Q. Why isn't my scooter as fast as it used to be?
A slowing scooter or overall lack of performance can be caused by many things. It can be a major issue such as a worn out engine with low compression, wear, or damage or it could be something much more simple. If your scooter has not received attention for many miles, it's very likely that your issue lies within overlooked routine maintenance and you should start there.
Low tire pressure can have a major effect on speed. Common pressures are 32-36psi, but refer to your tire's sidewall, tire manufacturer specifications, and your owner's or service manual to find out what's right for your scooter and tires.
If you have a compression tester you can get a basic idea of engine condition with a compression test
. Check a service manual for exact specifications, and modified engines will vary, but in general most scooter engines perform well with numbers near 150psi of cranking compression or above. Decreasing compression leads to a decline in engine output and performance. If you are lucky the problem may me as minor as tight valves requiring adjustment
. It could be as serious as worn or damaged engine parts.
Multiple components or a combination of issues in the CVT commonly cause low speed or poor performance. I would advise doing a complete inspection and cleaning of the CVT
to figure out if the CVT is indeed the problem and why. Worn roller weights, contra springs, and belts are prevalent causes of diminishing speed. As the drive belt wears it becomes more narrow and may not be able to travel as high in the front pulley, resulting in reduced speed often accompanied by increased RPM. A service manual for your scooter should have specifications for standard and service limit belt widths, but normally by the time the belt is about 1mm below original specifications speed and/or RPM will change noticeably. Roller or slider weights can be damaged or develop flat spots over time that change how they operate. A worn contra spring may loose stiffness and cause RPM to drop below where it was initially tuned. Even an accumulation of belt dust can have a negative impact on performance.
If temperature has changed a lot since a carburetor equipped scooter was tuned, it may need adjustments. Very cold weather requires larger main jets while hot and humid conditions may need smaller jetting. Often a main jet swap and mixture screw adjustment
will cover seasonal temperature changes.
Related Info :
Full Service CVT Inspection
Idle Mixture Adjustment
Carb & CVT Tuning
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