View Full Version : 250r gearing
nicescooter
02-25-2008, 10:36 AM
ok so ive got an 85 250r that runs like a demon, but im not feeling the power that I remember from when I rode a bike simular way back in the day. The guy who had it before me geared it down a little as to not have to idle the bike when he was ridin with his buddies. Its runnin 12/48 sprockets now and my question is...
"Will returning the bike to the original sprocket setup gain me back that elusive power i just gotta have?"
Its got a +5 swingarm on it so I know that affects how I feel the power, its not going to pull wheelies just ridin in the dirt, but im lookin for a little more if you know what I mean.
Dammit!
02-25-2008, 11:31 AM
12/48? You sure you don't mean 12/38? I didn't know they made 48 tooth sprockets for them.
TeamGeek6
02-25-2008, 01:58 PM
Id look at spark plug before chasing sprockets. Make sure its running properly.
By this calculator page:
http://home.earthlink.net/~gellett/250r.htm
stock was 13-39, 24 mph in 1st gear, at 12-48= 18 mph, so thats a low end gearing, and that tells me it isnt running properly.
Mines at 13-36 which is geared for higher speed, and cant use the power in low gears.
nicescooter
02-25-2008, 03:32 PM
It runs great always starts in 2 or 3 kicks never stalls i dont think thats the problem and the rear sprocket is a 42, i dont know where i got that 48 from. That puts 1st at about 21mph not to much slower than stock.
Dammit!
02-25-2008, 03:41 PM
12/42 will feel quite a bit different from 13/39. You're losing 10+ mph with that gearing. That +5 swinger isn't helping matters either. Extended swingers are great under the right circumstances but I think they also take some of the fun away from riding a trike. I always say if you don't NEED an extended swingarm, don't run one.
nicescooter
02-25-2008, 03:47 PM
with the 12/42 gearing im losing speed but I should have more torque correct?
Dammit!
02-25-2008, 03:51 PM
Yeah but you don't really feel it unless you're hillclimbing/shooting. I ran 12/39 at the dunes last weekend just as an experiment. Kinda weird feeling. I was often finding myself not knowing what gear I was in. I could pull an extra gear up the steep hills though. On the drag strip I lost 7 mph. I'm thinking about dropping the rear down to 37 and running 21 inch paddles instead of the 20's I have now and seeing how that feels.
What size tires are you running? If they're 18's that's like another 1-2 teeth smaller on the front sprocket.
DixiePlowboy
02-25-2008, 04:00 PM
Yes, but you're running through through each gear faster. Kinda like putting 4.56 in a stock cammed Mustang. You can run out of your useable RPM/power range and hurt performance.
You're geared lower than the happy medium and I'm willing to bet that (as long as you're motor is in good shape) you're going to feel faster and better with stock gearing.
On my last '85R I was running 13/35 on 18" turf tamers and it felt better to me than 13/39 with 20's. It wasn't as easy to ride in the slow terrain, but it sure was fun everywhere else.
nicescooter
02-25-2008, 04:00 PM
im not sure what the actual size of the rear tires is and I cant check right now im on the east coast for some business. When i get home im going to take her out to glamis and let her go in the sand...that oughta giv me a little better feel. Ive only been able to take this bike out twice and realy ride her and havent got much of a straight away either time.....should be hella fun though!
Dammit!
02-25-2008, 04:03 PM
In the dunes the +5 will be useful. I stll run a stock swinger but I really want a +4 for the dunes.
Sprockets are cheap. Buy a couple and try them out and see what you like.
nicescooter
02-25-2008, 04:05 PM
Yes, but you're running through through each gear faster. Kinda like putting 4.56 in a stock cammed Mustang. You can run out of your useable RPM/power range and hurt performance.
You're geared lower than the happy medium and I'm willing to bet that (as long as you're motor is in good shape) you're going to feel faster and better with stock gearing.
On my last '85R I was running 13/35 on 18" turf tamers and it felt better to me than 13/39 with 20's. It wasn't as easy to ride in the slow terrain, but it sure was fun everywhere else.
what do you mean "wasent easy to ride in the slow terrain"...just always down shiftin?
nicescooter
02-25-2008, 04:07 PM
In the dunes the +5 will be useful. I stll run a stock swinger but I really want a +4 for the dunes.
Sprockets are cheap. Buy a couple and try them out and see what you like.
I have to buy new tires soon, so I think ill pick them up and then work on my gearing. Im lookin to make a machine that scares me when I ride, im guessin a 310 kit is in my future.
DixiePlowboy
02-25-2008, 04:14 PM
what do you mean "wasent easy to ride in the slow terrain"...just always down shiftin?
Meaning that you had to use the clutch a little more to avoid stalling if you were riding slow/tight trails. You do have to pay attention to what gear you're in when you're geared taller and downshift a little more when slowing, but you won't be upshifting as often as with the lower gear ratio when transitioning to faster areas during you ride.
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