or other while slowly turning the motor over will clean it , i imagine once the brushes are seated it wont be so much of a problem , hard carbon brushes
eat the composite material of the slip ring and leave a deep groove in it

im surprised nobody has made sliprings with a jump spark set up as in a car distributer. its a far better system with less earth paths and is less suceptible to plug fouling ..

similar to holding the ht cap off a bit to clear an oily plug on a 2 stroke
 
After 4 heart/pacemaker opps (with failures!) I am very wary of HT shocks. Also have to keep clear of magnetic fields, so big gennys,speakers, MRi scanners,rotors,arc welding,drills, motors,magnets and god knows what else. Sparky women I can tolerate!.
 
You must log in or register to reply here.
Back
Top