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Discussion Starter #1
Has anyone tried the bipolar LED head bulb that is a straight swap from the stock bulb on a positive ground bike like my 77 Bonny ? I think Steadfast and Bonneville shop both sell them, very pricey at around $40 but worth it if it is a decent light and decreases the draw on my charging system too.
 

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Think I can assist?

 

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LED's are very good for seeing also. They come standard on most cars now a days. Problem is, they do not work well without a matching reflector/headlight assembly.
 

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Hi,

LED head bulb that is a straight swap from the stock bulb on a positive ground bike like my 77 Bonny ? I think Steadfast and Bonneville shop both sell them,
Just as a matter of interest, are you sure they'll be a straight swap specifically on your bike?

Reason I ask is @KADUTZ posted a while back it was during '77 Lucas and Triumph finally changed from BPF to P45t bulbs and lens/reflectors on US-market bikes. I couldn't find a LED headlamp bulb on Steadfast's site but the one on TBS's site is the latest BPF-base one also sold by CBS. Otoh, afaict none of the Triumph bits sellers have P45t-base LED bulbs, although they are available on the wider www.

Hth.

Regards,
 

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Has anyone tried the bipolar LED head bulb that is a straight swap from the stock bulb on a positive ground bike like my 77 Bonny ?
If you mean the LED headlight bulb pictured then yes I’ve tried the swap. Probably for the reason march1970 states there isn’t much difference in the spread of the light between the two, arguably the incandescent lamp is better. The LED provides whiter light but I can’t say it helped on my night riding trial (I won’t be repeating that anytime soon).

The big advantages of the LED lamp are that it’s far more visible to other road users during daylight and it gives the charging system a fighting chance of keeping up if your headlamp is on all the time.

A small downside on my bike at least (1972 T100R) is that I have to disconnect the high beam warning lamp to get high and low beam working at the headlight. With the warning lamp connected the LED only provides high beam, it flickers when I switch to low but immediately reverts to high.
715929
715931
715930
 

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Discussion Starter #8
I may have changed the socket for the headlight bulb already, to one that fits a car H4 bulb. So I may have to switch that back. The rest of the headlight is stock. I don’t ride at night with this bike other than by accident. I’m just trying to take the draw off the electrical system and still have a serviceable headlight.
 

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Hi,

may have changed the socket for the headlight bulb already, to one that fits a car H4 bulb.
The rest of the headlight is stock.
You might want to actually remove the headlamp from the bike and take a look at what it is now, because these two statements don't make a great deal of sense:-

. "H4" is the 3-spade plug:-

.. It was used with the P45t bulb and lens/reflector Triumph started fitting to US-market bikes during '77. It was also used with the sealed-beam headlamps Triumph fitted in the 1980's.

.. It can be used with a current standard automotive twin-filament headlamp bulb, P43t base.

.. It can be used with a version of the BPF bulb, but that particular bulb-plug combination cannot be used in any lens/reflector Lucas supplied to Triumph ...

... i.e. if the bike has an H4 plug, I can't see how the existing headlamp can take any of the LED bulbs you're asking about? :confused:

Regards,
 

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Good Afternoon and Happy New Year Stuart.

The 1976 parts book (99-2257 from engine 62501) published February 1976 lists a harness #54961593 using a #370 bulb. Note these are the same pieces/part numbers listed in the 1973/1974 parts books. The usage of these items for 1976 would appear to be practical as it is safe to assume a supply of #54961593 would be on hand from the beginning of the embargo. When production restarted they could be utilized as the machines were really the same EXCEPT for the new rear disc brake and D/S shifter T/S brake lever location. The same brake switch was used and location was similar but on the other side of the machine.

