Carbs lean

CARBURETTOR LEAN CONDITIONS

Correcting a lean condition -Roy Richards

The reason it is backfiring is because it is too lean and not too rich. Your motorcycle has diff carb circuits
that control diff parts of the throttle opening and RPM range. When you put the K&N in the bike it will lean
out the whole range. This may help you at highway and upper RPM ranges if you really are too rich there.
What I found.(and Im at sea level but it is Hot&Humid which means my air is thin as far as the bike is concerned.)
is that I had to fatten up the entire range with my Hindle. Drill out the little adjustment plugs on the pilot screws.
Back them out to about 4 turns to start. (The guy with the lean condition on the supertrapp mufflers needs to do
this too). This will fix the backfiring and surge or miss down low as it will fatten it up a little down there. Now
take the tops off the carbs and pull out the diaphram and needle assembly. Shim the needles up a little with a
pack of little washers you can buy @ radio shack for about $1. Now you will have more mid range roll on power.
You dont have to pull the carbs to do either of these things and your bike should run way better....

Low speed Carb tuning - Justin Lassy

The fuel mixture screws are indeed located behind the brass plugs. The brass plugs must be removed to access
the screws. Be *very* careful about drilling out the plugs-use a drill stop. If you hit the screws with the drill
bit, even for a moment, you risk running the screw down hard against its seat, destroying the screw and possibly
the carb seat. Bad. The fuel mixture screws deal w/ mixture at idle and a little bit above idle. They will determine
off idle throttle response and extremely low idle cruising. Turn screws in to lean the mixture out, turn them out to
richen the mixture.

Here are some rough guidelines to determine if you are running rich or lean at various RPM's. Examining the plugs
is really the best way to get accurate results, but these guidelines will help you shoot for a direction (leaner or richer).

Idle and off idle: Lean condition: Poor off idle throttle response, idle that flutters a little after a throttle blip
then slowly returns to the idle that you've set, popping back through the carbs when the throttle is blipped.

Rich condition: Off idle response may be good unless plugs are fouled from a way too rich mixture. After a throttle
blip themotor will dive down below set idle and will either die if way too rich or may return to set idle if it can recover.

Installing a dynojet kit - Justin Neville-Rolfe

Introduction:

A dynojet can enhance your Vmax considerably. There is a lean flat spot around 4500rpm designed into the US Import
Vmax so that it passes the emmission controls in most US states. This makes it unsmooth in the midrange. The original
needle and settings come with a needle that cannot be changed and small main jets. A dynojet kit is normally used to
remove this lean action. It has little effect when no other changes are made, but the addition of some competition
exhausts and open K&N air filters (or airbox mods -TH) increases the air flow without the increased petrol flow
making the bike run even leaner. In these cases, a dynojet is essential to increase the fuel flow to make the bike run
OK again. Dynojets do affect fuel consumption, but not much. It will probably knock 2 or 3 miles per gallon off your
current consumption.

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