Page 3 of 3
Re: Honda Pcx 150 yuminashi upgraded head for 150 engines
Posted: Tue Jul 01, 2014 3:51 pm
by dem0nk1d
dem0nk1d: does the new PCX 150 differ at all from the 2013 model, besides looks? Also the new modified head is using smaller valves as well. What is the theory behind this? Better swirl?
dem0nk1d: also are you guys coming out with a standalone ECU for the PCX?
Yuminashi Hi, difference between V1 and V2 PCX150 is different throttle body, different manifold, different injector, smaller valve springs, other V-belt and shorter v-belt (125cc eSP size), other clutch torque spring (shorter), and the water reservoir is now located near the radiator and no longer under the seat at the back of the bike.
Yuminashi Well, at the moment we are writing a new program with the auto-tune function for the standalone ECU for MSX/GROM125 and once this is finished we need to take a look then to see if we can introduce a standalone for the PCX as well...
Yuminashi @ dem0nk1d about the smaller valves: Larger valves can make more horsepower, but it takes longer to get there and keep in mind that the RPM's are limited from the PCX around 9500 RPM, so it's useless to select a valves diameter for a area where you never come...
We use smaller ports also and quiet a few words about the smaller valves and ports can be found in the article with this link
http://dirtrider.net/.../myth-5-you-nee ... rts-to.../
Re: Honda Pcx 150 yuminashi upgraded head for 150 engines
Posted: Wed Jul 02, 2014 1:57 am
by waspmike
Reaper wrote: The main idea of this kit is to rise the compression ratio from 10.6 to 12.5
[/quote]
So it is a 125 head?
Reaper wrote: and to rev the engine at the higher rpm zone (I didn't see any numbers yet).
So its the cam shaft that does most if it?
Re: Honda Pcx 150 yuminashi upgraded head for 150 engines
Posted: Wed Jul 02, 2014 2:45 am
by Reaper
Re: Honda Pcx 150 yuminashi upgraded head for 150 engines
Posted: Wed Jul 02, 2014 9:44 am
by Mgalutia88
Interesting.
Re: Honda Pcx 150 yuminashi upgraded head for 150 engines
Posted: Wed Jul 02, 2014 11:44 pm
by dem0nk1d
but here's the thing if your going to go big bore which is actually going to be cheaper, you'll waste money buy using this kit. i'm wondering if you can restrict the throttlebody / intake to achieve the same thing?
Re: Honda Pcx 150 yuminashi upgraded head for 150 engines
Posted: Thu Jul 03, 2014 3:10 am
by Reaper
dem0nk1d wrote:but here's the thing if your going to go big bore which is actually going to be cheaper, you'll waste money buy using this kit. i'm wondering if you can restrict the throttlebody / intake to achieve the same thing?
You may raise the compression ratio using the thinner headgasket, and to rev it up using high-rpm oriented camshaft with the double springs, lighweight retainers, rockers, etc.. But the big valves are heavy and can't move that fast, so this head kit seems a well balanced thing, which got everything needed to make your bike a high-rpm screamer.

Re: Honda Pcx 150 yuminashi upgraded head for 150 engines
Posted: Thu Jul 03, 2014 7:19 am
by Mgalutia88
Don't kid yourself. As long as the valve springs are tight and won't start to float before redline you'll be able to rev hard and fast. Racing engines use 2" intake and 1.6" exhaust valves for a reason. More air.
Re: Honda Pcx 150 yuminashi upgraded head for 150 engines
Posted: Sat Jul 05, 2014 10:09 am
by vamootsman
vamootsman wrote:It's available now. Will it work in the 2013? I'll give it a whirl if it will?
Question from me:
"Will the speed combo work in the 2013 pcx 150? If not, will there be one available soon that will work?"
Thank you
Answer from Yuminashi:
"The throttle body and the manifold aren't the same one as on the new 2014 PCX150.
At this moment we are working a specific combo out for the first generation PCX150 and this one will be available soon, so I would suggest to take a look from time to time if the V1 combo is available...."
Best Regards,
Kanokwan Bodden
Masato Co., Ltd.
Re: Honda Pcx 150 yuminashi upgraded head for 150 engines
Posted: Sat Jul 05, 2014 3:57 pm
by you you
Mgalutia88 wrote:Don't kid yourself. As long as the valve springs are tight and won't start to float before redline you'll be able to rev hard and fast. Racing engines use 2" intake and 1.6" exhaust valves for a reason. More air.
Is there a PCX race series?
Re: Honda Pcx 150 yuminashi upgraded head for 150 engines
Posted: Sat Jul 05, 2014 4:59 pm
by Mgalutia88
I was reffering to car racing engines. For example small block chevy and ford v8 engines.
Re: Honda Pcx 150 yuminashi upgraded head for 150 engines
Posted: Sat Jul 05, 2014 10:07 pm
by Mel46
So is the 2013 pcx 150 considered V1? I note that it is mentioned that the 2014 version 150 is different, but in the USA we don't have a 2014. The 2015 is suppose to hit the market here this month some time after the 15th. My assumption is that the new 2015 version will have body panels and engine all different from the ones currently sold here. The big question has been when can we get a big bore kit for our current 150s? From what I am reading here, it isn't available yet.
Re: Honda Pcx 150 yuminashi upgraded head for 150 engines
Posted: Sun Jul 06, 2014 8:32 am
by chainsaw
Yuminashi does still have a bbk available for the 150 but using an older heavier piston design, there was stock available when i was there in May. There is a new kit about to be released that uses a lighter design piston more suitable to the 150 engine.