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I recently took my dad's unused pulsar 180cc and gave it an overhaul.I replaced the carburettor,airfilter,spark plugs and clutch plates.But the bike doesn't run like other motorcycles of the same model.

I can't cross 110 kmph even on a sloping gradient with no headwind while the top speed of a pulsar 180 is 125kmph.I also find the speeds don't match the rpms.

It does 80kmph@7000rpm with 10kmph rise for every 1000rpm until it hits 9500 rpm redline at 5th gear.It is supposed to do 90kmph @ 7000rpm and 105kmph @ 8000rpm at 5th gear.

Its power and torque are 16.5ps @ 8000rpm and 15.22Nm @ 6000rpm.

The 5th gear ratio is 8.98:1 (24/26) ,the final drive ratio is 2.80:1 (43/15) and primary reduction 3.47:1 (66/19).

I thought the problem was clutch slippage and replaced the worn out clutch plates but the problem still persists.The clutch lever free play is according to specs in the owners manual.Even the dealership isn't able to identify the problem.

Would be grateful if somebody can identify the cause and suggest a fix.

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  • Welcome to the site.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Jul 16, 2017 at 21:49
  • Before anything else, check the accuracy of speedometer. Any modern smartphone can provide you with GPS application to test actual speed pretty accurately.
    – oryades
    Jul 17, 2017 at 7:10
  • checked it with my smartphone gps my speedometer shows a +5kmph innaccuracy at 100kmph
    – Sandepp
    Jul 17, 2017 at 12:59
  • Worn piston rings? What is the result of the engine compression test? In that test you remove spark plug and screw in a special pressure gauge. Crank engine and read the result. Low compression = low horsepower.
    – zipzit
    Jul 17, 2017 at 13:44
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    What about the sprockets? Are they the same tooth count as stock? Are your tires in good shape and stock size?
    – raydowe
    Jul 21, 2017 at 12:27

2 Answers 2

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The rpms not matching the speed tends to make me think someone changed a front or rear (or both) sprocket to increase acceleration at the expense of top speed. Try counting the sprocket teeth and see if you find less than 15 on the front or more than 43 on the rear.

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You did a tune up. Your engine isn't producing. Your transmission isn't dragging anything? Extra weight, extra friction, power loss? Overhaul some more: change the tranny fluid, rebuild that "new" carburetor, check the carb jets and passages especially, check the exhaust manifold/muffler for blockage(ie: rodent nest remnants?), ask the shop if they adjusted the timing or not, and lastly, make sure there are NO leaks...extra air into the carb, extra air out the manifold. That's all I can recommend to gain 8-12% power back from this sitting bike. I bet it's the fuel. Cheers!

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