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Triumph 650 engine rebuild, questions inside.
#569968 11/01/14 5:30 pm
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Guys,

Finally getting some time to get down to business on my Trump 650 overhaul. I picked up the bike two years ago and still haven't hit the street yet. After getting the bike assembled I encountered some issues, and once I started digging things didn't add up. So I decided to split the cases to start with a blank slate so I know what's inside.

So because everyone likes pictures, what was waiting for me inside-

[Linked Image]

[Linked Image]

[Linked Image]

I've already had the head redone with quality parts and valve job, purchased a new premium AMAL and purchased a Pazon EI.

So now my questions- what else is worth spending the money on? This is no race bike and I don't need a super high performance finicky engine. Looking to build a good, reliable engine. What stuff should be upgraded and with what brand parts? Should I balance the rotating assembly? ARP rod bolts? Mushroom tapper adjusters? Best factory cams to run and where to set them up at? Brand of gaskets that work well?

Any ideas or comments throw them out. I know a lot of this has been beat to death but I know it's good to revisit sometimes, things evolve.

Thanks!


1967 TR6 = 650 ways to waste money
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Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #569972 11/01/14 5:46 pm
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Do you doubt that the normal valve adjusters open the valves? I could say the same about the cams you already have.

Get the big end journals measured for ovality.

The pistons are a mess. How do the bores look?


Amateur Loctite enthusiast.
Re: Triumph 650 engine rebuild, questions inside.
triton thrasher #569984 11/01/14 6:35 pm
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Originally Posted by triton thrasher
Do you doubt that the normal valve adjusters open the valves? I could say the same about the cams you already have.

Get the big end journals measured for ovality.

The pistons are a mess. How do the bores look?


Well, no.

We have come a long way since then, hence the question. If there is no reason to upgrade I'll save the cash for gas money. Personally, I don't know the difference and came here to get educated.

I don't have any T-gauges here to measure the big ends or cylinders. I'm guessing the cylinder will need to go another .020 over. Then again, looks like they were too tight to begin with so a hone might do it.

Last edited by UGOTBIT; 11/01/14 7:49 pm.

1967 TR6 = 650 ways to waste money
Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #569987 11/01/14 7:17 pm
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Here are some pics of the rods, a few good dingers on them. Both small ends have similar marks, maybe someone botched a bushing replacement at one time?


[Linked Image]

[Linked Image]

[Linked Image]

[Linked Image]


1967 TR6 = 650 ways to waste money
Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #569989 11/01/14 7:42 pm
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UGO, you've the attention of TT which is a good thing and the other truly experienced will be along shortly I suspect but we need many more pics! The whole bike, parts of the bike etc.

A 67 TR6 is just a great bike, plenty fast and reliable. Hire an excellent machinist if and when that time comes. Don't skimp to save a few dollars. My two cents. :bigt dave



66 TR6R Trophy
67 T120R Bonneville
68 BMW R60/US
69 T100R Daytona
91 Honda ST1100
Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570006 11/01/14 11:14 pm
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You should remove and polish out the dings in the rods.

I sent my crank/piston assys/rods to Falicon for balancing & blueprinting. They balanced the crank and made sure the rod journals were round/lined-up, etc. Bike runs very smoothly.

Of course, check that small end bushes are okay first.

The only gaskets I use on my Triumphs are the head gaskets. For everything else I use Yamabond (sparingly).

As far as trick parts go, you already have what you need: Pazon and new carb. The stock stuff is fine for everything else. You might want to go with 6V coils though.

The most important thing is careful assembly. Remember though, don't dare trust any outside work without verifying it! That is, although you told the machine shop to bore the cylinder to .00X", be sure to verify clearances before assembly. Same with any other work that you didn't do yourself. Trust no one!

Few motorcycles in this world are more enjoyable to ride than a properly set up, stock Triumph!


When people who should have known better cautioned me about the dangers of motorcycle racing, I always told them that a fear of death is nothing more than a fear of life in disguise.
Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570017 11/02/14 1:04 am
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After looking at that small end bush work, I'd be checking the rods for parallel at the big end eye and small end eye.
To make some precision mandrels to check it, you're probably looking at more than the cost of new set of rods. It's OK for me, because I have them. Both eyes should be parallel within at least 0.002" in 6".

Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570032 11/02/14 6:44 am
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If the pistons had less damage, we could maybe see from wear patterns, whether the rods are straight.

Mushroom adjusters have a recent history of breaking. Fitting them is a gamble, with more to lose than to win. Even good ones won't noticeably improve your riding experience.

If your cams look worn, with scores and/or flat bits, replacing them is probably a good idea, although not compulsory.

3325 inlet and exhaust, 3134 inlet/3325 exhaust, or 3134 inlet and exhaust will all work just fine. 3134 is sportier and its use might take something away from the engine's low speed behaviour.

