Someone mentioned the base circle and that the lift shown in the video may not actually show the true increase in lift. But as you watch the base circle side of the cam come by the space to the straight edge, it's obvious that the A9 and stock cams are similar or at least close to the same. More than that is that obviously the profiles differ. The little stock cam has peaked domes, the A9 more radius, a longer curve, indicating more duration of open valve time. As to the question on timing the cam on install, it's simple. The two little holes parallel the head surface with the base circle side of the cam lobes against the rocker arms. If the peaks of the cam are against the rockers, it's 180 degrees off. Never mind the big hole. You always adjust rocker arms to the base circle of a cam. I don't care if it's a scooter or 600hp race car. But some A9 cams had the gear pressed on 180 out, so you can't always go by that big hole being up. Go by the low rounded side of the cam ( base circle) against the rockers. Now what I'd like to know is what brand A9 is this one, because all A9 cams are not created equal ?
@@davidg.5076 it's a glixal.. and it does show true lift, how would it not, its in place and it literally protrudes more , ie pushes the valve further whether the base circle is the same or not, the video in real world shows the cam turning and protruding further.
@@scooterarmy Just because a lobe is taller doesn't automatically equate to more lift. If the base is also fatter, the tappets adjusted accordingly, the lift could remain the same. Did you know that you can gain lift on a stock cam by grinding away from the base circle ? Why ? Because the tappet is starting closer to the center line of the shaft before ramping up to the peak. However that won't change the profile curve of the cam. Profile and lobe timing it could be said are just as important if not more so than just lift alone. That's how NHRA Stock eliminator cars get to rev crazy rpms and turn 10 second time slips with stock lift cams. Thanks for the Glixal info ! Good to know.
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.
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
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
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 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 …
@@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.
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.
Someone mentioned the base circle and that the lift shown in the video may not actually show the true increase in lift. But as you watch the base circle side of the cam come by the space to the straight edge, it's obvious that the A9 and stock cams are similar or at least close to the same. More than that is that obviously the profiles differ. The little stock cam has peaked domes, the A9 more radius, a longer curve, indicating more duration of open valve time.
As to the question on timing the cam on install, it's simple. The two little holes parallel the head surface with the base circle side of the cam lobes against the rocker arms. If the peaks of the cam are against the rockers, it's 180 degrees off. Never mind the big hole. You always adjust rocker arms to the base circle of a cam. I don't care if it's a scooter or 600hp race car. But some A9 cams had the gear pressed on 180 out, so you can't always go by that big hole being up. Go by the low rounded side of the cam ( base circle) against the rockers.
Now what I'd like to know is what brand A9 is this one, because all A9 cams are not created equal ?
@@davidg.5076 it's a glixal.. and it does show true lift, how would it not, its in place and it literally protrudes more , ie pushes the valve further whether the base circle is the same or not, the video in real world shows the cam turning and protruding further.
@@scooterarmy Just because a lobe is taller doesn't automatically equate to more lift. If the base is also fatter, the tappets adjusted accordingly, the lift could remain the same. Did you know that you can gain lift on a stock cam by grinding away from the base circle ? Why ? Because the tappet is starting closer to the center line of the shaft before ramping up to the peak. However that won't change the profile curve of the cam. Profile and lobe timing it could be said are just as important if not more so than just lift alone. That's how NHRA Stock eliminator cars get to rev crazy rpms and turn 10 second time slips with stock lift cams.
Thanks for the Glixal info ! Good to know.
@davidg.5076 Okeechobee
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.
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
Let us know if you succeed in your quest to have a better cam produced
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
Get the sspg cam
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.
What does the a9 go on
Engineering should say right?
THANK YOU i finnally know the diffrence
I am getting tapping sound with the a9 like the valves are to tight but they good
check for clearance, to be safe
you need to readjust them after installing the new cam
Dude . On the bearing end of the shaft . I got 2 cam shafts. One hole in middle of bearing is bigger then other. Why
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?
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.
@@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 …
@@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.
Hope you see this rn if I put the a9 cam do I have to change my valve adjustment from stock ?
Adjust to same specs..
More lift = more power‼️
LIFT, yeeyee goode!
Where did you get the A9?
Do you know where the "NCY" cam falls in the mix? Is it big like an A9 or just a gimmick?
I have yet to look at the ncy.. life got in the way, and my cam testing took the back burner.
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
Many different looks to these cams..
You didn't show yours.
@@mrcleanisin I'm confused about what your saying. What didn't I show that perhaps I should have?
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.
Will the a9 fit on a Chinese 49cc 2 stroke engine that is sold on Amazon?
2 strokes don't have a cam, or valves
@@scooterarmy ohh okay sorry I don’t know about engines I am only a teen (15)