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'09 yzf-r125 VS. '80 xs400


SirBieber
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1) So I saw a picture of the new '09 yzf-r125. The bike looks like its going 100mph when its not moving. I was very surprised to see that they made 125cc sport bikes. I'm used to seeing 125cc mopeds in India. Anyway it got me interested in comparing its specs with my '80 xs400. I'm very new to bikes, I got mine last month, but when I think of bike power I think of cc's. So my bike more than doubles the yzf-r in cc's, yet the top speed for both is very close. The xs400 @ 87mph, and the yzf-r125 @ 82mph (from a video I saw on youtube). I realize the xs is about 100lbs heavier, but what else makes a 125cc bike so incredibly fast? What would the diffrence in acceleration be?

Here are the specs of both bikes from bikez.com

1980 XS400

Engine and transmission

Displacement: 392.00 ccm (23.92 cubic inches)

Engine type: Twin

Stroke: 4

Power: 27.00 HP (19.7 kW)) @ 8100 RPM

Compression: 9.2:1

Bore x stroke: 69.0 x 52.4 mm (2.7 x 2.1 inches)

Valves per cylinder: 2

Fuel control: OHC

Cooling system: Air

Gearbox: 6-speed

Transmission type

final drive: Chain

Weight incl. oil, gas, etc: 182.0 kg (401.2 pounds)

2009 YZF-R125

Engine and transmission

Displacement: 124.66 ccm (7.61 cubic inches)

Engine type: Single cylinder

Stroke: 4

Power: 14.75 HP (10.8 kW)) @ 9000 RPM

Torque: 12.24 Nm (1.2 kgf-m or 9.0 ft.lbs) @ 8000 RPM

Compression: 11.2:1

Bore x stroke: 52.0 x 58.6 mm (2.0 x 2.3 inches)

Fuel system: Injection

Valves per cylinder: 4

Fuel control: SOHC

Ignition: TCI

Starter: Electric

Lubrication system: Wet sump

Cooling system: Liquid

Gearbox: 6-speed

Transmission type

final drive: Chain

Clutch: Wet, multiple-disc coil spring

Weight incl. oil, gas, etc: 138.0 kg (304.2 pounds)

2) Ive been big into car tuning with my '98 audi a4 1.8t as its become a hobby. I'm wondering what modifications are possible, if any, to help with acceleration/top end of a motorcycle. Im used to just installing chips/ehausts/bigger turbos but i dont think thats possible in this case.

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Well in the case of the YZF R-125 mine can go a damn site faster than 82MPH, infact it could do 86MPH when i baught it!

Now mine technically isnt a 125, as i baught a big bore kit taking it to 175CC, Straight threw exhaust, Nitro X Chip (Only works on fuel injected motorbikes) racing filters and a few other tweeks.

To be honest you can do alot to a bike to make it faster, aslong as you know what your doing that is. If you wanna know anything specific dont be afraid to ask

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1) So I saw a picture of the new '09 yzf-r125. The bike looks like its going 100mph when its not moving. I was very surprised to see that they made 125cc sport bikes. I'm used to seeing 125cc mopeds in India. Anyway it got me interested in comparing its specs with my '80 xs400. I'm very new to bikes, I got mine last month, but when I think of bike power I think of cc's. So my bike more than doubles the yzf-r in cc's, yet the top speed for both is very close. The xs400 @ 87mph, and the yzf-r125 @ 82mph (from a video I saw on youtube). I realize the xs is about 100lbs heavier, but what else makes a 125cc bike so incredibly fast? What would the diffrence in acceleration be?

Here are the specs of both bikes from bikez.com

1980 XS400

Engine and transmission

Displacement: 392.00 ccm (23.92 cubic inches)

Engine type: Twin

Stroke: 4

Power: 27.00 HP (19.7 kW)) @ 8100 RPM

Compression: 9.2:1

Bore x stroke: 69.0 x 52.4 mm (2.7 x 2.1 inches)

Valves per cylinder: 2

Fuel control: OHC

Cooling system: Air

Gearbox: 6-speed

Transmission type

final drive: Chain

Weight incl. oil, gas, etc: 182.0 kg (401.2 pounds)

2009 YZF-R125

Engine and transmission

Displacement: 124.66 ccm (7.61 cubic inches)

Engine type: Single cylinder

Stroke: 4

Power: 14.75 HP (10.8 kW)) @ 9000 RPM

Torque: 12.24 Nm (1.2 kgf-m or 9.0 ft.lbs) @ 8000 RPM

Compression: 11.2:1

Bore x stroke: 52.0 x 58.6 mm (2.0 x 2.3 inches)

Fuel system: Injection

Valves per cylinder: 4

Fuel control: SOHC

Ignition: TCI

Starter: Electric

Lubrication system: Wet sump

Cooling system: Liquid

Gearbox: 6-speed

Transmission type

final drive: Chain

Clutch: Wet, multiple-disc coil spring

Weight incl. oil, gas, etc: 138.0 kg (304.2 pounds)

2) Ive been big into car tuning with my '98 audi a4 1.8t as its become a hobby. I'm wondering what modifications are possible, if any, to help with acceleration/top end of a motorcycle. Im used to just installing chips/ehausts/bigger turbos but i dont think thats possible in this case.

The 400 wasn't a fast bike when it was new, the RD would ahnialate it, but you load up with the other half and enough kit for a weekend and for its sins it will still be relatively happy at decent road speeds.

Do that on the 125 and you will be lucky to pull away. If you do then take some spare clutch kit with you.

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