[Shotimes] Re: help.....valve chatter and rod knock...

[David P]

Erik,

    I assumed that since you were still driving your SHO that no serious
damage has yet occurred to the engine other than destroying the rod and
crank journal. If the piston has hit the head, you may as well be out that
piston and the head, but it doesn't sound as if you've reached this point
just yet.

    Also, I think I probably spoke too soon on the involved work. To replace
a rod, you will have to pull the head because the piston cannot be
re-inserted from beneath the motor. Looks like it IS easier to just put in a
replacement motor.

    Failing rod bearings do not typically make noises before they spin. You
can spin a rod bearing and not know about it for a few minutes, when the
overheated bearing and rod begin to eat into each other. This is why, once
you've heard the knock, it's too late. An indication, though, might be an
intermittent valve knock problem, caused by not getting enough oil to the
top end due to the bottom end being too loose, but I would not suggest
anyone use this to avoid rod bearing failure.

    Rod bearing replacement should become part of the 60k service, or at
least by 100k. Main bearings should be done every other 60k, or 150k at the
most. Some motors may not need the bearings, but the motor needs the oil
pressure to maintain other things, like the valvetrain. I replaced my rods
and mains at 70k and gained 3-11psi depending on the rpm.

    All this talk of rod bearing failures (through the years) has me
wondering why there are so many. What I am questioning is whether or not the
journal places enough pressure on the bearings to keep them seated to a low
enough psi to be considered reliable. Maybe for Yamaha's engineers. Most of
the stuff Yamaha builds is high maintenance, low duty (racing motors,
motorcycles, boats, etc...).



David P

95MTX



~
----- Original Message -----
From: "Erik Balser" <masho95@attbi.com>
To: "David P" <jpotter8@bellsouth.net>; <shotimes@autox.team.net>
Sent: Sunday, October 27, 2002 08:12
Subject: Re: [Shotimes] Re: help.....valve chatter and rod knock...


> Exactly what doing rod bearings that are failing sound like? Or is there a
> way to tell how bad they are without pulling the pan? And what's the
average
> life, mileage wise, for a set of rod bearings? Thanks
>
> '95 MTX
> masho95
> http://home.attbi.com/~masho95
> ----- Original Message -----
> From: "David P" <jpotter8@bellsouth.net>
> To: "Lee Kelsoe" <the_big_sho@phobia.net>; "SHO" <shotimes@autox.team.net>
> Sent: Sunday, October 27, 2002 7:16 AM
> Subject: Re: [Shotimes] Re: help.....valve chatter and rod knock...
>
>
> > You can put in a replacement crank and rod from another motor. However,
> > you've pretty much got to purchase another motor to get another crank
and
> > rod! Most would opt for finding a lower mileage motor, maybe get it
> > rebalanced, put in new bearings, re-gap the valve-train, etc, then put
in
> > the new motor. It's a great way to go, but if you are able to find a
> > replacement crank and rod, then you can swap out the parts, put in new
> > bearings, and be on your way.
> >
> > I doubt the oil pump is a problem. More likely you have a lot of miles
and
> > your rod bearings were too worn. Gotta take care of them before they
take
> > care of you, you know!
> >
> >
> > David P
> >
> > 95MTX
> >
> >
> >
> > ~
> > ----- Original Message -----
> > From: "Lee Kelsoe" <the_big_sho@phobia.net>
> > To: "SHO" <shotimes@autox.team.net>
> > Sent: Sunday, October 27, 2002 03:22
> > Subject: [Shotimes] Re: help.....valve chatter and rod knock...
> >
> >
> > > so I am guessing that the reply from fitz about his rebuilt engines
> means
> > > that there is no rebuild kit for the crank and bearings...that when
this
> > > happens, the concensus is that it is time for a new motor....if so,
what
> > > does anyone suggest i do....
> > _______________________________________________
> > Shotimes mailing list
> > Shotimes@autox.team.net
> > http://www.team.net/mailman/listinfo/shotimes
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