At Wits End!

[solomon]

It must have an earlier cylinder head fitted. 79 heads are parallel intakes.
I don't think the exhaust spigots will be welded on? Maybe head is retro fitted with screw-in push-over spigots?
Photos would indeed help.

 

[Rudie]

is a 79, and it’s a bit of a Frankin-bike. Amal 930’s are on it now, it has a splayed intake head

Thanks for the clarification.

someone had welded push on exhaust spigots, unless they came standard on a 79.

The head is from a Triumph twin (750 if it has two smaller fasteners between the combustion chambers, 650 if it has only one smaller fastener) made before the beginning of January 1978; from then, the reduced emissions mandated by the US EPA required the initially US only T140E with the previously mentioned Mk.2 carbs on parallel inlet ports. The "Mk.1" Concentrics correspond to the splayed intakes.

Otoh, Triumph changed to "push in" exhaust pipes (straight "in" to the exhaust port holes in the head) from 72 (previously "push over" exhaust pipes ("over" spigots threaded into the head)). The modification was not well tested before, manufacturing difficulties and/or owner neglect allowed poorly fitting push in pipes to wear the head's exhaust ports out of round. The most expensive fix was to machine worn exhaust ports back to round either oversize or after welding back to size, then tapping and fitting screw-in spigots and pre-72 pipes; naturally of course there were cheaper bodges such as hammer-fit and weld-in spigots ...

The bike is most definitely negative earth. Totally redone wiring

Standard 79 wire insulation colours used apart from around the Boyer Transistor Box?

All in all a very clean bike, lots of attention to detail

... apart from the wiring around the Boyer, clearly ...

changing things from stock
can cause it’s own bit of issues

Changing things from stock is not an issue as long as you know where the non-stock parts come from - e.g. the cylinder head and carbs.

Otoh, "negative earth" is stock on a 79 Triumph, what does not help anyone, particularly you, is some lazy Richard Cranium rewiring using wire and terminals he bought in the local hardware store; complete harnesses with the correct wire colours, terminals and insulators, or separate wires in the correct colours and terminals and insulators to build a harness, are all available in the US.

my 1972 Trident

You are clearly a man of taste and discernment.

Which "Boyer"; same blue box, or red or black box?

 

[Geezer]

Not so sure where all the parts came from, the seller gave me as much info as he had. I took a couple pics of the intake and exhaust areas, maybe you can defiantly identify the head. And the Boyer on my Trident is a black box using three 6V coils.

One last question. (yea, right!). The white wire from the Boyer is attached to the neg terminal of the battery. According to wiring diagrams I’ve seen and if I understand you correctly, should I move it to the frame?

 

[solomon]

Don't think you have to worry about asking lots of questions.

The priority now for me would be checking the timing. If you get a strobe gun and the tool below it will be easy enough to check your timing is correct, the Boyer is correctly advancing.

Doing it yourself will be quicker and cheaper than going to a mechanic. And you'll have to check the timing when problems arise like this, to at least eliminate the timing as the problem. It's easy once done once.

 

[Rudie]

Not so sure where all the parts came from
maybe you can defiantly identify the head.

The head is from a Triumph twin (750 if it has two smaller fasteners between the combustion chambers, 650 if it has only one smaller fastener) made before the beginning of January 1978
The "Mk.1" Concentrics correspond to the splayed intakes.

750 twins were made from the 73 model year, 650's were made into to the 74 model year; Triumph twins imported into the US had splayed intake ports until the end of the 1977 calendar year.

The "six bolt" tappet inspection covers on the rocker boxes are 74 onwards. However, rocker adjuster threads did not become 5/16"-24 UNF thread until 79; earlier are 5/16"-26 British Standard Cycle, a 1/2" AF wrench will not fit the earlier adjuster locknuts.

Be aware of the possibility the original 79 engine's rockers, boxes, etc. have been fitted to an earlier head.

The finned inlet manifolds are aftermarket. I believe the finned exhaust pipe clamps are also aftermarket as ime the similar originally pre-72 Triumph push over pipe clamps had smaller fins.

The white wire from the Boyer is attached to the neg terminal of the battery.
if I understand you correctly, should I move it to the frame?

You have not understood me correctly ...

The supply to the ignition circuit is the Transistor Box White wire connected to the battery -ve terminal as shown in your View attachment 55026,

... (the is deliberate).

if you re-read my previous posts, I have posted the Transistor Box White wire should be connected to the battery -ve terminal

According to wiring diagrams I’ve seen
should I move it to the frame?

While all e.i. makers' wiring diagrams show "earth" or "ground" to the frame, it is dumb - the ignition circuit is from battery -ve to battery +ve so making two extra electrical connections (battery to/from the frame and Transistor Box to/from the frame) is just two extra places for the e.i. to fail.

checking the timing

While I agree and have also posted this advice, imho at this time you do not need any "Top Dead Centre Timing Tool", you just need a strobe (also likely a separate battery to power it, do not connect the strobe to the battery of the vehicle being tested) because the only things you want to check at this time are:-

. engine spinning at about 4,000 rpm, the strobe shows the fixed line on primary chaincase and the moving line on alternator rotor line up;

. engine rpm reduced from 4,000 rpm, the strobe shows the lines moving apart - means the e.i. is retarding the spark at lower rpm;

. engine rpm increased above about 4,000 rpm, the strobe shows the lines stay aligned, do not move apart again - means the e.i. full advance setting is correct.

