K3 burning/loosing oil

[CodeJACK]

OK, so Im looking for some guidance with my understading of why my K3 is loosing oil and running rich.

• I know the bike is running rich because I can smell fuel coming from the exhaust
• Oil level I now need to watch like a hawk as its always dropping below low
• When I had bike in for service last year, the shop told me the throttle bodies were in perfect harmony
  • This I need to check myself but would it really contibute to my issues?
• My fuel economy is not great - Calculated at 32Mpg
• Need new rear wheel bearings but would any drag caused by these lead to poor fuel economy? there not a total loss yet
• When I started bike the other day I noticed hints of black (no white) smoke so going to watch for this more.
  • Is this unburnt fuel or my oil disappearing out the rear?
  • Is this a result of rich running and "washing" and oil from cylinder during combustion and potentially causing damage?
  • I have new plugs that I need to fit and maybe this will help combustion
• Valve clearances checked and apparently well withing clearances but would this affect any of the above?
• Anything else I should change/do?

Edit:

Forgot to add that there is no visable sign of oil leaking from any seals so I presume it is burning off some how

[Bibio]

from my experience of to much fuel washing the bores it causes the oil level to rise not drop.

i would look at replacing the valve stem seals. if there are no physical signs of oil leakage and its going through a lot of oil then it can only be 2 things, worn piston rings/bore or worn valve stem seals. my personal first port of call would be an engine oil flush additive then an oil/filter change to see if the rings have gummed up, if it still eats oil then its rings/bore or seals. if its just suddenly started happening my money would be on the valve stem seals.

check the plugs to see if its both barrels or just the one. oil burning will turn the plug insulator wet/black.

my understanding of engines burning oil would cause an increase in fuel usage as your not getting the combustion you should, add to that it will foul plugs so you end up with a weak spark which in turn will cause unburnt fuel.

[CodeJACK]

Originally Posted by Bibio

from my experience of to much fuel washing the bores it causes the oil level to rise not drop.

i would look at replacing the valve stem seals. if there are no physical signs of oil leakage and its going through a lot of oil then it can only be 2 things, worn piston rings/bore or worn valve stem seals. my personal first port of call would be an engine oil flush additive then an oil/filter change to see if the rings have gummed up, if it still eats oil then its rings/bore or seals. if its just suddenly started happening my money would be on the valve stem seals.

check the plugs to see if its both barrels or just the one. oil burning will turn the plug insulator wet/black.

my understanding of engines burning oil would cause an increase in fuel usage as your not getting the combustion you should, add to that it will foul plugs so you end up with a weak spark which in turn will cause unburnt fuel.

Actually, I like your engine flush idea. Last year when i had the clutch cover off to fit a new detent star, I was amazed by the sticky yellow slick that was all over the inside of the engine. Would this be the sort of crud you refer to? Is this just crap oil residue?

How do I use an engine flush? Any particular one I should use?

Would a compression test tell me if the piston seal was bad or is it hard to tell the difference between piston seal and valve seal?

[DJ123]

What oil are you using?

[CodeJACK]

Originally Posted by daddyjob

What oil are you using?

Castrol 10W40 Racing. Full Synth

[DJ123]

I think the synthetic is your issue. Run it on semi-synthetic and it should work fine with a lot less burning.

[CodeJACK]

Originally Posted by daddyjob

I think the synthetic is your issue. Run it on semi-synthetic and it should work fine with a lot less burning.

Holy crap, really?

I'll be so ashamed if it was that. My pockets might be thankful though. Its lashing rain here at the mo but as soon as I get an evening clear, ill whip the plugs to get an idea of condition.

What is it about fully synth that it burns? Would this cause the yellow sticky crap in the engine?

[DJ123]

Fully synth is a much finer oil, so it passes through all the smaller gaps. Semi synth is a bit 'rougher' as it is part man made and part natural and so doesn't eek past certain tolerances and burn.
Bit of a crude description but you get the idea.


Some engines prefer fully synth (especially at high mileage) others need/prefer semi synth.

[Bibio]

daddy could be on to something there, i hadn't thought of that.

no harm in trying a flush at the same time. just pick any of the ones you see in halfords. if your oil is on low just top up with the flush and then run your engine for 10-15min then drain. if your oil is full then drain down to the low and top up with flush. i personally like Wynn's stuff but they are all the same.

[CodeJACK]

Anyone used this oil?

Opinions?

http://www.morrisonbhp.net/apps/webs...s/show/5793466