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The original post did ask of any improvements so i doubt the owner will want to detune a nicely tuned T120. I have a lot of improvements on my 1971 bike that actually work very well. Nothing too radical but where i can, i improve suspension, seat comfort, tyres, and the 750 kit for a little extra power for a lot of pillion riding. 20 tooth drive sprocket instead of the 19 to lower revs a little. A Renolds chain which resists wear very well and a top quality rear chain. I sealed the drain plug on the primary and adjust the chain by removing the primary cover. I have notched the adjuster so it can be turned with a spanner.
The 71 bike has the frame too close to get a primary chain adjusting tool into the hole.
Lighting works fine with standard single phase alternator. I gain a little capacity back by using an LED rear light and removing the lamps in the dials. I use a 45 watt halogen lamp.
I fit two warning lights for the indicators so i can see if the left or right is on. These lamps are orange LED at 9 watt which is blinding light and hard not to notice if you forget to cancel.
Boyer works well until it fails one day. I have bought 3 in total over 22 years, one failed this week.
I have a podtronic unit which has been on for about 10 years and always works.
I have added a fuse to the + side and also wired in some spare fuses and holders for a quick change over if a fuse fails.
I also wired in a system which will allow the bike to run with all other circuits disconnected if a wiring fault happens when out on the road.
Michelin tubes have been the best at keeping air in for longer. The Continental tubes needed air every 3 weeks.
Remove the rubbers on the handlebars that allow the P clips to wobble about.
I do have a 4 valve oil pump but that requires some grinding of the cover to get clearance for the larger pump.
Stainless allen screws for all the engine covers.
External oil filter using a £6 filter.

I have made a fuel manifold to allow equal fuel to each carb rather than fuel going to one carb and then on to the other. Not really needed but it tidied it up.
Premier carbs because the originals wear out rapidly.
Clutch is standard 6 plate with cheap plates and never sticks or clonky noisy first gear engagement. Just start up,put in gear and go. No freeing up is ever needed.
I regularly run at 6000 rpm and over 80 mph for short periods. 6000 rpm indicates about 90 mph but that engine speed seems to shake bits off or fracture mudguards if done to long.
 

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Discussion Starter #22
Thank you so much Don really appreciate your knowledge with the Triumph. Just a thing the torque setting of 22LBS and not 28 LBS thats definitely for a 71 Triumph as all the literature says 28.
Thanks again
Hi Don,
Wow that is indeed what it says. Thank you for the heads up. Have ordered new nuts today so 22 it is.
Thank you for your time on this Don
 

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Discussion Starter #23
Hi Atickus, A few questions. How did the bike work before tear down? Did you have chance to put some hundreds or thousands of miles on it?
How do you feel it worked?
Did vibration feel worse that others or do you know?
How did clutch work for you?
How did trans work for you?
Did it idle well at stop lights after 20-30 miles of riding?
Do you feel power is good enough for you?

I used to think I could build a Triumph that would last a really long time & be able to ride it fast hour after hour. I no longer think that's possible. It is what it is. They can last well with gentle riding 30K+. Clutch parts are not long life items no matter. They cush hub steel parts wear, the basket & hub groove. Plates last ok for the most part.

The best thing is careful assembly. Flat surfaces, correct piston clearance. Correct hone. Use break in oil. Use best oil you can find with high zinc. Install real oil filter. Depending on your frame #, in frame, spin on, Trident cartridge type. All 3 work equally good. Morgo oil piston oil pump really is best on market right now. It has a little larger pistons & more desirable feed port position & quality control. I feel they are worth the cost should you need pump. Make sure driving block for pump is not worn.

Get quality parts. NOT EASY to do. Try to avoid Wassell. LF Harris is decent for the most part, but carefully quality control all parts you buy. Use only Viton O-rings through out. Silicon white lower push rod tube seals. Use covseal rocker box gaskets. Be very thoughtful on sealants you use. Emgo pistons seem good as does Harris. Rings is open to much debate. Good hone, break in oil, is key to a good start. Morgo sells break in oil.

If your carb is worn, don't mess around, it will never work right. Get new Amal Premier. Make sure it has .019 pilot jet, not .017 like original.

Good machine shop work you can't do yourself is very important. Ask around. Drive a few hundred miles or more for good shop as needed. It is worth it!!

Genuine New Old Stock Triumph is best parts you can buy. However.... Be careful. Much (most??) NOS is actually old stock Harris or something else aftermarket. In USA almost all true NOS is long gone. Ebay is full of NOS, but it's aftermarket parts not genuine. My #1 problem is getting good parts that fit properly. Hate to say it, but the parts quality is going to kill this hobby.

Your 650 is a solid motor. Well assembled they work very good.

