Z500 B3 - 6 speed : high oil consumption at high revs

 
Hi team,

New around here and as new when it comes to motorcycle mechanics. Was hoping to get some help on my 40 yo bike.

I've recently did a trip from London to Ely (80 miles) with some friends and have been notified that there was white-blueish smoke coming out of my pipes at high revs. When we stopped to check my oil level it was almost empty (you could only see oil through the glass if the bike was leaned to the right quite a lot). I had to top it up with 2 L.

Me being stupid, I didn't check the oil level before the trip, but it has been topped up on the 25th of May (the trip was on the 5th of June) when I got my regulator-rectifier replaced. This means that it went through 2L of oil in 2 weeks (only drove it in London prior to the trip).

After I topped it up, I have been monitoring the level, driving it only in London and it's pretty much the same. Is there any particular reason for it only consuming a high amount of oil at constant high revs (80mph, 7-8k rpm)?

To give you a bit more context, the top engine has been completely rebuilt at the end of March, with the following things being done to it:

• new cam chain
• new spark plugs
• new gasket set
• new o rings
• new valve seals

I've noticed a bit of oil residue in the airbox as well and smoke coming out of my right pipe at cold starts. (would attach some photos but my bike is in the shop having it's clocks replaced because I fried them when my reg-rectifier died earlier this month O_O).

Here's a photo of the bike

 

Assuming the bike is traveling at 80 mph at about 7500 rpm it sounds like your bike's clutch may be slipping quite a bit, and that may contribute to the high oil consumption.  Ed

Hi Ed, clutch got changed 2 months ago .

wrote:

Hi Ed, clutch got changed 2 months ago .
 

Was it properly installed?  If the springs were not tightened correctly or it the cable was not adjusted properly even a new clutch can slip.  Ed

The 550s (similar engine to your bike) will get through a little oil if you take long motorway trips on them. However, just a little top-up will be required.

Blue smoke noticed by your friends at high speed in broad daylight definitely isn't normal. There shouldn't be any blue smoke at all, at any speed, or upon startup, let alone noticed in those conditions.

What do your spark plugs look like? Do any of them show signs of burning oil?

You say it got new valve stem seals. That's good, if you're absolutely sure they were all fitted correctly.

I don't know where your crankcase breather hose leads, but you say there's some oil around your airbox. Does the hose lead into the airbox? I wonder if the crankcase is pressurising and spitting out oil. Obviously, it shouldn't be doing that.

Before taking your friends' word for it and suspecting the rings, test for other possibilities:

1) Take out each spark plug and inspect for signs of burned oil. Take a photo in case you want to consult someone or get a second opinion.
2) Not found anything? Then disconnect your crankcase breather, remove your airbox and check if it's full of oil. If it isn't, start up the bike with the hose disconnected from the airbox, and see if you can see oil spitting out.
3) If not, turn off the bike, clean it really thoroughly and remove all signs of oil residue, then let it dry completely. Start it up again, lie down on the ground next to it and watch and see if there's an oil leak developing underneath.
4) No? Then check around the head for signs of oil (for a leaky cam cover gasket or head gasket).
5) Check your clutch again, as the guy says, for signs of slipping.

If none of these turn up anything, then I don't see any other choice than to open it up.

Thank you so much guys, I'll have a look and get back with an update asap. 

By the looks of it it might be the crank case, there is a breather going up from it towards the airbox and it looks like there is a bit of greasy dirt around it.

I'll also check the spark plugs as my right pipe smokes a bit at start up on a cold morning.

Best,
D

Worst case but very unlikely, many years ago I had the same problem but also smoked under acceleration. My second oil rings were upside down causing the oil to blow through the rings (they have a small taper which scrapes the oil off the bore) food for thought.
Unfortunately in this case the compressions would show as good (have you checked the compressions?

Welcome Dragon.

Not familiar with the 500/550s so much.
I wonder if they have the Emission PAIR system that causes other Kawasakis to consume oil like my ZRX?

No’Flo! Emission PAIR Block Off Plug Set – ExpensiveLightweightStuff.com (kwick.biz)

The KZ pair system doesn’t suck oil like the ZRX system. A set of NoFlos from Kwik will fix your Rex.