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Post by dexameth on Jul 9, 2017 21:31:17 GMT -5
Yeah, Florida is pretty flat. There's a few bridges around connecting beaches, those are my hills. Still a pain on a stock 50. I finally got my Keihin 24mm 150cc carb installed and adjusted the needle all the way up (most fuel delivery). Man there's torque!! Yesterday I had a stock 150 carb on and it work, but bogged when the throttle opened too fast. I figured it was a velocity thing. More like too lean. After I adjusted the needle, the throttle is definitely snappy. I was pulling up the bridge today at 38 and still accelerating. I was holding 55 on US19... I'm gonna have a re entry on the speed list soon. I even got my wheelies back finally! Kinda lost them since the 49/17 gear swap but not tonight. I really wanna port match my head now and get the Airsal piston. Don't give up on your QMB! So Dex, Are you saying it was the 24mm carb that got you where you needed to be? The carb wasn't the final factor, but DEFINITELY helped. When adding so many more ccs I felt my fuel/air mixture should grow with it. So after testing it I really did feel a gain, I've ran it ever since.
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Post by humanshield on Jul 10, 2017 13:13:54 GMT -5
So Dex, Are you saying it was the 24mm carb that got you where you needed to be? The carb wasn't the final factor, but DEFINITELY helped. When adding so many more ccs I felt my fuel/air mixture should grow with it. So after testing it I really did feel a gain, I've ran it ever since. Reason I ask is that I went up to a true 20mm carburtor from the stock 18 and cant really say it made any noticeable difference. Well, the take off was a HAIR softer and top end picked up maybe 1 mph? But...a guy I know who knows scooters as good as anyone built a 100cc scooter that is really fast and it has a 24mm carb. He's always insisted a BBK'd QMB139 ran much harder with a 24mm carb and intake....I will probably try it but I do have the 150 that is every bit as fast as the fastest 4T built 50's with big kits in them so I have to really decide if it's worth it. May leave the 100cc BBK'd QMB139 for insane gas mileage and use the 150 for faster runs (or the sport bike)
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Post by aaronj863 on Dec 31, 2017 3:10:33 GMT -5
i know this is an old thread but has anyone tried swapping final drive gears from a 150cc cvt into a 50cc?
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Post by aaronj863 on Jan 1, 2018 23:58:40 GMT -5
nobody at all?
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Post by 90GTVert on Jan 2, 2018 14:17:19 GMT -5
Never tired. I assume the final drive parts don't interchange. Don't have my 150 around anymore to tell you 100%.
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Post by aaronj863 on Jan 2, 2018 22:38:33 GMT -5
ok looks like its just something ill have to try and report my findings
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Post by milly on Jan 3, 2018 9:54:06 GMT -5
Maybes you could find out from schematic diagrams online by comparing both engines.
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Post by GrumpyUnk on Jan 3, 2018 10:30:27 GMT -5
AARONJ: If you look at the gearset, the 150's have a longer output shaft, outside the gear case. I think the gears can be installed, but the best way to check is to compare part numbers of the gears in question. You might want to take a look at a web site carrying the complete set of gears for both, and see if the countershaft and final drive gear are the same from the 50's to the 150's. The replacement gear on the countershaft must be pressed onto the countershaft, and the final drive gear is a slide-on to the output shaft that carries the rear wheel. If the replacement will fit the counter shaft, it should work. Of note is that there are input shafts, that have the clutch on the external end, that have more teeth, and they are sold with a countershaft with fewer teeth. Again, the other gear on the countershaft must be pressed on, or the new countershaft has a 'normal' ratio gear already installed, so it is a 'bolt on' swap. If you really wanted a 'long legged' machine, you could install the new input shaft, and also a new output gear pair, but you'd have to have some power to make it go fast, likely more than a base 49/50 can use with the largest BBK.
FWIW, there is a set of posts on the site from someone who successfully used a gear-puller to R&R a new gear on the countershaft. No press needed. tom
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