Charging system is marginal from new. Using modern bright headlight is impossible with old 2 wire alternator.
High output 3 phase & electronic regulator/rectifier allows modern lighting options.

However if you don't ride at night or don't care about seeing well in dark it works fine. Fitting 16LED bulb is an improvement in every way for $35US. Old rectifier & Zener diode work fine so long as they are working properly.

Points ignition works fine if you don't mind maintaining points. Modern electronic ignition works good so long as charging system, battery are working properly. Electronics have improved timing curve which reduces ping also.

You must have all needed special tools & torque wrenches. Use Loctite of appropriate type on flywheel bolt, crank pinion nut, clutch nut, alternator nut, kick start pinion nut. Watch the lock tabs on alternator & kick start lock washers that they actually engage spline or keyway. Bend tab as needed. Bend both tabs on kick start pinion nut.

If you want a daily rider & not a hot rod, consider LF Harris 7.1 pistons. Avoid high performance cams, oversized carbs. Always use a real air filter such as stock one, or the earlier Bonnie type if you go retro. With wire/gauze elements. If you want a hot rod I can't help you. I don't build those.

In the end of the day, perfect assembly, correct fitting of parts is key to good motor. The entire motorcycle must have this in mind in everyway. Then it will be best it can be. The devil is in the details. One short cut will bite you. These bikes are not forgiving if you want long life & reliability.
Don
Thank you so much for this information > I am printing it of and putting it in my garage . Brilliant...
 

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I think i am wasting my effort on this so passing it.
Hi Rambo,
It certainly was not wasted on me, I took every word on board.
Especially the lower compression ration to 8.5 :1 then increasing the CC’s to bring the torque up again.
The best of both worlds trialed for 12 years.

I will be insisting on Michelin tubes from now on, thanks for the tip.

Regards
Peg





You can lead a horse to water, but you can’t make it set your ignition timing correctly!
 

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I'll try to repeat this result with a special BSA I'm building currently from parts.
I sold former BSA in Thunderbolt trim, but this very special cylinder head stayed with me together with 2 carb 4 gallon tank and side covers. :)
This time it will have 9 : 1 comp pistons.
 

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The original post did ask of any improvements so i doubt the owner will want to detune a nicely tuned T120. I have a lot of improvements on my 1971 bike that actually work very well. Nothing too radical but where i can, i improve suspension, seat comfort, tyres, and the 750 kit for a little extra power for a lot of pillion riding. 20 tooth drive sprocket instead of the 19 to lower revs a little. A Renolds chain which resists wear very well and a top quality rear chain. I sealed the drain plug on the primary and adjust the chain by removing the primary cover. I have notched the adjuster so it can be turned with a spanner.
The 71 bike has the frame too close to get a primary chain adjusting tool into the hole.
Lighting works fine with standard single phase alternator. I gain a little capacity back by using an LED rear light and removing the lamps in the dials. I use a 45 watt halogen lamp.
I fit two warning lights for the indicators so i can see if the left or right is on. These lamps are orange LED at 9 watt which is blinding light and hard not to notice if you forget to cancel.
Boyer works well until it fails one day. I have bought 3 in total over 22 years, one failed this week.
I have a podtronic unit which has been on for about 10 years and always works.
I have added a fuse to the + side and also wired in some spare fuses and holders for a quick change over if a fuse fails.
I also wired in a system which will allow the bike to run with all other circuits disconnected if a wiring fault happens when out on the road.
Michelin tubes have been the best at keeping air in for longer. The Continental tubes needed air every 3 weeks.
Remove the rubbers on the handlebars that allow the P clips to wobble about.
I do have a 4 valve oil pump but that requires some grinding of the cover to get clearance for the larger pump.
Stainless allen screws for all the engine covers.
External oil filter using a £6 filter.

I have made a fuel manifold to allow equal fuel to each carb rather than fuel going to one carb and then on to the other. Not really needed but it tidied it up.
Premier carbs because the originals wear out rapidly.
Clutch is standard 6 plate with cheap plates and never sticks or clonky noisy first gear engagement. Just start up,put in gear and go. No freeing up is ever needed.
I regularly run at 6000 rpm and over 80 mph for short periods. 6000 rpm indicates about 90 mph but that engine speed seems to shake bits off or fracture mudguards if done to long.
You can get to the primary chain adjuster in the '71 but you need to make a tool. I took a 1/4"' short extension and ground a flat screw driver tip on it just long enough to where the female end was almost completely in the plug opening. that way it clears the frame and you can get it into the hole. Then i snaped a 1/4" flex joint into it and a longer 1/4" extension into that. the whole thing lets you get past the frame member and use a 1/4" ratchet or whatever to turn the adjuster.
By the way this thread had been a joy to read. Kept my TR6C pretty stock and in 120K miles, only did one bottom and three(one during the bottom end) rebuilds in the 120K miles i had on it. bought it in 1973 with 3K mile on it and rode it till i got out of riding 5 years ago with a 5 or so years break while it sat needing work and the tires rotted till the wife said ride it or sell it. so i got it back on the road for another 10 good years ....
 

