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Post by millsc on Aug 2, 2013 8:53:05 GMT -5
not so sure that is a big valve head i think its just ported, i could be wrong though
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Post by jerseyboy on Aug 2, 2013 9:21:29 GMT -5
[replyingto=millsc]millsc[/replyingto]If that's the case will the 30mm intake I posted accommodate my 24mm carb,and is the intake port on these heads 30mm or close?
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Post by millsc on Aug 2, 2013 9:59:11 GMT -5
Its looks to be ported for the 30mm manifold and yes a 24mm carb will fit
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Post by jerseyboy on Aug 2, 2013 10:31:48 GMT -5
[replyingto=millsc]millsc[/replyingto]Good news,,I may buy a whole new motor to build and keep the one I have now for a back up,,it runs so good and I did want two motors in case something happens...I can still get around!
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Post by brandjur on Aug 2, 2013 11:24:25 GMT -5
The size, 61mm vs 63mm is the radius cut on the head. You can see it from below. The valve sizes might be the same size for 61 vs 63.
I measured my intake port on the NCY big valve 58.5mm head and it was 26mm (+2mm than stock). The intake and exhaust valves were both 2mm larger diameter than stock as well.
Even if you get a 30mm intake manifold w/ built in spacer and 30mm carb, you still have restrictions in the head. Some people might port match. That is up to you. If I were looking for straight bolt-ons, I would look for 26mm matching components. Do a search and you might find that some people have a difficult time tuning a 30mm carb for the 150 even with bbk. Those 30mm carbs are really meant for 250cc.
What you are doing is very very good. I see a lot of people that buy stuff and then they are like....."uh, I need help. How do I do this." It is very important to blueprint your mods before you purchase them so it is balanced as well as understand how to install and tune.
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Post by jerseyboy on Aug 2, 2013 14:41:33 GMT -5
[replyingto=brandjur]brandjur[/replyingto]Man,,
Thank you so much bro for the useful info..its really gonna save me a ton of time and $$ on my BBK build!
Tom
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Post by jerseyboy on Mar 12, 2014 15:53:24 GMT -5
I'm getting ready to do the big bore soon here,, I see scooter elements has some new cams taida t-100 and 300,,anybody have any experience with these and I assume the 100 would more fit my setup for torque and taller gears..I plan on doing the 62mm BBK with the 62mm head he has,along with a cam and possibly better springs...will have to do some more research on the gearing,,need to find out whats in there first..I'm looking for more power so I can cruise at a faster speed with same or less R's also keeping my reliability.. Thanks guys! www.ebay.com/itm/161226174108?item=161226174108&viewitem=&sspagename=ADME:X:AAQ:MOTORS:1123&vxp=mtr |
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Post by scooterguru on Jan 25, 2021 13:14:18 GMT -5
millsc, jerseyboy, brandjur Guys, y'all are spending too much money for very little performance gain. I have a speedbump scraping, long as a Baptist sermon, custom GY6 150cc scooter that will out run most 250cc bikes and rides just as smooth and easy as you could want. Her name is Civil Disobedience and from starting out a year ago with a free 50cc Taotao that I got maybe 1000 miles out of, I've put maybe $650 total start to finish. That's everything including some tools and welding supplies. Not to say I haven't traded a little labor here and there for spare brake pads, variators, etc. You don't have to spend much at all really but you have to work for it. I've watched a guy throw hundreds if not thousands of dollars at his bike and still not understand why my pieced together P.O.S. ran and rode so much better. Here's what $650 and some bartering and begging got me in the way of parts. $100 went for a blown up Taotao 150cc with good 13"x3.5" tires, suspension, brakes and various sections of frame. I had swapped and traded for a 150cc engine that lightyears on it and had it mounted in that naked 50cc frame for most of the year. I bought a 30mm flatslide pwk powerjet carb, built an intake manifold and straight exhaust (no muffler), installed a $15 performance ignition system, 10 gram sliders, notched the pickup coil bolt holes and advanced the timing a few more degrees more, along with a few more tweaks and adustments. I rode it like that for the better part of the year. I was about $250 in on the build at this point. The engine was still running strong but getting weaker when I bought a brand new engine on Amazon with some of my stimulus money along with a few more parts. Around $400 worth of awesomeness. Before I even took it out of the box I pulled the head off and port and polished the runners, installed a A-9 cam, a homemade intake manifold, 9 gram Dr Pully sliders, and painted the engine covers. I rejetted the 30mm flatslide carb, 39 pilot and 125 main jets. All I can say is WOW!!! I'm just now out of the break-in period and I am blown away by how strong this engine is. It takes off like being shot out of a canon. If it wasn't 7ft long wheel to wheel it would pull the front tire off the ground. It does break the rear tire loose on anything but perfect pavement. Top speed is something around 70-75 mph right now but I have slightly taller final drive (15/38) on its way that should push it to over 80mph. Civil D is one sexy ride, long and low, with a voice like an opera diva. I've caught myself on numerous occasions just staring at her amazed that I actually built something so freakin cool, and for only $650. I have had people ask me how much I would sell her for. All I can say to them is that they wouldn't be willing to pay what I would want for her. I have no idea what I would sell her for, because I'd never sell my girl. Haven't even thought about it. Civil D and I are forever. Throwing money at a build doesn't do anything but waste money. If you want to go faster or just liven up your engine a little you're going to have to get your hands dirty. Porting and polishing the head and upgrading your cam is THE single best option for making more power out of a GY6. In my opinion if you don't port and polish the head FIRST it's really not going to breathe well enough to take advantage of any other upgrades. Since port and polish was basically the last thing I did it turned my scooter into a rocket ship. Save your time and money and do the head work first, you'll be glad you did.
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Post by chewbaca on Mar 28, 2021 2:00:20 GMT -5
the stock cam is already pretty good and is not actually the problem most of the time. I have found that the stock valve spring actually starts to float at 5000 rpm on a 150 it still makes power at higher rpm but it's limited and not very good. I think perhaps this is why many gy6 have a 5000 rpm limited ignition. Stiff springs is a possibility and will even help a lot. I have found it much better however to use stock springs and instead cut and polish the rocker arms and replace the valve spring retainer with titanium.
The cam following pad is massively over sized and can be trimmed significantly.
all this has the benefit of significant power increase without the extra frictional loss and increased wear from
heavy spring pressure
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MJ, Orange coil, Blue Performance CDI (Orange NCY did not work), NGK Iridium, 5g Sliders
