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Old 06-06-2011, 03:50 PM
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mapbike mapbike is offline
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Join Date: Mar 2010
Location: Central Texas
Posts: 5,379
Default Re: what did you do to your motor bike today?

Originally Posted by 5-7HEAVEN View Post
I replaced the engine's 62t chainring sprocket to 72t. That lowered my total gear ratio from 32.46-24.82-21.96-19.09-16.23-14.32-12.41 and 10.5:1 in eighth gear...
to 37.08-28.37-25.09-21.82-18.55-16.36-14.1 and 12:1 in eighth gear.

The gears are closer in ratio now, with an extra gear between first and second gear. There is still a big gap between first and second, because first gear is the stump-pulling, up-the-ramp gear. Now, instead of using only five gears, I can shift down to sixth gear and still be pulling hard.

This is all theoretical, but I'll find out when I commute to work.

I took it for a test ride yesterday, but couldn't see a marked increase in performance yet. The first few gears might've been a bit snappier. I'm having issues with the drivetrain, due to this sprocket swap. I need to address these problems before doing a series of comprehensive testing.

The bicycle chain jumped off its 30t chainring sprocket, a mile into the test ride. I was doing 30 mph on flat ground. There have been some clunks and clanks coming from the bottom bracket area, more than likely due to the sprocket swap. I used new sections of 8mm(T8F) pocket bike chain to lengthen the engine drive chain. I MIGHT have reinstalled the 30t bicycle chainring sprocket bass-ackward. I don't remember which way the sprocket's "dish" was facing. Relying on memory, the bicycle chain is now a fraction of an inch inward. This is noticeable in 8th gear. I recall that the bicycle chain used to contact the outer edge of the front derailleur. Now it's maybe 1/8" inward, towards the front derailleur.

The sprockets will be removed & reinstalled today. Hopefully, that should clear all of the issues.
Honey, it's just a bicycle. and i REALLY need it to excercise, and to ride it to work.(hehe)
Hope that fixes your issue, Man I really wont a shifting bike.....and I'm gonna have one before long, I've got 2 Sturmey Archer 3sp Hubs and one SunTour 3sp hub.......and I'm thinking this bike in the pic below will make a nice shifter set up since I dont think I can mount a sprocket on that wheel since the 3 spd hub is so much larger than the standard coater hub.

Attached Images
File Type: jpg 3speed bikes6.jpg (112.5 KB, 30 views)
I dont always ride WOT, but when I do..I do my best to keep the rubber side down..Ride safely my friends!
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