Smokey Joe

Sp!ke · Post by **Sp!ke** » Tue Sep 11, 2007 12:01 am

After a high speed 4000 mile blast across europe on my TRX engined Super Tenere, its now burning oil at an alarming rate. Clearly the engne didnt like sitting for 12+ hour stretches at 7k rpm

hmm... usually I have bikes that are tougher than I am, but alas it doesnt seem to be the case with this beast.

On my return leg I was using 1 litre of oil every 500 miles

and its smoking visibly now and sounds a little rough. (top end rather than bottom I think)

Anyway, I'm planning a strip down sometime this winter but before I get started I want to know what to expect here and what my options are. I'm hoping its just new rings required. Is it likely I'll need a rebore or new sleeves put in?

Obviously while the head is off, I may as well clean it up and reseat the valves, maybe get rid of casting marks etc, anyone recommend someone to do this or is it a relatively simple DIY.

So calling on the forums combined wisdom, what would you lot do or recommend? What are my options?

Post by **phuk72** » Tue Sep 11, 2007 8:53 am

is there oil on the plugs?

You may find that a complete oil change helps

Valve seals or rings are the most likely escape routes for oil especially if it is blowing out of the exhaust

top end noise prob due to oil be fecked

prob no need to rebore but you may find that the bores need honing

dfh · Post by **dfh** » Tue Sep 11, 2007 9:41 am

phuk72 wrote:is there oil on the plugs?

You may find that a complete oil change helps

Valve seals or rings are the most likely escape routes for oil especially if it is blowing out of the exhaust

top end noise prob due to oil be fecked

prob no need to rebore but you may find that the bores need honing

I'm with phuk with that one, but will add an extra.

If its hard to start cold then its taken up the valve clearances.

If its an 96 or earlier then it will, in the fullness of time, streach the inlet valve stems. This causes two issues. Firstly it will become impossible to find shims thin enough to reset the valve clearances. Secondly the inlet stem seals can't seal against the stems and oil consumption goes through the roof.

The cure ( on my bike at least) is new later model inlet valves ( they have a new part # after '97) and new stem seals, plus new piston rings.

My valve seats were not recessed, the head only needed seats recut and a bit of a clean up and the bores only a light hone.

Now at 91,000km my "rex goes like a steam train ( without the smoke..

) and uses virtually no-oil... better than a new one $\:D/$

DFH

Post by **phuk72** » Tue Sep 11, 2007 9:57 am

good point well made

Sp!ke · Post by **Sp!ke** » Tue Sep 11, 2007 10:23 am

Thanks for the advice, I'll try and escape to the garage to have a closer look at the clearences over the next week or so.

As for the oil needing changing, I've put so much oil in over the last month, I'd thought it would be pretty clean unless its burning off the new stuff and retaining the old.

Anyway, I guess the first thing is to check the clearences and change the oil and see what happens. If its still bad, I'll be cracking the engine open once the dark nights draw in.

Cold starting is a bit of a problem just lately so I think you may have hit the nail on the head. Any recommendations for swift supply of replacement shims - probably mail order? My local Yamaha dealer has just closed down.

dfh · Post by **dfh** » Tue Sep 11, 2007 10:36 am

Sp!ke wrote:Thanks for the advice, I'll try and escape to the garage to have a closer look at the clearences over the next week or so.

As for the oil needing changing, I've put so much oil in over the last month, I'd thought it would be pretty clean unless its burning off the new stuff and retaining the old.

Anyway, I guess the first thing is to check the clearences and change the oil and see what happens. If its still bad, I'll be cracking the engine open once the dark nights draw in.

Cold starting is a bit of a problem just lately so I think you may have hit the nail on the head. Any recommendations for swift supply of replacement shims - probably mail order? My local Yamaha dealer has just closed down.

I live in Oz... so my cheap shims are not yours...

What year is the motor and how many kays on it? .... try a leakdown test, that will soon pick up any valves being held open.

DFH

Sp!ke · Post by **Sp!ke** » Tue Sep 11, 2007 1:13 pm

Think its a '98 or 99, mileage is about 30k.

kebab19 · Post by **kebab19** » Tue Sep 11, 2007 4:52 pm

I believe Wemoto sell the most popular shim sizes - individually.

Their Mail order has always been pretty swift.

Sp!ke · Post by **Sp!ke** » Tue Sep 11, 2007 9:32 pm

Just thinking... how would the valve clearences being too tight increase oil consumption. Would this in some way effect the valve seals?

Post by **phuk72** » Tue Sep 11, 2007 9:40 pm

More likely they have gone the other way but, either could affect the seals

dfh · Post by **dfh** » Wed Sep 12, 2007 2:04 pm

Sp!ke wrote:Just thinking... how would the valve clearences being too tight increase oil consumption. Would this in some way effect the valve seals?

The loss of inlet valve clearances and a considerable rise in oil consumption together are symptoms of streached valve stems.

The difficulty in cold starting is a symptom of one or more valves being being held open, with the subsequent loss of compression. If you can start it and get it warm enough to ride then as long as it does'nt get too cold it will restart all day.. thermal expansion of the valve and seat will help give you compression. Eventually, of course you will burn out a exhaust valve if that's the one held open or one day the bike will not generate enough compression to start.

Don't bother buying shims.. just check the clearances first.

DFH