Oil past cylinder head?

Welcome to the forum for all things related to the internal combustion engine and or driving in Taiwan. Topics including (but not limited to) drivers' licenses, vehicular issues, what to do in traffic accidents, driving in Taiwan, good mechanics, etc. are all excellent candidates for this forum.

Moderator: John

Oil past cylinder head?

Postby Super Hans » 23 Jul 2012, 16:28

It was a nice country road near LinKou, at night. But I needed to stop for a minute to render the services of some local shrubbery by the side of the road. So I parked up and put the machine on it's side stand with it's engine still running, crossed over the road and proceeded to carry out some business required of nature.
Then behind me there was the tell-tale crash of a bike toppling over onto it's side. There wasn't much I could do at the time because my widget was still hanging out, but fortunately the auto cut off tripped and the engine stopped.
When I straightened her up and got her going again, I went back across the road to pick up the motorcycle. It started fine but there was some whitish smoke coming from the exhausts. The smoke from the right side vanished after letting the motorcycle idle for about 3 minutes, however, the smoke on the left side lingered until I got home - 30 minutes later.
I took the bike for ride today and for the most part, the smoke has disappeared. However, I noticed that if I accelerate abruptly, thick light blue coloured smoke is still emitted from the exhaust on the left - the side the motorcycle fell onto.
So I put it down to oil getting past the cylinder heads while the bike was on it's side. It still pulls fine and it sounds the same, but I'm not sure whether I should let the oil burn off gradually or take it in, get it opened up and cleaned out.
Any advice?

No ribbing about dropping the bike, please.
The bones got the wrong detail I hoped it would have for you
Safe for a shin bone or even a hand
It's such a lonely ride...
Forumosan avatar
Super Hans
Street Dog Chaser (zhuīgǎn liúlàng gǒu)
Street Dog Chaser (zhuīgǎn liúlàng gǒu)
 
Posts: 1299
ORIGINAL POSTER
Joined: 05 Mar 2011, 13:07
Location: Localiser Established
42 Recommends(s)
150 Recognized(s)

6000

Re: Oil past cylinder head?

Postby Ducked » 23 Jul 2012, 20:59

Not sure I understand what you mean by got "past the cylinder heads".

You might mean you think the oil has slopped up into the rocker cover (perhaps up the timing chain route, if it has one) and got "past the cylinder head", presumably down the valve guides, since I can't think offhand of another route.

Seems slightly unlikely, since there's always oil in the rocker cover anyway, though probably not so much.

A (more plausible?) alternative might involve pooled sump oil getting forced past the rings on one side of a "horizontally descending" piston. The piston hitting the pooled oil might be what stalled the engine out when it hit the deck.

I wouldn't have thought it'd bend anything at idle. I'd just burn it off, but if it doesn't stop, I'd suspect a displaced or broken piston ring.

This is just speculation and not based on any experience of this situation.
We reach for the sky. Neither does civilisation.

(Incidentally, if the search button is your friend, you must have some bloody useless, dysfunctional friends)
Forumosan avatar
Ducked
Overpaid Foreign Athlete (duō fù xīn shuǐ guò gāo de wài jí yùn dòng yuán)
Overpaid Foreign Athlete (duō fù xīn shuǐ guò gāo de wài jí yùn dòng yuán)
 
Posts: 3348
Joined: 09 Feb 2006, 16:46
7 Recommends(s)
44 Recognized(s)

6000

Re: Oil past cylinder head?

Postby Super Hans » 23 Jul 2012, 23:49

Thanks for your reply, Ducked.

I wouldn't have thought it'd bend anything at idle. I'd just burn it off, but if it doesn't stop, I'd suspect a displaced or broken piston ring.


This is what I was worried about. However, the amount of smoke has reduced somewhat - there was a lot at first, especially at idle, but now there is no smoke at idle - there is only smoke if I pull away sharpish.
The bike has an auto-cut off system designed in, where it detects if it is on it's side. You have to turn off the ignition, turn it back on again and wait for it to reset before you can start it again.

A (more plausible?) alternative might involve pooled sump oil getting forced past the rings on one side of a "horizontally descending" piston.


This is actually what I meant - so oil is now being burned off in the chamber and the exhaust gas contains the smoke and stench of burned off oil. It now smells like a 2 stroke machine.
Again, there is .no loss of power. 0-60 is the same, and I'd expect a bit of loss if there were broken rings. I am hoping with all my might here as ring replacement will be expensive.

Thanks again.
The bones got the wrong detail I hoped it would have for you
Safe for a shin bone or even a hand
It's such a lonely ride...
Forumosan avatar
Super Hans
Street Dog Chaser (zhuīgǎn liúlàng gǒu)
Street Dog Chaser (zhuīgǎn liúlàng gǒu)
 
Posts: 1299
ORIGINAL POSTER
Joined: 05 Mar 2011, 13:07
Location: Localiser Established
42 Recommends(s)
150 Recognized(s)

6000





 
 
 x

Return to Cars & Motorcycles



Who is online

Forumosans browsing this forum: No Forumosans and 2 visitors

Those who make the worst use of their time are the first to complain of its shortness -- JEAN DE LA BRUYÈRE