On Oct 12, 8:20 am, motoboi <irvingm1....RemoveThis@aol.com> wrote:
> On Oct 11, 10:53 pm, IRONDOG <iron....RemoveThis@jfrance.com> wrote:
>
>
>
> > motoboi wrote:
> > > Hey guys i posted a add over the summer about the honda cl350 jetting
> > > issue.
> > > thanks to some of your guys input it is running great. Now i have a
> > > Yamaha xt500
> > > i picked up this summer for 50 bucks , what a steal right it was a
> > > little bit
> > > better than a basket case . The biggest issue was that it was missing
> > > a SWING
> > > ARM. Any way i took the motor down becuase?the top end?was slightly
> > > frozen .?I
> > > purchase a used cylinder from ebay and i got a used piston with rings
> > > from a
> > > buddy of mine who had a Yamaha sr500 and had the pison as a spare .?I
> > > put the
> > > thing back together and started it and it started blowing white smoke
> > > immidiately. That was about a week ago and it is smoking a little less
> > > if not
> > > the same, it smokes just like a two stroke if not more. i asked my
> > > buddy what
> > > was the status on the motor that the piston came out of and he said it
> > > ran
> > > perfect so i am looking for any advice on what the problem?might be?
> > > and how i
> > > would go about fixing it. any input is welcome.? THANX.
>
> > You bought a used cylinder from one bike and a used piston and rings
> > from another and assembled them- that is your problem. Did you re-use
> > the gaskets, too?
> > Take either of the two cylinders you have to a motorcycle shop and
> > tell the hopefully competent person there that you want the cylinder
> > fixed right- either hone for new rings if the cylinder is reasonably
> > within spec or bore to oversize if needed. A job worth doing is worth
> > doing right.
>
> Hey, Irondog before you bash me any more let me explain, the cylinder
> i bought from ebay was already honed, the only thing that i neglected
> to do that was stupid on my part was to check the ring end gap and to
> check bore to see if it was oversize. Knowing that the bore was
> already honed , chances are that the cylinder was oversized and then
> honed or the seller i bought the cylinder from was considerate and
> honed the cylinder before he sent it to me.
I still can't believe you didn't mic it or check the
diameters of the piston and cylinder some way or other.
You don't really know what kind of clearances you're
running and even if you bought it from a buddy, you
don't know whether the piston is good or not. The skirt
could easily be partly collapsed even if it looks OK.
I've had this experience with pistons that looked perfect.
Pull it apart, measure the bore, measure the piston in
several places to make sure it's really OK and measure
the end gaps on the rings. I'd probably go for new
rings myself and be done with it.
It really doesn't make sense to try to put an engine back
together without checking all your parts clearances.
Either buy a micrometer and guage for the bore or
take it to somebody who has this stuff and knows
how to evaluate the parts you're trying to use.
While you're at it, what kind of shape are the valves
valve guides and valve train in ? Might's well get it all
fixed right at the same time.
Best of luck on your project. I think you've got
some work and a learning curve ahead of you.
>> Stay informed about: Yamaha xt 500 smoking issue 
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