Re: K&N Air Filter

[Bill Hussey <vfrboy@home.net>]

"Ng, Kevin (Bank of America Commercial Finance)" wrote:

> If this is the case, then how can K&N claim that you get better fuel mileage
> with their filters? Are they making this claim only for engines without EFI?
>
> BTW, Bill, I plan on re-jetting my bike next spring. Is this something that
> can be done by the average DIY'er? The dealer quoted me $290 for labor.
>
> Kevin Ng
> 97 GLX Windsor Blue

    As far as K&N goes ... they can say what they want, and I'm sure they have
an engine that proves their statement, but I have been on many many lists for
all different types of vehicles and have NEVER heard of a K&N filter alone
increasing gas mileage.  If you increase the air flow by itself, your mixture
will run lean, the FI MUST add more fuel to compensate or, depending on just
how lean the mixture gets, the damage can be extremely costly.

    As far as rejetting the bike, I'd recommend getting the manufacturers
repair manual and doing it yourself.  Getting to the jets and changing them is
not hard .. but setting up the needles and pilot jets properly takes time and
patience.  At the 16,000 mile mark, I had a local NYC shop install a full TBR
exhaust system and a Dyno Jet jet kit for my '97 VFR.  I paid an additional $75
to have the bike put up on the dyno so they shop could "fine-tune" the jets.
When it was all said and done, they had done nothing more than a before and
after run to show me how much power I was making, and did the world's shittiest
job on my jetting.  I had a huge loss of power below 7,000 rpm, and only a 4
peak HP gain up top -- $1300 for 4HP -- I was pissed!  Then I found out that my
lack of performance was due to an OVERLY OVERLY rich mixture on both the pilots
and the needles.  I found this out the hard way ... I was running through spark
plugs (at $12 a piece) every 2 weeks.

    So after about a month and a half of torture, I found, through the VFR
Mailing List, a shop by the name of Dynamo Humm in Quebec.  So I took off right
after work one Friday night in December, and drove straight north.  Got there
around noon Saturday, two guys ripped the bike apart, let me watch as they
worked on my carbs and modified my air box extensively, did a few dyno runs and
a few tweaks, and when it was all said and done .... I had power gains all over
the rev range, with a 12 peak HP gain up top (14% gain in HP).  I learned a lot
by watching those guys .. most importantly, that it is NOT hard to work on the
carbs, but you have to really put some time and testing into it if you're going
to do it in your garage and get it done right.

    If the shop you want to bring it to is just a dealer with a service
department, I'd say DEFINATELY don't do it.  But if the shop is a performance
only shop, they kinda have a reputation to uphold and will probably get it
about as right as anyone else can.  If you are scared to go into the carbs
yourself, have them do it.  See if they'll let you watch though, cause now that
I have a full exhaust system, high flow filter, and modified airbox, the engine
is far more responsive to climate changes so I tweak my jetting twice a year as
the weather turns.  It's not overly necessary, but when you put as many miles
on a bike as I do, you want it to run right.

Bill
'97 VFR (The daily driver and all purpose machine)
'98 Valkyrie Tourer (1520cc Horrizontally opposed 6 cylinder with 6 seperate
carbs ... try rejetting this sucker!)
'00 CBR929 (375lbs/150+HP .. drag race anyone??)
'98 Jetta GLX (The Date machine and thing to take when you NEED a trunk)