300cc bore Kit

[Ben]

Did somebody try this 300 cc bore kit from Taiwan on Grand Vista 250 ? and result ?

http://www.ebay.com/itm/300cc-BIG-BORE-CYLINDER-KIT-KYMCO-Dink-250-Grand-Dink-250-Grand-Vista-250-/400400526605?_trksid=p2045573.m2042&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D27%26meid%3D6053818796708962417%26pid%3D100033%26prg%3D1011%26rk%3D1%26sd%3D400400526605%26

Riding GV in California  on Car Pool lane, I need some more ponies left when reached 85 MPH (ODO)

Thanks

[windwheeler]

So 50cc more...  all other left the same you gain in the best case about 4 HP.   THAT you can gain by machining the head for higher compression and fine tune your variator, all for much less effort and money...  Other wise you need to change to a different cam and carburetor to get a true benefit out of the 300cc pot.  Not worth it.

Fine-tune your engine and variator weights on your 250cc and you will run about 95 mph indicated, about 80-83+ real GPS mph.

[Ben]

Thanks Windwheeler for the info...
By changing variator weights to increase top speed, do I sacrifice something such as take off power ?
If not, which variator weights I need ?
Ben

[windwheeler]

I have done tests, with different weights, roller and sliders.  Compared to OEM Kymco (which are when new/not worn not bad either) the Dr.Pulley 18g work for me the best; better acceleration (with higher rpm), but then higher top speed at lower rpm than OEM.  This is the characteristics Slider vs. Roller weights.

[Ben]

1. Dr Pulley 18 g you mentioned, are they sliders or rollers ?
2. Better acceleration ( with higher RPM ) means you have twist the throttle more to have higher RPM to accelerate ? In another word, with Dr Pulley 18g , it takes longer to go from 0 to 60 for instance ?
Thanks

[windwheeler]

1. Dr Pulley 18 g you mentioned, are they sliders or rollers ?
2. Better acceleration ( with higher RPM ) means you have twist the throttle more to have higher RPM to accelerate ? In another word, with Dr Pulley 18g , it takes longer to go from 0 to 60 for instance ?
Thanks

The 18g are Dr. Pulley Sliders. As I said I did several real life tests with "bench mark performance" (meaning not just how it feels", real world speed data by recorded confirmation).  The 20g Dr. Pulley sliders weights were not good, worse. The original 20g Kymco roller weights are very close in performance, but did not get the acceleration speed like the 18g sliders, and also the top speed was at much higher rpm with the Kymco 20g rollers.  When new both can run about the same top speed, but OEM at much higher rpm.

So the 18g Slider weights are the best.

No, you do not have to twist the throttle more, actually reduce the throttle a bit more compared to OEM for acceleration.  The acceleration is quicker/shorter, clearly faster with 18g slider weights.  After 70 mph (GPS, 78 indicated) at full throttle the rpm drops with the slider weights (like it shifts into a "overdrive" gear), while with the OEM weighs the rpm keeps on climbing.

Summary: The original Kymco weights are really not bad (as long they are not worn), but the 18g slider weights make the Scooter a bit faster in every aspect.

[Ben]

Thank you so much Windwheeler.
I was advised by you and others not to invest $ into 300cc bore kit unless I know what I am doing.
This route is probably the best.
Tsie Tsie Ni ( thank you in Mandarin, language spoken in Taiwan )

[Ben]

One more question Sensei:
My top speed now is 88 MPH ( ODO and flat surface), it takes a long time to get to that and I have nothing left...what is your top speed with 18 g Dr Pulley sliders ?
It a big deal here on Carpool lane in Southern California, everybody drive at least 75 MPH
Thanks

[windwheeler]

Once again:  "Fine-tune your engine and variator weights on your 250cc and you will run about 95 mph indicated, about 80-83+ real GPS mph." 

75mph indicated is easy to get, real 75 mph a bit more difficult and depends on the wind and if up-hill or downhill, but mine runs it fairly easy in traffic.  Important is that you have the original windshield, the GIVI for example is a "big brake" and takes away 3-4 mph top speed.

PS:  how many miles are on your GrandVista?

[de dee]

    you need a 300i downtown or gt. scoot but after a while you will want more speed again, so you may go for a 500 right off the bat, on and on for ever,.

[Ben]

4 K miles, second owner, all stocks.
Dee Dee, you got a good point there. When I started getting into scooter 2 years ago I first got a Kymco Super8 150cc, now 250cc and not fast enough.
The Grand Vista is perfect for around town and occasional freeway. I am 5'7" 150# and the Grand Vista fit me well. Its top speed made me feel  little unsafe on Freeway.
By the way, last week I test rode the new 2013 BMW 650cc GT, it is nice but cost is $13,000 OTD and wait at least a year for a lower seat version.
Thanks

[windwheeler]

Well, yes, there is a big price difference.  I am sure you paid very reasonable money for your Grand Vista.  That's not comparing apples with apples.

I looked also at the D/T 300i and the engine has plenty power and speed, I do not think you need a 400 or 500cc unless you want to give up serious fuel economy.  Look what those guys get with the 500's cc...  credulous;  in the 50's mpg. Why ride a scooter then???  I have 3 real motorcycles besides the G/V, one gets over 50 mpg (if I "behave), and I had a BMW F650 that got constantly 63-73 mpg;  all those bikes you can buy used with low miles for the same price as a 500 scooter.