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Discussion Starter · #1 ·
Greetings all and happy New Year.

My first ride on this bike today!.
Brilliant.......馃憤.
Only taken me 10 months to get ET up and running,馃槀.

First thing I checked after a 100km run was the plugs. I know there's a thousand images on internet but I value this forums comments. Bit black (not sooty) around the edge and tan on the top. I am running a 180 main jet.
Seems to run ok but I have never ridden an old Triumph so don't know how it should feel. Didn't expect the vibration to be so strong馃槀馃槀 but I'm guessing it's the infamous trait?. Can ride with 'comfortable' vibration at around 90kph. After that ..................well I'm sure all here know.

Have fun wherever you are,
Cheers..... Wood Gas Metal Machine Circle
 

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Hi,

Happy New Year to you too. :)

My first ride on this bike today!
(y)

plugs.
Bit black (not sooty) around the edge and tan on the top.
Looks good. However, if the fuel is effinol-laced, the colour is better-judged looking at the bottom of the centre insulator. Not easy tho' ...

Didn't expect the vibration to be so strong
Can ride with 'comfortable' vibration at around 90kph.
Mmmm ... unfortunately hard to judge without trying the bike ... :(

One factor is whether you become more 'used' to it; another could be whether stuff loosens even after you tighten it and/or whether stuff start to break ... :(

A thought is final-drive gearing? If the SA army prioritised good off-road performance, and the bike still has the same gearing, it might have a relatively-small gearbox sprocket (18 teeth?) and a relatively-large rear one. Depending whether the bike's rear wheel has 'quickly detachable' hub or not varies the available options. Can you post the number of teeth on the gearbox sprocket and a photo. of the hub taken from the right-hand side of the rear wheel, of the 'inner' side of the brake drum?

Hth.

Regards,
 

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lol

stuart, you not being american means you didnt hear all our eyebrows pop up when you said the SA army prioritized good off road performance

. . .

as in single action army
 

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Discussion Starter · #4 ·
Hi,

Happy New Year to you too. :)


(y)


Looks good. However, if the fuel is effinol-laced, the colour is better-judged looking at the bottom of the centre insulator. Not easy tho' ...


Mmmm ... unfortunately hard to judge without trying the bike ... :(

One factor is whether you become more 'used' to it; another could be whether stuff loosens even after you tighten it and/or whether stuff start to break ... :(

A thought is final-drive gearing? If the SA army prioritised good off-road performance, and the bike still has the same gearing, it might have a relatively-small gearbox sprocket (18 teeth?) and a relatively-large rear one. Depending whether the bike's rear wheel has 'quickly detachable' hub or not varies the available options. Can you post the number of teeth on the gearbox sprocket and a photo. of the hub taken from the right-hand side of the rear wheel, of the 'inner' side of the brake drum?

Hth.

Regards,
Thanks for that Stuart.
Changed to 190 main jet (from 180) and took it for a spin this morning. It ran well. I've inserted updated picture of plug after my ride!. Still can't believe it runs as well as it does after my grubby hands have messed around over the past 10 months!. The forum has played a huge part of this success so many thanks to all helpers.
Re the final drive. I had considered that the gearing (sprockets) might have been changed from standard. Best I ride it for a while before I consider different gearing.
By the way, I can't find the Drive chain FREE PLAY dimension in my manual. Do you know this measurement offhand?.

Cheers..... Wood Flooring Road surface Electric blue Asphalt
Tire Plant Fuel tank Wheel Automotive fuel system
 

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With the bike on the centre-stand, 45mm slack halfway between the sprockets.

Here is a simple gauge you can make, that makes checking the tension both quick and easy.
Push the chain upwards and rest the top end on the top of the chain. Now holding the gauge carefully in position, pull the chain downwards. If the tension is correct, the bottom of the chain, will just reach the bottom mark.
The 59mm distance allows for the thickness of the (5/8 x 3/8") chain used on your bike.

Terry

Rectangle Material property Measuring instrument Font Magenta
 

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Hi Furbrain, Love the pic of your bike in "civilian" guise. I've saved a copy of it. During my national service in the SA Army, these T100SC's were the first Triumphs that I worked on and rode. Until then, I had only experienced Jap bikes and the experience with these started a life-long affinity for Triumph. In fact, less than 4 weeks after completing my service, I went out and bought a brand new T120 Bonneville.

