Last lap, last corner, 110 mph, two wheel drift... passing on the outside,
bike carefully controlled by just the subtlest of weight transfer and just
a "finger's touch" on the throttle... you run out of rpm and need to
upshift to complete the pass.... you need to shift.... it's ok.... a tap
and you are in the 4th, still in a drift....... you keep slightly
pulling... around.... slowly past....
Our Trans Detent Spring Kit
Shift Kit? Not us! B&M owns "Shift kit" name - so... don't call it
a "shift kit'!
For years and years, bikes have been sold and replaced with others
for the simple reason that they don't shift well.
Over my last 30+ years, many hours have been spent shimming,
undercutting, tweaking, nudging and cajoling the elves inside the
engine cases to slip the desired cog into it's "happy place", quickly
and without jumping back out....
One of the things that I noticed was that most modern gearboxes
were essentially the same lengths, widths and ratios, but they all
shifted and felt different when shifting - a Honda tended to "shift
like a Honda" and a Yamaha tended to "shift like a Yamaha".
The first engine that we really looked at was the Suzuki Katana
600. Same gearbox and the gsxr750, but my riders missed shifts
constantly on the 600 - but not the 750. Weird. (I left out the reason
why - you guess!)
Flipping the 600 engine over in the old shop let us look at the shift
detent star, detent arm and detent spring. I rotated the shift drum till
the detent arm would just "high center" between 3rd and 4th gear.
Aha! THAT's a "missed shift".
I took a pencil and pushed down on the arm with the eraser end and
"Snick" - it slipped off the center of the arm and right into gear. So,
I see. That's a "missed shift"! The gear tries to engage the mating gear
and the dogs and slots bounce off each other and make the arm "high
Got to get the dogs to move quicker towards the slot and get further
engaged before my anxious riders get the throttle back on!
So - Lessee, 2 stock springs..... WOW! No way to miss a shift... and
maybe no way to use your foot to shift, either.... a little too
stiff...... So.... there we go..... spring manufacturing - a "little"
stronger spring. That was our "$29.95 Spring and a gasket kit". I
figured that was about as much as I could sell it for, as once again
(story of my life), I
was fixing a part that people didn't know was broken........ Well, at
last count, we'd eliminated over 7,223,243 missed shifts and saved about
32,711 2nd gears and shift forks.
Transmission gears and forks get damaged when you miss a shift.
A year or so later, we introduced the "Pro Shift
In this step, we added some elegance to the concept - We build
new detent arms equipped with a microbearing instead of a riveted disc,
as the stock arms have. This time, instead of just "pushing harder" like
the first "Shift Kits", we went the next step and removed a bunch of
rotational friction - so with the slightly heavier spring to push harder
and the microbearing to reduce friction - ahhh!!! Even easier, even
quicker and it made missing a shift as rare as a lottery win in a 300
million lottery or that call from that big roadrace team......
So...... then...... I still wanted to make it better.....
(the EVO Shift STARtm)
We spent weeks and weeks playing with "Shift STAR" profiles. Since I'd
never seen anybody work on the profiles and I hadn't either, it was a
long process - We didn't know much beyond kind of a general od and a
general id - but no clue about arcs and angles and radii.......
Weeks went by - the CNC was never idle and new variously designed Shift
STARS popped out in all sorts of permutations. Some were horrible
shifting, some were just awful shifting and, luckily, some weren't so
bad. I would say that, right off, we established what "didn't work" -
Interestingly, you can find, stock, some of those designs that "didn't
Since we were working with only 3 bikes, all the same model, and had a
dedicated mechanic just for this project, we tried dozens and dozens of
designs and got very good, repeatable feedback.
Eventually, we arrived at a now copyrighted design that
accomplished everything that you could ask for -
easier foot pressure
quicker shifts and
virtually zero missed shifts
at any throttle position or rpm you could think of.
In the end, we developed a shift mechanism that shifted exactly
the way that "I" wanted.
(Lordy, lordy, I'd fire myself if I worked for me!)
EVO Shift STAR Kit benefits?
Easier upshifts under hard use. A "tap" and it's done. Awesome for race,
track days and street.
Since it's quicker and easier to upshift, the bike is less unsettled
when shiftin' and driftin'.
Effortless downshifting - cram all the downshifts as fast as you want.
One less thing to think about.
Smoother shifting in town - a tap and a big gsxr1000 or ZX10 snicks into
3rd as easily as a 125!
Driving in flip-flops? The STAR is a "must have"!
I want you to know that I was really impressed with the shift kit in my
Kawasaki 636 ZX 6R.
The bike (not me) has missed shifts before and once I got the kit in it
not only didn't miss
anymore but felt smooth and positive and actually easier all around to
shift it. The best part
of it was I just didn't have any attention on it at all.
Thank you for making such a fine product. It WORKS.
California Superbike School
It's everything that I ever wanted to do to a shift mechanism
Nothing much more can be done. Expect that it will take the manufacturers
about 2 years to copy it - so wait 2 years and buy a new bike - or have it
One already tried to buy one. Geez!
Slightly stronger detent spring - a new MicroBearing detent arm and the
final piece... A completely redesigned, empirically refined, multi angled,
variable radii, repeaked and valleyed:
EVO-7 DETENT STAR
This part will totally change the feel of the bike as a whole. The
shifting effort is about the same - but the speed at which the gears
actually engage is dramatically improved - Quicker, easier, shifting - A
"twitch" on the lever and the throttle and you are in the next gear!
Perfect for track use and road riding for effortless downshifts into a
corner and just a "tap" to upshift without any more than a "twitch" off
the throttle -
even mentioning that missed shifts virtually disappear!
In town? Low rpm cruise in second - shift to third?
So quick and smooth that it will surprise and amaze - NO more clunky, lazy
shifting in town - As I said - it's totally different and improved -
concept - Virtually all the Factory Pro Support riders in the AMA and WERA
multi- Champions Vesrah Racing tested and proved the EVO-7 Stars in 2003-2005.
performance that everybody used to take as a "given" will be regarded as
"slow and lazy" after riding a bike with this kit -
Foot stomping, "Hayabusa" shifting disappears..... Honda's and Suzuki's
lose their clunky in town shifting..... Suzuki's stars stop falling off,
Kawasaki's lose their, well, err.. Kawasaki shifting "feel". Hey and even
ZX12's stop shedding pins off the stock star!
Kit includes a new detent arm with a low friction microbearing roller,
a performance shift spring and the NEW Factory Pro EVO-7 Detent Star.
Make shifting MUCH quicker. MUCH easier, MUCH lighter and virtually eliminate missed
Just wanted to let you know that your EVO-7 Shift Star
Kit ROCKS! I've been having problems getting a lot of
missed shifts between 3 & 4th gears in my 636 and
after installing your kit, the problem is 100% GONE. I
raced out at Streets of Willow this past weekend and
didn't have one single missed shift anywhere and the
positive engagement feel is perfect.
Thanks for making my 636 an even better bike!
I got the shift kit installed, and it works like a charm.
Thanks Marc... I got the parts and they are
already installed into my bike.
It was amazing what a difference the
shift star made into the bike!!! :)
I'm waiting to get the bike tuned on the
dyno to see what is the affect of velocity stacks. :)