A9 Cam - Riding Impressions - Scooter also has 50mm BBK
May 4, 2015 10:49:14 GMT -5
90GTVert, kkzxxx, and 2 more like this
Post by humanshield on May 4, 2015 10:49:14 GMT -5
Well, today I installed the A9 cam. My scooter already had a "100cc" (in reality it's 83cc - 50mm) Big Bore Kit.
Except for the 50mm BBK, this new A9 cam and green uni filter replacing the stock air filter element in the stock air box, (and a 90 main jet), nothing else has been modified in my scooter.
Here are my real world first impressions after first driving my scooter with the new A9 cam.
It feels like a different scooter.
Start up -
Interestingly, the scooter turns over better now. When you install a BBK, you tend to raise the compression. What that does is make it harder for the starter to crank over the motor. Apparently, the lift and duration of the A9 cam seems to alleviate that problem slightly because the valves are open longer and open higher.
So an unexpected benefit to the A9 cam was easier starting. A very welcome benefit because until the A9 cam, my scooter was sluggish cranking over due to high compression.
Idle -
Idle was unaffected. It idles about the same now as before.
Launch and Low End-
Ok, here we go. Undeniably better pulling at launch. I was a bit surprised. I was "expecting" this change to mostly benefit top end but right off the bat, the low end is MUCH better. There is a definite improvement in low end torque across the board. This seems to be telling me that the 83cc BBK is having trouble breathing through the stock head. Opening up the breathing capabilities of an 50mm BBK unlocks the potential of the added displacement.
Now with the A9 cam, the scooter accelerates from launch with what I call "authority". It is no longer a twist and wait proposition. Twist the throttle and the scooter responds with a definite pulling acceleration. STILL..not equal to a 150cc...but definitely far far better than any 47mm or even 50mm scooter without the A9 cam. I have ridden stock 150cc scooters and I can tell you that a 150cc scooter will still walk away from my scooter decisively. There is no replacement for displacement they say...but things are getting interesting as far as my scooters performance is concerned.
Mid Range -
Honestly, the mid range is also much improved. I can attain 35 now with ease and hold it with ease. There happened to be a pretty stiff wind blowing this morning so for testing purposes, I picked roads that ran both perpendicular to the wind as well as into and against the wind. I can feel more torque available in the mid range. Twisting the throttle at 35 now results in positive acceleration whereas before, it would accelerate as long as there were no winds....and it was slow to accelerate. Now it responds fairly good with a roll on from 35. I can sum it up like this....before when I was at 35 I could accelerate higher, but it depended on whether or not the road was level and the headwinds. Under windy conditions or up a slight incline, acceleration was slight if not difficult. On flat ground it would accelerate to 40 fairly easily. NOW...there is no doubt. A roll on from 35 WILL result in acceleration even with a stiff headwind or going up a slight incline. This is a big improvement from the drivers seat perspective.
Top End -
As mentioned above, my first test ride was in very windy conditions. I fully expect to get better results when it's calm.
Perpendicular to the wind I attained the highest speed to date with my scooter of 44.18. My previous high was 41.72
I expect my new top GPS verified speed to be around 45-46 under calm conditions because I have always reached my best top speeds in no wind conditions. So on the next calm day or night, I'll go get my real new top speed. I wouldn't be surprised if it hits 47-48 under calm conditions the way it feels now. But even in buffeting winds, top speed is markedly better.
I also have a Big Valve Head on hand that I'm going to install soon. But I wanted to install just the A9 cam first and ride it a while to see what difference it made. Seems it made a lot of difference. If the Big Valve Head makes as much difference as the A9 just made, I'm going to have quite a fun little scooter. I'll do that write up soon, after installing the Big Valve Head. First I'm doing some porting work on it to clean up the factory imperfections.
Conclusion -
I wish I had done it sooner.
Top end is now in the 45 mph range.
Overall driveability is improved. What I mean by that is that the scooter just feels "BETTER" across the board. Seems to run smoother, is more responsive and torque is up without a doubt. A difference you can FEEL.
I'm going to say what I actually feel having just test ridden it with the A9 cam. I honestly feel that the A9 cam did as much to improve the performance of the engine as the 83cc BBK did. The difference with the A9 cam is just as big as the difference was adding the 50mm BBK. Of course, your mileage (or performance) may very, but this is my honest assessment in my case.
Now whether or not adding an A9 cam to a stock 49cc scoot would make that kind of difference is uncertain. I tend to doubt it. I think the 50mm BBK is trying to push more air through the head than the head can handle so the A9 helped with that and thus the big difference. At least that's my reasoning. No science to back it up tho. I would expect similar gains on a motor with a 47mm BBK as I had with my 50mm BBK.
