Re: What did you do to or for or with your Laverda today?

Fitted new exhaust gaskets- not the copper rings, t'other type made of what looks like aluminium and some sort of asbestos stuff.

Motorcycle_Exhaust_Gaskets.jpg


The gaskets are quite thick didn't compress too much on initial tightening which wasn't ideal.  Used some Loctite 5920 high temp copper/silicon stuff to help the seal (dunno if this will work either given the heat).  Anyway, hope it works- all three ports were dribbling oil after a fast run which was getting right on my nerves.  Don't really understand why, after making these bikes for so many years, the problem was never fixed.
 
No, brand new precision honed guides.  The problem is poor sealing of the exhaust to the head, a known problem with the triples, dunno about the twins. Oil is sucked down the valve guides somehow.  Maybe someone with more technical knowledge will be along shortly to explain...  ::) I'll run her up tomorrow and then nip down the exhaust roses and see what happens.
 
My guess would be some sort of venturi effect with the air peak at the header pipes allowing oil to be sucked down the valve guides.
 
Reggie3cl said:
No, brand new precision honed guides.  The problem is poor sealing of the exhaust to the head, a known problem with the triples, dunno about the twins. Oil is sucked down the valve guides somehow.  Maybe someone with more technical knowledge will be along shortly to explain...  ::) I'll run her up tomorrow and then nip down the exhaust roses and see what happens.
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The "poor" sealing of the downpipes only shows up the "problem".  Once they're properly sealed, the oil is blown out the back, it's still there though!

Seriously doubt it can be traced to the quality of the guides or valve-guide clearance.  I think Keith is well aware of the excessive oil supply connected with the stock guides.

Nip up the clamps and keep an eye on oil consumption on longer runs.

Only one port affected, or all?  Cracked head?  Scored head-guide bore?  Unlikely, reckon Keith would have found that...

piet
 
Reggie, Keith fitted oil seals to both valve guides on my new rgs head a few years ago....no smoke? No oil drips or consumption...sorry but maybe the head has to come off  wait till winter!
 
Only one port affected, or all?  Cracked head?  Scored head-guide bore?  Unlikely, reckon Keith would have found that...
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Reckon the head is OK, Keith went through it top to bottom.  Oil is evident in all three ports and I was sure I read somewhere that oil can be sucked down the guides if the pipes don't seal properly.  BTW, I fitted the pipes, so that's entirely down to me. ::)
 
I used those seals for a while, Will frond them. You need to keep nipping them up as they do continue to compress for a long while.
 
Richard,
Those gaskets are metaflex or sometimes called spiral wound. They require an ideal crush to store up energy or spring to seal with expansion / contraction due to temperature cycles.
Not sure if 7mm studs have enough oomph.

Usually filled with graphite these days, which is brilliant for high temperature, but crap at strength - hence the metal sandwich.
I would be amazed if your filler is asbestos, it is a fantastic gasket material but has an image problem these days, what with people dying painful early deaths.
The copper rings with filler are more crushable, but not so much spring, perhaps the studs provide that.

Sorry if any typo's, these smartphones aren't so smart sometimes.
 
Hi Simon

Yeah, realised they weren't asbestos, but it looks similar.  I don't think I would have ordered them if I'd realised they were so deep, but now i've got them I'll give 'em a go and see what happens.

Sorry Vince- didn't realise Will was a person!
 
He makes that very clear,or did last night at the club meet, its a shame they are not a bit thinner as the nuts are a long way out with them fitted. I always found my nuts loose every time I checked,in the nicest way.Its not fun checking with big bore headers and the still not working horns in the way. Loose nuts and broken horn, go your hardest boys.
 
if they are thoughtful as well as deep you"ll be alright.
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Last thing I need is motorcycle parts that can think for themselves-I may get an inferiority complex...

He makes that very clear,or did last night at the club meet, its a shame they are not a bit thinner as the nuts are a long way out with them fitted. I always found my nuts loose every time I checked,in the nicest way.Its not fun checking with big bore headers and the still not working horns in the way. Loose nuts and broken horn, go your hardest boys.
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Hmm, will take the appropriate socket out with me to tighten things up.  Do they settle down eventually?

 
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