Terry
 

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Hi,
(y)

final drive. I had considered that the gearing (sprockets) might have been changed from standard.
Mmmm ... if the SA army :sneaky: did prioritise off-road performance, there are two "standard" possibilities:-

. The bike has specifically a wide-ratio gearbox. I've haven't ridden one so no first-hand experience but I'm told they're characterised by a noticeably-wide "jump" between 2nd and 3rd - the engine has to be revved quite high in 2nd or it bogs down when changed up to 3rd? :(

. The bike has high final-drive gearing - 18-tooth gearbox and 46-tooth rear wheel sprockets. My T100 has always had a 19-tooth gearbox sprocket; however, both @Shippy Terry and @BrianG have posted in the past 43-tooth rear works well so I've lashed out on same for mine (however, downside of having a QD rear wheel is the sprocket's part of the brake drum ... :().

Drive chain FREE PLAY dimension in my manual.
The Owner's Manuals say 3/4" off the centrestand and 1-3/4" on. In practice, I've found that too slack. (n)

Renold say a roller chain should have free play equal to its pitch at its tightest point.

The tightest point in the final-drive chain on a Triumph (most bikes) is when the centres of the gearbox sprocket, swinging arm pivot and rear wheel spindle are in a line. For clarity, I don't mean the primary drive has to be stripped to see the gearbox sprocket; the clutch adjuster plug is over the end of the gearbox mainshaft, which is concentric with the centre of the gearbox sprocket.

Standard chain is 5/8" x 3/8" so the minimum free play when the three centres are in line is 5/8". Having set that, I put the bike on its centrestand and measure the free play again, simply because checking it with the bike on the centrestand is more convenient. Again for clarity, having done this once, the "on the centrestand" measurement won't change unless you fit a different engine.

However, having set the 5/8" free play, when checking the "on the centrestand" measurement, note you won't necessarily see the Owner's Manuals 1-3/4", simply because not every bike has exactly the same relationship between engine (gearbox sprocket centre) and frame (swinging arm pivot centre); I found this true of Japanese bikes also.

Aside, for years, I went just by the manual "on the centrestand" measurement for both my T160's; nevertheless, one always needed the chain adjusting more often than the other? :confused: However, when I went through the above procedure, I established the "on the centrestand" measurement for that T160 was slightly smaller than the other one and the manual measurement; i.e. for the same years, I'd been setting that one incorrectly, 馃槚 which is why it needed the chain adjusting more often than the other one.

Fwiw, when checking chain slack, I've always just used a normal steel ruler against a fixed point near the chain - ruler under the chain, note ruler against fixed point, push chain upwards with ruler, note ruler against fixed point again; if the difference is more than 1-3/4" (or whatever's established correct for the bike), adjust chain 'til correct for the bike.

Hth.

Regards,
 

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Thanks for that Stuart.
Changed to 190 main jet (from 180) and took it for a spin this morning. It ran well. I've inserted updated picture of plug after my ride!. Still can't believe it runs as well as it does after my grubby hands have messed around over the past 10 months!. The forum has played a huge part of this success so many thanks to all helpers.
Re the final drive. I had considered that the gearing (sprockets) might have been changed from standard. Best I ride it for a while before I consider different gearing.
By the way, I can't find the Drive chain FREE PLAY dimension in my manual. Do you know this measurement offhand?.

Cheers..... View attachment 774562 View attachment 774563
That plug shows a rich condition... You need to use new or cleaned plugs for every reading and may have to ride 10 miles to color it properly
 
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Discussion Starter · #10 ·
With the bike on the centre-stand, 45mm slack halfway between the sprockets.

Here is a simple gauge you can make, that makes checking the tension both quick and easy.
Push the chain upwards and rest the top end on the top of the chain. Now holding the gauge carefully in position, pull the chain downwards. If the tension is correct, the bottom of the chain, will just reach the bottom mark.
The 59mm distance allows for the thickness of the (5/8 x 3/8") chain used on your bike.

Terry

View attachment 774564
Hi Terry,
Thankyou, your description/Photo is brilliant.
 

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Discussion Starter · #11 ·
That plug shows a rich condition... You need to use new or cleaned plugs for every reading and may have to ride 10 miles to color it properly
Hi Truckedup, thanks for reply.
Plug shown was brand new. Did at least 15miles on my test. Sedate cruising with a couple of yee haa give it some handfull moments. Its 40掳C here today (summer norm) and so will try again when it gets a bit cooler. Maybe I should try the 180 main jet again with new plugs.
I'm just so relieved that it goes at all馃槀!.
Will play, fettle and update at some point.
Cheers.......
 

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Discussion Starter · #12 ·
Hi,

(y)


Mmmm ... if the SA army :sneaky: did prioritise off-road performance, there are two "standard" possibilities:-

. The bike has specifically a wide-ratio gearbox. I've haven't ridden one so no first-hand experience but I'm told they're characterised by a noticeably-wide "jump" between 2nd and 3rd - the engine has to be revved quite high in 2nd or it bogs down when changed up to 3rd? :(

. The bike has high final-drive gearing - 18-tooth gearbox and 46-tooth rear wheel sprockets. My T100 has always had a 19-tooth gearbox sprocket; however, both @Shippy Terry and @BrianG have posted in the past 43-tooth rear works well so I've lashed out on same for mine (however, downside of having a QD rear wheel is the sprocket's part of the brake drum ... :().


