| Re: Valve Stem Seal replacement [message #498621] |
Tue, 01 November 2005 08:23 |
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In article <1130518217.044446.34930 [at] g44g2000cwa.googlegroups.com>,
"skimmer" <rynchops_niger [at] yahoo.com> wrote:
> Nomen Nescio wrote:
> > A couple of things. Its mandatory for anybody who owns a motorbike to be a
> > motorbike mechanic. That is my secret for two wheel motoring.
>
> And it would be so much better if you kept your weird secrets to
> yourself.
>
> > As for your
> > valve stem oil seals, some bikes don't even have them.
>
> Name one. Don't name 2-smokes though.
>
> > You only need seals on intakes because no oil goes down the exhausts
> > because there's no suction.
>
> Bullcrap. Oil goes down the exhaust valve stem too, lubricating it.
> Engines run a lot better with lubricated valve guides. That's why we
> add chemicals like Rislone to the crankcase oil.
>
> > Cars need oil seals more than bikes because
> > cars flood their valve train with oil but bikes just gently drip oil.
>
> Never heard of the Suzuki Advanced Cooling System (SACS), huh? It
> floods the top end with oil, the two return tubes are over an inch in
> diameter. There are millions of SACS engines on the roads.
> >
> > Forget about chemical overhauls. All those after market additives are
> > gimmicks and totally ineffective. That includes STP, TCP, Mink Oil, Motor
> > Medic, Bars Stop Leak, Axle Grease and Elastic Keepemfromfloppin.
>
> Chemicals work well for various applications. Some are temporary fixes
> and you may find yourself getting tired of buying the same product over
> and over and actually do some mechanical repairs, but some products
> will still help your engine overcome minor leaks or friction problems
> or whatever and you'll keep on buying them regularly.
> >
> > You need a genuine Yamaha shop manual.
>
> The OP was *thinking* about buying a *Honda*. What would he do with a
> Yamaha manual?
>
> > You will need a torch to free stuck parts driven on and remember every bike
> > has a lot of press-fit parts. To install such parts, you heat the female,
> > freeze the male and couple them while in that state, using a heavy sledge
> > to drive them home.
>
> Maybe somebody will use a "heavy sledge" to drive this idea home:
>
> You're a nut case, Nomen Nescio!
>
Relax, breath deeply, there are few absolutes. Brit bikes and cars
didn't use seals in the 50's and 60's, they did have a little o-ring on
the intake valve that pressed against the intake guide when the valve
was fully open. I think the first Harley overhead valves didn't use
anything on the exhaust valve guides wanting a little extra oil for
cooling the valves. Yes, a bit of oil goes over into the exhaust guide
but with a bad seal, a lot goes into the intake guide when the engine is
engine braking and has a lot of vacuum. The exhaust doesn't see the same
level of vacuum. I had the guides cut for seals on several Brit motors
like my MGB because the o-rings only lasted about 5,000 miles and then
the engine would suck oil like crazy and coke up the intake valves. Some
air cooled engines with a soft alloy brass guide expected a fair amount
of oil and putting seals on them would gaul the valve stems. For those I
replaced the guides with better stuff and used seals. I believe that
some race motors like the old Offenhousers would run without seals to
keep the valves a little cooler. As to SACS, it works well but the
biggest spray is under the pistons for cooling. On high lift cams in
race motors, there can be inadequate oil on the cams causing rapid wear
or failure. Ape sells a great external oil kit for the top end to
increase the flow to the cam area when using a high lift cam on the SACS
motors. I think Holeshot is now selling one for the Bandit version as
well. But you are correct that there is a lot of oil there anyway. The
post part about replacing seals with the head in place, ie using high
pressure air to hold the valve in place while the spring is removed and
the seal replaced is very common, especially on motors where the seals
aren't very good and have to be replaced often (or those stupid o-rings
on the Brit motors).
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| Re: Valve Stem Seal replacement [message #498622 ] |
Tue, 01 November 2005 15:06 |
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Ray Curry wrote:
> In article <1130518217.044446.34930 [at] g44g2000cwa.googlegroups.com>,
> "skimmer" <rynchops_niger [at] yahoo.com> wrote:
>
> > Nomen Nescio wrote:
> > > You will need a torch to free stuck parts driven on and remember every bike
> > > has a lot of press-fit parts. To install such parts, you heat the female,
> > > freeze the male and couple them while in that state, using a heavy sledge
> > > to drive them home.
> >
> > Maybe somebody will use a "heavy sledge" to drive this idea home:
> >
> > You're a nut case, Nomen Nescio!
> >
>
> Relax, breath deeply, there are few absolutes.
If there's just *one* absolute in this imperfect universe. it's that
Nomen Nescio is a nut case, trying to slide bad suggestions into his
typical off-the-wall advice.
Sledge hammers are used to destroy and demolish old buildings.
If somebody has parts that need to be pressed together, an arbor press
is the correct tool, and there are a variety of jawed pullers and
special tools for the purpose.
There are situations where ball peen hammers and rubber mallets are
used, and I had a special lead weighted hammer for loosening the knock
off nuts on my Triumph TR-4's wheels. But that was the closest I ever
came to using a sledge hammer on a vehicle.
Soft faced lead hammers are also used to "true" pressed-up crankshafts.
But this is done by skilled experts in shops, not by madmen like Nomen
Nescio at computer keyboards.
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