In August of 1976 there was an updated parts book issued #99-2557(REVISED AUGUST 1976) and on the cover it states for 1976-1977. Note this parts book doesn't reference a starting engine which is unusual for Triumph. The wiring harness is listed as #54962258 again with a #370 headlamp bub. The bulb is incorrectly listed and should have been shown as a #410. The 1978 parts book (99-7003) list the same harness #54962258A with a #410 bulb. One of the differences between 54961593 and 54962258 is the headlamp bulb connection. You cannot use a 370 bulb with the latter harness. Also note in the revised parts book the new UK tank is introduced. This is the tank where the fuel petcock location was moved forward to allow better tank drainage. UK Silver Jubilee's
used this tank also and the 410 bulbs. The original Supplement parts listing for the Jubilee listed no changes for electrical parts from the Revised 99-2557also later factory parts books for 1978 T140V/TR7V included a listing of all Jubilee parts.

Just my opinion If I had a 76 model I would use the earlier parts book and the revised on for a 77 model

K
 

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Hi duc69cr, Without knowing exactly what bulb you are currently using we don't know. Can you post photo of your current bulb?

Regarding electrical consumption without question LED can help. However if you have any faults in charging system a LED cannot overcome that.

The effective night vision of LED will depend up the LED you purchase & your reflector/lens version. If you could photo backside of reflector & straight on front of lens I'll give my thoughts. I have a lot of experience with the BPF LED in many real life miles day & night on 3 bikes now. Most find the LED better at night also.

Regarding the flickering & no difference between high/low beam. The high beam indicator is feeding back a signal so both beams are on at same time even though switch is on low beam. Disconnecting indicator wire will cure that. Of course you'll not have indicator. Installing diode in indicator wire might fix it & still allow the indicator to work. I haven't tried that yet.
So if possible post the photos & we'll go form there,
Don
 

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Hi duc96cr, Ok, after reading your post in "what I did with bike today" I get what this is about. Refresh my memory, where in USA do you live? Can you ride bike this time of year for an hour or more?

To be clear, you have '77 T140V Bonneville?

Fixing your idle problem is a process, not a crap shoot. Voltage is very important. NO GUESSWORK!! You must have voltmeter that can read volts with motor running. The Harbor Freight cheapie cannot do that. If you don't have a volt meter you must get one.

How many wires come out of your thick black alternator wire? 2 or 3?

I want you to disconnect your battery & charge it for several hours. Let battery sit idle for overnight. Then test voltage of battery. What is voltage? Record voltage to hundredths if possible. ie: 12.67v

Reconnect battery. With your old tail bulb back in & your old incandescent head light back in I want you to start bike. If possible ride it at least 5 miles to warm motor. If not ridable, put fan in front of motor & run it for 3-5 min, blipping throttle as needed to keep it running. Now hook up volt meter. Head light OFF test voltage, ilde, 3000, 4000, 5000 rpm. only need to hold 5k rpm for a moment, just long enough for meter to stabilize. Record those voltages. Again to hundredths.

Now turn on headlight & do same voltage tests, idle, 3000, 4000, 5000. Record those voltages.

Don't worry about what it is, just record what meter reads. Post your readings & we'll go from there.

What ignition system are you using?
Have you recently adjusted valves?
Have you checked ignition timing?
Is the hot compression good?
Are the spark plugs good?
Are there any intake manifold, carb to manifold, crossover manifold hose leaks? Meaning air leaks into intake.
Are the air filters good?
Is there clogging in mufflers? (this is a tough one to test with removing mufflers).
As we will soon learn is the voltage good.

After we know these things we'll get into coil voltage, ignition system volts etc.
All these are prerequisites to good carb operation.

Exactly what carbs are you using? Original Amal concentric from new? New concentric? New Premier concentric?

What air filters are you using? Very important.
What exhaust & mufflers are you using.

