vapor lock, and more

The Masons masonjs at
Sat Aug 15 17:47:08 PDT 2009

Like Art--sometimes you get lucky.  This morning I put fresh gas in the '75 
Honda and decided to ride it down to the rental cottage about 4 miles away 
to cut the lawn.  It doesn't have a choke cable or lever (removed by some 
previous owner) so I usually just suck some gas into a 5 cc syringe and 
inject it straight into the carbuetor throat.  Its lights on the 2nd kick. 
I head up the driveway and make it about 40 meters down the road before the 
engine died.  I hadn't turned on the petcock.  I know the bike is not warm 
and I'll just kill myself trying to kick start it without the syringe.  It 
is much simpler to push it back the 40 yards and then bump start it on the 
200 yard sloping driveway.  This bike has no plates. insurance or ownership. 
While I'm pushing back an Ontario Provincial Police cruiser drives by very 
slowly.  They really frown upon the locals riding around the roads with 
similar bikes.  He rolled down his window and just said "you're not from 
around here are you?"
I rolled it back down the driveway and took the truck over to the other 


----- Original Message ----- 
From: "William K Denton" <wkdenton at>
To: <gpzlist at>
Sent: Friday, August 14, 2009 6:16 PM
Subject: Re: vapor lock, and more

> Jim said, "The manual petcock is only as good as the operator as I found 
> out this morning."
> ------------------------------------------------------------------
> Jim,
> Agreed.  However, at least with a manual shut-off, you can correct the 
> "behavior" [no one to blame but yourself].  With a vacuum shut-off tap, 
> you are at the mercy of the rubber supplier's QC and the ravages of time 
> and fuel reformulation effects on elastomers [everyone to blame but 
> yourself].
> On the brighter side, the OEM petcock packing (4-hole rubber gasket P/N 
> 43049-1075) is cheap (<$5.00) and plentiful, as it is used in Vulcans, 
> ZX6's, ZX9's ZRX's, GPz's and ZX11's.  At that price, one should just add 
> "replace every five years" to the scheduled maintenance routine in the 
> shop manual.
> Bill Denton
> Yardley, PA
> wkdenton at
> Lazarus Cycleworks, LLC
> Breathing New Life into Old Bikes

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