If your cams and followers don't look worn, then keeping them, all matched up to each other, is best practice.


Amateur Loctite enthusiast.
Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570051 11/02/14 10:40 am
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The one thing that is helpful when diagnosing these kind of pistons seizures is the wrist pins.

These kinds of seizures happen because of lack of clearance. But there are two reasons it can have too little clearance:

The cylinder was finished with too little clearance for NORMAL operation. The piston did not have enough clearance for what would be considered normal piston expansion. It is normal for the heat of combustion to migrate into the piston and the resultant piston expansion is compensated for with the factory recommended piston clearance.

It is when we have abnormal combustion that we get the other reason for this kind of piston seizure. When a piston reaches normal operating temperature, and expands in the bore, there is very little extra clearance available for additional expansion. If the engine suffers prolonged detonation, which can be inaudible to the human ear, we are going to drive additional heat into the piston. If this is more heat than the engineers planned for when they specified piston clearance the piston will become "to big for the bore." We have a seizure.

So what can the wrist pin tell us. Well for one thing it was there during this event. It is also polished steel and discoloring because of it being exposed to heat will be available for us to examine. For centuries metal workers have been using the color of polished steel to tell them the temperature of the metal as it heats up. Long before the pin starts to glow red the surface will start changing color. At around 390 degrees F the bright steel color will start to turn a faint straw color, 445°F it becomes light straw, 465°F it becomes dark straw, 480°F it becomes Brown, 520°F it becomes brown/purple, 520°F it becomes purple, 540°F it becomes dark purple, 575°F it becomes blue. The thing that is handy about this is when the pin cools the color the pin reached remains there for all to see.


The bottom line to all this
If the pin comes out of the piston the same color as it was when installed - and thus only exposed to normal engine operating temperatures - the cylinder was set-up with too little clearance.

If the pin comes out displaying ANY color the engine was operating in conditions where there was abnormal temperatures and detonation is always a prime suspect in these engines! All this is especially true if there is also signs of detonation on the top of the piston or spark plug.

Why do I think the problem was detonation, not lubrication? Because lack of lubrication seizures typically start at the bottom of the skirt and go up. This seizure started just under the oil ring, a point where abnormal heat causes the most problems

Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570052 11/02/14 10:44 am
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Thanks for all the responses guys!

The rod bearings are not showing any signs of weird wear patterns, obviously they are scored from all the trash going around in there. Hopefully they are straight and not out of round. I planned on sending them to Franz and Grubb for inspection, and if they were good having the bushings replaced and ARP bolts installed/stretched.

This engine was covered in yamabond, so I'm guessing that's standard practice.

I'll snap some pics of some other parts and see what you guys think.


1967 TR6 = 650 ways to waste money
Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570055 11/02/14 11:01 am
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For John-

[Linked Image]


1967 TR6 = 650 ways to waste money
Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570060 11/02/14 12:17 pm
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There was some abnormal heat present as the pin was exposed to abnormal heat for a period in its life. The brown/purple color is an indication it did reach nearly 500°F. So there was a good possibility that there was some detonation. To have it purely an abnormal combustion problem, and not involve some clearance issues, more of the pin would have to have been discolored. Not just the area between the pin and the rod where there is no chance of radiational cooling.

You would need to examine the valves, especially exhaust, top of piston, THE UNDERNEATH of the piston dome, spark plug, etc. to get a better idea. But just this small area of discoloring alone would not normally account for the seizure. I have seen this much localized discoloring on motors that had a long happy life. I suspect that the piston was set-up with .0035" clearance. This is common these days and a throw back to when Triumph used their own production low expansion pistons (Lo-Ex). While in a perfect world you could get away with .0035" with a Hepolite (or JCC) there is little in the way of a safety factor available for the the heat generated by any inevitable abnormal combustion.

When they switched to out sourcing the pistons from Hepolite the minimum clearance spec. on the 650 changed to .0045" and a .0035" clearance and some extra heat from some abnormal combustion most likely caused a seizure.

Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570063 11/02/14 12:49 pm
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John my 500 60 over pistons standard compression, emgo set @ 4 thousands, anything to worry about?

Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570088 11/02/14 3:40 pm
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The 500 is a different animal and the .0035" clearance for those pistons is applicable. Your .004" is perfectly acceptable.

Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570090 11/02/14 3:50 pm
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This bike was ridden by the previous owner for some time with a loose exhaust valve guide on the timing side. I got it running after installing the new AMAL and the Pazon EI and knew something wasn't right. Once I found that I knew it was time to take it all the way down and get it sorted out.

What is the leading cause of detonation with these engines? Not enough octane? Too much timing? Lugging the engine?


1967 TR6 = 650 ways to waste money
Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570155 11/03/14 5:48 am
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Quote
Not enough octane? Too much timing? Lugging the engine?


