My Dad left me a 72 T120R i'm trying to get it running he put a boyer micro-mk3 and accel super coil but never finished installing everything before he passed away and i'm trying to finish it for him and me. i'm not sure how to wire it all up i have some of it done. But i really don't want to mess anything up. I guess what im asking can anyone help me out with the wiring.
72 Triumph T120r Help
- Thread starter scottr1
- Start date
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Firstly, my condolences on your Dad's passing.
Some clear photos of you bike would be useful, both sides and also closeups of the handlebar controls and the electrics under the seat, particularly where the "MicroMarkIII" box is located. Take the photos with a phone or digital camera, post them on the site in one of the formats that can be enlarged by the viewer.
Reason these photos will be useful is we can tell how close to, or far from, standard the bike is, particularly the electrics. Boyer do have a wiring diagram online but, perhaps strangely to some, the closer your bike's electrics are to standard, the less the Boyer wiring diagram applies. No sense in anyone launching into a complicated "if it is this, do x ... but if it is that, do y ..." explanation when any explanation will be clearer and simpler for you when it applies to your bike ...
Looks good in theory; in reality, pita proverbial "solution in search of problem":-
. You must measure the electrical resistance between the coil's two low tension terminals accurately, or ask someone with an Ohm or multimeter to do it, The resistance must not be less than 3 Ohms but, ideally, should be less than 4 Ohms - less than 3 Ohms will trash the Boyer (any electronic ignition for these bikes), the more above 4 Ohms, the less well the coil will work.
. If your Dad did not do it, the Accel coil will need proper rubber anti-vibration mounting - is why the two holes behind the battery for the standard coils have thick rubber grommets as standard.
Standard '6V' coils specifically by PVL or Tri-Spark (not new "Lucas") work very well with any electronic ignition for these bikes, just push into those rubber-grommeted holes behind the battery ...
Lowbrow Customs has a wiring diagram on their web site that one of their guy drew up on paper that is easy to follow unlike all other wiring diagrams. Getting the bike to Top Dead Center and then getting the Boyer metal rotor set in the correct position on the shaft is the trick. After that getting the white dot in the hole on the Boyer plate will get you timed up perfectly. Timing these bikes is #1 Carbs are #2 then they run like champs. I've had a '72 T120V in my chopper for 24 years.
Link? It would be interesting to see the Lowbrow diagram.
Not TDC.
If you read Boyer's fitting instructions:-
The "full advance timing mark" is one of the lines on the alternator rotor lined up with the fixed pointer set in the primary cover. If the alternator rotor has two lines 180 degrees apart:-
. these represent ~38 degrees Before TDC and ~38 degrees Before Bottom Dead Centre in conjunction with the fixed pointer;
. you will need to remove a spark plug, look into the cylinder, pick the rotor line when you can see the piston is closest to the spark plug hole (~38 degrees Before TDC).
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Not always. Again from Boyer's fitting instructions:-
Boyers instructions are good but the marks on his Stator Rotor are another thing and finding TDC on the Stator side(left) and then advancing 38 which may have been marked by somebody on his Stator (51 years old) and he may have a 38 degree metal pointer pressed in the case to help him. Then set it up on the ignition (right) side with the Boyer rotor and plate. Remember the Boyer plates screw slots only have so much travel so you can line the plate up to the middle of the screw slots just finger tight then center the dot by moving the rotor on the shaft. Then go to the Stator side and see how it looks with the pointer and the TDC mark if nobody ever made a 38 mark on the Stator because there will be a TDC mark. Then he can tighten the Boyer rotor and plate and give it a go. He sounds new and may not have a degree wheel or other tools. Accel coils I would not use tried all that Hi Preform stuff with no luck just a set of old cylindrical ones and copper wires to the plugs. Get a box of 4 or 8 plugs for carb adjustment.
I have seen that one before. However, if the o.p.'s bike has standard wiring, it does not look anything like that - the o.p.'s bike electrics will only look like that if the o.p.'s father used that diagram to wire his bike.
This is confusing for the o.p.:-
. Original alternator rotor on the o.p.'s bike was marked - stamped - by Lucas. They had been stamped for at least four years previously (Triumph introduced the separate alternator cover on twins' primary covers in 68) and possibly even longer - I cannot ever remember seeing a 74 mm Lucas rotor (introduced 1962) that had not been stamped during manufacture.
. The correct alternator rotor mark combined with the fixed pointer Triumph fitted in twins' primary covers under the alternator cover should indicate the model's spark fully advanced (e.g. 500 fixed pointers are not in the same position as 650 fixed pointers, because 500's full advance is not the same as 650's).
. The fixed pointer was never placed by Triumph to indicate TDC when combined with the alternator rotor mark. So, unless the o.p. posts that his bike is missing rotor mark(s) and/or fixed pointer, he does not have to "find TDC on the Stator side(left) and then advance 38 (degrees)".
. If the o.p. does set up the Boyer static timing with the pistons at TDC, the engine will not start, the spark will be too far retarded. Otoh, if he uses the most likely stamped mark on the bike's alternator rotor combined with the standard fixed pointer in the primary cover, the engine should start and he can then use a strobe on the running engine for final timing adjustment
Why would the o.p. need a degree wheel?
Because if nobody in the past made a 38 degree advance mark on the Stator he would have to find that position on the Stator in relation to the TDC Mark imprinted on the Stator. The wheel does that but if his case has a pointer he can use that. There are 2 BTW so he needs to have the pistons up at the top and use the mark at the bottom of the Stator advance it 38 degrees and then set your Boyer rotor and plate so that the dot on the rotor is seen through the hole in the plate with the screws in the plate slots being as centered as possible for any fine tuning adjustments (timing light) if needed later either advance or retard to get it running smoothly.
You are confused. And, if the o.p. ever comes back to read this thread, the above post will confuse him too.
There are no marks on the alternator stator, not TDC, not 38 degrees BTDC, not King Tut's cartouche.
Lucas stamped first one and later two lines on the alternator rotor, because the rotor is fastened to the end of the crankshaft and rotates with the crankshaft. The one or two lines are stamped on cast raised areas of the rotor.
68-75 - so including 72 T120R - Triumph incorporated a circular cover in the larger primary cover. When this smaller circular cover is removed, it exposes the alternator rotor. It also exposes a steel pointer fixed in a small lug that is cast part of the larger primary cover. If the circular hole in the primary cover is considered a clock face, the pointer and lug are in about the 5 o'clock position.
From the 1972 Triumph 650 Owner's Handbook, page 26:-
... page 27:-
You have confused the alternator rotor-primary chaincase setting with the crankshaft flywheel setting. Again from Owner's Handbook page 26:-
... nevertheless, neither method requires a "degree wheel".
If there are two stamped lines on raised areas of an alternator rotor, they are 180 degrees apart. Afaik, Lucas did this first on 1971 rotors because a new 1971 range would have been the Bandit/Fury twins, that were 180-degree twins. 76 on, the Co-op changed "the circular plate at the forward end of the primary chaincase" to a smaller plug higher up in the primary chaincase, that exposed only a small part of the alternator rotor behind it. The fixed timing mark also exposed by removing the plug is positioned 180 degrees from the 68-75 fixed pointer under "the circular plate at the forward end of the primary chaincase".
I gave him a wiring diagram and a good description on how to set up a Boyer electronic ignition. That was his question ! I see nothing in your replies that would in anyway help him more and nothing that contradicts what I stated besides Stator rotor or alternator rotor same thing.
... that contradicts both the electronic ignition's maker's and the motorcycle maker's very clear and specific setting and fitting instructions ...
