Posted October 16, 200915 yr 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.
October 16, 200915 yr 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
October 16, 200915 yr Moderator 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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