Do I need a top end rebiuld?

[JeffM]

Greetings and salutations fellow Doggers.
All those who follow this mad Aussie and his affair with his K9 would know i am ok with the spanners and quite happy (sometimes) to try something new ie: AUTO CLUTCH - thankfully i can say i have it working perfectly with NO help from the suppliers, but with grateful thanks to the members on the forum.

Next issue, my motor has 40,000 klm (whatever that is in Dog miles) and i am blowing blue smoke at idle, that said i don't appear to be using oil.
Last weekend my friends and i did 1500 klm over 3 days of quite quick riding (the new 114 HD still can't beat the 117) but i noticed the smoke when stopped.
I don't seem to be down on power- allowing for general wear and tare from new.
I have rebuilt several HD motors over my years, live by the addage -"IF IT AINT FUCKED DON"T FIX IT".
However this is my baby, and i don't want to kill it.
I thought a hone, re-ring, maybe guilds and a re- lap of the valves would fix this problem.

Thoughts?

 

[bigkelk9]

Sounds like u have it all figured out really

 

[pauly]

Hi Jeff,
I'm not a mechanic but it would be easy to check few things first before you start
pulling the motor apart. At idle there is more vacuum in your intake manifold which can
suck oil mist with crankcase gases into your combustion chamber. I'm assuming that you haven't
modified breathing arrangement on your motor yet.
Disconnect your front head breather hose from intake manifold and plug the hose and cap the manifold hose connection.
Disconnect the rear head breather hose from filter backing plate, cap the hose connection on backing plate and
leave the hose vent to atmosphere.(might want to extend the hose and run it to ground) Now go for a ride and see if you still have smoke coming out of your exhaust at idle. Also check your oil level after the ride you might over filled it a bit. Restrictive oil filter can cause problems as well. If that helps I would use one of the crankcase ports and put another went hose with check valve there as well.

Paul.

 

[BWG56]

Hi Jeff,
I'm not a mechanic but it would be easy to check few things first before you start
pulling the motor apart. At idle there is more vacuum in your intake manifold which can
suck oil mist with crankcase gases into your combustion chamber. I'm assuming that you haven't
modified breathing arrangement on your motor yet.
Disconnect your front head breather hose from intake manifold and plug the hose and cap the manifold hose connection.
Disconnect the rear head breather hose from filter backing plate, cap the hose connection on backing plate and
leave the hose vent to atmosphere.(might want to extend the hose and run it to ground) Now go for a ride and see if you still have smoke coming out of your exhaust at idle. Also check your oil level after the ride you might over filled it a bit. Restrictive oil filter can cause problems as well. If that helps I would use one of the crankcase ports and put another went hose with check valve there as well.

Paul.

That was my first thought and you prolly already know this but I would test the compression before I would take anything apart.
I no mechanic either.

 

[pknowles]

Always nice to see members helping other members

 

[Sven]

Generic blue oil smoke:
Rings:
1. Oil is not scrapped off via the scraper ring. The excess oil on the walls burns with the gas.
2. Excessive ring end gap plus loss of tension at the ring. Compressed air is forced down the wider gaps and cause blow-by.
3. Detonation can pound so hard over the dome of the piston, it can lock the rings in the grooves and no longer expand out to seal the chamber, or scrape the oil off the wall.
Cause/Effect... Every time the cylinder fires, the oil loss remains a constant and burns oil in the constant.

Valve Guides:
a. Excessive OD to ID clearances cause the oil to be sucked thru the gap via intake stroke.
b. Guide seal rubber is broken/hard/moved off the guide and floats on the valve stem, then add the intake draw filling the chamber with oil.
c. Oil flows from head, past the seal's lip, travels down the valve, drops oil onto the piston and is burned upon startup.
Cause/Effect... Every time the engine lights off in the morning or cold start, it took a few hours to drip oil into the chamber and smoke upon startup and then clears up. When you lift off the throttle and cause the vacuum to pull air from all sources, this vacuum will pull oil from around the OD/ID clearance and leave a bellow of smoke upon throttling back up to speed.

Conclusion:
Rings = Constant smoke when running.
Guides = Smokes upon lift then acceleration, then stops smoking.

Which is it?

 

[Srodden]

Generic blue oil smoke:
Rings:
1. Oil is not scrapped off via the scraper ring. The excess oil on the walls burns with the gas.
2. Excessive ring end gap plus loss of tension at the ring. Compressed air is forced down the wider gaps and cause blow-by.
3. Detonation can pound so hard over the dome of the piston, it can lock the rings in the grooves and no longer expand out to seal the chamber, or scrape the oil off the wall.
Cause/Effect... Every time the cylinder fires, the oil loss remains a constant and burns oil in the constant.

