Tri spark and carb issues

Mike750 · Feb 26, 2023

I have a 73 Commando with a single 34mm mikuni and a tri spark ignition. The problems I'm having: in order to get it to run decently the air screw on the carb has to be completely screwed in and the tri spark, I actually had to file the slots so I could rotate it further clockwise. Any ideas as to why this would be?

Fast Eddie · Feb 26, 2023

If you’re having to file the slots, surely you have simply fitted the rotor in the wrong orientation ?

Regarding the carb, sounds like a partially blocked pilot jet to me.

Mike750 · Feb 26, 2023

That makes sense. Motor was recently rebuilt. They possibly installed rotor incorrectly. And will check pilot. Thanks!

L.A.B. · Feb 26, 2023

Mike750 said:
Motor was recently rebuilt. They possibly installed rotor incorrectly.

An M8 extractor bolt is normally included in the Tri-Spark kit so use it (or another M8) to extract the rotor, then reposition the rotor to put the adjustment back within the range of the slots.

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RoadScholar · Feb 26, 2023

Carb should have a 35 or 40 pilot jet.

If you have stored the bike with ethanol in the fuel it can clog the idle jet in less than 2 months.

Best.

marshg246 · Feb 26, 2023

Mike750 said:
I have a 73 Commando with a single 34mm mikuni and a tri spark ignition. The problems I'm having: in order to get it to run decently the air screw on the carb has to be completely screwed in and the tri spark, I actually had to file the slots so I could rotate it further clockwise. Any ideas as to why this would be?

The latest Tri-Spark (Tri-0006) manual is here: https://www.trispark.com.au/assets/files/TRI-0006 Classic Twin Manual 2021.pdf

You may have the earlier version:

The instructions are the same but the markings on the stator different.

The troubleshooting instructions for the older version (Tri-0005b) are here: https://www.trispark.com.au/assets/files/Testing the Classic Twin Igntion System.pdf

Tri spark and carb issues

Mike750

Fast Eddie

Mike750

L.A.B.

Moderator

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marshg246

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