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Scooters - 125 to 300 => People 150 => Topic started by: stejospot on May 08, 2012, 09:28:16 PM

Title: Need some advice on Big Bore'ing engine.
Post by: stejospot on May 08, 2012, 09:28:16 PM
So the engine on my People 150 completely blew this past weekend.

The guy at the shop gave me all the options... replace camshaft and other parts... completely buy a new engine... all of them came to about the same price point: between $300-400

and THEN he said, "or...for that price, we could just throw in a GY6 with a big bore kit and bump it up to about 180cc."

What!?  30 more cc's for the same price?

I've heard about these kits, but don't know anything about them. But I won't lie... having an extra 30cc's for about the same price as getting a new OEM engine definitely catches my interest.

Do these big bore kits really boost performance? If so, are there any big risks of putting them on a bike designed for 150 displacement? I could use some insight!

Thanks.

Title: Re: Need some advice on Big Bore'ing engine.
Post by: MikeKymco on May 26, 2012, 08:52:20 PM
I want to know too.  Subscribed.
Title: Re: Need some advice on Big Bore'ing engine.
Post by: zombie on May 27, 2012, 12:05:22 AM
I posted this one before. It all depends on the quality of the BBk as to how long it will last. Some are good, and some crap! . You NEED to have steel valve seats, and a very good mechanic. In 50cc scoots changing jugs is close to 100% displacement increase. In the 150 to 180 swap it is more like 20%. The performance is similar but torque is increased. You will feel a better pull but not much else. I am not trying to deffer you but let you know the increase is not major, and the quality of parts/install will make or break the end result. Stadium Yamaha gives us a GREAT discount so I would lean toward getting the OEM parts, and have your mechanic install them. You may save more than money going this way.
Title: Re: Need some advice on Big Bore'ing engine.
Post by: MikeKymco on May 30, 2012, 02:20:12 AM
Thanks, Zombie.  That's disappointing, but not surprising.  And sounds like excellent advice, sticking with known quality parts.