Got Triumph T120 !970 but has 1971 engine fitted,second last of production line with oil tank, assume they ran out of 1970 engines and fitted later grom 71 model,need to know how to set up selectors as all manuals I have do not cover the 4 speed box with leaf spring fitted to side of inner cover. Thanks

Hi!
It seems your fuel pump fails at idle speed. I would first ensure that fuel pump is well fitted, no leaks, and good diaphragm condition.

Sounds like either a blocked oil pick up.
This starves the top end for oil hence when you rev it the light comes on.
When was the last time you changed the oil?
Sludge builds up if oils arnt changed regularly and block the oil pick up strainer.
Put 500mls of diesel fuel I to the engine and run it until up to running temperature.
Then dump the oil whilst it's hot.
The diesel will break down the sludge and allow it to run out easier.

I ran one of those on several 60s-70s Triumphs.....great ignition!

Both plugs fire at the same time so there is no left/right to worry about.

Remove spark plugs and gap .018. Remove timing cover (right hand side of engine) over battery ignition points.
Disconnect and tape (insulate) all battery connected wires. Better yet, unhook battery hot wire from battery terminal.
Hold breaker cam in opposite direction of rotation (advanced position) and rotate engine until the points on #1 cylinder just start to open. Note: Use .0015 feeler gauge.
Remove breaker plate, breaker cam advance mechanism, and dowel pin from internal taper if your model used a dowel pin to position breaker cam and advance mechanism. CAUTION Do Not Rotate Engine. If engine is rotated, reverse rotation until piston is down and the cylinder at least one inch before top center on the compression stroke.
Rotate engine in normal direction of rotation until piston is 5/16 from top center on compression stroke. Install magnetos adaptor plate and adaptor shaft in cam taper. DO NOT TIGHTEN SHAFT. CAUTION 1963 to 1970 Triumph unit construction twins have a different length taper on shaft and internal threads are dissimilar. Suggest checking threads and taper. 1963 to 1970 bolt has BSF 1/4 x 26 threads. 1971 and later bolt had 1/4 x 28 thread. Early shafts are marked with the letter "A". Later shafts are marked with "B".
NOTE: Some applications will require drilling and tapping engine with 1/4 x 20 for better security of magneto mounting adapter. Some customers with severe service report that they heli aced adaptor to cam cover with approximately one inch length bead, top and bottom for security.
Remove Magneto cover. With shaft slightly loose in taper mount Magneto so that points are just starting to open and bolts are approximately in center of slot (for timing adjustment later).
Carefully remove Magneto and tighten center bolt in shaft. Re-install Magneto and time. Install cover and plug wires. Hook up ground wire to a separate kill switch to ground only. DO NOT HOOK ANY BATTERY CURRENT TO MAGNETO.
Point Gap .012 to .015

Ok, let me brush some cobwebs off here and see if I can remember how the lines go on the FXR. On that model, the oil tank was under the seat and one line off the bottom of it and two at the top as best as I can remember. Of course the line off the bottom of the tank was the feed line and goes to the inlet of the oil pump. As best as I can remember, the oil pump had one fitting in the middle of the outer plate on the oil pump. This would be the inlet. If the fittings are on the top, the outer fitting is the inlet. The outlet from the pump was under the cam chest facing towards the front of the bike. A metal line ran from it to the oil filter and another line ran from the oil filter back towards the tank. The line changed from a metal line to a rubber line right about even with the oil pump and then it went up to the large fitting at the top of the tank. There was another oil line that came from the cam chest just above and slightly to the inside of the oil pump. This is a vent line that goes to the top of the oil tank. The crankcase vent comes from a fitting below the pump and to the inside and runs up and into the backside of the air cleaner. This is the best that I can remember on that model. 1986 was a long time and a lot of bikes ago. Remember, the oil comes from the tank to the pump, into the engine out of the pump through the oil filter and then back to the tank. If you have trouble figuring out the pump connections, Squirt a little oil into one of the fittings and spin the engine with the starter. Watch the oil, if it goes into the fitting, that's the intake. If it blows it back out, it's the outlet. If you have any problem, contact me directly and I'll make a drawing or something to send you. This forum will only allow for a file transfer of 150Kb and my files are usually larger than that. I'll send them as jpg files. Contact me at [email protected]

Steve

it's been a while, and there always a different spec depending which manual you got, preset 17 thou for exhaust and 14 thou for intake, run engine till warm , if still noisy let engine cool and tighten a couple of thou each, repeat if necessary, it sound wishy washy but it has worked for me in the past

the bike can run on unleaded but it will be rough .
you mwill have loss of power and radical .
what i would suggest is to ask a mechanic about the effects of unleaded petrol to an old engin .
all i know is that the bike will run as i did it to my old BMW and all i had to do is replace some gaskets .
Best of luck .

Oil pressure switch. Check it and make sure oil level is correct. The oil switch will cause this

If you need further help, I’m available over the phone at https://www.6ya.com/expert/craig_3fa289bf857b1a3c

Several things could be at play: Type or weight of oil, confirm this first. Not to question the rebuild but if not done properly (improper bearing clearances, too large) the oil pressure can be low and perhaps a worn pump too. While I am unfamiliar with the engine and oil pump loaction I'd check it if your able too. You'll probably need a good set of feeler gauges to check this if these clearances are outside of the pumps limits the pump will be less able to create pressure; this is of course more evident when the oil heats up.
Another cheap fix is to use a heavier weight oil.
Hope this might help,
Tom