I'll be checking gas mileage over the next few weeks and will give a detailed update on how this affected my gas mileage which I have been carefully documenting because one reason I ride scooters is to beat the oil giants. I love saving on gas expenses.
If you have a BBK....GET THE A9.
Nuff said.
Except for the 50mm BBK, this new A9 cam and green uni filter replacing the stock air filter element in the stock air box, (and a 90 main jet), nothing else has been modified in my scooter.
Here are my real world first impressions after first driving my scooter with the new A9 cam.
It feels like a different scooter.
Start up -
Interestingly, the scooter turns over better now. When you install a BBK, you tend to raise the compression. What that does is make it harder for the starter to crank over the motor. Apparently, the lift and duration of the A9 cam seems to alleviate that problem slightly because the valves are open longer and open higher.
So an unexpected benefit to the A9 cam was easier starting. A very welcome benefit because until the A9 cam, my scooter was sluggish cranking over due to high compression.
Idle -
Idle was unaffected. It idles about the same now as before.
Launch and Low End-
Ok, here we go. Undeniably better pulling at launch. I was a bit surprised. I was "expecting" this change to mostly benefit top end but right off the bat, the low end is MUCH better. There is a definite improvement in low end torque across the board. This seems to be telling me that the 83cc BBK is having trouble breathing through the stock head. Opening up the breathing capabilities of an 50mm BBK unlocks the potential of the added displacement.
Now with the A9 cam, the scooter accelerates from launch with what I call "authority". It is no longer a twist and wait proposition. Twist the throttle and the scooter responds with a definite pulling acceleration. STILL..not equal to a 150cc...but definitely far far better than any 47mm or even 50mm scooter without the A9 cam. I have ridden stock 150cc scooters and I can tell you that a 150cc scooter will still walk away from my scooter decisively. There is no replacement for displacement they say...but things are getting interesting as far as my scooters performance is concerned.
Mid Range -
Honestly, the mid range is also much improved. I can attain 35 now with ease and hold it with ease. There happened to be a pretty stiff wind blowing this morning so for testing purposes, I picked roads that ran both perpendicular to the wind as well as into and against the wind. I can feel more torque available in the mid range. Twisting the throttle at 35 now results in positive acceleration whereas before, it would accelerate as long as there were no winds....and it was slow to accelerate. Now it responds fairly good with a roll on from 35. I can sum it up like this....before when I was at 35 I could accelerate higher, but it depended on whether or not the road was level and the headwinds. Under windy conditions or up a slight incline, acceleration was slight if not difficult. On flat ground it would accelerate to 40 fairly easily. NOW...there is no doubt. A roll on from 35 WILL result in acceleration even with a stiff headwind or going up a slight incline. This is a big improvement from the drivers seat perspective.
Top End -
As mentioned above, my first test ride was in very windy conditions. I fully expect to get better results when it's calm.
Perpendicular to the wind I attained the highest speed to date with my scooter of 44.18. My previous high was 41.72
I expect my new top GPS verified speed to be around 45-46 under calm conditions because I have always reached my best top speeds in no wind conditions. So on the next calm day or night, I'll go get my real new top speed. I wouldn't be surprised if it hits 47-48 under calm conditions the way it feels now. But even in buffeting winds, top speed is markedly better.
I also have a Big Valve Head on hand that I'm going to install soon. But I wanted to install just the A9 cam first and ride it a while to see what difference it made. Seems it made a lot of difference. If the Big Valve Head makes as much difference as the A9 just made, I'm going to have quite a fun little scooter. I'll do that write up soon, after installing the Big Valve Head. First I'm doing some porting work on it to clean up the factory imperfections.
Conclusion -
I wish I had done it sooner.
Top end is now in the 45 mph range.
Overall driveability is improved. What I mean by that is that the scooter just feels "BETTER" across the board. Seems to run smoother, is more responsive and torque is up without a doubt. A difference you can FEEL.
I'm going to say what I actually feel having just test ridden it with the A9 cam. I honestly feel that the A9 cam did as much to improve the performance of the engine as the 83cc BBK did. The difference with the A9 cam is just as big as the difference was adding the 50mm BBK. Of course, your mileage (or performance) may very, but this is my honest assessment in my case.
Now whether or not adding an A9 cam to a stock 49cc scoot would make that kind of difference is uncertain. I tend to doubt it. I think the 50mm BBK is trying to push more air through the head than the head can handle so the A9 helped with that and thus the big difference. At least that's my reasoning. No science to back it up tho. I would expect similar gains on a motor with a 47mm BBK as I had with my 50mm BBK.
I'll be checking gas mileage over the next few weeks and will give a detailed update on how this affected my gas mileage which I have been carefully documenting because one reason I ride scooters is to beat the oil giants. I love saving on gas expenses.
If you have a BBK....GET THE A9.
Nuff said.
(as long as they're stock). 
