Interested in a 250cc to 300cc or larger engine upgrade kit ....

[mrbios]

Dear BettinANDlosing,

It looks like you upgraded your B&W aka GV aka GD 250cc scooter.  Do you have advice on purchasing a kit to upgrade the stock 250cc GY6 engine?

I'm thinking about replacing the Grandvista (GV) with a larger scooter like the Piaggio BV350 or Burgman 400 OR keep the good times rolling with the GV which now has 16K miles on it and still running good.  Just looking for a little more power and speed on the freeway. 

Questions after the larger motor is installed:
1. Is the power gain worth it?
2. Can the stock carb be used with larger jets?
3. Can the stock exhaust be used or an exhaust that isn't too loud?
4. What will the MPG be?
5. Is there a kit or if you buy parts how do you know what you will need?

[BettinANDlosing]

Hey there, I used the MRP 300cc kit that is no longer made. It's a direct copy of the Polini 78mm kit for the 250cc motors. Not sure if you can buy that anymore, if you can I believe the Polini one is about $400. Performance is greatly increased, top speed is about 10mph faster than stock, and overall torque and power are a LOT more, 0-60 is about 8 seconds. MPG is still great at about 65mph average. My case is bad to compare stock vs. my build, because I got my bike all blown up and rebuilt it with all these parts, so I have no idea how this particular bike performed before. But it's much faster than stock 250's I work on. Maintenance is more frequent, I adjust my valves every 1000km, but this might be due to the high lift camshaft more than the kit. I use my stock carb with no issues, slightly larger main jet is all you need if you keep stock exhaust and intake. Downside is it's pretty hard to install, you'll want a good shop to do it not just a hole in the wall. I have ordered the parts to rebuild my setup, rings gaskets, cam chain and some other stuff. Not like I NEED too, but I feel i'll get slightly more compression after I freshen it up. There was another guy on here that had the 300cc kit, he said his exploded but then said it looked like no oil, which is not the cylinders fault. I have 13000km on mine still going strong, I'll be exited to crack it open and see how the cylinder looks, it's Nikasil coated so It should look like new.

[mrbios]

Thanks B&L.  I saw a great deal on a Piaggio BV350 2012 for $3200 low miles.  Cash is a little tight so I have to hold off.  Also, it is hard to beat success.  I bought my GV with 2600mi on it almost 3.5 years ago.  Now I have over 16K miles.  I run it 6 to 7 days a week with only minor maintenance.  Mainly motor oil changes around ever 1300 miles.  I put a new rear tire on - WOW was that a LOT of work.  I think the front will be easier.  Again thanks for the info and guidance.  Will see how things go down.

[BettinANDlosing]

You should just keep going with good maintenance and get 30k+ miles out of it while you save up. The new bv350 is amazing. With the mileage on your scooter, have you gone through the service stuff, most importantly getting all the cvt parts clean and replaced at that mileage. That alone will make the bike feel almost new, Dr pulley sliders will add a bit off top end and overall performance. Valve adjustments kept up on. Synthetic oil will help you get the most longevity out of the engine.

[mrbios]

I turn my own wrench and I stay up on almost everything.   Valves I do at every 10,000 or 8000mi. I changed the belt a little early at 10,000.  Air filter fuel filter antifreeze final drive brake fluid all changed. recently installed a new interstate battery. Also, recently painted all the black plastic because the Sun was destroying it I'll post pictures.

[BettinANDlosing]

Looks great, yeah your treating that bike well it'll last you forever. If you really need the extra umph let me know I'll give you more details.

[mrbios]

Looks great, yeah your treating that bike well it'll last you forever. If you really need the extra umph let me know I'll give you more details.

I've been surprised by how consistently it starts and runs.  250 to 350 is an ideal size for a scooter motor. The automatic CVT enclosed belt drive and transmission is a fantastic low maintenance system.   Several years ago at around 12K miles I switched to the Dr pulley flat sliding weights.  Centrifugal clutch still has lots of meat on the pads even at 16K miles. 

Minor complaint - rear brake pad wears fast!  I changed it about 3K miles ago and it already appears almost 50% worn!  I have been concentrating on using the front brake as much as possible. 

Coming to the world of scooters from many years of motorcycles is the best.  Thanks again for the info.

-Paul

[BettinANDlosing]

I've been surprised by how consistently it starts and runs.  250 to 350 is an ideal size for a scooter motor. The automatic CVT enclosed belt drive and transmission is a fantastic low maintenance system.   Several years ago at around 12K miles I switched to the Dr pulley flat sliding weights.  Centrifugal clutch still has lots of meat on the pads even at 16K miles. 

Minor complaint - rear brake pad wears fast!  I changed it about 3K miles ago and it already appears almost 50% worn!  I have been concentrating on using the front brake as much as possible. 

Coming to the world of scooters from many years of motorcycles is the best.  Thanks again for the info.

-Paul

Yeah I've found that about my B&W also, that rear brake is too small. I wish our bikes had the dual front disc that some of the other Kymco's do.

[mrbios]

Yeah I've found that about my B&W also, that rear brake is too small. I wish our bikes had the dual front disc that some of the other Kymco's do.

I think part of the problem in the rear is I notice as I rotate the rear wheel on the center stand that the disc hits in one spot then spins freely.  That probably causes lots of wear.  It is like a minor warp in the disc or the wheel.  I don't like double disc in front because of the extra hoses and caliper - one is good enough except when serious performance is needed like a sport motorcycle. 

[BettinANDlosing]

I think part of the problem in the rear is I notice as I rotate the rear wheel on the center stand that the disc hits in one spot then spins freely.  That probably causes lots of wear.  It is like a minor warp in the disc or the wheel.  I don't like double disc in front because of the extra hoses and caliper - one is good enough except when serious performance is needed like a sport motorcycle.

Sounds like you have a warped rotor, do you feel it while stopping? Have you installed a new tire, it's really easy to bend the rotor. You would notice this while braking, a pulsing in the brake lever. If the dragging is just slight, almost cant feel it with your hand, then it shouldnt do any damage to the pads. These bikes use floating calipers, and ALWAYS drag slightly, it's part of how they work. If you feel it sorta bind up this is a different problem.

[mrbios]

I have changed the tire 2x and dismounted to fix a flat.  I don't feel pulsing while braking.  I wish the rear pad was either a little bigger or thicker.

[BettinANDlosing]

Yeah, if the rotor was warped you would feel it pulse when braking soft or hard. I too wish the brakes were bigger, but hey they are only $25 and 10 minutes to put new ones in so it's not too bad. I use EBC pads and they tend to last a tad longer than the OEM kymco brand ones.

[mrbios]

...I use EBC pads and they tend to last a tad longer than the OEM kymco brand ones.

I would like to use EBC do you have a part #.  I didn't order EBC / aftermarket because I didn't feel confident that the seller had things matched up correctly.

[BettinANDlosing]

I would like to use EBC do you have a part #.  I didn't order EBC / aftermarket because I didn't feel confident that the seller had things matched up correctly.

FR EBC SFA197
RR EBC SFA356
I have the fronts in stock, rear I would have to order.

[mrbios]

FR EBC SFA197
RR EBC SFA356
I have the fronts in stock, rear I would have to order.

Refresh my memory - do you run a scooter repair shop?  Are you located in the US?  Also, can you also get OEM Kymco parts?