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#896536 11/27/22 3:50 pm
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I've been working part time on a '72 t100r. I've got it runnuning good and have been taking short rides thens working out the bugs and oil leaks. so the other day I went for a short run up the road and after about 3 miles I see smoke in the mirror.

Back home it's smoking bad out of both pipes, and the plugs are COVERED in oil. Must have a good coil in there to fire them.

Anyway, I popped the head and the pics tell the story. The head had been torqued 3 times and seemed to have settled in.

What would have caused this to happen after 6 or 7 short rides.

IMG_20221127_084645108.jpg IMG_20221127_084738238.jpg IMG_20221127_084750400.jpg IMG_20221127_084755832.jpg IMG_20221127_084847017.jpg

Rich
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Is the oil pump return/scavenge side working? If the engine is filling with oil, massive smoking can occur. Check your oil level for starters.

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Pull the barrel off, I'm sure more answers will be found looking at the rings and the condition of the bore

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Improper engine break in. Lots of short rides probably at low speed.


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Richrd Offline OP
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it always amazes me that when someone asks a question, it is assumed that person knows nothing. desco, I know how to break in a motor, the rings were seated nicely, maybe you have a different idea of what " probably at low speed." means.

So lets say I pull the barrels, what am I going to see that would make both sides suddenly start smoking at the same time. other than thaat the bore is new and set at 4 thou clearance.

Up to this time, I have been watching the oil with no problems. At this time, I measured 9 oz. of oil in the sump. I will look at the pump again while it's on the table,

Thanks to you trying to help. If you just post to make yourself seem smarter than someone else, don't bother.


Rich
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Richard,
Sorry, I was in construction for a long time. The safest way to approach a new employee was to assume he knew nothing. I was right most of the time. I should have looked at the number of your posts first.


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Oil drains from the rockers plugged (silicone)? Oil line upstream of the rocker arm feed partially blocked? My Triumph 250 single had a similar issue when I first got it. Turned out the base gasket was missing one of the holes for the drains from the top end.

Ed from NJ

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"I measured 9 oz. of oil in the sump" That's much more than I would expect (more that half a pint). I'd expect 2-3 oz ~100ml or so.

That high level could throw much oil up the bores.

Yes, check scavenge function as Stuart Kirk suggested.

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Richrd Offline OP
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Ed, I'm usually careful about checking gaskets, drains and silicone. (I use very little gasket sealer and no silicone). But I could have missed something and plan to check again. But even if this is the case, why did it wait a long time to show up?

I checked how much oil was in the sump after sitting for over two weeks out of curiosity. it was only 2 - 3 oz at that time. So it's looking like that may be it.


Rich
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Hi Richd, How many miles did you put on motor after overhaul? Then all of a sudden smoking both sides evenly?

You don't visually see problem with bores. This may take some time to sort.

At this point is it best to reassemble & road test or pull pump now & inspect? If/when you remove pump bench test it upon removal. The bench test is very accurate if you do it correctly. Any drop of oil in port is a fail..

After bench test, remove balls & inspect for dirt of any kind. Inspect seat. My experience is return ball seat is much more prone to wear. In my opinion due to particulates in the oil. I've observed this on 100% of the pumps I've taken apart. I've personally had bad luck with reseating balls like it says in shop manual. I can't post photos here. If you PM me your email, I'll send videos of pump test, & photos of worn ball seats. When ball seat starts wearing too much you can get hit & miss operation of return. Thing is, it's not like dirt that holds ball open. The return volume slowly degrades until it can't keep up.

Diagnosis is critical. If you don't find a problem you don't know if you fixed it or not. If pump fails test, that tells you something very important. If pump passes test perfectly, where does that leave you? I've observed on pumps beginning to fail from worn seat, the oil will very slowly drop. (this is after you removed ball & verified no dirt in seat). Do not put the pump back in until you have absolutely zero drop in port for at least 15 seconds. I mean zero!! A perfect seat will hold over 5 minuets.

Once too much oil is in sump the flywheel throws huge volume of oil onto bores, no ring can keep up with this much oil & the smoking starts. What's odd is it can take some heat to bring the smoking on. At the same time, not seated rings can show no smoke at first. After the oil gets warmed the smoking can be profuse. I can't explain this but have observed it a few times.

