Trispark rotorshaft removal.

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Are you sure, that the extraction threads are not just at the bottom the bore?
Unlikely/illogical, but I’ve seen stranger things in machinery.
You could tap it in situ as well.
JMWO
 
That’s what I originally thought but I could not feel any with my scribe.
 
auldblue said:
There are no threads inside my rotor shaft and an M8 bolt does not fit in the centre maybe the shaft was sent unthreaded, who knows! I await an email or another method of removal that avoids damage.
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The rotor can be removed by using a brass drift placed 90 degrees from the magnets. If you very gently apply the blows, almost "love taps", the rotor will disengage its' tapered fit. The other possibility is to find a piece of bar stock that fits tightly in the un-threaded rotor bore and tap on that. Keep in mind that magnets do not like shock.

Best
 
The rotor has been removed already, I’ll give it a try .... show it some love!
 
I see that I miss understood your terms, my bad.

The threads in the cam (rotor shaft?) are deep. Try the socket headed fasteners (5/16-26 & 5/16-24) by hand, if either one of these fails to catch the threads you have bigger issues to address. Be careful here because the incorrect fastener will start, if the threads are intact. The correct fastener will fully thread in, assuming undamaged cam threads; I'd clean the cam bore with a solvent and compressed air and follow up with some light oil applied via Q-tip to give yourself the most favorable conditions.

LAB might be able to help you determine which thread pitch your cam has, if original equipment, by the year and engine number. 5/16-24 taps are very common, 5/16-26 taps are available.

Best
 
auldblue said:
The rotor has been removed already,
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RoadScholar said:
I see that I miss understood your terms, my bad.
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So the FireBox 'rotor' and 'shaft' are separate parts.
I wasn't aware of that either!

RoadScholar said:
LAB might be able to help you determine which thread pitch your cam has, if original equipment, by the year and engine number. 5/16-24 taps are very common, 5/16-26 taps are available.
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If it's a standard Commando camshaft then normally 1/4" x 26 BSF, however, I have an idea the bike might not be a Commando?
 
RoadScholar said:
I see that I miss understood your terms, my bad.

The threads in the cam (rotor shaft?) are deep. Try the socket headed fasteners (1/4-26 & 1/4-28) by hand, if either one of these fails to catch the threads you have bigger issues to address. Be careful here because the incorrect fastener will start, if the threads are intact. The correct fastener will fully thread in, assuming undamaged cam threads; I'd clean the cam bore with a solvent and compressed air and follow up with some light oil applied via Q-tip to give yourself the most favorable conditions.

LAB might be able to help you determine which thread pitch your cam has, if original equipment, by the year and engine number. 1/4-28 taps are very common, 1/4-26 taps are available.

Best
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Corrected.
 
The cam is a PW3 supplied by Norman White and the motorcycle is a 750 commando, the Firebox pro ignition was supplied by LP Williams in about April/May 2019. Here is a photo of the bike( the one on the left)
Trispark rotorshaft removal.
 
Trispark rotorshaft removal.


A punch up the inside of the shaft a couple of gentle taps and it’s out, with no song and dance. Here is a photo of the rotor and shaft.
 
Cool. Gotta realize that most of us are seeing one of these for the first time. Didn't know what you were referring to by "shaft".
 
A taper fit, on a shaft, with no provision to withdraw it is an engineering FAIL. Simply mimmic the original AAU, or one of the multiple competitors.
Be sure to add threads before re-assembling.
 
Apart from that shortfall it looks a nice bit of kit though, and you can adjust the position of the magnet along the axis of the camshaft by moving the collar. ( easier than cutting up a coke can as Boyer suggest) :D

Cheers,

cliffa
 
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There is only a single magnet on the rotor as it only fires on the compression stroke, it is not a wasted spark system.
 
RoadScholar said:
Your Tri-Spark kit was supplied with a long hex-headed bolt, it was intended for rotor removal. The rotor is tapped for M8-1.25. To remove the rotor first remove the 5/16-26 or the 5/16-24 black oxide center fixing socket headed fastener (which fasten to the camshaft), screw the M8-1.25 bolt into the rotor until it is snug, then VERY gently, with light weight hammer, tap the metric fastener; the rotor will disengage quickly and cleanly. Again...GENTLY.

Best
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I agree -- M8-1.25 bolt - that's the way I removed the tri-spark from my 74
 
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RoadScholar said:
Your Tri-Spark kit was supplied with a long hex-headed bolt, it was intended for rotor removal. The rotor is tapped for M8-1.25. To remove the rotor first remove the 5/16-26 or the 5/16-24 black oxide center fixing socket headed fastener (which fasten to the camshaft), screw the M8-1.25 bolt into the rotor until it is snug, then VERY gently, with light weight hammer, tap the metric fastener; the rotor will disengage quickly and cleanly. Again...GENTLY.
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joe czech said:
I agree -- M8-1.25 bolt - that's the way I removed the tri-spark form my 74
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This particular Tri-Spark electronic ignition, however, is the FireBox Pro, not the 'Classic Twin'.
https://www.trispark.com.au/firebox-pro-for-british-twins
 
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L.A.B. said:
This particular Tri-Spark electronic ignition, however, is the FireBox Pro, not the 'Classic Twin'.
https://www.trispark.com.au/firebox-pro-for-british-twins
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maylar said:
The latest version is not threaded.
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sorry, didn't know - all I can say is, what was half installed in my 74 had a black anodized rotor, requiring a M8-1.25 threaded bolt for removal. the empty box (with instructions) was marked "tri-spark classic twin for: Norton. whether it the latest version or not, I have no idea. the previous owner must have purchased the unit around 2012
 
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