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Carb switching.... very crazy but very rewarding
- Subject: Carb switching.... very crazy but very rewarding
- From: Ben Barkow <dr.ben@xxxxxxxxx>
- Date: Thu, 03 Feb 2005 11:37:27 -0500
> Not that I have ever seen. Stan Smith at Rocky Point Cycles sells Mikuni
> kits for Airheads, maybe he could be persuaded to develop some Oilhead kits.
> Tom Cutter
Yes, Stan Smith is an excellent source. The nice folks at Sudco, the big
carb source are helpful in every way except when you ask about bikes which
they have no experience with, then you are on your own.
When I started measuring intake vacuum, I was shocked to find vacuums as
high as with carbs. My expectation was that with FI, the vacuum would be
minimal and the volumetric efficiency is therefore great. With carbs, you
need vacuum to draw the fuel into the venturi and vacuum is the enemy of VE.
Sooo, maybe carbs are not such bad creatures on modern bikes.
Few hobbyist biker activities are more challenging, rewarding, frustrating,
and beneficial that carb switcheroos. CRAZY. I've done it twice on Airheads
with never-before-attempted carbs.... crazy. Carbs are very very subtle and
have maybe 6-8 variables which you must tamper with to get passable
performance. And not cheap.
Some mechanical issues (mounting, cables, hoses, small rodents hibernating
in the air filter box) but they are easy enough to address.
With an Oilhead, you will also need to address ignition timing. Most ECUs
(Bosch???) do fancy tricks with spark timing, quite remarkable tricks and
well beyond the 19th century steam engine flyball governors found on bikes
and well beyond the vacuum advances found additionally on old cars too.