motor still smokes

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OldBritts sells the valve seals with a spring inside. Helps reduce oil consumption with loose valve stems.

But if the head has been swapped and it still smokes, one would deduce that the oil is comming from below. A leakdown test will tell you if the rings aren't seating.
 
Ludwig...i noticed from the Mercades V8 link..the engine turned over easy! their bore surface finnish must be a lot finer that our normal standard "cross hatch pattern"! Imagin trying to turn over 4 commando engines by hand with new pistons.. :lol: i remember a friend rebuilding a 2.5 six pot Triumph....when the pistons where it we couldn't turn it over...when it did,,,boy did in sound nasty!!..unlike the silky youtube V8! i bet there cylinders are like mirror's .. our work shop manuals still state " correct cross hatch pattern" for ring bedding."
 
Good point John. Not to pour gasoline on the oil-less break in debate, but I'm thinking that comparing AMG's process to building Nortons isn't a bit of apples and oranges. I would bet the Merc engines have nickosil cylinders instead of iron as well as a much finer honing pattern.
 
Now.Now Ludwig! stone age? Nope the commando as progressed to the Iron age! I got rid of my stone axe's and flint knives, going for a more gental iron chisel,and crow bar. I have heard about the cyber,hyper coating that Merc use...its a plasma based speleamin alloy thats mined in Belgie!..... Yes we have rumbled YOU MATE!!!! riding about with not a coughing Flem in sight!!!!
 
Why does the BMW expert hold the revs at 3500 rpm, :?: to get the motor to throw oil around everywere to get the rings and pistons and cams lubricated :!: hmmmmm,a small splash of 30w oil on the rings and pistons and he wouldn't run the risk of burning the rings or scoring a piston and get exactly the same result
john robert bould said:
i remember a friend rebuilding a 2.5 six pot Triumph....when the pistons where it we couldn't turn it over...when it did,,,boy did in sound nasty!!..unlike the silky youtube V8! i bet there cylinders are like mirror's .. our work shop manuals still state " correct cross hatch pattern" for ring bedding
Click to expand...
Some of those motors had real ugly high tension oil rings to cope with the poor honing techniques of the time, just think how well they might have gone with good rings and a proper finished hone job,nice little motor for the time,I'll say it again and again and again,properly finished honing, not some backyard mechanic crap who doesn't understand what he is really trying to achieve.As for dry or wet assemly do what ever the internet tells you,it never lies :|
 
Yes i now remember using one of those spring steel wrap a round ring compressers..the one that used a square key...loads of oil and the end of a lump hammer! the ordeal was real iffy...can you remember fitting rings with red grinding paste? called something like cargraph? :oops: wonder if Merc as heard of this! :idea:
 
I noticed some of the auto production engines, Ford's 5.4L in particular, are under square. Years ago, I'm talking fifties thru eighties, an under square production auto engine was a no-no. Supposedly, piston speed per stroke was too high for the rings to bear. I think there have been advances in rings, pistons and cylinders that now make an under square engine practical. Probably a lot less friction, as pointed out by John. Maybe this technology could be applied to our Nortons. I did have my pistons coated by HPC, both thermal barrier tops and slippery skirts. For some reason the cylinders would ring like a bitch at 2000-3500 rpm with these treated pistons. Got so annoying I replaced them. My theory was there was not enough heat getting to the pistons to expand them properly leaving too much clearance once the cylinders expanded.
 
ludwig thank you
had smoking problem after new pistons and rings. every thing from old brits good stuff.
figured after reading all the break in advice i babied her to much and glazed the cylinders.
rehoned new rings head gasket. head was gone through 1000 miles ago figured everything cool.
fired her up took her out for 10 min. and ringed her neck power was fantastic.
next day did the same all good. next day noticed lots of smoke on decel f@#k!
next day took your advice 10 min. ride, smoked! 15 cooldown disconnect oil line run 1 min. no smoke crystal clear
reconnect oil line smoked. since valves and guides are new i think its the seals?
is there a way to change seals without removing head? its so nice and sealed up no oil leaks i hate to tear her apart
i know you can with auto engine,air pressure etc.
thanks mike
 
I had a tool made by ROTHENBURG, it was basicly a hollow cylinder with a magnet inside, and another tool to push the collets back in. It worked like this, tdc, lock engine, pressurerise cylinder, the magnet part was then placed over spring collar and given a good sharp crack with a hammer, result, valve stays still, collar moves down and collets pop out and get caught by magnet.To reassemble you sat the collets in the retainer sat all the parts together and pushed down by hand, it pushed the spring down far enough to let the collets slip back into place.
 
motor still smokes


thats the way i like it,when things go the way you hope.
thanks forum and ludwig used your tool to great success!
didnt have valve spring compresser so used socket, exstintion and block of wood,
aginst chest press down with body weight,remove keepers,replace new seals. oh yeah!
NO SMOKE! COMBAT RUNS LIKE ONE NOW!
thanks preston
ps weathers been bitchen lately for riding!
 
forgot to add how long it took.
total 5 hrs. that includes making tools and ALOT
of figuring things out.
to do it a second time about an 1 hr
preston
 
I've always just used a cotton rope to feed into the spark plug hole towards the valve in question, run the piston up towards the compression stroke. The valve is forced close this way and you can work freely on the valve. Just reverse the motor then and pull the rope out when done.

At least this is what I've done on other motors, haven't had the need to do it on the norton yet but see no reason why it would not work.
 
santa barbara ca.
born here and never found it neccesary to move thank goodness
snows couple times a year maybe on top of mountains
preston
 
Yea I can see a bit of snow on top of Baldy, Preston snow in Santa Barbara? (Looks like another sunny day, I love L.A.) you know the song. Now if we could just get rid of about 5.9 million people it might be nice.
 
it does snow in s.b.
finally down loaded pics from phone.

motor still smokes


motor still smokes

pics looking from top of peak at santa barbara the harbor and islands
and back to the back country lake cachuma s.b.water supply i love riding here

motor still smokes



tried loading engine photos before changing seals giving up wasted hr. hope this worked
 
Hey Preston,

This is what it looked like near Preston UK recently

motor still smokes


Love the bike.....but the jacket? Hmmmm :shock:

:mrgreen:
 
Hi Lads,

re: 1975 850 ES (920 conversion)

I've found this thread really interesting & informative, thanks to all.

I just had my Commando out today & noticed it is smoking from the RHS only. As I rev the bike there is what looks like white smoke coming for the RHS exhaust only.

From doing a search from this great forum I've narrowed down these possibilities:

1. Rocker shaft orientated incorrectly

2. Valve guide seal

3. Worn valve guides

4. worn bore (but compression is OK & the 920 barrels only have 1500 miles on them)

I read about the rope trick allowing you to release the valve spring & get at the seal.

I've also read about disconnecting the banjo feed to the rocker box. Can you just put the banjo bolt back into the head using a plain nut as a spacer?

Since you've disconnected the banjo is this not a feed pipe? will oil just start coming out of this rocker feed pipe?

Thanks in advance

Kevin
 
OK OK Preston, I guess it does snow there. We better get our rides in today as they say we are going to have rain this next, Need to get the Norton out for a spin today. Thanks for the pics. Chuck.
 
ludwig said:
Kevin ,
don't disconnect the oil lines at the head .
Ride the bike first for a short distance , to make shure the rocker shafts are well lubed .
Disable the oil feed at the timing cover ( bottom banjo) by replacing the drilled bolt by a plain bolt .
You can safely ride the bike like this for 5 to 10 min .
Don't forget to restore the oil feed afterwards !
Click to expand...

Hi ludwig,

Dooh!!! :roll: should have figured that out myself :roll: :roll:

Thanks for clearing that up.

Kevin
 
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