To be clear, the only reason to have a "Top Dead Centre Timing Tool" when setting up an e.i. is to check the line on the alternator rotor lines up with the line on the primary chaincase, for final strobe timing after setup - the alternator rotor is mounted on the crankshaft, the flywheel (bolted to the crankshaft) has a 'dent' in it at 38" degrees BTDC, the pointed end of the "Top Dead Centre Timing Tool" drops into that dent, you can then check visually if the line on the alternator rotor lines up with the line on the primary chaincase (and make allowances when strobe timing if they do not). However, at this time, because you know already the engine starts and runs, even if possibly the lines do not line up on your engine, it cannot be by much; imho, do the tests with the strobe then decide if you need the "TDC Tool"?

 

[Rudie]

@Geezer

When you get the bike running, View attachment 55050 indicates several things that could need attention:-

. Amal sells a small plug (part #4/137) to seal the 'choke' cable holes in Mk.1 Concentric tops (the thread is Model Engineer 7/32"-40).

. The clutch cable is too short - out of the adjuster in the gearbox outer cover, the cable should be in line with the adjuster at least for a short distance before curving under the tank along the frame's top tube.

. Unless the bike is fitted with an aftermarket "7 plate" clutch conversion (7 pairs of drive and driven plates instead of the standard six pairs), the standard clutch springs Triumph fitted strain clutch cables; posts on other forums suggest Barnett cables are the best to resist the strain, due to their particular construction.

750 twins were made from the 73 model year, 650's were made into to the 74 model year; Triumph twins imported into the US had splayed intake ports until the end of the 1977 calendar year.

. If you look at any Triumph 750 twin parts book from 73 to 78, you will see your bike's carbs mounting is not standard. Triumph used 'stepped' studs - 5/16" o.d. through the carbs and inlet manifolds into the head, 1/4" o.d. to secure the carbs; reasons for the 'step' are two-fold:-

.. Secondarily, it allows carb securing nuts to be 7/16" AF to give more wrench clearance between nut AF and carb. body; standard nuts are also self-locking.

.. Primarily, carbs are mounted between:-

,.. a thick O ring (70-9711) between a carb and its manifold;

,,, two rubber washers (70-9554) inside steel cup washers(70-9555) between carb and securing nuts.

.. If studs are made with the 'step' in the correct relative position, the 1/4"-28 carb securing nuts plus their steel cup washers can be tightened against the 'steps' without compressing the O ring and rubber washers fully, allows them to prevent at least some of the engine vibration reaching the carb, plus the gap between carb and manifold (sealed by the thick O ring) prevents heat conducting from the head to the carb.

 

[Geezer]

So, I picked up a strobe timing light. I see many posts about not using the bikes battery, but another battery to power the timing light. Why and is it important? Checking my timing position, when the pointer is lined up with the center line on the alternator rotor, the Boyer rotor is lined up properly with the view holes in the timing plate. So far, so good I think. Tomorrow I’ll be starting the bike and checking that the Boyer advances like it should. I’ll report back once I get that finished up.

 

[solomon]

Not necessary to use a lead acid battery if you don't have a spare one. I've used a small 12v lithium power pack. Read somewhere a battery charger would work, I think, but don't know if that's true, or whether it could damage charger. Using the bike's battery can cause a false reading, apparently.

I use the TDC tool to check an ignition rotor position. Not sure it can be properly checked without one. You can't know if any scribe marks are in correct position.

But, as Rudie says, as it starts anyway, not necessary to confirm rotar position for now. It's presently either okay at idle, or retarded, most likely.

If it starts advancing, but doesn't advance enough, rotar will need slightly tweaking.

 

[Rudie]

strobe timing light. I see many posts about not using the bikes battery, but another battery to power the timing light. Why and is it important?

When I started using a timing light, they were red and could be run from the vehicle's battery. Since timing light makers switched to the brighter while light (long before there was an internet). makers' user instructions have said to use a separate battery. So I suspect it is important.

Read somewhere a battery charger would work

In this case, the timing light is to check the spark timing is set correctly (accurately) and the e.i. is working correctly. If your timing light maker's user instructions say, "use a separate battery", why would you not follow them, avoid any possibility of the timing light giving incorrect indications?

 

[solomon]

your timing light maker's user instructions say, "use a separate battery", why would you not follow them, avoid any possibility of the timing light giving incorrect indications

A charger is a separate 12v source. The strobe won't know whether it's a battery of a mains reduced voltage. My only concern would be overloading charger, although they often run several amps during a charge

 

[grandpaul]

Of all EI manufacturers, Boyers are notorious for playing up at the slightest hint of less than 12 volts. Newer model Boyer units less so.

Use of a charger may cause the timing light to draw excessive amps depending on it's internal circuitry. The charger thinks its a dead battery and flows high amps to it. Poof! Time to go to Harbor Freight for another $10 timing light.

ANY secondary 12v source will run the timing light, including your car battery parked next to the bike.

Sounds like you are close enough to get 'er done, but point a large fan at the front of the engine while testing.

 

[amer14]

So Geezer, how is it coming along ? Have you fixed the issue of the bike not hitting high revs ?

 

[Geezer]

So Geezer, how is it coming along ? Have you fixed the issue of the bike not hitting high revs ?

YES!!!! PROBLEM SOLVED!!! The timing was very retarded (kinda like me!). Set the timing, and now it revs up to and past 7000!

Thank you thank you thank you to all who gave me advice. Much appreciated.