Monday, November 4, 2013

Another spice from Jpn!!

It's been long time from last post. We've been work in Japan little while.

Koji brought back great production tire from Japan!

"Dunlop K180" 

Design for dirt track and it is street legal. We never seen in US this size! Dear dunlop tire, please sell this tire in North America, please!! 

Switching front wheel..

 And done. How looks cool with black wheels..!

And we going to take dirt track ride so,,


remove front brake, mirror and tape up to all lights.


Down exhaust pipe is another (used) parts from Japan.

back view.


We will report next time how's running at track.



Thursday, August 29, 2013

Wanna have some fun?

It was busy August!

We had motoGP world grand prix, XDL, Bikers night at down town, GNC Indy mile and Local flat track race at Marion county fair.

Furuhashi Racing had guest from Japan. This young man name Masahiro Komazaki. He wanted try American dirt track race so, we have a chance to join this time.

We knew he has experience for flat track but wasn't sure how's he going.

Nice looking!

Dog fight against CRF150R.

He whipped stock XR100 ! It was great show we could see, his potential, and another side how XR100 is fun bike! Only you need to do for flat track race is change rear tire. 

Here is Gopro shot.

Main race.

Honda XR100 stock only has 9.8hp. We can see that hard to catch up other MX bike on straight. But if you want to try flat track race. This bike gives you really good experience.

You can see his good turn speed. 

Everyone want to win when we race. And this, flat track race is easiest for ride. But after the race, you'll see how hard to get 1st place. 

Mid-America Speedway has many choice of entry classes. 

No matter what place you finished, you can tell after ride that how fun it is. It just simple oval race but this race has been exist when motorcycle race born and keep going till today. You will see why after ride.

Now, that Japanese boy rode three flat track races and watched GNC Indy mile,



He was flight back to Japan after all event.

Watch or ride either way, August in Indy have great time for all motorcyclist!

Let us know when you need information about Indiana flat track.
Mail to:


TW200, TTR230 Exhaust big valve for sale

Sunday, July 21, 2013

Yamaha TW200 / 250 modified.

All information in this article is not for the amateur or person who is inexperienced at motor work. This is not a tuning manual. Motor work has many kinds of risk and motorcycles can cause you serious injure or death. Take your own risk and responsibility if you attempt to work or to ride. We hope we can leave this article open public for enthusiast. Thank you.


Yamaha TW200 is street use bike. Nothing special, nothing high performance, but people like this because they can enjoy modifying many ways.

In picture bike looks like normal except Super Trapp down exhaust pipe but It has 249 cc tune up by Yamaha genuine parts. 

Modified point:

XT250 piston
TTR230 crankshaft
Webcam 89 cam with valve spring
KFR Big valve (Exhaust) 
WPC treatment
Ported cylinder head
2001~ model ECU and electric wiring etc.

This bike came here with extra used motor. It wasn't running. We picked and put in good parts together and rode for while. But we knew that motor needed  rebuilt. One day, bike start leaked motor oil. Now it's time, we decided split motor and rebuild with a little more fun. 

This is the first motor condition. Amazed this motor was running.

  Of course, sleeve looks same way. 

Transmission. Cavity tooth all over.


Here is some picture and detail about modified. 

Bore x Stroke 74.0 x 58.0 mm as XT250.

After re-sleeved

First what we needed was cylinder re-sleeve. XT250 piston is bigger than stock. This work we've ordered and done by LA sleeve. They could put nikasil aluminum sleeve and that will be great combination with aluminum forged piston but we didn't put this time by running purpose and cost.

measure, measure,,

We need bored out crank case hole caused by bigger cylinder sleeve.

Before (stock)


Still crank case needs grind work little bit for cylinder sleeve install.  

Grind needed both sides little..

Fit in finally.

Cleaned off crank case and repainted.

Now it's time for assemble TTR230 crankshaft and other all parts. 
All bearings, transmission parts are new of course.

Assemble is nothing special, just make sure every piece is set right position.

stock 200cc motor off. 

We clean off and repainted swing arm at once. Looks nice!

Let's see TW stock piston and new XT piston. 

