TT-R125 Frequently Asked Questions
Note: Some of the items discussed in this FAQ are no longer available. This
information has been left online for historical reasons and to assist current owners of these now
discontinued items. If any of these parts are still available (new, used, or otherwise), they will
be listed on our product pages. To see all product listings for the this model click
Our BBR Product Identification section has more information about older products from our past.
Will your parts fit the 125 and 125L?
Yes, all our parts will fit the 125 and 125L. The only difference
between these two bikes is wheel size, swingarm length, front disc and
spring rates. Everything else--frame, engine, seat, tank, body work, etc. is
I broke the rear hub on my TT-R. Do you have a replacement?
BBR currently does not make a rear hub for the TT-R. Your local Yamaha
dealer is still your best bet. 2002 - 2008 TT-Rs have a different rear hub
(and use a different sprocket). This is stronger than the earlier year hubs.
What gearing should I run?
BBR recommends the stock gearing, which is 13/54, for most applications.
For tighter tracks try a 55, and wide open tracks a 53. BBR stocks a wide
variety of TT-R front and rear sprockets and chains.
How much horsepower does the TT-R have?
The TT-R has slightly more than 7 horsepower stock at the rear wheel on a
DynoJet 200. Yamaha reads at the countershaft which is why they come up with
a higher number. Basically, if you're in shape, you can run a little faster
than the bone stock TT-R will go. This is why the bike is so fun to ride and
handles so great.
Does BBR sell an O-Ring chain for the TT-R?
BBR does not recommend using an o-ring chain on a 7-horsepower bike unless
you are constantly riding underwater. We run the DID ER Gold Series chain on
all of our race bikes and carry them in stock.
What jetting should I run?
The stock TT-R comes with a 105 main jet, which is slightly lean. This is
why you have to leave the choke on so long unless the weather is hot.
We recommend a 110 or 112 main jet with the BBR exhaust system, depending on
weather, elevation, and riding style. With the BBR 150 kit, camshaft and
free-flow filter, BBR recommends a 112-115 main jet in both the stock carb
and our 26mm Keihin carb kit with 100 octane gas. We are located near sea
level so any further fine-tuning might best be done by a good tuner in your
area. See our Jetting FAQ for more info.
Can you put YZ forks on my TT-R?
Yes, we can. But it costs a lot to do it from the local Yamaha parts dealer.
We recommend trying to find a used YZ80 if you really want to do this. Here
are the Yamaha part numbers and prices (from Yamaha of Troy, your local
dealer may be higher):
YZ80 Fork Leg Left
YZ80 Fork Leg Right
YZ80 Left fork guard
YZ80 Right fork guard
YZ80 Fork guard guide (right)
YZ80 Fork guard guide (left)
YZ80 Fork guard guide bolt (4)
YZ80 Fork guard bolts (6)
YZ80 Upper cable bracket
YZ80 Lower cable bracket
YZ80 Lower cable bracket bolt
YZ80 Brake caliper assembly
YZ80 Front brake hose
YZ80 Front brake master cylinder
YZ80 Front brake lever
YZ80 Brake lever rubber cover
YZ80 brake hose bolt (2)
YZ80 brake hose bolt washers (4)
48-1952 (White Bros)
Tag Triple Clamp (YZ80)
51-1442 (White Bros)
UFO Front number plate (YZ80)
BBR Motorsports TT-R 125 Swingarm
Works Performance TT-R 125 shock
Note that you can probably get away without the brake parts if you can have
a longer brake hose made for the TT-R lever and caliper (please don't call
or e-mail us about this - you are on your own...). The YZ80 hose has
different ends. Also, this total is parts only. You will also need to
fabricate new wheel spacers, brake caliper spacers, and need various nuts
and bolts not listed. This also assumes that you can get the lower bearing
off the TT-R triple clamps without wrecking it. If not, add that cost. If
you are robbing the whole front end from a YZ80, you can use the front
wheel to simplify installation. Realize, though, that you will need to get
the front rim and spokes from Yamaha. No one else makes a 19" rim and spokes
for the YZ80 hub.
Because the YZ80 forks are longer (and work better), you really have to do
something to make the rear of the bike match. Our best luck has been with
our swingarm (which raises up the back by 1 1/2") and the Work Performance
shock. And, no, the YZ80 shock does not fit the TT-R 125. While on that
subject, pretty much none of the parts on the YZ80 fit on the TT-R 125.