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Hi Rambo,
It certainly was not wasted on me, I took every word on board.
Especially the lower compression ration to 8.5 :1 then increasing the CC’s to bring the torque up again.
The best of both worlds trialed for 12 years.

I will be insisting on Michelin tubes from now on, thanks for the tip.

Regards
Peg





You can lead a horse to water, but you can’t make it set your ignition timing correctly!
Hi Peg, the pistons on the 750 have a machined edge around the crown which i am told is the squish band. It keeps the top edge down a little from the cylinder head.
Michelin tubes have been excellent. The last 10 years i have had tubes that lose air. Some of the cheap tubes lost a little but the Continental lost the most. I check them after any lay up of 3 weeks anyway and adjust. More expensive but pay off in not having to pump up every outing. I use an auto stop battery pump now. Just set poundage and it stops when up to the set level. Accurate to around a pound.
 

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Hi Peg, the pistons on the 750 have a machined edge around the crown which i am told is the squish band. It keeps the top edge down a little from the cylinder head
In stock form the 750 squish band is about .065 ,too much distance to be effective. With a 3 inch bore and the narrow squish band .035 is needed
 

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Discussion Starter #30
You can get to the primary chain adjuster in the '71 but you need to make a tool. I took a 1/4"' short extension and ground a flat screw driver tip on it just long enough to where the female end was almost completely in the plug opening. that way it clears the frame and you can get it into the hole. Then i snaped a 1/4" flex joint into it and a longer 1/4" extension into that. the whole thing lets you get past the frame member and use a 1/4" ratchet or whatever to turn the adjuster.
By the way this thread had been a joy to read. Kept my TR6C pretty stock and in 120K miles, only did one bottom and three(one during the bottom end) rebuilds in the 120K miles i had on it. bought it in 1973 with 3K mile on it and rode it till i got out of riding 5 years ago with a 5 or so years break while it sat needing work and the tires rotted till the wife said ride it or sell it. so i got it back on the road for another 10 good years ....
Thank you so much for this really good insight as to what i need to be doing. For someone like myself, a first time engine re builder this is absolute gold dust . Thanks very much..
 

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Discussion Starter #31
The original post did ask of any improvements so i doubt the owner will want to detune a nicely tuned T120. I have a lot of improvements on my 1971 bike that actually work very well. Nothing too radical but where i can, i improve suspension, seat comfort, tyres, and the 750 kit for a little extra power for a lot of pillion riding. 20 tooth drive sprocket instead of the 19 to lower revs a little. A Renolds chain which resists wear very well and a top quality rear chain. I sealed the drain plug on the primary and adjust the chain by removing the primary cover. I have notched the adjuster so it can be turned with a spanner.
The 71 bike has the frame too close to get a primary chain adjusting tool into the hole.
Lighting works fine with standard single phase alternator. I gain a little capacity back by using an LED rear light and removing the lamps in the dials. I use a 45 watt halogen lamp.
I fit two warning lights for the indicators so i can see if the left or right is on. These lamps are orange LED at 9 watt which is blinding light and hard not to notice if you forget to cancel.
Boyer works well until it fails one day. I have bought 3 in total over 22 years, one failed this week.
I have a podtronic unit which has been on for about 10 years and always works.
I have added a fuse to the + side and also wired in some spare fuses and holders for a quick change over if a fuse fails.
I also wired in a system which will allow the bike to run with all other circuits disconnected if a wiring fault happens when out on the road.
Michelin tubes have been the best at keeping air in for longer. The Continental tubes needed air every 3 weeks.
Remove the rubbers on the handlebars that allow the P clips to wobble about.
I do have a 4 valve oil pump but that requires some grinding of the cover to get clearance for the larger pump.
Stainless allen screws for all the engine covers.
External oil filter using a £6 filter.

I have made a fuel manifold to allow equal fuel to each carb rather than fuel going to one carb and then on to the other. Not really needed but it tidied it up.
Premier carbs because the originals wear out rapidly.
Clutch is standard 6 plate with cheap plates and never sticks or clonky noisy first gear engagement. Just start up,put in gear and go. No freeing up is ever needed.
I regularly run at 6000 rpm and over 80 mph for short periods. 6000 rpm indicates about 90 mph but that engine speed seems to shake bits off or fracture mudguards if done to long.
Thank you so much . This is such good information i really can't thank you enough. Absolute gold dust, as i have not done an engine rebuild before.
Many thanks
 
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