Wasted Tuning Interesting Article in Scootering Magazine
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Addicted
2007 Stella 150
Joined: 02 Nov 2019
Posts: 657
Location: Rochester, Minnesota
Sun Jun 28, 2020 4:48 am quote
https://youtu.be/SxQV0xz4q6E


I read through parts of those articles and found them interesting. Also along with the old article on Stella tuning where the larger carburetor didn't help because they didn't open up the intake holes to match the larger carburetor, but it did help when the bar between the two reeds was removed, which allowed more flow. I

I've never understood, not looking for a debate it's just me. Why open up a hole in a piston that already has twice the area of the intake. Then you have a matching hole on the other side. Then you have another boost port, which adds more area.

Would be interesting to see an article like this on a BGM 177 or similar.
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2134
Location: London UK
Sun Jun 28, 2020 6:30 am quote
Interesting segment from Dan. He didn't go into when it does matter enough but certainly there is a point.
If he's following the CM BGM he may comment.
Ossessionato
05 Stella, '62 VBB, 76 Sprint V, 63 GL
Joined: 16 Jun 2011
Posts: 2567
Location: Chicago. Well, Evanston, but that's almost Chicago
Sun Jun 28, 2020 12:14 pm quote
I found it to be an interesting video, but ultimately, it took him 15 minutes of talking to kind've miss the point, IMO.

In every process or system, there's a bottleneck that defines the upper limit of performance. That's why we tell people not to install 24mm carbs on their scoots if they haven't removed the other bottlenecks in the system. What he described as the changes that made no difference probably didn't make a difference because other bottlenecks in the system made those tuning steps irrelevant.

So in that respect, I agree that the key to getting more performance is not to just "do everything." What he doesn't discuss, though, is the process by which we can test if a particular change eliminates that bottleneck or not. And if it does, if you want to go further, you have to find the next bottleneck, and so on, until you hit the theoretical maximum output of a particular size & type of motor.
Addicted
2007 Stella 150
Joined: 02 Nov 2019
Posts: 657
Location: Rochester, Minnesota
Sun Jun 28, 2020 3:28 pm quote
chandlerman wrote:
I found it to be an interesting video, but ultimately, it took him 15 minutes of talking to kind've miss the point, IMO.

In every process or system, there's a bottleneck that defines the upper limit of performance. That's why we tell people not to install 24mm carbs on their scoots if they haven't removed the other bottlenecks in the system. What he described as the changes that made no difference probably didn't make a difference because other bottlenecks in the system made those tuning steps irrelevant.

So in that respect, I agree that the key to getting more performance is not to just "do everything." What he doesn't discuss, though, is the process by which we can test if a particular change eliminates that bottleneck or not. And if it does, if you want to go further, you have to find the next bottleneck, and so on, until you hit the theoretical maximum output of a particular size & type of motor.
I agree, I think some of the points like people just do everything to do it is true. They don't for instance, measure a transfer port area at the piston. Then open up the port at the base so it's the same size or a little bigger. I know I didnt measure mine, I just opened up the gate to match the base and moved on.
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