Generally we recommend that customers look at our aluminum frame kit for the
TT-R motor. The end result is a better bike (no frame flex and much better
layout). The brakes are much better (even better than the YZ80 brakes) and
the suspension is worlds better. Cost may seem high, but if you consider the
other parts that you need add to your stock framed TT-R, it isn't bad. The
aluminum framed bike is the ultimate mini-four stroke.
Will the rear disc brake from the YZ80 fit my TT-R125?
No. It can be cut, welded, and wedged on but it costs a lot of money. As the
above FAQ shows, buying the parts from Yamaha will cost you a pile of money.
Same goes for the disk brake parts. Remember that you will have to buy the
larger rim and spokes from Yamaha for the YZ80 rear hub. Special axle
spacers have to be fabricated, a special brake master cylinder mount has to
be welded to the frame, a custom caliper mount, the swingarm modified, etc.
We've done a several of these, but it isn't cheap (figure up to $2000 for us
to do it). For a good do-it-yourselfer, robbing parts from a complete YZ80,
this is probably do-able. Just don't call us...
Will the YZ80 graphics (from company X) fit my TT-R125?
No. You might cut and grind and fit it, but it is going to look
pretty bad. Remember that NOTHING from the YZ80 fits the TT-R 125L.
Regardless of what the sales guy at your dealership said (or a magazine
story), the TT-R is it's own bike. It is not based on the (current) YZ80.
The rear suspension is similar to the 1982 YZ80 and that caused some of the
early confusion with some of the magazines (one misprinted it as 1992). Even
the similar looking rear fender is different. The front fender might swap
between the bikes with some drilling, but they are different.
How fast does the TT-R go?
Not very fast. That's why it's so stinkin' fun to ride. We do not measure
top MPH of any motorcycles. In motocross, it isn't how fast it goes, but how
quickly you get there.
What's the difference between the BBR exhaust system and all the rest?
BBR uses a stepped, tapered header which allows for both bottom-end torque
and top end over-rev - the best of both worlds. When we originally designed
the first BBR TT-R exhaust, we had 10 different prototypes and found out we
had 10 different riders, each with a different opinion. Most of our
competitors use a straight header; this results in a one-dimensional
powerband, all top end or all bottom end. Extensive testing with the tapered
design allowed us to come up with an exhaust system that both the secretary
and Lance Smail can agree on. Our pipe starts out at an 1 1/8" header and
ends at 1 1/2" back at the muffler.
Why don't the other guys use this setup?
Because it's expensive to do it right. The tapers and the quality of the
materials used on the BBR pipes are not cheap, but you get what you pay for.
Basically, by bolting on the BBR exhaust system, you are widening the power
spread considerably, cutting down on shifting and letting you ride a gear
What about the disc-style exhaust systems?
The disc setups work pretty good, but you have to run so many discs to get
modern-day power characteristics (high over-rev) that it defeats the purpose
and ends up being louder and heavier than is necessary. An aggressive rider
will beat the disc-style into pieces because of the extra weight and number
of parts involved. You're not going to see a national pro win with a
disc-style exhaust system. The 1980s are over.
How much does the BBR exhaust system weigh and how loud is it?
The BBR exhaust system weighs in right at 4 pounds, which is 2 ½
pounds lighter than stock. Most of our competitors' pipes were one to one
and a half pounds heavier than ours. Our exhaust produces 96 decibels
(measured at 20" from the outlet at a 90 degree angle, as per AMA
requirements) while stock is about 92. Our exhaust is noticeably louder than
stock but not ridiculous. We have neighbors too. Unfortunately, power and
sound go hand-in-hand - don't let anybody tell you different. BBR currently
offers a quiet core that considerably reduces sound output ( 220-BBR-1004 )
$39.95, and it will keep your neighbors happy.
How much horsepower do your parts add?
Dyno charts will be added to each product as time allows. See our product
pages for more info.
What is a port job?
The port job allows more gas (air and fuel) to flow past the valves, producing more top-end
over-rev. The TT-R is very sensitive to porting. The ports look small, but
traditional porting will wreck the powerband of the TT-R. We recommend
leaving the ports alone (with minor cleanup and matching) for most people.
Unless you really trust the person doing the porting, you should leave it
alone. We've seen dozens of ruined TT-R heads on slow bikes.
Should I lighten my flywheel?
