Post by Nomen Cognomen on May 1, 2022 10:56:33 GMT -5
I recently bought a 2019 Ruckus, sub 1000 miles. I know more about two strokes than four strokes, and most of my research suggests that too many Ruckus enthusiasts are morons whose claims and ideas can't be trusted, so I'm hoping this forum will prove better. So any input/advice on what I'm considering is appreciated.
Partly motivated by this site, which at least comes across as a more legitimate source of info than most other things I've seen. They claim to have gotten near 50mph out of 50cc, though the build wouldn't be reliable in the long run. I know I won't be able to get to that point, but hopefully I can get some modest improvements on top and bottom speeds, with some modest upgrades. Here's what I'm contemplating:
Carb and air-fuel mix: Upgrade to 18mm carb from Scooter Swap Shop.
I might not have otherwise thought about bumping up the carb, but I've noticed that my bike is clearly running lean on the bottom, and is perhaps a touch lean on top as well. Some of my research seems to allege that upjetting and carb upgrades have resulted in noticeable power improvements, so perhaps the stock carb is somewhat starving the engine after all? Not sure.
My bike seems okay in 70s temperatures, but sputters quite a bit when the temperature is in the 50s. Clearly needs better tuning. But keihin jets are hard to come by, and considering that I'd probably spend $30-$40 on a jet kit if/when I find one, the modest upgrade in carb size seems like a decent investment, so long as it really does have some modest performance increases to offer.
For air flow I plan to keep the airbox stock, and drill small holes if/when it proves to be necessary (though I'm assuming at a small increase in air will indeed be necessary in the end).
Partly motivated by this site, which at least comes across as a more legitimate source of info than most other things I've seen. They claim to have gotten near 50mph out of 50cc, though the build wouldn't be reliable in the long run. I know I won't be able to get to that point, but hopefully I can get some modest improvements on top and bottom speeds, with some modest upgrades. Here's what I'm contemplating:
Carb and air-fuel mix: Upgrade to 18mm carb from Scooter Swap Shop.
I might not have otherwise thought about bumping up the carb, but I've noticed that my bike is clearly running lean on the bottom, and is perhaps a touch lean on top as well. Some of my research seems to allege that upjetting and carb upgrades have resulted in noticeable power improvements, so perhaps the stock carb is somewhat starving the engine after all? Not sure.
My bike seems okay in 70s temperatures, but sputters quite a bit when the temperature is in the 50s. Clearly needs better tuning. But keihin jets are hard to come by, and considering that I'd probably spend $30-$40 on a jet kit if/when I find one, the modest upgrade in carb size seems like a decent investment, so long as it really does have some modest performance increases to offer.
For air flow I plan to keep the airbox stock, and drill small holes if/when it proves to be necessary (though I'm assuming at a small increase in air will indeed be necessary in the end).
Transmission: Polini Hi-Speed variator, stock clutch, details to be determined by tuning
I've seen tons of claims that the polini variator increases top speed, but I don't believe any of it. It makes no sense. There is no reason that the variator should increase top speed, unless it's larger than stock. And at least from the photos and videos I've seen, the polini appears to be the same size as the stock variator they are pulling off their bikes. Also, considering that all the sources I've seen seem to be clueless as to how to tune a CVT, I suspect anyone claiming the variator improved their speed are either repeating the lies they heard elsewhere, or they are confusing poorly tuned CVTs with poor performing variators.
That being said, I know that polini variators have typically provided much better acceleration in 2t bikes, and I'm inclined to believe the same will be the case for my Ruckus.
If anyone has any hard data on the polini variator size and the stock variator size, or can shed more light on these claims of top speed gains, I'd love hear what you know.
Exhaust: Unknown, need help
This is where I really am in a bind and could use the most guidance. The motoiq project went with the JDM Yoshimura pipe. But that's expensive as Hell, and I don't have the first clue how to evaluate my own needs for a 4t engine. All the upgrades I can find out there seem to be rather expensive, and the last thing I want to do is to spend a few hundred dollars on a pipe that is a poor match.
It seems to me that, in a nutshell, the goal should simply be to aim for a pipe just big enough to let the engine fully exhale, but no bigger. Is that about right? Any suggestions on a pipe that would be suited for that with an 18 mm carb?
I've read several things that say it's important not to diminish back pressure too much with too large of an exhaust pipe. But I'm having a hard time wrapping my head around that. It makes sense for a 2t engine, but shouldn't that be a moot consideration in a 4t? I would imagine that in a 4t engine the escape route for exhaust is one of the few times when bigger really does equal better.
Things that will be avoided: As I mentioned before, I'm not looking for an engine swap to a gy6 (more money than I want to invest), or boring out the engine (beyond my skill level). Nor do I want to swap it for a Zuma motor that could be more easily upgraded with a 70cc kit for even better speed gains (want to preserve better fuel economy). I also do not plan on changing the CDI to max out RPMs, as I will at times use this bike on longer rides out of town, where I'll be WOT for extended times and I don't want to float the valves. I don't want to get involved in doing any header or valve work at this time, as that gets into things outside of my experience, and I don't want to risk hurting reliability by biting off more than I can chew.
I want to settle on a plan and perform all the installations and major tuning in one sitting, so I'm trying to make as informed of decisions as possible. Any advice and guidance is greatly appreciated.
