Originally Posted by JOBAfunky
Thanks for the advice. I already have the carb needle set to as lean as possible. I was considering the $25 speed carb off bikeberry. Anybody have any experience with that? Or should I just rejet my stock NT carb? Also any opinion on Jaguar vs. Lightning CDI? Oh, and by short trips I mean about a mile.
Big and dave, how does the expansion chamber with muffler compare sound wise to the stock muffler?
Speed carb offers no performance gain, only gives an extra fuel shut off valve and allows the use of 1/4" fuel line instead of the 3/16" that works best on the standard NT carb.
The NT carb or speed carb will allow you plenty of fuel and air flow makes good power whan the rest on the engines set up is right, having the needle set at its leanest (highest) setting only affects low to low medium throttle, from about 3/4 throttle to wide open throttle the metering needle does nothing, the factory main jet that comes in the carbs is to big and causes a rich run condition like has already been mentioned, the main jet in the carb has to be reduced in size to solve that issue and make the engine smooth up at lower to mid throttle cruising.
A better flowing exhaust along with a quality spark plug and better quality spark plug boot are what I consider the two best mods that can be done initially to these little engines, one thing to remember is that you should settle on the exhaust you plan to run before jetting down the carb, a better flowing exhaust will cause to engine to run a bit leaner, so I recommend doing everything else first and then re jet the carb to work with the final set up.
Since you're a big fella I would not recommend going any smaller than a 40T rear sprocket so you dont loose all your pulling power for hills.
The sick bike parts expansion exhaust is the best bang for the buck in my opinion if you dont habe a way to build a custom exhaust and need easier bolt on thing to upgrade the bike, its easy to install on most bikes.
Something else that will have an affect on jetting is the oil/fuel mix ratio, you will get many differing opi ions on what people think is best and what oil they like the best, most people run anywhere from a 25:1 mix all the way to a 100:1 mix with oils that are designed for those ratios and all the in between, personally I run a 100:1 mix of Opti2 2 stroke oil and my engines are tuned for that mix, most people agree that with conventional dino oils its a good mix @ 32:1 and with some synthetic blend oils a 50:1 works good like the Echo oil that can be found at an Home Depot.
The main thing to remeber is that the cab must be tuned to everything else and until you have about 100 miles or so on the engine I wouldn't do a lot since it will get better and beyter as it breaks in, I personally dont wait and I jet mine to whete I know from experience is a leaner than stock but safe level and then I ride mine pretty hard for the first 50+ miles and constantly check on things to make sure all is good and then I will start tweaking the tuning as I figure out the exhaust set up I plan to run.
Best wishes on the bike, use the search feature here on the forum and you will find loads of info to help you solve problems and get you china girl tuned in just right.