Valve stem oil seals

My YZF750 has always been one for a drop of the old semi-synth but
recently its oil consumption is getting into the realms of dipsosis[1]

I'm fairly sure its the valve stem oil seals as they're a weak point on
this bike and its blowing oil spots out the exhaust rather than burning
it.

HBOL gives the job a full 5 spanners and TBH I neither have the spanner
twirling ability or the tools to do such a job. Does anybody know of a
decent engine shop in the Staffs/West Midlands area, preferably one
where I can just drop the bike in and any ideas how much it would cost.


[1] About a ltr every 500 miles.

 

Pete Fisher would know a place but he hasn't posted for a week, presumably
over at his French bolt hole.

 

Stem seals are not really a problem, they just waste oil until it
gets bad enough to fail the MOT for smoke and emissions.
Harmless so long as you keep the oil topped up.
OTOH there might just be other problems, check the compression
pressure on each cylinder and keep a wary ear open for noises.
Check that the crankcase breather is not blocked, this can cause
similar symptoms.

 

dipsosis[1]

I rode behind you for about 30 seconds and I understood how Kiran
felt sitting behind my RGV.

 

My pet theory on this is: if it smokes (mostly) under power it's rings,
if it smokes after the overrun or idling it's top end. It could be worn
valve guides rather than just defective seals.

How high is the mileage and how old is the bike?

As to the job itself the biggest ballbreaking consumer of time for a
workshop will be the removal and replacement of the engine.

If you can do that yourself and hand over the engine it will be
significantly cheaper.

However, if you're paying someone to do the job we're in the realms of
the economic reality being to scrap the bike and recover costs by
breaking it.

I'm going to have to change the cylinder head and rings on the Armstrong;
I expect it will still take me the best part of a weekend to do the job
on a simple single.

 

Its not so much smoking as chucking it out the exhaust unburnt.

16700 Miles and its a 96. Looking back at the past MOT's it looks like
its been stood for a few years which could have lead to the seals
hardening I suppose.

I reckon I could remove the engine. Its the 20 tiny valves , springs and
god knows how many pingfuckits in the head which worries me.

Be a shame to break it as apart from the oil the bike is pretty much
spot on.

Bring back 2 strokes that's what I say.

 

No strange noises and the bike doesn't seem down on performance. I'll
check the crankcase breather thanks. I hadn't thought of that.

 

Why not just keep the oil topped up and ride it until it either breaks
or fails an MOT. Then break it for spares.
In the meanwhile start saving for the replacement.
A classic case of bangernomics.

 

A whole weekend?

You just cannot put this go slow dinosaur thinking union shit down can
you?

 

What is the price of oil going to be next week when merkania defaults on
it's debts?

A classic case of you failing to understand the consequences of turmoil in
the global economy upon a gentleman's pleasures.

 

I don't think you'd say that if you'd actually seen the bike but given
that you're something of an idiot I'm probably wrong.

 

1. Check I.D of suggester.
2. Check layout plan of bike/engine.
3. Assess point diametrically opposite crankcase breather.
4. Start there.

 

Sounds about right, if it runs clean at full power and billows smoke when
you shut the throttle its inlet stem seals.

Tends not to happen with exhaust stem seals as there's pressure as opposed
to inlet manifold vacuum on overrun.