How many miles was your first short rides each?

It is sounding like oil pump problem... 9oz is about 260cc.

On parked bike a good oil pump feed side should not allow oil to drain into motor for several weeks. Oil in tank might drop 1/16 max. My bike & others I checked can set 2-4 weeks with no measurable drop.

I use the cheap baby bottles from grocery store. 3 pack is about $3.50. They are marked in both oz & cc. Quite handy for measuring oil.

Looking like this will remain a mystery until more diagnosis is done.
Don

Last edited by TR7RVMan; 11/27/22 9:12 pm. Reason: changed sentence

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Richrd Offline OP
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Don, I agree with everything you say and will pull the oil pump tomorrow. I once saw a problem like this on t150 that was never found. it eventually led to the most total destruction of an engine I have ever seen.

Anyway, as I said before, this bike sat for two to three weeks and when I checked the sump out of curiosity there was the normal 2-3 oz. What that tells me is everything was ok before this last ride. Maybe the pump picked up some debris on this ride.

This bike has been kind of back burnered. It's had 5 or 6 rides of 5 to 10 miles each. I've always broke engines like I plan to ride the bike. Never too gentle.

But the one thing different is that before this ride, I pulled the sump plug. It's just a plug and a screen, but is there any way I could have done something to cause this?


Rich
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also if it means anything, there was a lot of leaking from the head gaskket joint on the outside of the barrel


Rich
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Did you happen the thread in an oil pressure gage & note the results before diassembling?


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Just tell everyone it's a rare 2 stroke version.

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Hi Richrd, There is some thought that removing motor sump plug leads to contamination in the scavenge side of oil pump.
If the plug area is not cleaned before removing it is possible to push dirt up into sump which might get into pump ball seat. Also there may be ring of dirt or metal particles around upper end of threads that may be dislodged.
The sump screen is fairly course and can pass larger particles compared to oil tank screen.

Saying that, I’ve removed the sump plug on every Triumph I’ve changed oil. I’ve changed oil on many bikes. I’m mindful of chips & dirt, not to introduce any. I clean threads in motor carefully. I clean the sump plug & screen very well.

Did you introduce particulates into pump removing plug. Who knows? Did you split & clean cases on during overhaul?
If you did I’d expect the inside of motor to have been carefully cleaned. I doubt you introduced particulate.
On the other hand, if you just did top end & the sump screen hadn’t been removed in years I suppose it’s possible removing sump plug caused problems.
At this point we don’t even know if pump is bad or not. We’ll know more later.

Regarding the leakage at head gasket that is likely because head head surface is not flat. With flat surfaces & new head gasket you should have zero leaks. I doubt there is relationship between oil leaking at head & the profuse smoking.

Also the valves show a lot more deposits than I’d expect to see at such low miles. We’re talking less than 100 miles.
Was head cleane & overhauled?
I’m wondering if there is more going on here than we know about? I would carefully check head & top of cylinder for flatness. Pay special attention looking for dips in gasket surface. Top of cylinder can be sanded flat with 120 paper on flat surface. Head is harder to sand flat. It would be better to skim on milling machine. With non flat head I would not reuse the old gasket. It will not be flat. Use new gasket. I’d probably decarbonize head at this point as well.

Combustion gas when leaking out head gasket looks like oil. Since you have so much oil in combustion chamber no telling what you have leaking out now. But it should have zero leaks.
Lots going on here. Triumph motors are not very forgiving at all. They might be simple but demand precision & careful assembly.
Don


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Dirt on the ball,. Could it be this easy

IMG_20221128_115453170.jpg IMG_20221128_115438420.jpg

Rich
"It's not always about going fast. Sometimes it's nice to slow down" (Wendy E.2016)

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Originally Posted by Richrd
Dirt on the ball,. Could it be this easy
By the looks if it, it certainly could be that easy.

But I have to ask, how fresh is that engine? The photos make it look pretty dirty, old and worn. The oil looks black.

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Great you found the cause of the problem. Useful topic, thanks for posting it.


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Hi Richrd, Of course it could be that easy.

What happened on the bench test after removal?

Again, bench test pump before installing. Don't screw yourself by not bench testing.

Why is the oil so dirty? Up above you say bore is new, set at .004". I've had hundreds of motors apart. Even the diesels don't turn oil black in less than 100 miles. What ever?

