stock cam vs a9 (139qmb gy6 50cc)

Рет қаралды 4,802

Күн бұрын

I don't know the specs but here is a visual representation of the difference between stock and a9 cam for 139qmb gy6 50cc
scooter modifications, big bore kits for gy6 139qmb 50cc
znen, chinese scooter, moped, taotao, ruckus, chickus, bbk for scooters

Пікірлер: 30

@waynesteinmacher9794 11 ай бұрын

THANK YOU i finnally know the diffrence

@thelagmeister 11 ай бұрын

It definitely has more lift which will help low rpm. I had one in my 171cc and the thing would take off quick. Top speed was another story though.

@thundercatt5265 6 ай бұрын

I think I'm gonna try one on my big bore head it's got 23 mm /in.And 20 mm/ex. Valves and 64 instead of 69 Valve length on a 50 mm cylinder with a hybrid supercharger...it decel pops because of my stock intake and exhaust

@scooterarmy 6 ай бұрын

Get the sspg cam

@robertmason8341 8 ай бұрын

Actually the straight edge across there doesn’t prove it has more lift unless both cams are ground on the same base circles! I don’t know if your familiar with camshaft terminology or how they are made, but to compare them you need to measure the diameter of the lobe at the portion where there is no lift-(that’s called the base circle). Then measure the total height of the lobe going across the shaft. Then subtract the base circle from the total height of the lobe-this gives you the cam lift. Take that times the rocker ratio (usually anywhere from around 1.3-1.9 depending on the specific engine) and the result is your actual lift. Think about it, those two cams could have been ground with different base circles and still had the exact same lift. Look it up it if your not familiar. Duration you need a special jig/fixture called a cam doctor to measure precisely, or install the cam in the engine with a degree wheel mounted on the crank and a dial indicator tracking the axis of the valve to measure linear valve motion precisely! From there you can figure out actual duration at any set point be it .040”1mm or .050” such as most aftermarket cam manufacturers in the US do. Total duration is hard to track as ramps are so fast and often less meaningful as flow below .040” is relatively small. I’m trying to get an American company to grind me up some real performance scooter cams cause the Chinese cams are basically garage IMO.

@scooterarmy 8 ай бұрын

Hmm.. I'm going to read and reread what your saying.. maybe I'm using the wrong term when I say, more lift. Clearly, the lobe opens the valve more as it is longer, as can be seen by the use of the straight edge

@scooterarmy 8 ай бұрын

Let us know if you succeed in your quest to have a better cam produced

@scooterrehab6295 Жыл бұрын

More lift = more power‼️

@scooterarmy Жыл бұрын

LIFT, yeeyee goode!

@jacken9343 Жыл бұрын

Where did you get the A9?

@0643wes 6 ай бұрын

I am getting tapping sound with the a9 like the valves are to tight but they good

@joshgnzlez116 3 ай бұрын

check for clearance, to be safe

@damianosplay9457 2 ай бұрын

you need to readjust them after installing the new cam

@seanmayo206 5 ай бұрын

Dude . On the bearing end of the shaft . I got 2 cam shafts. One hole in middle of bearing is bigger then other. Why

@zorroblings6886 11 ай бұрын

I want to get a performance camshaft with higher lobes but I’m afraid it will mess with my timing. My previous scooter caught on fire because of a backfire a few months ago so the last thing I need is the valves not fully closing during the power stroke and having a fire under my ass. What do you think?

@scooterarmy 11 ай бұрын

Without sounding like a jerk. Set your timing properly? I run a9 cams and many others do too. My big bore video shows how to set timing.

@zorroblings6886 10 ай бұрын

@@scooterarmy do you see a noticeable difference with the a9 cam? Alot of people have recommended it to me but when I look at pictures online and compare it with a oem cam the lobes don’t seem any longer or wider …

@scooterarmy 10 ай бұрын

@@zorroblings6886 a lot of fakes and different grinds out there. You may have ordered an a9 and got a stock one. With the one in this video you can clearly see a noticeable difference in lift. It may a noticeable difference, yes.

@williamlawrence406 9 ай бұрын

Hope you see this rn if I put the a9 cam do I have to change my valve adjustment from stock ?

@scooterarmy 9 ай бұрын

Adjust to same specs..

@GhettoWrench 4 ай бұрын

Do you know where the "NCY" cam falls in the mix? Is it big like an A9 or just a gimmick?

@scooterarmy 4 ай бұрын

I have yet to look at the ncy.. life got in the way, and my cam testing took the back burner.

@mrcleanisin 4 ай бұрын

Why didn't you show the timing marks when it's in the neutral position where you can set the valves one has a different holes drilled

@scooterarmy 4 ай бұрын

Many different looks to these cams..

@mrcleanisin 4 ай бұрын

You didn't show yours.

@scooterarmy 4 ай бұрын

@@mrcleanisin I'm confused about what your saying. What didn't I show that perhaps I should have?

@mrcleanisin 4 ай бұрын

You didn't show how it looks from the cam side so we could see the top hole/marks and the two smaller holes at the horizonal. The A9 cam in my gy6 is not properly marked at the top, so when I looked at your video, I still was not sure which side was to be turned up. I figured it out later. It was the side with the smaller hole straight up and the two smaller holes at the horizontal. I guess you realize that the cam not only has more height but also longer duration on the lobes.