Posted by: scootswla | 27December'09

Project Kymco Update

For those of you that have been following the saga of my Kymco People 150 rebuild, here’s a little update. (if you haven’t look Here and Here)

I finally chose, ordered and received a new top end for the Kymco. I ended up going with a 62 mm ceramic kit made by NCY. NCY is a Taiwanese company so I hope the quality will be on par with Kymco. Maybe L can read some of what’s on the box to confirm this.The stock bore was 57.4 mm with a stroke of 57.8 mm for a displacement of 150 cc with the same stroke but a bore of 62 mm the displacement will be a whopping 175 cc. Because the piston is so much bigger naturally the sleeve of the cylinder has to be bigger also, in fact its too big to fit in the engine cases. That means that the cases have to be machined out to accommodate the bigger kit.Now I should say that when I bought this kit it said that it should be installed by a professional, but like our good friend Ed says “The Tooth Fairy, the Easter Bunny  and a Scooter mechanic…..”  I’m sure they would also suggest a professional machine shop to bore out the cases but I think a Dremel and a devil-may-care attitude is sufficient. The outside engine half was easy, I just took it apart and went to work. The other half had the crank and con rod in the way though so all of that would have to be removed.To remove the crankshaft you have to start on the other side of the engine. First we remove the variator cover, the variator is attached directly to the end of the crankshaft. (For more info on your varitator and how it works see this older post.)Removing the variator is one of those times an impact wrench is invaluable. If you don’t have an impact wrench it can be done with a socket but you’ll need a variator holding tool or some other way to hold the variator from spinning. Remove the first half to the variator.

 Then the second half.Then you can pull out the crank shaft. You have to get the timing chain off  the crankshaft to pull it out. How you get the timing chain back on is something I’ll have to figure out later. Circled above is the end of the crankshaft that the variator was on. The chain hanging there is the timing chain, the oil pump chain goes on the other side of the crank where my thumb is. The other do-hicky hang down is the connecting rod, the piston goes on the small end of it. With the crank removed I can get at the area of the case that must be enlarged (circled above). I have ordered a new set of gaskets, a good idea whenever you split the cases, by the time they get here hopefully it will all be ready to put back together. A lot of dry fits will be necessary in the meantime.

Since I had to take the variator off it was a good time to examine the roller weights as well. There were a few sort of flat spots so I’ll probably replace the weights as well or maybe even upgrade the whole variator. I may go to lighter weights to increase acceleration. If I do upgrade I’ll be sure to detail that in a future post.

More on the rebuild soon, stay tuned.



  1. It looks to me like you are a good mechanic. You lost me on the first pic. LOL I sure when you put it back together it will run Sweet.

  2. Paul, thanks for taking the time for pic’s and explaining the process.

  3. 超合金高速汽缸(Super alloy high-speed cylinder)?!
    That sounds like fun, Paul! Great job!
    I am about to start on a BBK for my 50, too.
    More power to our scooters in 2010, definitely.


  4. Hey, Paul
    You coming for the “cool” first ride tomorrow?
    Got my power-up kit today!
    Happy New Year!


  5. […] back in December of last year I started rebuilding my Kymco People 150. (Catch up here, here and here) I installed a NCY big bore kit but a few snags came up and with plenty of Vespas to work on the […]

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s


%d bloggers like this: