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Post by billythegrape on May 31, 2013 12:16:55 GMT -5
Well, since no one answered in my build thread, I will ask again.
Put an open exhaust on the bike (08 JMStar 150cc) despite having read it was crappy. Well, it was. Loud, annoying, blahblahblah.
I had rejetted the main to a 114 from a 107. I put a muffler on yesterday, low end is back. Yes, with both exhausts I followed the procedure for adjusting mixture.
Bike seems to be missing, like a car miss, under load. It is 3 1/2 turns out on the fuel air screw, and when I plug read, it was normal. Could this be the coil dropping out?
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Post by scootnwinn on May 31, 2013 12:19:17 GMT -5
How old is the gas in the tank? BBK? Approximate compression ratio? Fuel type?
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Post by billythegrape on May 31, 2013 13:41:22 GMT -5
Gas is brand new  octane, which is what the manufacturer's label recommends. Tank has been emptied, refilled, fuel filter changed. Plug is NGK iridium. Valves have been adjusted properly. Carb is stock with the exception of the main jet. No idea of the CR, sorry. |
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Post by oldbikerider on May 31, 2013 15:04:06 GMT -5
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Post by billythegrape on Jun 6, 2013 8:31:47 GMT -5
Hey guys, thanks for the helpful responses, and sorry it took so long to write back- computer is dead and the iphone is too much of a PITA to write posts with.
Oldbikerider's jet FAQ was awesome, cut my teeth on fuel injected Volvos and know nothing about carbs, car or otherwise- highly recommend reading this handy piece of material. Rode with a piece of duct tape partially covering the air box inlet as recommended, bike would barely move before exhibiting the "miss" condition. Rode open airbox- no issues except a couple of hiccups from takeoff. I leaned the mix screw until I didn't feel safe doing it, made it a bit better, but it's at like 1 and 7/8 turns and still hiccups on hills and heavy accel. Think a bigger pilot and open air filter will help? Any thoughts?
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Post by oldbikerider on Jun 6, 2013 9:43:58 GMT -5
Glad my link helped. I've been playing with carbs for years and Fuel Injection confuses me.
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Post by billythegrape on Jun 14, 2013 8:00:48 GMT -5
Ok, fixed my problem. Wanted a better exhaust, started with a muffler gut and internal smoothing, upjetted main from 107 to a 114. No low end, sounded like crap, was burping and farting under load.
Cut muff off, put huge long (bout 18") tractor muffler I had sitting around on. Sounded amazing, gained some low end back, but was still burping and farting. Performed Alleyoop's carb adjustment, got some power back, but was fighting a rich condition that was a losing battle.
Went to the bike store yesterday, grabbed a 108 main jet, installed. Problem solved. Now bike is way more powerful, got back my low end and then some, and it still sounds like a cafe racer with the slick muff.
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octane, which is what the manufacturer's label recommends. Tank has been emptied, refilled, fuel filter changed. Plug is NGK iridium. Valves have been adjusted properly. Carb is stock with the exception of the main jet. No idea of the CR, sorry.