So long as pump is now passing bench test, it will likely fix the smoking.

Back to the head gasket leak. Yon want head flat to ".0005". Normal feeler blade kit is .0015" thinnest. So you'll need to order thinner .001 .0005".

Use a real straight edge if possible. High quality combination square like Starrett will at least get you close. Stanley square, not so good.

If you have surface plate (who does?) using 120 belt sanding paper or large sheet of emery you can attempt to flatten head. Usually only takes off about .003". Should you attempt this DO NOT do figure 8s. Push very evenly front back ways. Then turn head 90 degrees, again front back ways. Clean chips from paper every few passes. Do not rush. If you have steady push you can flatten well within .0005". But.... It's very easy to crown head meaning removes more metal on ends than in center. The gasket only crushes a tad over .001". So low spots are a real problem. Head can be bent also. Head is sort of flimsy & some curve will flatten & seal fine. Dips will not flatten so little clamping pressure on the low spots will seep/leak.

Loctite 574 or 510 will really help sealing. Hugely greater than copper coat. 574 you must work very, very quickly. 510 gives more time. I always use loctite. If you don't use that, use copper coat with an even of coat as you can.

We like to avoid skimming if possible. Sanding if you're careful can work. Not careful will make head worse. Skimming is hard to take off less than about .006-.010". I know some say less, but I'm talking real life. For all we know head may have already been skimmed?? Thicker head gaskets work very well to compensate for skimming & they help to put rocker geometry closer to new. If you can deal with the head gasket leak at this time, it would save dealing with it down the road. If head gasket blows it often erodes the head & even more metal will have to be removed during skimming.
Don


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I do not know why the oil is so black. I started with the motor apart in a tub. pulled the crank filter. assembled with all clean parts. new bores with .20 over.

Checked the head on the surface plate and sand paper. it's good.

I've always used two coats of copper seal, I check out the loctite.

I'll get into the bench test proceedures next.

the oil is not as black as the pictures make it look, but it is darker than I would expect as well.


Rich
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I once had an old truck with a Perkins diesel engine. Fresh oil would turn jet black within 5 minutes. God knows what the insides of the sump looked like.

Just on the head skimming, I can't see any reason why it would be hard to take less than .006" off. It should be possible to take .001" off (if any less, it doesn't need doing anyway)


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As long as you are in this far, I would make sure the scavenge oil line doesn't have any obstructions, including the passage way into the oil tank. You might also want to take off the oil tank and make sure the inside is clean. Finally, the black oil usually means that there is significant blowby. Could the breather be blocked as well?

Ed from NJ

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breather is open. I plan to check lines and tank.

Following the videos I got from tr7, my oil pump is not in the best shape. It may be usable, but I'm not putting it back in.


Rich
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Originally Posted by edunham
As long as you are in this far......You might also want to take off the oil tank and make sure the inside is clean......
A dirty oil tank could be why the oil is dirtying up so quickly on a fresh build. Proper cleaning is a must in my opinion.

Last edited by Stuart Kirk; 11/30/22 2:32 am. Reason: Thought of something else.
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Hi Tigernuts, Absolutely after routine oil change diesel oil turns black in 5 mins. But not after overhaul when all the black oil is cleaned off. At least not on Mercedes diesels. I went through several motors personally, installed dozens & dozens of factory exchange motors.

I worked in automotive machine shop for a period of time. We bored cylinders, fixed cracked blocks & heads. Did hundreds of head reconditioning. Lots were after overheating so head was warped. Anyway The cutter seems to struggle to cut smoothly less than .003-004". Sometimes (often?) top & bottom of head are not parallel, so not so simple to set flat to cutter. If head needs skimming will often have low spots. The cutter must go below those. So it's not so easy.
On blocks with pressed in liners, the top of liner usually had to be skimmed down to block. We did our best to remove little as possible from block. Block was secured on arbor jig by main bearings for boring & skimming. Tried to not remove more than .003". The cutter was like a thick disc with several cutter bits clamped to it. A place ground the bits on the disc to be true. I thought it did a really good job. They only let me do guides & seats. I left before moving up the ladder.

If the shops can do the tiny amounts they are really good. Better than the guys I know of.
Don


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