Engine burning oil

[Nobby the Bastard]

First part of my query.


My FZ is losing some oil. It's not got any obvious leaks and it's a bit smokey exhaust-wise so that points at rings or valve stem seals.

I think it's the valve stem seals for the following reasons.

1) it's only smokey on first startup in the morning, it isn't particularly smokey if I park up for an hour or so and then start it up.

2) It stops smoking quite quickly once its started (within a couple of minutes)

3) First start in the morning is now becoming progressively harder to achieve. I think it's the spark plugs getting fouled with oil (will check at the weekend, will pull the plugs before I attempt to start and then again after trying to start.) It's no trouble to start within a few hours of being run, but after about 8 hours (a day at work) you can hear that a couple of the cylinders aren't firing to begin with. This makes me think that the oil is seepng down from the valve gear onto the spark plugs over time, rather than the plugs getting a coating due to rings going as the starting problems would occur all the time.


Views?


Second part of my query.

I'm inclined to replace the seals rather than stick a different engine in as 1) The seals plus a head gasket would cost me about £80, and 2) aside from that, it seems pretty strong. It happily holds it's own at the traffic light grand prix.

Is there any advice anyone can give me on this? Are there any unusual tools that I would need (Preferbly, I'd have to beg or borrow a torque wrench and a valve spring compressor rather than buy.)
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[RhynoCZ]

What is the color of the smoke? It sounds like a normal steam to me, the exhaust is very cold over night and you push through there hot exhaust gases. Like when you breathe in winter and there's smoke coming out of your mouth/nose.

Worse starting can be result of faulty choke or it's cabel (it just doesn't choke the carbs enough, I've been there), or sparkplugs, or battery, or valve clearences, or old fuel...

If FZ is what think it is, 80's sport-touring bike, then try some Seafoam (fuel system cleaner, helped me alot with my GPz).

About the oil, if it's the 80's sport-touring Yamaha, then I'd be surprised if it didn't eat oil. How do you measure it?
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[Nobby the Bastard]

It's not steam, it's white smoke. And tiny droplets of oil spray out.

It does give out steam on cold days, so I know the difference.

I'm having to add about 300ml every 1000 miles.

Battery is fine, valve clearences done about 10k miles ago, and I know what the symptoms of that is.

Not a fuel problem, starts fine when cold, only have a problem when it's been stood unused over night.

Choke has never been used at any time in the last 4 years (even through the depths of winter). The bad starting has grdually got worse over the last 6 months
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[RhynoCZ]

Well, that is bad, if it spits oil out of the exhaust. It'd rings or one of those 20 valves then, if the engine's dry.

EDIT: The only unusual tool to have would be torque wrench, people say you don't need one, but I think that if you want to put the head back on the engine right, then you should do it with torque wrench.
When you have the head done, put in all valves and plugs, put it on table upside down, so you get the insides of the combustion chambers and pour in each some petrol, nothing should leak through. If it's done right
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[Nobby the Bastard]

[RhynoCZ]

[Robby]

Valve stem seals are on of the things that people like to diagnose because there isn't any particularly good diagnosis - the only way to check is to replace them.

They don't fail that often. Like many things, the killer is leaving the bike standing for years, in which case they may dry up and perish, or the valve stems may develop a bit of surface corrosion to rip them up. If the bike has been used regularly for a good while, I wouldn't start suspecting the stem seals.

Looking at the issues:
1. Poor starting. When did the bike last have a full service, what state is the battery in, and how old are the HT leads?
2. Smoke on start up. The last few days have been humid and a lot cooler, so you will see an awful lot more smoke (steam) on start up. You may also be spending longer on the choke, which can add to the problem.

The test to valve steam seals going is smoke on the overrun - long straight road, open the throttle up, close it, look for smoke in the mirror as the revs die down. The high revving engine is trying to suck in air, the throttle is closed so there is more pressure trying to suck air and oil past the stem seals. If they have failed you can expect to see a decent amount of smoke.

[Nobby the Bastard]

[0l0dom0l0]

[Aff]

I thought the most reliable sign of valve seals failing was blue smoke on start up after sitting while hot. The thin oil will seep down and pool above the valves, then be burnt on start up.

Also if left at idle for a while then harshly accelerated you would see blue smoke. Manifold depression at idle pulls the oil past the seals which collects in the ports, which aren't hot enough at idle to burn it all off, when you pull off the oil gets burnt.
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Current Bikes:Honda 929RR Fireblade, Honda CD200 Benly (Project), Stomp Z2 140
Electric Bike Project

[Nobby the Bastard]

It's giving out smoke on startup when cold (i.e. after its been sat for a good few hours.) That's what make me think it's the seals, it's getting time to seep down the seal and above the valve.

