Chewed up push rod and vexing oil leak

[vince998]

The temp push rod is doing its job and the bike seems to be running
fine-ish...It seems to pull well and idle well and cruse well in 2nd 3rd
most of the time...Then all of a sudden it gets a tad rougher running and
may or may not tend to stall. A bit of time on the carb air mixture screws
seems to have helped? I still think she is running a tad rich as I get
white smoke out the pipe and wet black plugs...

I have 32mm Amal's MK1's running w/o filters and an open pipe with 210
mains...what do you think a good first adjustment would be to lean it out
JUST a TAD? As I said the stand in push rod seems to work acceptably with
just a bit of exhaust popping on the
over run..Which may be the rich mixture or a response to the less then
perfect push rod I am using...Its end being less the perfectly round.

As far as the leak goes more testing with powder had determined that the
lower ft exhaust push rod tube seal was contributory to the leak at the
front of the cylinder. The other 3 sets of push rod seals are also
misting a bit, they are next....I dug the offending seal out and replaced it
and went for a ride...No leak .....

Ahh the difference a day makes....

Cheers,
Eric

Hi Eric,
Just a thought.
1.) sounds like you are burning oil.
2.) backfire on the overun could probably mean a loose exhaust nut.
3.) if it´s the front nut that´s loose, this is probably where your oil on the mag cover is coming from. (took me 3 months to find this leak on mine (no popping) but my oil was on the front mudguard. Thought at first it was coming from the damper, but it was black )

 

[Ducdude]

White Smoke???? Surely black smoke for rich!!! Blue smoke for oil. White smoke signifies something not good, but I can't for the life of me remember what, I seem to remember it being head gasket on a car (water cooled), but that can't be your problem. Are you sure you're not burning oil?

I'm running 32 mm Mk1s on 240 main jets, and may go bigger yet. In my book, exhaust popping is weak, not rich - on the pilot.

H

Hmm OK maybe the white smoke is condensate (water) from sitting all week or could it be a too lean mixture. Still the exhaust does not smell like burning oil... 240 mains eh? Are you running air filters? Is your muffler restrictive at all? If you have clean plugs with 240's then my 210's cant be to big...with out air filters and no back pressure in the muffler to speak of..

Thanks,
Eric

 

[Ducdude]

I did say the other day it takes 10 years to sort out ones Vincent!!-If the pushrod seals persist in "leaking" it can be a sign of too much crankcase pressure-but that is another story! White smoke? all I ever get with this horrible modern fuel is black soot! it sounds "weak".

Thanks Alan...I am only one year into my 10 years and at least she runs..So I am happy about that. The push rod seals are the original ones and once I pulled out the worst leakers they fell apart like a 4200 year old mummy... so no wonder they leaked.. Now to do the other three. Once I changed the worst one it dried up like the Sahara..
Weak charge eh? Well I guess I can put on the air filters that may help a bit maybe. Do MK-1s have needles I can raise a notch to richen it a bit..?

Thanks,
Eric

 

[Ducdude]

I have found the exhaust popping on overrun can come with any leak in the exhaust system. .

Thanks Ian,

I bet the clamp on the muffler is the leaker...A few moments with a spanner will fix that I bet..!

Cheers,
Eric

 

[Ducdude]

Hi Eric,
1.) sounds like you are burning oil.
2.) backfire on the overun could probably mean a loose exhaust nut.
3.) if it´s the front nut that´s loose, this is probably where your oil on the mag cover is coming from. (took me 3 months to find this leak on mine (no popping) but my oil was on the front mudguard. Thought at first it was coming from the damper, but it was black )

Thanks Vince..I would be surprised if she was not burning any oil as this girl has been sitting for 40 years and has never been opened up so she has the stock pistons and rings and 40 years of crud and rust...I have been wishing that a good hard fast run will help seal her up a bit...The compression is good at 140-150psi and the leak down showed 7%-8% or so. The numbers seem to say she is pretty tight for a 60 year old.... The exhaust also does not smell of oil..Go figure..
I agree with the exhaust leak and I also agree that it is probably the muffler clamp..
The oil on the front cylinder turned out to be from spraying past the front exhaust pushrod seal, freaky but true..I changed both the upper and the lower set of seals and that leak just went away...
Now the other three are weeping and the oil actually migrates forward along the cylinder bases and down behind the mag and under the bike all the way to the back of the motor...Man isn't that against a rule of nature or something?? Well, I'll have that fix at hand soon enough..

Thanks,

 

[bmetcalf]

T.I have been wishing that a good hard fast run will help seal her up a bit.../QUOTE]

I guess a guy named DUCdude would favor the Italian Tune Up.

 

[Ducdude]

T.I have been wishing that a good hard fast run will help seal her up a bit.../QUOTE]

I guess a guy named DUCdude would favor the Italian Tune Up.

Oh I have been trying I really have! Evey time I get the RPM's and the speed up the whole back of the bike gets coated by oil from some new leak...

Cheers
Eric
Rev happy

 

[Howard]

OK maybe the white smoke is condensate (water) from sitting all week or could it be a too lean mixture. Still the exhaust does not smell like burning oil... 240 mains eh? Are you running air filters? Is your muffler restrictive at all? If you have clean plugs with 240's then my 210's cant be to big...with out air filters and no back pressure in the muffler to speak of

Eric

I was running with air filters on 230 jets, but they were showing signs of being slightly too weak. Hard to tell with fuel here, plug chops don't seem to be relative anymore. My silencer is more restrictive than a straight through pipe, but still quite open. I'd expect to go up at least one main jet size if I fitted a pipe instead. I've recently changed to long bellmouths instead of filters (never liked them) and gone up to 240 main jets. I haven't done many miles due to other problems, but I wouldn't be surprised if I needed to go up to 260.

You seem to be confused about carb settings have a read of a few internet sites like this one. http://www.jba.bc.ca/Bushmans Carb Tuning.html

There are lots of reasons for popping in the exhaust on overrun, but if you're playng with carb settings, you'll most likely find the pilot air screw is screwed out too far (weak) - turn it in a 1/4 turn at a time.

I started with 240 mains, 107 needle jet, #30 pilot jet, No 3 slide, needle clip in middle groove, pilot screw turned out 1 1/4 turns. No 2 engines are the same, and I'm sure there are lots of alternatives, but these work for me.

H

ps I'd stay clear of "hard fast runs" for now. If you're running as weak as I suspect, it could be quite a few dollars before your next hard fast run!