14/38 Gearing on A 300ex Need to Know by Friday

[hondaracing0144]

I have a 01 Honda 300ex and the engine is stock but i have a K&N air filter and a full cobra Exhaust with a 120 Jet to run it and i was just making sure that a 14/38 gearing would be okay for my kind on engine and if it will not tear up anything im planning on getting the sprockets Friday so if you can help please do thanks *HONDA RACING*

[JohnT_98300EX]

If the pipe and jetting worked well 14 38 is a good start.My engine is stock with an FMF Q2 and air box relief, jetted to match. And I run 20x10 rear tires. Rear tire size makes a big difference.
14x38 pulls real hard but is slow on top. You will be turning some r's at trail speed. 14x37 seems to be good over all.
Now, this is with 20 x 10 rear tires. If you have the stock 22's 14x38 will run well overall.

[hondaracing0144]

yea im still running the stock 22' back tires so it should be good right?

[bwamos]

The jetting sounds lean (unless it is a dynojet jet).

The higher gearing won't damage your motor.

But the optimal gearing all depends on what you are using it for.

The 14/38 would work fine for fire roads, and open fields.

Tight woods or MX you'd want stock gearing or even a tad lower than stock. I liked 12/36 on 22's w/ the stock engine & aftermarket pipe/filter.

[hondaracing0144]

well i was trying to set my bike up for racing and im putting a little money into every month but the 38 tooth sprocket is the stock sprocket so im only doing the front

[John451]

Originally posted by bwamos
The jetting sounds lean (unless it is a dynojet jet).

The higher gearing won't damage your motor.

But the optimal gearing all depends on what you are using it for.

The 14/38 would work fine for fire roads, and open fields.

Tight woods or MX you'd want stock gearing or even a tad lower than stock. I liked 12/36 on 22's w/ the stock engine & aftermarket pipe/filter.

Gearing confuses me. Would 12/36 be more torquey than 14/38? because to me it kinda seems like they would both be the same... but only if the tooth difference was the same.
I had 14/38 on my 300 and it was great btw still hauled wheelies and was a lil faster.

[bwamos]

Actually there is a lot of difference between those 2 options.

Pretty simple if you just divide the rear by the front.

Stock 13/38 = 0.342 That's your benchmark.

Basically your rear wheel will rotate 0.342 times for every time the front sprocket rotates.

Higher number = more top speed potential if you have the HP to pull in. (higher gearing)
Lower number = more "torquey feeling" bottom end. (lower gearing)

12/36 = .333 so you'd be geared slightly lower
14/38 = .368 you'd be geared higher.

Now we'll assume you're top speed is 55mph w/ stock gearing on 22" tires.

You can take the new gearing ratio, divide it by the benchmark, and multiply it by the benchmark speed to see the new top speed (assuming you can hit the limiter in the new gearing).

(.333/.342)*55 = 53.6 mph
(.368/.342)*55 = 59.2 mph

[John451]

Ohh, I always put way too much though and too little thought into these things. I used to look at that as the bare bones way which is right but doesnt tell u as much the smaller the front the easier it is to turn but fewer revolutions the bigger the front the harder to turn but the faster it will go and the opposite for the back. But I didn't know there was a way to find the IMA of the gearing. Thanks alot, that's awesome and very helpful.

[hondaracing0144]

ok well i switch tire sizes lol and went to 18s and i can tell a big loss in power its like ive went dont in gears like my 3rd is 2nd and my 2nd is 1st what should i do

[fmftrx300ex]

I have this sproket set up just know that you will have to grind ur case saver or take it off and there is a good difference in 13 to 14. we have a hill climb up in my woods thats f**king narly and i used to do it in third or forth but now im normally in second at the top. i can ride tight trails no problem but i have 20's in the back also. good luck id do it again