# of teeth needed to move up 1 gear

[njrealtor55]

I ride a 92 KX250 in the woods on a track I built myself - I am lucky to have a father in law with 10 acres of woods and all the construction equiptment you can imagine.

The issue is the track is very very tight in some places. So tight, that my kx is literally at the bottom of 1st - so low i have to clutch it to navigate thru the turns.

this is the way the track has to be due to property lines and large rocks in the woods. I have no problems with the track, and the bike runs well thru it as is - but it is a handful. It also tires me out faster having to use the clutch that much.

I know a flywheel weight is gonna be on order in the future (12 oz.), but i would like to re-gear so i am not at the bottom of 1st in the tight sections.

The stock gearing is 14/49 , and I do have to double check as the previous owner installed new renthal chain and sprockets before I bought the bike.

I was thinking going to a 13 in the front, but adding or subtracting teeth from the front or rear is not the issue. I know changing the front to 1 lower # (13 in this case) is about the same ratio of 3 additional teeth in the rear.

I also am aware of the additional shifting, and reduced top speed and the peaky powerband it will have, but being able to lug 2nd (after getting the flywheel) on my track is better than running out of gears and stalling.

So to wrap up a long post... how many teeth will bring me from the bottom of 1st to.... let's say the bottom of 2nd?

 

[MX-727]

Do you have either the owner's or service manual for the bike?
If you know the gear ratios for each gear, you can calculate the info you need based on total gear ratio in each gear including the final drive ratio.

 

[MX-727]

OK, I checked on Kawasaki's website, the specs are not listed before 96, but here are the 96 KX250 Specs for the transmission:

Transmission
Clutch Type Wet, Multi-disc, Manual
Transmission 5-speed, Constant mesh, Return shift
Shift Pattern (Bottom up) 1-N-2-3-4-5
Gear Ratios
—1st 2.13 (32/15)
—2nd 1.69 (27/16)
—3rd 1.39 (25/18)
—4th 1.14 (25/22)
—5th 1.00 (24/24)
Primary Ratio 2.75 (55/20)
Final Ratio 3.50 (49/14)
Overall Ratio (Top Gear) 9.62

gear ratio*primary ratio*final ratio = overall ratio for each gear.

Overall ratios
1st - 20.49
2nd - 16.26
3rd - 13.37
4th - 10.97
5th - 9.62

With that info we can figure out (3.5*20.49/16.26) that we need a final drive ratio of 4.41 to make the move you want. If you do the math (rear sprocket/front sprocket = 4.41) you can plug in the various front spocket sizes to come up with the rear sprocket.

Hear are the answers:

14/62
13/57
12/53

Now, you may wonder why I didn't just give you the answers. I hope by explaining it you will understand how to figure it out next time. The only viable option is going to be the 12/53, so you probably should compromise and go with something like a 13/52. You should be able to now figure out what kind of ratio that will give you.

Good luck.

 

[njrealtor55]

thanks. i appreciate your help & effort in explaining it. i was still trying to figure it out when i saw you replied.

 

[#1YZ125RACER]

to rap it up just drop 1 tooth in the front....if thats not low enough then add a few in the back...a front sprocket is alot cheaper and has better effect

 

[sick 96 250]

the last few bikes of mine i always ended up going up 2 teeth in the back and it has seemed to help a lot. I just get my stuff off egay cause its cheap. Just got a new rear sprocket for $5. Only prob with goin up a lot in the rear is sometimes the chain wont be long enough anymore.

where exactly do you ride in NJ? I'm not far from there and we have a decent spot over near my way as well. It would be cool to ride with some more people.

 

[njrealtor55]

i am going to buy a 13T & 12T countershaft sprocket from RockyMountian to see how it works. Not sure abot the 12, but @ $7, you can't go wrong. I'll also have to get a chain splitter tool as I am sure I do not have enough adjustment in the rear to compensate.


my track in in Hopewell, NJ zip 08525

rode yesterday a little - not bad, can almost do the entire track with out clutching it. RPMS get real real low in some spots though.

if you want to come ride that would be cool. i could use some help in making the track better & longer thru the woods though. I have all the equiptment to do it - just need some creative ideas on track layout considering how the woods are laid out.

I'll most likely be extending the track on saturday morning & hopefully riding it by late saturday afternoon. Have plans to go to paragon on sunday, but if people wanted to ride with me at my place, then i'd stay home.

email me if you want to ride sometime. njrealtor55@yahoo.com

 

[bikepilot]

I raced a 1993 KX250 in harescrambles and MX and actually liked 14/48 gearing best. there is nothing wrong with slipping the clutch at low speeds, it actually gives you better controll and drive out of the turn imo. Don't worry about wearing the clutch out, they are quite sturdy. I slipped mine a lot, had the bike for 5 years, raced it for two full seasons, went though 3 top ends and one crank but the origional clutch was still in it and working perfectly when I sold it.

I did use a 12oz flywheel weight and found it helped the bike hook up quite well, I was faster on the MX track and woods with the weight. Only place I didn't like it (and thus took it off, a 5 minute job) was the sand dunes. I really liked that bike. Its an amazing machine and capable of running with the new bikes in its class with just a little work. Mine had a mild port job and race tech gold valves + stiffer springs. Also had the PC dog bones which raised the rear end of the bike a bit makeing it turn quicker. Frankly, I was just as fast on it as I am on my 01 CR250 or would be on a frinds 06 CR.

 

[njrealtor55]

yeah, i love this bike. it needs rear bearings, so i will prob just order all bearings made for the bike and replace them all over the winter - my wife calls me "the preventative maintenance man" :laugh:

i need to get springs, but i do not want to attempt rebuilding the shocks or the forks & the springs are $100 for front set and $100 for the rear. So, $200 plus seals, fluid and the cost for a local shop to rebuild them and it gets expen$ive. I am going to wait untill next winter to do the springs - this winter it is bearings and top end.

i am planing on going to paragon sunday and will determine how much of 4th and 5th gear I use. I figure i will not use them a lot - 5th prob not at all (even in the play area). I figure if i re-gear i will be 1 gear higher at all times (compared to stock gearing), and as long as I am not using 4th and 5th a lot with stock gearing, i can afford to re-gear and obtain a happy medium of the correct gearing for my track and public tracks.