All three but the low octane is more likely caused by oil getting into the combustion chamber and effectively lowering the octane than by the wrong fuel being used. So rings not bedded in or loose guides will introduce oil into the combustion chamber, then the next hill will cause the engine to lug etc etc.

Re: Triumph 650 engine rebuild, questions inside.
kommando #570171 11/03/14 12:07 pm
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Originally Posted by kommando
Quote
Not enough octane? Too much timing? Lugging the engine?


All three but the low octane is more likely caused by oil getting into the combustion chamber and effectively lowering the octane than by the wrong fuel being used. So rings not bedded in or loose guides will introduce oil into the combustion chamber, then the next hill will cause the engine to lug etc etc.


So since we are sort of on the topic, what is the best way to beak in a new engine/seat the rings?

I have heard to heat cycle the engine a few times before getting out on the road. To me that could compromise the bedding of the rings.

This is my first Trump, so I could be off base.


1967 TR6 = 650 ways to waste money
Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570184 11/03/14 1:42 pm
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Do a search on running-in.

Forget "heat cycles before getting out on the road."

Last edited by triton thrasher; 11/03/14 1:43 pm.

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Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570225 11/03/14 6:14 pm
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Triton thrasher, will do thanks!

Well further inspection found that I have "R" stamped cam followers.

Leave them in, ditch them for stockers?


1967 TR6 = 650 ways to waste money
Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570247 11/03/14 8:13 pm
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"R" radius tappets were standard equipment on most Triumphs fitted with 3134 cams.
If they're in good condition, fit them back on the same lobes and facing the same way. A small amount of wear is still normal, and shouldn't be confused with real damage.

Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570254 11/03/14 8:53 pm
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Pete R- thanks for the info!

Anyone have any good sources for Triumph machine work? I'm located in the North East, but will ship. I have an email into Franz and Grubb, but I'm worried they will be pretty back logged.

Thanks!


1967 TR6 = 650 ways to waste money
Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570258 11/03/14 9:45 pm
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Originally Posted by UGOTBIT
Pete R- thanks for the info!

Anyone have any good sources for Triumph machine work? I'm located in the North East, but will ship. I have an email into Franz and Grubb, but I'm worried they will be pretty back logged.

Thanks!


Bore Tech in Ohio. If possible, have them prepare your cylinder also.


When people who should have known better cautioned me about the dangers of motorcycle racing, I always told them that a fear of death is nothing more than a fear of life in disguise.
Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570285 11/03/14 11:44 pm
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FWIW, a DPO'S experience.
We found my first project out in the woods in South Atlanta, a 1972 T120RV...it had been picked over, and sitting there for who knows how long...Brought it home, cleaned out the gas tank, which wasn'nt bad, checked for oil pressure, now granted, this is my FIRST experience with these machines, and I did'nt have a CLUE....Got it running fairly well, and about 12 minutes later, it locked up....Pulled it apart, crank was shot, lower skirt of the right cylinder was broken off, sludge tube 90% clogged. Went thru 2 crankshafts, 2 sets of pistons and rings, then ran for about 10 miles and locked up again....removed cylinder, machine shop honed it in 10 minutes, re-assembled, ran perfect since then. Both rods were fairly well "dented", which I cleaned up with sandpaper, didn't have a torque wrench to torque anything, just "common sense" approach to all that, never balanced or blueprinted anything, just bare bones replacement of parts, and man that bike ran STRONG! Had ALOT of good times on it, and put about 5000 miles on my "back yard" overhaul...Paid $200 for the bike from the property owner, sold sight un-seen for $3000. Had "spray-bomb" paint job, but boy was I proud of that little bike once I got all the issues ironed out...Looking for another "project" as I write.....Very hard to come by....Don't sweat the small stuff, they are VERY forgiving apparently!

Last edited by DPO; 11/03/14 11:45 pm.

If you love it, let it go. If it comes back, you've highsided!"
2016 Triumph Bonneville America LT
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Re: Triumph 650 engine rebuild, questions inside.
UGOTBIT #570329 11/04/14 10:21 am
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Originally Posted by UGOTBIT

Anyone have any good sources for Triumph machine work?


Leo Goff has been recommended by John Healy on more than one occasion....

http://www.memphismotorwerks.com/shop

https://www.facebook.com/pages/Leo-...-Werks-Cordova-Tennessee/167919913393892

Cheers,

Steve


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Re: Triumph 650 engine rebuild, questions inside.
John Healy #570601 11/06/14 12:19 am
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Originally Posted by John Healy
The 500 is a different animal and the .0035" clearance for those pistons is applicable. Your .004" is perfectly acceptable.


no kidding? I only hear people preach the the .0045 for triumphs, so I had my 500 done at that and just had to hone it again after the rings didn't seat.

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