I'm going to pull the spark plugs on Saturday morning without having run it, and check the condition.

Then put them back in, turn the engine over (without letting it start) and then check the plugs again.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[orac]

Compression test when cold and then when hot check against specs, if ok that chances of being rings is extremely slim, same goes for head gasket. By deduction it leaves one option, stem seals.

if you are so inclined you can even do a leak down test which will even pick up loss of compression that compression testers cant.

fyi my old motor would smoke when cold, and when you gave if a hand full, it had ovalled the bores. Had gs5 that had done seal, only ampked when cold and when give a hand full
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Current rides - 2016 Triumph Street Triple Rx, 1994 Suzuki Bandit 400 VM, TGB 204 Classic 125cc
"with nothing left to lose, there is everything to gain. It's not the size of the dog in the fight, it's the size of the fight in the dog"

[Nobby the Bastard]

To be honst, I don't think it's worth my spending any money on a compression test. If the rings were going, I'd have noticed a loss of power by now and it's still just as rapid as it always was.

I'll b checking for smoke on the overrun tomorrow.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[orac]

Don't be so sure about that, the ovalled bores in 400 didn't show much power loss what so ever, specially when hot, it was only 12psi down when hot - well with in spec. Cold showed nearly 50psi low on all 4 which ws well out of spec, this is why i said to do a cold and hot test, compression tester can be gotten quite from machine mart and ideal for this of thing
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Current rides - 2016 Triumph Street Triple Rx, 1994 Suzuki Bandit 400 VM, TGB 204 Classic 125cc
"with nothing left to lose, there is everything to gain. It's not the size of the dog in the fight, it's the size of the fight in the dog"

[MarJay]

[Nobby the Bastard]

Right, inspected the inlet and outlt ports (via carb and exhaust) today before I attempted to start it.

To start, though, this is the crap that my bike sprays all over my front door when it's starting sometimes....

https://i428.photobucket.com/albums/qq9/Nobbythechihuahua/OilyBike007_zpsdf1dd4e2.jpg

Used a long thing (thin bamboo, longest thing I could find as none of my screwdrivers were long enough) I dipped the inlet ports...

https://i428.photobucket.com/albums/qq9/Nobbythechihuahua/OilyBike002_zpsd0926743.jpg

https://i428.photobucket.com/albums/qq9/Nobbythechihuahua/OilyBike003_zpscf7b5aba.jpg

https://i428.photobucket.com/albums/qq9/Nobbythechihuahua/OilyBike004_zps496968ed.jpg

I'm pretty sure that black stuff shouldn't be in my inlet ports.

No sign of oil in the exhaust ports, but a little white speckling in the exhausts themselves. Could this be burned oil?

Anyway, got it started (after the usual faff), and here's the video of the exhuast smoke. It's usually a bit more than this, but it had been running for a minute or so when by the time I'd sorted out the camera. It's difficult to see due to the grey smoke not really contrasting with the pavement.

https://i428.photobucket.com/albums/qq9/Nobbythechihuahua/th_OilyBike005_zps48b2293b.jpg

Then a second video taken a couple of minutes later when wrm. No smoke....

https://i428.photobucket.com/albums/qq9/Nobbythechihuahua/th_OilyBike006_zpsb964c08b.jpg

Views?
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[Kickstart]

Hi

Think later FZ / FZR engines could often burn a bit of oil (early 1FN FZ750s had different designs of pistons). From memory the quoted max oil consumption for an FZR1000 (very similar engine to your FZ) is far higher than you are getting.

Getting the head off the FZ is a minor pain due to the tools you need. You need a long allen key (from memory 6mm, but I could easily be wrong on that) which you can attach to a torque wrench to do the head up (the nuts are under the top half of the head, and there is a small hole to put the allen key through to get at the nuts).

With dipping down the inlets I would suggest that fuel residue is more likely to be found than oil.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Nobby the Bastard]

There was fuel as well (yellowish wet stuff).

I couldn't tell if the black stuff was wet or not because of the fuel.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[Kickstart]

Hi

With valve stem oil seals I thought the usual symptom was that the bike put out a load of blue smoke after slowing down with the throttle closed, rather than it dribbling down particularly much when parked. With the throttle closed there is a large low pressure in the intake, sucking the oil down the valve stems.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing