Topic: Sudden white smoke from cam cover breather and exhaust

[PeWe]

Head thickness (height)
72.3mm written here when scrolling down.
http://forums.sohc4.net/index.php?topic=119848.0

72.3/25.4 = inch

[Tracksnblades1]

That’s about 0.004 difference than Kenny’s showing…
He shows 2.842 as the head thickness… see attachment


72.3 = 2.846457. ** I didn’t do the math, google did…😁

[Jonm99]

Just an update post for anyone who is reading through this thread and experiencing similar issues...

So apparently I had two issues on the top end of the engine.
1. Last mechanic that buttoned up the top did a poor job which ultimately led to excessive heat and finally warping of the cylinder head. Cylinder head was resurfaced.
2. One of the tower (?) seals was damaged as apparently the matching cylinder sleeve was offset ever so slightly which left a sharp edge. That wasn't an issue as long as there was no excessive heat. Once the surface warped it was all downhill from there. Dremeled the edge off (just a bit) and replaced the seals. Attaching a pic for reference.

Thanks to all that helped with the diagnosis.

[grcamna2]

Just an update post for anyone who is reading through this thread and experiencing similar issues...

So apparently I had two issues on the top end of the engine.
1. Last mechanic that buttoned up the top did a poor job which ultimately led to excessive heat and finally warping of the cylinder head. Cylinder head was resurfaced.
2. One of the tower (?) seals was damaged as apparently the matching cylinder sleeve was offset ever so slightly which left a sharp edge. That wasn't an issue as long as there was no excessive heat. Once the surface warped it was all downhill from there. Dremeled the edge off (just a bit) and replaced the seals. Attaching a pic for reference.

Thanks to all that helped with the diagnosis.

Was the cyl. head resurfaced this time ?

[HondaMan]

Just an update post for anyone who is reading through this thread and experiencing similar issues...

So apparently I had two issues on the top end of the engine.
1. Last mechanic that buttoned up the top did a poor job which ultimately led to excessive heat and finally warping of the cylinder head. Cylinder head was resurfaced.
2. One of the tower (?) seals was damaged as apparently the matching cylinder sleeve was offset ever so slightly which left a sharp edge. That wasn't an issue as long as there was no excessive heat. Once the surface warped it was all downhill from there. Dremeled the edge off (just a bit) and replaced the seals. Attaching a pic for reference.

Thanks to all that helped with the diagnosis.

Yeah, that picture of the head with the round 'divots' in it (around where the dowels top out) is strange. I haven't seen that before, in stock engines. I suppose it's possible that someone once installed some too-long dowel(s) in those hole(s) and bolted down the head: this would explain both the marks into the head's surface and the warpage of the head. Those in-the-seal dowels are 12mm long, while the 2 outer dowels are 18mm long (some are actually only 16mm in factory engines I have seen) and I'm supposing the 2 outer ones got put into these 2 rubber dowels and the head torqued down, leaving those marks: after the head would not close, but was then warped, it was disassembled and the right dowels installed, but by then the cylinder head surface would leak from the damage.

Sort of like 'engine forensics'...?

[Jonm99]

Just an update post for anyone who is reading through this thread and experiencing similar issues...

So apparently I had two issues on the top end of the engine.
1. Last mechanic that buttoned up the top did a poor job which ultimately led to excessive heat and finally warping of the cylinder head. Cylinder head was resurfaced.
2. One of the tower (?) seals was damaged as apparently the matching cylinder sleeve was offset ever so slightly which left a sharp edge. That wasn't an issue as long as there was no excessive heat. Once the surface warped it was all downhill from there. Dremeled the edge off (just a bit) and replaced the seals. Attaching a pic for reference.

Thanks to all that helped with the diagnosis.

Was the cyl. head resurfaced this time ?

Yep.

[Jonm99]

Just an update post for anyone who is reading through this thread and experiencing similar issues...

So apparently I had two issues on the top end of the engine.
1. Last mechanic that buttoned up the top did a poor job which ultimately led to excessive heat and finally warping of the cylinder head. Cylinder head was resurfaced.
2. One of the tower (?) seals was damaged as apparently the matching cylinder sleeve was offset ever so slightly which left a sharp edge. That wasn't an issue as long as there was no excessive heat. Once the surface warped it was all downhill from there. Dremeled the edge off (just a bit) and replaced the seals. Attaching a pic for reference.

Thanks to all that helped with the diagnosis.

Yeah, that picture of the head with the round 'divots' in it (around where the dowels top out) is strange. I haven't seen that before, in stock engines. I suppose it's possible that someone once installed some too-long dowel(s) in those hole(s) and bolted down the head: this would explain both the marks into the head's surface and the warpage of the head. Those in-the-seal dowels are 12mm long, while the 2 outer dowels are 18mm long (some are actually only 16mm in factory engines I have seen) and I'm supposing the 2 outer ones got put into these 2 rubber dowels and the head torqued down, leaving those marks: after the head would not close, but was then warped, it was disassembled and the right dowels installed, but by then the cylinder head surface would leak from the damage.

Sort of like 'engine forensics'...?

Well, your guess is better than min! I'll just say that I never had a leak from the top of the engine (just smoke from the exhaust and breather), and I didn't replace the tower bolts (if that is what you were referring to), as I didn't see what you see. Anyway, it is what it is at this point so I can only hope we don't end up repeating this conversation down the road 🙃 In meantime, no more smoke, bike starts easy, sounds great, and runs like a tiger....for now!

[Rosinante]

Yeah, black smoke is usually fuel and white or blue smoke is usually oil (or water), but always ignore my inputs when they conflict with advice from HondaMan.

[PeWe]

My K6 blew hole in a piston 1984 (836cc). I suddenly saw white smoke in the mirrors, lots of it. I continued to ride my smoking bike to a friend.

If your head was not sealed against bores due to too long "special pins" for oil return holes.
Oil can be sucked into the bores (Smoke from exhaust + oil)
Overpressure from these bores find its way to  the oil return holes, overpressure  released via bleeder hose from head cover plus the other hose to the atmosphere.

I think my "special pins" are 14.1mm long.
All these pins and knock pins must be measured before assembly, verified with the holes depths they are fitted into.

Cylinder can be milled, these  pins will be too long.
Same with the 2 front corner knock pins fixing the head in place.

The 2 under cylinder also to check.  Hole depth in upper case + cylinder hole. Using thinner gasket will be a factor too.