The lightened flywheel is a personal preference item. By shaving a pound off
the flywheel, the TT-R motor revs considerably quicker which is great for
motocross and people who like to pin it. If you're riding in the mud, sand,
tight woods or play riding, BBR recommends leaving the flywheel alone.
What makes the TT-R better than the XR?
Everything! The TT-R is a modern version of the 20-year-old XR. Yamaha has
jumped right into the early 80s with the TT-R. The TT-R has a beefier
transmission because it was designed for the road, has a bigger clutch that
is bulletproof, bigger valves, a counter balancer, a roller cam, ignition
that runs in the oil, etc., etc. The TT-R motor is bulletproof and starts
with one kick, every time. The XR is still the greatest bike of all time
because everybody has one and learned to ride on one, but it's time for an
Is my TT-R legal in the mini or super mini class?
Every track and sanctioning body is different. Contact your local event
promoters or AMA district representatives to find out. Remember that the TT-R
125 is a mini 4-stroke playbike. The CR/RM/KX/YZ80/85 are full on race
bikes. Nothing that you do to the TT-R will make it the equal of a modern
2-stroke race bike. Regardless, the TT-R 125 will still be more fun to ride.
What are the benefits of BBR tripleclamps?
The BBR upper triple clamp allows the fork tubes to be slid down 1" which
raises the front of the bike. It also grabs a larger surface area of the
fork tube which prevents fork flex. BBR offers the clamps in both standard
and oversize handlebar mounts, and we have a wide variety of handlebar bends
and colors. The bar mounts are two-way adjustable to customize the rider
compartment. In addition, the bar mounts are taller.
What will BBR fork and shock springs do for my TT-R?
BBR fork and shock springs are 30% stiffer than stock. BBR tested a wide
variety of spring rates and settled on these as the best all-around rate for
the TT-R, regardless of rider weight. The stiffer springs hold the TT-R up
into the softer part of the travel and help to keep it from bottoming. BBR's
springs are of the highest quality and will not sack out. BBR recommends
using them as a set.
What does the air filter do?
The BBR free-flow air filter can add up to ½ horsepower to your TT-R. It's
like taking your hand off the exhaust - it completely un-corks the TT-R. The
free-flow filter kit includes a large air filter and backing plate designed
and CNC-ed to flow the maximum amount of air. BBR does not recommend cutting
out your stock backing plate to match your tiny stock air filter. On the
dyno, bikes with mangled backing plates were actually slower than stock, due
to turbulence created by the small filter's inability to flow that much air.
Want a big off-idle hiccup?
Will the YZ 80 wheels/shock/swingarm/rear disc/ fit my TT-R?
Will the TT-R motor bolt into a YZ 80/CR 80 frame?
No, but a BBR complete aluminum frame kit starts at $3250 and a rolling
chassis starts at $6500. These kits allow you to use all the 96 and newer CR
What are the benefits of the BBR chain guide?
The stock chain guide only runs on one side of the chain. The BBR billet
chain guide wraps all the way around the chain and sprocket making it almost
impossible to derail the chain. Our chain guide has plastic on the sides,
too, to keep from destroying your chain.
What is a BBR cradle kit?
The cradle kit is a skid plate that ties the frame tubes together and helps
to prevent frame stretch and, in a worst case scenario, engine damage. It
also protects the engine cases from rock damage. The BBR engine cradle is
made from heat-treated 6061 aluminum and anodized gold.
What fork oil should I run at what level with the BBR fork springs?
BBR recommends running the stock 10w fork oil at the stock level, which is
130mm or 5.1" from the top of the tube with the fork compressed. For faster
or heavier riders, try 15w at 4.8" from the top.
Should I run a flat slide carb on my TT-R/XR?
If you enjoy driving to your local dealer to buy jet after jet in a futile
attempt to get rid of the big flat spot (off-idle hiccup), then this carb is
for you. If you prefer your bike not to idle or start easily and enjoy
spending more time jetting than riding, then you should install the flat
slide carb. The BBR guys finally found a use for the flat slide carb:
What should my suspension sag be set to with BBR springs?
We recommend you set the sag at about two inches. Adjust the sag to rider
preference for how quickly you would like the bike to steer. The tighter the
spring, the sharper the bike will steer. The looser the spring, the slower
the bike will steer.
Please feel free to call any of our expert sales staff who have spent many
hours riding the TT-R's for any additional questions.