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Hi, So I've nearly reached the total the end of my strip down of my 71 T120 right down to separating the crank cases,sludge trap etc.I know nothing of possible improvements and must do's on the re-build. Any chance of some definitely do this pointers please. Thanks
 

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Never had my cases apart, but there is a series of u-tube videos, from Lowbrow Customs, that features all of the segments to a major rebuild. Likely worth a look, just to watch it happen.
 

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Get an Aerco 750 kit. Just a bolt on and no need to rebalance the crank. You will find a lot more pulling away power. Fit a 20 tooth engine sprocket. Use 200 main jets in the carbs.I tend to keep the tappet adjustment a little bigger than the 2 and 4 thou in the manual.
If you have ridden it as a 650, the 750 kit will really surprise you. I would never run mine as a 650 again after about 12 years with this kit. It uses standard T140 rings when they wear out. About £340 for the cylinders, pistons and head gasket. Also has the benefit of much thicker gudgeon pins although i cannot see why the metal needs to be thicker than standard.
Before you think about taking cams out, check to see if the cam bearings really need changing as i have never needed to replace mine.
 

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If you can find someone to balance the rotating assembly it does smooth the vibration.
I always polish the valves and smooth the ports to reduce carbon build up.
A seven plate clutch conversion and electronic ignition is nice.
 

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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
 

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Discussion Starter #8
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
Don,
Thank you so much for this information > This is exactly what i was looking for>
Im going to print this out and put it in my garage.
Thanks again i really appreciate you time .
 

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Discussion Starter #9
Don,
Thank you so much for this information > This is exactly what i was looking for>
Im going to print this out and put it in my garage.
Thanks again i really appreciate you time .
Don,
Thank you so much for this information > This is exactly what i was looking for>
Im going to print this out and put it in my garage.
Thanks again i really appreciate you time .
One more thing Don ...... Do i need to change the nuts and bolts which hold big ends together..(con rod)
 

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Hi Atickus, If the rods, bolts look good I reuse bolts. Always new lock nuts for rods. I use blue Loctite on rod nuts also. Makes me sleep better. As TT said new bolts must be good quality. ARP are known high quality.

Mark your rod caps so they go back same way on rod. Take lots of crisp detailed photos so you have a detailed record of how things were.

Your bike would have come with the newer version necked rod bolts. The torque is 22#. Early bolts were higher. I've had a hard time measuring bolt stretch & get repeatable results. So I just use torque wrench. I have 2 torque wrenches. A smaller one for lower torques & a large one for larger torques. Often a 150# torque wrench is not accurate at 22#.

Sometimes bolts are hard to remove from rod, sometimes they push right out.

It's important to inspect rods for loose small end bushing. Generally it is obvious, but push hard with thumb & see if they move at all. Look close & see if you see signs of spinning in rod. It is poor practice to replace small end bushings in rods. My friend did & rod when through case or right side. Matching #s bike. Found a donner right case. Line bored & milled top. Very costly. We want to avoid that at all costs!

Even simple things like big end bearings are a crap shoot. If you have micrometers & bore gauge you can check big end clearance by direct measurement. However most don't have that. I recommend using plastigauge to check clearance. For this test use plain nuts & torque to spec. Then use new nuts & Loctite on final assembly. YouTube plastigauge for instructions. I was not too keen on the new Hepolite brand bearing shells. I think they run larger clearance. Who knows who makes Hepolite parts?? Some say Clevite, or Glacier/Vandervell is better. Also depends on what you can get in your area.

Cleaning sludge trap is tricky & simple at same time. Try to save & reuse old parts if possible as new tubes & plugs often don't fit the same. It is most important to heat crank at flywheel bolt area till spit boils to release Loctite or bolt will break on removal. Heat gun or propane torch. This bolt is often BS (Whitworth) head. Then bolt comes out easy.

The plug is easy to remove if you do it right. Drill the center punch with 1/8" drill. Grind a drag link socket to a perfect fit to the plug. Heat crank/plug until spit boils. If possible use impact gun set on about medium. 1/2" drive ratchet handle does work. Put all your weight onto socket to keep it in slot. If you fit slot perfectly with tool & slot is not already damaged it will come out.

Removing sludge trap without damage is very easy. But... you must make puller. Well worth the effort. With plug out use drill bit by hand to drill out sludge as needed. Gasoline works well on sludge, but carefully!! Clean until tool will slide in tube & you can see through bolt hole into tube. Then use tool to pull out trap. Tool works good to install. Perfect alignment of tube on install is important. The tool allows you to rotate tube as it is moving to allow easy alignment to bolt hole.

Tappet blocks will need new Orings. Be sure viton. Use only a tool that replicates the factory tool with the 2 pegs. It reduces chance of damage. Any other tool is risky. Alignment of blocks is important. We'll cover this when you get there. It is not hard.

All this is very, very time consuming, but pays off with good operation for years to come.

You'll need a tap/die set to make the sludge trap tool. Imperial or metric is fine depending on what you may have. In USA imperial is easy to get so that's what I use.

You'll need cam gear & crank gear pullers also. Never jury rig this as risk of damage is great. Almost all crank gear pullers will need some grinding of jaws to fit. So you'll need grinder. Try to get a spare crank gear as they work great for holding gears during torqueing. If you want a simple life buy a real ring compressor tool & make piston boards.

Here's a few photos to get you started. PM me anytime.
Don
 

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In the UK, with 99 octane fuel available, i would not think 7.1 compression would suit a 650 triumph. You will have 9.1 when new. The 8.5 to 1 i am using with the 750 kit avoids any pinking from the ethanol E5 fuel. Use Shell fuel and try and avoid the Tesco Momentum. Fortunately, your head was made with unleaded valve seats so no need to replace those. Some restorers tell you to change them as is good for their profit. I have come across most problems on the 71 model in the last 40 years playing with one. Where are you in the UK ?
 
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