The Honda PCX / Forza / ADV150 / SH Forums

I ordered about $550 worth of parts for my PCX yesterday:

Performance:
1 x [SP TAKEGAWA] S Stage Big bore Kit 170 cc (01-05-0064) = 39,800yen
1 x [MADMAX] MADMAX Racing BigInjector (MK06-0001-FI) = 6,505yen
1 x [KITACO] High gear kit (305-1426010) = 6,800yen

Cosmetic:
1 x [MADMAX] Oil gauge Silver (MM19-0124S) = 1,419yen
1 x [NBS JAPAN] Rear brake adjustment Nut (311834) = 900yen

It should be here mid-April.


I've never been a big fan of performance. I could sell my PCX and buy a Reflex for the same amount of money, saving $500 on performance parts and hours and hours of my labor.

But, the PCX is the best bike I've ever owned. I have the most comfortable seat I've ever sat in as a saddle. The windshield streamlines over me perfectly, and there is the perfect amount of legroom. Maddie rides me with more ease than I've had on any other scooter -- the dash is the perfect height, and she sits close enough that I can make sure she doesn't go anywhere without cramping her.

With how expensive our newborn is, my wife suggested I drop down to only one bike, and I agreed with her. This should get the PCX up to highway-capable speeds, let me keep on enjoying the great ergonomics and light weight of the PCX, and allow my dog to keep riding with me.


I'll be doing two epic how-to's as a result -- how to completely dismantle a PCX, and how to install a big bore kit. This thread's to talk about the mods, logic behind choices I've made for parts, and logging all my performance testing.

Disclaimer: Everyone's bike is different, and the results I see may or may not be consistent with yours. Mechanical differences, atmospheric conditions, altitude, and many, many other factors all affect end performance. I have received no compensation for any of my mods from any vendors, and have no affiliation with any performance part manufacturers. If you choose to mod your PCX as a result of my experimentation, proceed at your own risk.

Also, please note that my bike, and all the parts I have used, are for the original 2011 Honda PCX 125. They WILL NOT FIT the 125esp or the 150, or the 2014+ models.


The Parts
Variator: TAKEGAWA High speed pulley kit (02-01-0025) = 5,800yen

• The variator is already installed, and was originally posted about in this thread: http://hondapcx.org/viewtopic.php?f=9&t=1835.
• The variator increased the stock speed from about 55mph to 65mph, allowing me to comfortably cruise on the highway inside the city.
• The top speed of 65mph is not sufficient for riding interstate highways between cities, and the engine lacks power to sustain 65mph on steep hills.
• I have seen no noticeable decrease in fuel economy with the variator, and average roughly 95mpg with mixed driving, 100mpg city, and 90mpg highway.

Larger piston / sleeve (Big Bore Kit): TAKEGAWA S Stage Big bore Kit 170 cc (01-05-0064) = 39,800yen

• The kit's main advantage is a larger bore.
• This is provided by replacing the cylinder and piston. This increases the area for combustion, allowing more fuel and air to mix and go boom, increasing power. More displacement always == more power.
• The stock head (the assembly on top of the cylinder that houses the valves) can be used with this kit, making it a simple bolt-on kit.

Performance Camshaft: Included in the above big bore kit.

• The big bore kit includes an aftermarket camshaft to allow more performance-oriented valve timing.
• The engine on our PCX is a four stroke, meaning the engine goes through four phases per combustion cycle. These phases are intake, compression, combustion, and exhaust. Our PCX has two valves, one for intake and one for exhaust. With a standard camshaft, the intake valve is open through the intake cycle and otherwise closed. The exhaust valve is open though the exhaust cycle, and otherwise closed. Both valves are just barely open for a extremely short amount of time between cycles, when the exhaust cycle ends and the intake cycle begins again. With a performance camshaft, the intake valve opens sooner and the exhaust valve closes later, resulting in a rough idle, but far more airflow to the engine when under load. This drastically increases power.

Larger injector: MADMAX Racing BigInjector (MK06-0001-FI) = 6,505yen

• The injector sprays fuel into the engine, and is controlled by the PCX's fuel injection system (PGM-FI).
• The stock injector is too small for a bore this large, and can't provide enough fuel to effectively run such a large bore. A larger injector like this one ensures enough fuel reaches the engine, decreasing the potential for the engine to run too lean, increasing power and longevity of the engine.
• This injector is actually the stock injector for a CBR150. I have no idea why it's labeled as a MADMAX brand by the vendor, but the actual manufacturer is KEIHIN, and their part number is CB22. You may be able to find it easier with those part numbers, especially if you're in Asia.

