Performance Matrix

[ThaiGyro]

Happy Moms Day!
Just had a conversation with some scoot crazies here.  They are not on the forum, because their English is not quite up to speed.

Our conversation about performance mods was interesting, as it is here.  Newbies get some mixed up ideas from others who may not know or understand completely...especially when looking for upgrades.

My personal preference is to first steer them to cleaning/tuning/fixing their stock scooters.  The smarter ones comply and get huge smiles!  Those who have more monies or attitude spend a lot to gain a little, or in many cases gain nothing but noise.

Today, I was asked if there was some kind of matrix or guide that showed what the gain potential was for what parts or modification were performed.  Sadly, I said no...but could be useful for newbies and others. Even without Dyno data, there is still an advantage.

I have my own ideas, but would prefer to hear what the greater good has to say...a matrix might be difficult, but a guide might be very useful...The "performance" sector of anything car/bike/boat/scooter/airplane usually puts things into stages..nice if you understand the stage definitions. (Stage 1, 2, 3 etc)  For example: I consider "Stage1" modifications as anything you do can simply with little expense.  Advancing ignition timing...carb upsizing/tuning...CDI installation...simple port shaping/piston port matching.

Should we consider something like this as a potentially helpful tool?  Not specific to a brand or model...but more like expectations of 49cc by itself...and BBK by displacement categories by themselves. (~70...80...90...over that). I ask because there are many threads that allow for much discretion and understanding...and therefore confusion. I am thinking that a guide can be useful for initial planning, then the detail is in the threads...or pudding or butter.

Thoughts?

[Lucass2T]

Without measured data its impossible. You'd have to rely on peoples subjective feelings instead of objective data.

[90GTVert]

It's not a bad idea, but it could be confusing and tough to make universal. I'll tell you why I think that. So, let's say stage 1 is the most basic. Get the scoot in good working order, clean and inspect the CVT and carb and tune both. Cool, that applies pretty well universally. Maybe you could call stage 1 the stuff that involves getting the scooter shaped up and stage 2 the tuning. Either way, the next stages get fuzzy. People have different needs and wants when they mod. Some people wish to stay true to displacement rules, so even though I think BBKs are great mods for most small scooters, they don't work for those people and some other option has to become the next stage. Maybe someone is mostly concerned with speed and doesn't want to open the engine. Then, at least if it's a 2T, it makes more sense to do a tuned pipe instead of a BBK. Perhaps on one scooter a variator makes a big difference, while on another scooter the stock variator works pretty well. Maybe someone doesn't want a loud intake or exhaust sound, so then that throws off the stages. What determines a new level of a stage... the order of install suggested, the effectiveness, the cost? It could be generalized, but then it may be less effective or accurate.

I guess I've never been a fan of stage mods on any application, unless it's a specific part. For example, a stage 1 BBK for a 2T may be mild timings, a stage 2 would be midrace, stage 3 would be race or something like that.



That's my two cents, but here's a quick start/mock up anyway, just for an idea of what I imagine.

Stage 1 : Establishing a solid base. Get the scooter in a good state of repair. Make sure everything is working and working well. Check a service manual and be sure the scooter is up to date on all maintenance routines. Don't just focus on the areas that you consider to be performance aspects; cover it all. Drivetrain, brakes, steering, frame, wheels, tires, electrical. This should include carburetor tuning. While some see carburetor tuning as a performance modification, and it may improve performance, it is necessary to have a carburetor in a relatively good state of tune for reliability and longevity.

Stage 2 : Basic CVT tuning and ignition mods. Once the scooter is in good working order, evaluate the CVT. Monitoring operation with a tachometer is suggested. The goal of CVT tuning for maximum performance is to keep RPM within the engine's peak output range as much as possible when WOT. In the real world, there are compromises. Some don't like stiff clutch springs because of the way they have to rev to take off every time, or some may prefer to keep RPM a little lower while cruising in hopes of improving fuel economy or engine life or decreasing noise. Tune with the combination of roller/slider weights, contra spring, and clutch springs that gets nearest your goal. CVT tweaks may also be helpful here, such as altering the drive boss or spacers used on it, elongating paths in the torgue driver, etc....

Advancing ignition timing by way of a CDI or changing the clocking of the pickup relative to the flywheel may show mild improvements, though too much advance at cranking/idle RPM can cause hard starting. Premium pump gas may be required. An iridium spark plug may make starting easier or last longer than a traditional spark plug, but actual performance gains tend to be non-existent or minimal.

Stage 3 : This is where it gets complicated to me. Most of the time I put a BBK here. There are other easier to install mods that gain less, but for me it makes the most sense to use a BBK early in the performance work because of the cost for the gains realized in most applications. BBKs don't make the most sense for everyone though. Maybe it also makes sense to skip the carb and CVT tuning if the BBK is going on immediately, so then the stages are screwed up again. Maybe you find that compression is low on stage 1 checks, so you skip to 3 or wherever a BBK lands? I get lost in the details here.



A flow chart could clarify things a bit more, but that would be one complicated flow chart. "If you don't mind a lot of throttle use for takeoff, proceed to clutch springs." "If you wish to remain within legal moped/scooter displacement guidelines, skip stage _ and go directly to stage _." "If you aren't comfortable with installing a BBK or professional installation is not within your budget, go to stage _." I would end up with a maze.



I think some things can't be dumbed down to step 1 through 5 or 10. Sometimes you need to come to a place like our forum and ask real live humans. Alternatively, do a lot of reading and research and make an educated decision on your own based on your own parameters required to make a good scooter.

[Lucass2T]

This has been tried so many times on several dutch fora (which i before this, was a longtime member from). It never really worked. You'll only get more questions (and heated discussions!!!), especially about the stages themselves which ppl should use as a tool instead of something that confuses. You need to have a certain amount of knowledge to be able to inplement the stages. When you don't, the whole stage idea goes out the window since its too complicated for a beginner and too universal. Beginners will implement one of those stages and expect a certain result....which is often off from their expectaitions since they didnt know how to mount a pipe, tune a carb, torque a head down, and other things you'll only learn from experience or studying workshop manuals.



It does work on automobiles though. Cars are way better documented and ppl keep to the workshop manuals in comparison to the moped/scooter community where everybodi is just randomly using tools and methods like they want.

[aeroxbud]

Great idea in theory. The problem is so many scooters have there own strong and weak points. The Yamaha standard variator for instance is very poor. Something I would change early on. On the Piaggio scooters the standard variator is very good. I would only change it later on for an over range once some serious tuning had been done.
You could even have a whole matrix on two stroke pipes alone.