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Scooters - 125 to 300 => Downtown 300 => Topic started by: Yoni159 on June 13, 2020, 01:33:24 PM

Title: Can oil viscosity affect on engine performance?
Post by: Yoni159 on June 13, 2020, 01:33:24 PM

I put 5w50 in my scooter instead 5w40 because i saw in the owner manual that 5w50 is the perfect viscosity... But my scooter runs really bad he loose so much power and the rpms go high than usual it could be because that? Or its something in the variator?

Title: Re: Can oil viscosity affect on engine performance?
Post by: john grinsel on June 13, 2020, 01:48:21 PM

My opinion---if is not the oil

Title: Re: Can oil viscosity affect on engine performance?
Post by: Stig / Major Tom on June 13, 2020, 02:21:48 PM

Certainly has nothing to do with the oil.
When was the last time the belt and roller weights were replaced with Kymcp parts?

Stig

Title: Re: Can oil viscosity affect on engine performance?
Post by: Yoni159 on June 13, 2020, 02:39:51 PM

Immediately after i changed the oil i go to the mechanic to do variator service he change the belt and the rollers but after that the scooter start to run really bad he loose Power and rpms are hifh than usual that it can be? I go to him tomorrow but i want to know

Title: Re: Can oil viscosity affect on engine performance?
Post by: Yoni159 on June 13, 2020, 02:48:12 PM

And the fuel efficiency get worse

Title: Re: Can oil viscosity affect on engine performance?
Post by: Stig / Major Tom on June 13, 2020, 03:23:40 PM

Should be an interesting conversation between the two of you.
Did he use Kymco belt and stock roller weights?

Stig

Title: Re: Can oil viscosity affect on engine performance?
Post by: CROSSBOLT on June 13, 2020, 03:29:26 PM

Your mechanic probably did NOT get the belt jammed as far into the rear pulley as possible BEFORE he tightened the nut on the front pulley. Common mistake made by all beginners! It ran good before mechanic, ran bad after mechanic, problem CAUSED by mechanic. Verry carefully and gently ride your machine to mechanic. Better yet, take it back in a trailer.

Title: Re: Can oil viscosity affect on engine performance?
Post by: Yoni159 on June 13, 2020, 04:27:08 PM

Quote from: Stig / Major Tom on June 13, 2020, 03:23:40 PM

Should be an interesting conversation between the two of you.
Did he use Kymco belt and stock roller weights?

Stig

yes the belt was original kymco belt the rollers i think so.. he put new yellow rollers they looks like kymco

Title: Re: Can oil viscosity affect on engine performance?
Post by: Yoni159 on June 13, 2020, 06:19:22 PM

Can the oil viscosity cause to worse fuel efficiency when i used 5w40 i am did 24-25 km per liter on normal ride now with 5w50 i am doing 22-21km per liter

Title: Re: Can oil viscosity affect on engine performance?
Post by: CROSSBOLT on June 13, 2020, 06:34:05 PM

Yes. Thicker oil will cause a very slight decrease in mileage. The bigger effect in milage in the US is the difference between summer and winter gasoline. Winter gives poorer fuel economy.
Your situation may be affected by an improper CVT assembly. Or a worn belt will cause a drop in km/liter.