Sprocket size/gearing ratio - 2011 YZ450F

Drive Chain & Sprocket Kits Yamaha YZ450F

11 replies to this topic
  • Giygas

Posted January 09, 2016 - 02:36 PM

#1

I have a gearing question. On my bike, I currently am running a 14/52 sprocket size. My problem is that it makes it impossible to putt around in 1st. The gear ratio is 3.71 for my current set up. If i switched to say a 13/49 or 48, while the gear ratio would be similar, would that lower front sprocket allow me to "putt" around a little more in first? I mainly ride tracks, but if I'm riding around the pasture or trail and need to turn around, my current 14/52 set up makes it obnoxiously quick off the clutch. I guess one positive of the 14/52 is that 2nd and 3rd gear is absolutely blistering fast.

What are some of your favorite set ups?



  • mikedabike

Posted January 09, 2016 - 03:25 PM

#2

It would be pretty much the same.  1 in the front is like changing 3 in the rear.

 

Stock is 13/49.

 

You are never going to get 1st gear low enough to "putt around" on the MX bike.  The internal 1st gear ratio is just too tall.  Try putting a 13 on the front and leave the 52 on the rear and see how you like it.



  • Giygas

Posted January 09, 2016 - 04:06 PM

#3

Thanks for the reply. Do you think the mapping could be a reason as well? I've ridden many 450s, but this one is just so aggressive out of 1st.


Edited by Giygas, January 09, 2016 - 04:08 PM.


  • poppa

Posted January 09, 2016 - 06:42 PM

#4

Thanks for the reply. Do you think the mapping could be a reason as well? I've ridden many 450s, but this one is just so aggressive out of 1st.

 

shift



  • grayracer513

Posted January 09, 2016 - 07:30 PM

#5

The trouble with lowering the gear ratio to make it easier to do something the bike was never designed for is that it will make it even MORE "aggressive out of 1st" than it already is.



  • Giygas

Posted January 10, 2016 - 12:00 PM

#6

shift

 

Were you dropped on the head as a kid?



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  • Giygas

Posted January 10, 2016 - 12:05 PM

#7

The trouble with lowering the gear ratio to make it easier to do something the bike was never designed for is that it will make it even MORE "aggressive out of 1st" than it already is

 

Well i'm just confused. I don't understand why I can't get this bike to where I can ride it from the pits to the starting gate without endangering peoples lives. Like I said, I've ridden/raced my whole life and I've never had a bike that is either going 0 or 15 mph. I guess I am going to look at the mapping since that may play a role (this is my first fuel injected bike).

 

So to reiterate, a 13/50 (3.85 ratio) combo would be even more touchy than my current 14/52 (3.71 ratio) combo?



  • grayracer513

Posted January 10, 2016 - 12:38 PM

#8

It's a lower gear ratio.  Lower gears exaggerate any tendency to lurch on tip-in in low gear, which is incidentally why the guy you blew off as a troll said, "shift".

 

The fault for the behavior lies in the throttle body.  Injectioneering does a mod to the butterfly angle that tames this a little, and some of the maps are said to reduce the jerky off-idle behavior to some extent, but for the most part, the rider is the part that needs to adjust to it.  



  • Giygas

Posted January 10, 2016 - 01:20 PM

#9

It's a lower gear ratio.  Lower gears exaggerate any tendency to lurch on tip-in in low gear, which is incidentally why the guy you blew off as a troll said, "shift".

 

The fault for the behavior lies in the throttle body.  Injectioneering does a mod to the butterfly angle that tames this a little, and some of the maps are said to reduce the jerky off-idle behavior to some extent, but for the most part, the rider is the part that needs to adjust to it.  

Well thank you for at least replying with something of substance, unlike "shift" dude. I guess I'm going to just have to push my bike everywhere in the pits.



  • grayracer513

Posted January 10, 2016 - 03:25 PM

#10

That might be a solution, but other people don't seem to be experiencing the same degree of difficulty with this particular quirk.  Using the clutch a little more under those conditions is generally enough. 



  • powdermuncher

Posted January 30, 2016 - 01:30 AM

#11

Looking at the same bike right now , and from what I have seen it needs heavier flywheel GYTR use power tuner richen up and pull some timing of the bottom, had some good results with that. One mod a friend just tried is a throttle cam that comes on softer between the 3 mods It should be way more ridable for of road work.



  • cpetz24

Posted February 01, 2016 - 06:37 AM

#12

Little confused on what you are trying to accomplish.  If you just want to ride slower in the pits then yes a 13/50 would accomplish that.  A 13/52 would make 1st gear even slower.  Problem is, you're going to have a bike that will have a tendency to want to bring the front end up very easily.  You will get more bottom end, but will fall off on the top. 

 

I personally ride hare scrambles and I run a 13/50 setup which works great for me.   It still is geared rather tall for riding in the pits, but that is not where you win races.  Just clutch it when you're trying to "putt" around in the pits.  Your gearing should be set up for what you're trying to accomplish on the track and not just for that 5 minutes before the race.    







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