Can You Port Your Own GY6 50cc 139QMB Maddog Head and make it High Performance to Avoid Valve Float?
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- Опубліковано 5 жов 2024
- I watch of lot of great head porting on youtube and wondered if I could “Port Match” my head and make it any better on the 49cc Icebear Maddog. I use NCY Titanium Valve Springs good to 11000 RPM in the process.
Awesome video like always thank you for making these videos
Another great video - given how long people have been fiddling with GY6’s, there are zero people actually testing for results…
I’ve gotta feeling at the end of all this the advice is going to be put any tuning effort into a motor swap 😂
That was always my complaint. No before and after results. Im sure an engine swap could have already happened. LOL. I'm running outta ideas to try and get this faster in 49cc mode. NCY performance variator is 89mm vs the 95mm one. I may have one of those. I think that big ass wheel and tire are what kills these things. But that is also the cool look. 😎
Thanks for the video! I look at it with pleasure. It is very interesting what will come out in the end with a maximum tuning of 50cc. I'm looking forward to the sequel!
Thank you
69 mm valves give about 0.5 kW. Intake tuubing length is important for resonances.
So is the 65mm preferred over the 69 then? My new BBK 52.4mm came with the 64mm valve head and the valves are bigger. 20/23 I think.
Thank you. Very interesting!
I think it’s worth it every time especially if you already have to replace springs or a valve. Any gains are good gains right? I think you did a good job
Good point. Everything adds up. And on these 50s the gains are tiny since we start so low in HP.
The fact that you actually used a spacer as a guide is a great way to get consistent port matches. By eye is how you get wonky ports so great job with that. Only thing I would have suggested was under the valve on the short radius of the port, the tight turn can usually use just a touch of smother and the casting rings are usually there, be careful of nicking the seat. Also there is a actual difference in the heads. 64 Mm valve length because of the short valve stem have the valve seat lower than the 69mm valve stem with the taller valve seat. Easy way to tell the difference is top of valve springs will be flush with the valve cover gasket, 69mm valve are just above the sealing surface. 69mm valve stem heads because of the taller valve seat can take more porting to the floor than the shorter 64mm valve heads. 64mm valve stem heads have a lot less material and are easily blown through. There are videos of people cutting the 64 and 69mm valve stem heads in half. So be mindful of which head you are going to port and for why. Otherwise great video buddy 👍 👏 👌
@@jeremyhope6869 thanks so much. That is great info. My new 52.4mm kit has the 64mm head. I don't think I'm gonna touch that one. LOL.
@@GhettoWrench Google 69 vs 64mm valve head should show you the difference so you can see how much you can actually touch up and where you can actually improve the flow. Seeing a cut away actually helps. Another thing I liked to do when I was seriously with the gy6 was use the old cylinder and cut away a pie cut so you can bolt your new head on and check your valve clearance with the cam bolted on and the valve fully opened. Should tell you exactly how much you can shave off the head for max compression. Think old stroke using a wire on the piston to check squish. Same concept except valve clearance and simple way to check the clearance before shaving the head blind. Gasket thickness and since you can bolt cam on and actually get a idea of what cam is actually holding valve open for what and if your high performance cam is actually a performance cam for you. I know it sounds excessive but buddy you are way past simple bolt on and everything now is going to be custom made or modified 😆 🤣
@@jeremyhope6869 my brain just exploded. What a good idea compared to using clay with that cutaway. I do have extra old heads. Thanks.
I keep my 150cc rpm between 8-9 max. Ive garage ported a bunch of old chevy heads and tbi heads. Turbo manifolds etc. I blame you for this next project though because i was looking for something else and got sidetracked with this one. Im going to have a. Extra 150cc head for my matte red one. Im curious if i go ahead and give it the port and polish what cam would you recommend to throw in with it for the trouble? I have the one rolling wrench sent me with my big bore kit on my other. I just remember in another of your clips you said you loved on of the cams and it was close to the big bore kit performance with carb and cam swap.
@tiredofinsanity I do love that rolling wrench one. It is a Taida T100. Mid range. I trialed an A9 and hated it, but... I think I had my RPMs too low to appreciate it. I could not make RPM with it and don't I think I tried lighter rollers. That bike has an SSPG A12 in it now and seems to be a mid range like the T100, but way less money.
Man I hate this guy, WHATEVER I ain't got no money, I might not be smart, but at least I aint good looking. As always another good vid. I seem to recall in ITB situations in the yester years it was the runner length that had substantial effects on rpm tuning .. Do we want to tune the pipe resonance to intake pulse frequency at desired rpm? HOW DOES IT WORK. lol
Over my paygrade...LOL! I don't know those words mean. 🤪🤘
Can I install thicker washers to the bottom of my valve springs to act as a more stiffer valve spring?
@JonahNAloha Yes. They are "valve shims". You can run 2 on there instead of the stock 1. I think 50s and 150s might be same if you have any spare ones laying around. If not just thicker same size washers.
PS can you tell me which app you use? Thank you.
For the speed? It's called DRAG RACER but when I try to get link for you in app store it says it is gone.
You didn't change the cam or valves so you didn't need heavier springs. Also you could have the best porter ever do the work, but the carb or exhaust can't support more airflow. You will not see gains. More air in more air out, more power.
I have an NCY Cam and 19mm PE Nibbi on it. Thinking about putting that 21mm PWK back on. It made more RPM on top. But ran worse down low.
@@GhettoWrench Pretty typical of a cam. They lower dynamic compression. Shave the head to pick it back up and regain more bottom.
@@davidwickboldt712 how much can I shave the head? It already has a super thin head gasket. I put a thin head gasket in my ghost 212 and holy crap... the difference was amazing.
@@GhettoWrench .02 - .03 should help
Can u wire it back. I'm in a bind. Waiting on harness. I'm no nechanic
Wire what back? The entire bike? You can make any harness. Check out my "chuck-it" videos. I am pretty much making that harness. Even tho I am using the originals wires so i don't have to buy more wire. All the connections I am doing from scratch.
I did it
Do you recommend the stiffer springs?
Not so far. I am gonna drop roller weight again and see. I really felt like they taking power. Could be all in my head though. I never got to a high enough RPM to justify them yet.
@@GhettoWrench have you thought about using a two wire coil from a car to see if you get a hotter spark
@jeffkrauss5582 I have not. I thought about testing the "NCY" coil/Plug thing but have not bought it yet.
@@GhettoWrench I believe the nyc is just a 96 caprice or crown Vic coil
@@jeffkrauss5582 oh... interesting. Thanks
How does porting affect valve float?
Well in theory when you get into stuff like porting and cams you also get into higher RPM which can exceed your OEM valve springs. It was not the case for me. LOL. They kind of all go together in making a performance head.
When i ported my big valve head for my 90cc i think i did more harm than good it pulls like hell at low rpm but higher rpm it looses allot of power so top speed is 70kmh 43mph
So i probaly made them a bit too big i do have a 24mm carb with it tho
@@DiyNuke ahhh.... that almost describes what mine felt like. Quicker, but struggled on top.
😂