I can promise you when all problems are solved the bike will run perfectly & idle perfectly. It really will. It will start perfectly also.. I do about 100 mile ride a week. Occasional 3-400 mile rides. In city, freeway, mountains up to 8000', sea level. I know what these bikes do in real life. I know what the original charging system does in real life in these conditions. I'm learning more all the time. The more I learn, the more find I don't know, but I know these bikes can run perfectly. I mean so good you can't believe it.
Don
 

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Discussion Starter #16
Thanks to all for the detailed help. I will go through it all inch by inch when I return to Michigan. It’s cold and snowy, no riding the bike, it’s in the basement. I’m leaving the state tomorrow until it warms up. When it gets too cold to ride I do my maintenance and modification for the coming year. The bike is a ‘77 Bonny with original concentrics. It runs real well and starts pretty well. The only fault it has ever had is stalling at lights when it’s really hot. The electrical system is stock other than the just installed Podtronics unit, and as I mentioned, I seem to remember that there was an automotive headlight bulb installed. The headlight plug was burned and I replaced it with one from the parts store. My memory is not good on this, as I’ve had two T140’s and sometimes forget which bike I did something to.
So, I’m upgrading my electrical system with the Podtronics and LED bulbs. The bike always starts and runs, even through a long day of multiple starts, so I know it’s generating electricity. This is a planned upgrade that did not require deep analysis into the electrical output. I may buy some new Premiers when I return, unless my upgrades have improved the stalling in traffic. The carbs we’re getting very hot, so maybe the carb insulators will help. I had the valve clearance too tight (T120 specs) so have those adjusted to the correct looser spec, and that may also have been a contributing factor in the stalling. Points ignition, by the way.
 

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Hi duc96cr,

Points are not very sensitive to low volts, but if blinkers go very slow you are low & it will start to effect even points. I know that from personal experience. Turning off headlight if incandescent will help in this case. That is also a sign of low volts.

I have observed on my own bike and a few other worn carb slide/bore will cause stalling at idle, especially with heat soaked motor. A test for this is heat soak motor by riding 30 miles or more. Let motor idle about 1.5 -2 minutes. Very slowly open throttle bike in neutral only a tiny amount. I mean slowly & raise slide only like .005". If motor dies or tries to die that is bad. On same test open throttle normal speed to pass this point. If motor does not die, that indicates wear test is valid. If motor still dies you could have other problems. As wear increases the motor will die while rolling on throttle slowly. Feels like a flat spot, but momentum keeps motor running. Slow traffic pulling up to stop lights this can be felt. Sometimes will die. You can learn to blip throttle to keep if from dying at standstill & more quickly give throttle & extra rpm on take off. I had to do this for some months while Premiers were on back order. When you get new carbs verify slide & jet sizes before purchase. YOU MUST have .019 pilot jets with premiere. The normal size of .017 that old carbs had is wrong for premier. Sellers sell what they have. You must have them verify you get what you want!!
Don
 

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Hi,

‘77 Bonny
electrical system is stock other than the just installed Podtronics
seem to remember that there was an automotive headlight bulb installed. The headlight plug was burned and I replaced it with one from the parts store.
Imho, when you actually get to remove and look at your bike's headlamp bulb, reflector and electrical connection:-

. It's sounding less and less likely your bike has a BPF headlamp bulb - pictured by @Rusty1 in post #7 and you've seen sold by TBS, CBS, etc.; these are all the same LED headlamp bulb.

. Otoh, it's sounding more and more likely you'll find a P45t bulb:-

.. P45t was the international automotive standard in 1977, Triumph had been using it already for several years on bikes certainly for European continental countries, that was another reason they finally started fitting it to US-market and right-hand-drive-market (GB, Aus, NZ, SA, etc.) bikes.

.. P45t electrical connection is "H4" - three spade terminals arranged as if around three sides of a square - more likely you were able to "replace it with one from the parts store".

upgrading my electrical system with
LED bulbs.
IF the existing headlamp bulb and reflector on your bike are P45t:-

. none of the LED headlamp bulbs pictured by @Rusty1 in post #7 and sold by TBS, CBS, etc. are direct replacements;

. nor are the specific Philips Lumileds linked by @Transgarp in post #9 a direct replacement;

. they aren't direct replacements because none have the same bulb base - to fit in the headlamp reflector;

. LED headlamp bulbs specifically with a P45t base are available; however, I don't know of any that are "positive ground" or "ground"-independent;

. nevertheless, absent knowing the specific headlamp bulb type on your bike, further speculation is pointless.

carbs we’re getting very hot, so maybe the carb insulators will help.
750 twins never had "carb insulators" (a spacer made of phenolic resin); there isn't space to fit them.

