Notice:
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.
We apologize about took so long from last up date.
Now, Furuhashi Racing's FTW (we calling our TW like this way) project is keep on going!
We decided install Mikuni TMR carburetor this season.
This pumper carb can make nice throttle response and power feeling to bike.
Koji kept this carb for many years in his garage. 28mm diameter is perfect size for TW200 stock displacement.
This sound made us lean into it.
This sound made us lean into it.
For fitting:
This carburetor require couple of modification for install to TW. Most issue are Interference with frame and rear shock.
1st: Throttle wire holder.
Throttle wire needs more slunt angle for fit. This parts release from Yoshimura Japan.
2nd: Rear shock and carburetor, air filter fitting.
TMR stock angle and position.
Yoshimura TMR
Throttle wire needs more slunt angle for fit. This parts release from Yoshimura Japan.
2nd: Rear shock and carburetor, air filter fitting.
Standard intake manifold mount.
Flip upside down.
We can fit in after intake manifold 180 degree upside down.
But there is no space for air filter or filter connecting.
This idea is only work for funnel version like this photo.
"Air filter is necessary for dirt track racing use."
We decided to go to standard intake manifold by original equip angle after many try and error.
Grind off frame and carburetor throttle wire holder just little bitt for made clearance.
Shorten spigot by lathe would make more space between carb and frame.
Cut and weld 180 degree bend mandrel aluminum tube for make air filter joint.
roll up aluminum sheet metal for joint part and weld together.
Check fitting
Original Idle adjust screw (right side in photo.) has interference with rear shock spring. We put left side one to carb. This piece has long thread length that needed to shorten.
This is how fit looks like. K&N filter stick out from side.
Side cover will not fit together so, we decided intake tube curve back to inside.
Final shape.
Side cover can stay now.
Adjust carb jetting few and put back together.
3rd: Electric wire and components.
We made this panel from aluminum sheet metal.
Rear fender is totally gone after air cleaner box off so, we made simple & light weight rear fender by fiber glass sheet. Strong and flexible too.
It's time to ride.
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Koji take this machine to Mid-America Speedway other day.
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Koji take this machine to Mid-America Speedway other day.
His Impression:
"Fun, fun and fun. Power feel is big changed. I can tell it has much more power than before. This effect from total tuning so, not only by pumper carburetor. I am not sure how much weight air cleaner box had but bike feel so much lighter and I didn't feel rear wheel mass weight like last I rode here. Race track is little too dry and slipply but now, rear tire making power slide by my throttle control. That couldn't happen before. This bike is totally different from street model. People judge motorcycle by displacement and spec these days. FTW is street model base air cooled 200cc motor. Maybe some people think "Young donkey" but I can not tell that way anymore. It just great and fun to ride on dirt track! "
"At main race after sunset, track was packed well by nice moisture down into soil. that meaning we can get really smooth grip like asphalt. FTW runs well as heat race. I wouldn't say power sliding was exact same as heat race track condition but this power feeling is real. I could really enjoyed race and finished 1st place in mad dog class. I'm trying to make simple expression, this bike just so much fun!"
"At main race after sunset, track was packed well by nice moisture down into soil. that meaning we can get really smooth grip like asphalt. FTW runs well as heat race. I wouldn't say power sliding was exact same as heat race track condition but this power feeling is real. I could really enjoyed race and finished 1st place in mad dog class. I'm trying to make simple expression, this bike just so much fun!"
Furuhashi Racing thanks to : Mid-America Speedway
Special thanks to : Red Stone Performance Engineering , WPC treatment, WESTFIELD POWER SPORTS.
We service TW/TTR motor maintenance / tuning up and deal WPC treatment in midwest area. Email us furuhashiracing@yahoo.com if you have interest.
KFR original big Exhaust valve for sale : eBay link here.
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