Steeper final drive gearing: KITACO High gear kit (305-1426010) = 6,800yen

• The stock gearing is designed for a bike with much less torque. The increase in engine torque allows a steeper final gear, meaning each turn of the engine will equate to more turns of the rear tire.
• You can think of this like shifting gears on a bike. If you're in 2nd gear and shift to 4th, you have to pedal harder, but get way more rotations at the rear tire as a result of the same revolutions per minute.

There are other kits available, from Yuminashi, Chameleon Factory, MADMAX, etc. I chose the Takegawa because it's supposedly the most mildly tuned, and therefore longest-lasting. I expect OEM reliability, and hope to get well over 10,000 miles out of this kit.

Content coming soon.

Content coming soon.

Content coming soon.

well, once yours is up and running I will have a better idea as to whether it will be worthwhile for me to change out the variator and belt on ours for the Yuminashi. If so, then we should have a lot of fun riding together. Heck, yours will be more powerful than our little 150. We still haven't seen the new Burgman 200, and that is our big hold up. We don't want to put all this money into the PCX and the sell it in order to buy the Burgman. She loves her PCX, but she also loves my Burgman 400, so she will have to make up her mind before I move forward. Still, if we end up just upgrading the PCX and changing the shocks, would you mind helping me? I thought the shocks would be easy but I have read some discussions about changing them and wonder if I will need special tools.

Are you getting the updated valve springs as well?

Alibally wrote:Are you getting the updated valve springs as well?

+1 on this one,from my experience and especially since youre going to take the head of and install the cam you would be 10 times better of doing them at the same time,also performance boost at top rpm is well worth while...

Cool!

I'll watch this space with interest.

Mel46 wrote: Still, if we end up just upgrading the PCX and changing the shocks, would you mind helping me? I thought the shocks would be easy but I have read some discussions about changing them and wonder if I will need special tools.

Sure, would be glad to.

Alibally wrote:Are you getting the updated valve springs as well?

I would have if I could have found a source for them... I've heard the stock springs cause valve float at higher rpms because they can't get rebounded fast enough.

Pcx racing and rz racing sell them.

Linky? You can PM me it if you want, or reply here.

So the ECU will work happily with these engine performance mods?

Yuminashi do them.

http://www.yuminashi.com/2-valve-spring ... Position=0

Maddie,

I sent you a PM about the injector. If you want some Honda Sonic double valve springs let me know.

iceman wrote:So the ECU will work happily with these engine performance mods?

Yup. Pcxdemon is using the stock ECU in his 170cc PCX. It's a very capable little computer.

Alibally wrote:Yuminashi do them.

You can't order through their site though.

waspmike wrote:I sent you a PM about the injector. If you want some Honda Sonic double valve springs let me know.

PM replied. Isn't the Sonic a 125? I'll likely go aftermarket for the spring kit if I get one. Thanks though.

OK I just so you know all the quick 125 guys here use Sonic valve springs. Yes its a 125

So here is the RZ Racing link - you have to call or email him to ship to the USA
http://rzracing.nl/honda-pcx-tuning/hon ... -head.html

Here is the PCX Racing link
http://www.pcxracing.com/product.php?id ... &id_lang=1

Mgalutia88 wrote:So here is the RZ Racing link - you have to call or email him to ship to the USA
http://rzracing.nl/honda-pcx-tuning/hon ... -head.html

Here is the PCX Racing link
http://www.pcxracing.com/product.php?id ... &id_lang=1

Is there anything to suggest that they are not in fact stock Honda Sonic valve springs? If any one has a set to compare, let me know and I'll go to Honda and buy a set! I'll probably go tomorrow anyway just for curiously's sake . Then the question will be does anyone have a set they can measure to compare to the stock Honda components I will have in my hands.

I'm not saying there is anything wrong with them being stock Honda parts being offered for sale but wouldn't it be more honest simply to say so?

No reason not to think they're the same -- the injector is a Honda OEM part that they label as MADMAX just to resell.

How much will a set of Sonic springs cost?