On 750 twins, the "insulator" is the gap between carb. and manifold that should be visible even when the carb. securing nuts are tight. The standard 'stepped' studs (5/16" OD through the manifold and carb., 1/4"OD for the carb. securing nuts), cup and rubber washers should not press the carb. against the manifold even when the nuts are tight. The gap between carb. and manifold should be sealed by a thick O-ring, correctly-numbered "70-9711" in the parts book.

What isn't correct in the parts book is the "622/101" in the "Makers Part No." column; that's the Amal part number for a much thinner O-ring, used to seal between carbs. and manifolds on triples and C-range (unit 500 and 350). Be aware this error isn't known by many parts vendors, who supply the thin O-ring even when specifically 70-9711 is ordered. :(

Hth.

Regards,
 

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Hi K, :)

Happy New Year to you too. (y) Apologies we haven't had our usual state-of-the-nation conversation but C&NY was more hectic than usual here (I'd have added more frequent-flyer miles if Easyjet did 'em ...).

The 1976 parts book (99-2257 from engine 62501) published February 1976 lists a harness #54961593 using a #370 bulb. Note these are the same pieces/part numbers listed in the 1973/1974 parts books. The usage of these items for 1976 would appear to be practical as it is safe to assume a supply of #54961593 would be on hand from the beginning of the embargo. When production restarted they could be utilized as the machines were really the same
Uh-uh. Bear in mind (HN)62501 simply restarted the production of FMVSS-compliant bikes that could be exported to the US; the immediately-preceding DK61000 to EK or GK62239 couldn't because they didn't comply certainly with the '75 FMVSS foot-shift-rear-brake and kill switch mandates. Insofar as modern images of 35-year-old bikes can be relied upon, "K"-year-code twins used '73/'74 electrical and other parts.

Bikes made after 1st January 1975 for export to the US simply couldn't use harness #54961593 if it was "the same pieces/part numbers listed in the 1973/1974 parts books"; the handlebar switch clusters have to be different because the kill switch has to be a proper on-off, the 1973/1974 button isn't FMVSS-compliant '75-on. In fact, the February 1976 book illustrates/lists the new left-hand switch cluster but the 1973/1974 right-hand switch cluster, which is impossible in practice because some switch functions would be duplicated while others (including any kill switch) would be missing. It's the August 1976 book that lists the right-hand switch cluster that must've been fitted to any FMVSS-compliant bike '75-on.

Also, the later switch clusters connect to the main harness with AMP plugs, the earlier switch clusters connect with bullets and snap connectors.

In August of 1976 there was an updated parts book issued #99-2557(REVISED AUGUST 1976) and on the cover it states for 1976-1977. Note this parts book doesn't reference a starting engine
:) Your copy might not but the one on the Kim The CD Man CD does - "62501" again.

The wiring harness is listed as #54962258 again with a #370 headlamp bub. The bulb is incorrectly listed and should have been shown as a #410. The 1978 parts book (99-7003) list the same harness #54962258A with a #410 bulb. One of the differences between 54961593 and 54962258 is the headlamp bulb connection. You cannot use a 370 bulb with the latter harness.
With respect, this is an incorrect interpretation. The actual headlamp connection is irrelevant to the main harness, because the relevant main harness wires terminate with bullets; the wires out of 370 (BPF) bulb plugs or 410 (P45t) bulb plugs also terminate with bullets; so it's simply a matter of attaching the desired plug to the main harness with snap connectors.

If I had a 76 model I would use the earlier parts book and the revised on for a 77 model
Imho, no. The error count in the February 1976 book is high even by Meriden's usual low standards, proof-reading must've been done by the newest Co-op employee with the least experience of Triumphs ... The August 1976 book says "Revised ..." for good reason ime.

Hth.

Regards,
 
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