Left is stock TW, Right is XT250 (forged) piston.
 Piston rings are much thinner.

Newer design piston has thinner wall thickness also. And more holes.
Sophisticated design.

TW stock piston with rings 184.7g

XT piston with rings 191.9g

New piston and rings are treated by WPC treatment.  (Yamaha stock XT piston has not same color shown as pictures.)

We forgot measure and take picture with piston pin! Pin is also shorter design than TW's. We can expect total lighter weight but again, XT piston is bigger and forged.

Installed piston.

Mount cylinder head and check piston-valve clearance. 

Put too much clay. Closest clearance In 1.9mm Ex 2.0mm at least, good enough.

Things don't go smooth usually, cranking by hand feels something not right. 
It happen when piston position around bottom dead center.

We found piston skirt has interference with balancer. NG.

 We decide to cut off piston skirt this time. (Sorry, don't have pictures.) That work made piston weight 0.3g lighter, well done.

Back to assemble again with custom head gasket.

Cam chain will stretch easily than stock after changed to strong valve spring so, better keep watch tensioner adjustment. You can think of cam chain is like "Drive train" as well. It is very important for this motor.

Time to run!

27% bigger displacement from stock motor pulls so much torque and HP. Gearing is 15-50 now, and you can still release clutch from idle for start.

 We can recommend this modified to TW200 or TTR230 user however, better remind always, engine modified has effect and side effect. Good effect is nothing but more torque and power. Side effect is you have to always pay attention to motor health and operation. It is tuning up motor even if built by Yamaha genuine parts. It will be short overhaul cycle than stock for sure. Cam chain stretching is common problem for this motor. And running will not have the same handling feel as 200cc motor, it is bigger bike. Someone like, someone maybe not.

Currently, we made 1000 miles test ride for custom cylinder head (with KFR original big exhaust valve) and 500 miles for whole motor without problem. What surprise thing that runs fine without any carburetor jetting or adjustment. Possible reason are  large piston making more vacuum suction and all stock (regulated) intake system. We can think about this motor possible to make more high output. But this bike is for street use mostly. High power performance is not everything for street stage. This motor making 72~73MPG actual gas on city ride. Stock 200cc was made about 74~75MPG. Do you like or not?

Our best recommend is up to 223cc by Yamaha TTR parts. You can tell that is still "TW". This 250 motor is 'not racing horse but not work horse' as stock motor. Better not take serious ride. 

You can make what you like. Hopefully you enjoyed this example.


KFR wants to send thank you very much to these nice people:

Three "camshaft magicians" from WEBCAM  

WPC treatment

We will take riding movie and upload soon.

Friday, May 3, 2013

TW200, TTR225/230 Big valve for sale

+1.0mm Stainless steel exhaust valve for Yamaha TW200, TTR225/230 (All year's model) 

Furuhashi racing original product. $32/piece  (+Shipping. 7% sales tax will charge if you are Indiana state resident.)

Paypal accept.

Purchase or question, Email to Koji.  
Mail: furuhashiracing"at" 

*Limited quantity, required valve seat cut job for install.

Notice: It is built for high performance racing engines. Because of potential abuse, no warranty is offered.

Tuesday, April 30, 2013

Base design.

Fuel tank is locate under seat.

This bike has very unique design. But it make sense for ideal. 

Just took out storage space box. We can see battery and air filter box on left side.

What we have to do first is take motor out from frame and measure all geometry for flat track purpose.

After motor off.

This bike has very well frame design. All heavy parts is sits low or stay close to center even frame. Lot's media web telling this bike has great fuel economy and price but that is just part. We still can feel part of motoGP machine or competition MX bike design idea in this model.

Media or some people always say, "what's good, what cons" to new bike but it's only price matter and we can modified our own purpose basically so, we say no problem! Motorcycle is just like music instrumental. Focus point should go like  "how do we going to play." 

New frame
Tank and swing arm
Triple tree
19"Wheel sets
Rear wheel brake system
All fitting parts 
Electrical parts

And high performance engine parts.

Looks like easy to build but there is so many things have to comes together. Team work will be very important. We look forward machine roll as soon as possible but maybe until this year end.