The Owner's Manuals say 3/4" off the centrestand and 1-3/4" on. In practice, I've found that too slack. (n)

Renold say a roller chain should have free play equal to its pitch at its tightest point.

The tightest point in the final-drive chain on a Triumph (most bikes) is when the centres of the gearbox sprocket, swinging arm pivot and rear wheel spindle are in a line. For clarity, I don't mean the primary drive has to be stripped to see the gearbox sprocket; the clutch adjuster plug is over the end of the gearbox mainshaft, which is concentric with the centre of the gearbox sprocket.

Standard chain is 5/8" x 3/8" so the minimum free play when the three centres are in line is 5/8". Having set that, I put the bike on its centrestand and measure the free play again, simply because checking it with the bike on the centrestand is more convenient. Again for clarity, having done this once, the "on the centrestand" measurement won't change unless you fit a different engine.

However, having set the 5/8" free play, when checking the "on the centrestand" measurement, note you won't necessarily see the Owner's Manuals 1-3/4", simply because not every bike has exactly the same relationship between engine (gearbox sprocket centre) and frame (swinging arm pivot centre); I found this true of Japanese bikes also.

Aside, for years, I went just by the manual "on the centrestand" measurement for both my T160's; nevertheless, one always needed the chain adjusting more often than the other? :confused: However, when I went through the above procedure, I established the "on the centrestand" measurement for that T160 was slightly smaller than the other one and the manual measurement; i.e. for the same years, I'd been setting that one incorrectly, 馃槚 which is why it needed the chain adjusting more often than the other one.

Fwiw, when checking chain slack, I've always just used a normal steel ruler against a fixed point near the chain - ruler under the chain, note ruler against fixed point, push chain upwards with ruler, note ruler against fixed point again; if the difference is more than 1-3/4" (or whatever's established correct for the bike), adjust chain 'til correct for the bike.

Hth.

Regards,
Ok,.......so I've got a 46 Rear sprocket and 18 front. I don't notice a huge difference between 2nd and 3rd gear but will see next time I go out. I must admit that going down 3 teeth on rear would probably work well. I pulled 135kph in top and on the flat. She didnt have much more to give than that!. Thats 84mph in old money. Doubt the speedo is accurate but seems a reasonable turn of speed???????.
I won't bother with different sprockets until the chain needs renewing.

Happy days are here again馃幎............
 

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Hi,
original petrol tank?. Looks different to other triumphs. Maybe they used this one for the army only.
Uh-uh, yours is a T100C so has the C-range "2 (British) gallon" tank; if Terry's is 'UK & General Export' spec, it has a "3 gallon" tank. Also, yours is a '66, Terry's is a '72; major frame and other cycle parts changes from '67.

Hth.

Regards,
 

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Hi Truckedup, thanks for reply.
Plug shown was brand new. Did at least 15miles on my test. Sedate cruising with a couple of yee haa give it some handfull moments. Its 40掳C here today (summer norm) and so will try again when it gets a bit cooler. Maybe I should try the 180 main jet again with new plugs.
I'm just so relieved that it goes at all馃槀!.
Will play, fettle and update at some point.
Cheers.......
Sedate cruising would mean the fuel mixture is controlled thicker part of the needle and possibly the pilot and throttle cutaway .Perhaps drop the needle one notch.. So long as the bike responds cleanly to moderate throttle changes it's not too lean at sedate cruising speeds. On the plugs also pay attention to the black carbon on the lower plug shell threads..Your plugs show a bit too much in my opinion
 

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Discussion Starter · #16 ·
Sedate cruising would mean the fuel mixture is controlled thicker part of the needle and possibly the pilot and throttle cutaway .Perhaps drop the needle one notch.. So long as the bike responds cleanly to moderate throttle changes it's not too lean at sedate cruising speeds. On the plugs also pay attention to the black carbon on the lower plug shell threads..Your plugs show a bit too much in my opinion
馃憤. Do you think I should go back to a 180 main jet also, or is that defeating the object of lowering the needle?.
 

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Your plugs look fine.. I always jet and set up the carbs via the service manual and go from there.. Very seldom do i have to change anything unless major mods have been done to the engine.
 

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Discussion Starter · #18 ·
Hi

Your plugs look fine.. I always jet and set up the carbs via the service manual and go from there.. Very seldom do i have to change anything unless major mods have been done to the engine.
Manual says 190 so I'll keep it there for now. Needle and housing are brand new.
 
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