Lean Running 2014 TPGS-809 [scooter] By townzlblx150 (Read 479 times)

[townzlblx150]

i have a 150cc Bashan that has burned out 3 mufflers before I became familiar with this forum. After reading some of the different threads I came to the conclusion that this thing was running really lean because my mufflers would burn out right where the header pipe connected to the muffler body. I originally had a sealed carburetor, A/F screw plugged and the bowl was riveted, so I got a new one. I had a performance exhaust and a cone shaped air filter, I jetted the carb up to the #110 size and it was doing fairly well but I was still getting a little burp at WOT and Top End.
Well one day after tinkering with it I didn't tighten the air filter all the way and it came off on a ride out. I went the next day and picked up a Uni and installed it, I knew I was going to have to do some tweaking with the A/F mixture so I ordered an additional pack of jets and also a TTO tachometer/hour meter to help get it dialed in. Since then I have stepped up through all the jet sizes I ordered and am currently running the #118, it's getting up to about 50-52 mph(GPS), but I was getting 60-65 before and I am still getting a little burp @7280-7300+ rpm's. I can roll back the throttle a 1/4" and the rpm's go up a little on the tach. I am also thinking about getting a new clutch and variator because the TTO is at about 2700 rpm's before I get any clutch engagement, but I digress.
My question is should I continue stepping up the jet size, the pilot jet is a #35. I've sprayed the hoses for air leaks and could not find any, but when I leave work I am going to get some cable ties and replace the spring clamps on the vac lines just to be sure. I've done the pull the plug test after installing the #118 and I am still coming up lean.
It has just over 9000 miles on it but is on it's 4th muffler, any advice?

[townzlblx150]

It's been a while since I created this post and a lot has happened since then with me and my scoot. I've gained a lot of knowledge from this forum and also the "It's The Ride" forum, thanks to all you guys. I've also come to realize that each of these machines can react differently to changes you make in their set-up and you really have to do what suits you and your particular machine. I was having a problem with my scoot burping @7200>7300 rpm's or at least that's when it would occur. I was trying to stay within a certain recommended range of jet sizes while trying to set my A/F mix but that didn't work well once my rpm's reached the range I mentioned earlier. I mentioned I had a #118 installed when the problem occurred and I was unsure about stepping it on up to the #120-122 range, well that's what finally worked. Before that 7200 was as high as it would go because it would run irratically after hitting that point, yesterday it ran smooth throughout to about 8500 rpm's, then I backed off. I ran the set-up with the #120 and I have not had a burp since, during this trial and error period my gas mileage had dropped to about 65-75 mpg's. Now I'm back up to 100-107 mpg's and my top end has gone back to 65-70 mph. Of course I've played with the variator and the weights, my stock variator was upgraded to a 115 and my stock rollers were 13g's, but I installed some 15g's after I got her running good and she really seems to love that weight( I'm still experimenting with it but for now I'll stick that weight). What I've really learned is that CDI's, Air Filters, Ehxausts.., any changes in these may send you back to check your Carb set-up to accommodate any imbalances in the A/F from your add-ons.