Valve Guides:
a. Excessive OD to ID clearances cause the oil to be sucked thru the gap via intake stroke.
b. Guide seal rubber is broken/hard/moved off the guide and floats on the valve stem, then add the intake draw filling the chamber with oil.
c. Oil flows from head, past the seal's lip, travels down the valve, drops oil onto the piston and is burned upon startup.
Cause/Effect... Every time the engine lights off in the morning or cold start, it took a few hours to drip oil into the chamber and smoke upon startup and then clears up. When you lift off the throttle and cause the vacuum to pull air from all sources, this vacuum will pull oil from around the OD/ID clearance and leave a bellow of smoke upon throttling back up to speed.

Conclusion:
Rings = Constant smoke when running.
Guides = Smokes upon lift then acceleration, then stops smoking.

Which is it?

Good explanation Sven

 

[chubs]

Good explanation Sven

X 2

 

[pauly]

Jeff mentioned smoke at idle after riding not at start up after sitting.
Another thing to check is oil return line for blockage-restrictions.

Paul.

 

[pauly]

How did you go Jeff?
Have you looked into it yet?

Paul.

 

[francoblay1]

Generic blue oil smoke:
Rings:
1. Oil is not scrapped off via the scraper ring. The excess oil on the walls burns with the gas.
2. Excessive ring end gap plus loss of tension at the ring. Compressed air is forced down the wider gaps and cause blow-by.
3. Detonation can pound so hard over the dome of the piston, it can lock the rings in the grooves and no longer expand out to seal the chamber, or scrape the oil off the wall.
Cause/Effect... Every time the cylinder fires, the oil loss remains a constant and burns oil in the constant.

Valve Guides:
a. Excessive OD to ID clearances cause the oil to be sucked thru the gap via intake stroke.
b. Guide seal rubber is broken/hard/moved off the guide and floats on the valve stem, then add the intake draw filling the chamber with oil.
c. Oil flows from head, past the seal's lip, travels down the valve, drops oil onto the piston and is burned upon startup.
Cause/Effect... Every time the engine lights off in the morning or cold start, it took a few hours to drip oil into the chamber and smoke upon startup and then clears up. When you lift off the throttle and cause the vacuum to pull air from all sources, this vacuum will pull oil from around the OD/ID clearance and leave a bellow of smoke upon throttling back up to speed.

Conclusion:
Rings = Constant smoke when running.
Guides = Smokes upon lift then acceleration, then stops smoking.

Which is it?

and here he is, da man is back!!! welcome back Sven!

 

[JeffM]

How did you go Jeff?
Have you looked into it yet?

Paul.

No Paul,
Work intervened.
I decided to attack tyres, rims and wheel bearings first.
Curtis will be getting an email shortly, stripped the hex out of most of the socket dome head screws, they are out and so are the bearings.
Once i have it rolling again i will try what you mentioned, makes sense. Also i have over filled my oil tank. I usually add about 4 oz before i go on a trip this way i don't have to carry oil and that amount has proven to be what i use in 2000klm.

 

[pauly]

 

[kickstart]

No Paul,
Also i have over filled my oil tank. I usually add about 4 oz before i go on a trip this way i don't have to carry oil and that amount has proven to be what i use in 2000klm.

That could be your problem.

 

[SEAL-rider]

No Paul,
Work intervened.
I decided to attack tyres, rims and wheel bearings first.
Curtis will be getting an email shortly, stripped the hex out of most of the socket dome head screws, they are out and so are the bearings.
Once i have it rolling again i will try what you mentioned, makes sense. Also i have over filled my oil tank. I usually add about 4 oz before i go on a trip this way i don't have to carry oil and that amount has proven to be what i use in 2000klm.

Be careful when you torque the dome head screws on the rotors and pulley. They are not 50 or 60 pound feet as the manual states (they will strip at 50+). Rotor bolts are 25 fl lbs and the pulley I think is 35. Both use red loctite.

 

[pauly]

It would be so useful to have all mistakes in our manual listed in one thread.
I have done my bearings while back and probably over tighten those screws.
Thanks for the warning Spencer.

Paul.

 

[pauly]

Since Big Dog is Back haven't they updated or released new workshop manual?
If not I reckon they should.

Paul.

 

[SEAL-rider]

Even better if we could have the moderators delete all the threads that have errors. When you do a search on the forum for torque values the lists show up and many have errors. I will search them out and try to make it easy for the moderators. It would be great if anyone has a clean complete list of correct torque and bolt thread prep.

Dent, BWG

 

[woodbutcher]

Since Big Dog is Back haven't they updated or released new workshop manual?
If not I reckon they should.

Paul.

a simple thing called Liability. if Big Dog Is Back put out a manual saying "this is everything corrected that was wrong" at that point, if ANYTHING went wrong, they could be held liable for ANY future problems, damages, injuries, etc. that would or could occur. I wouldn't touch that with a 20' pole.

 

[pauly]

Every vehicle in the world has one. Weather it is available to everyone (for a price )
or just the service centres.
They would have to get it right of course,not like the previous BDM manuals.

Paul.