gearing/jetting for 300ex

[zoe17]

Okay I have a 2001 300 ex with t-4 pro ciriut slip on, K&N filter, and run a 168 main jet all is well. I do not know if it is stock bore and stock cam. If it where stock would it be running rich?

I have t-9 baja wheels on back with 22" Itp tires. I run woods and do not care about top end, what should the front and rear sprocket be. 13/38??? The bike had 18" tires when I got it. Just seems slower with the new tires.

I am considering a aftermarket head pipe, will this help any? If I go with .30 over and new springs will it be noticeable?

I am pondering selling it for something faster but I love the size and way I can get through tight stuff. Not to mention reverse.

Thanks in advance for your replies.

[VTRJason]

The 300 comes stock with a 122 keihn jet so a 168 is huge. Try a 125. If it has a different cam and compression it's a new story. Don't know much about the gearing though.:devil:

[frosti108]

i might be able to help you out with your gearing troubles.

if the bike seems less powerful with the new tires, its true.

the 22" tires weigh more, sucking power, and they also give your quad taller gearing.
1st off i think you should sell those tires and buy yourself some new 18s or 20s. you could always gear down, but its so much better to change to a smaller tire... the bigger the spinning mass, the harder it is to spin it. this is how they suck your quads power. so unless you want a high top speed (which you said you dont) i would definatly get some smaller tires.

if you decide to keep your big tires, youll want to go with a smaller sprocket in the front, or a bigger sprocket in the rear. since you dont really want to go bigger in the rear due to clearance, you should go smaller out front. if youve got a 13 tooth front sprocket like you say, you might as well grab a 12 and see how you like it.

now if you do get smaller tires like you should, i would still go down to a 12 tooth front, just because it will add to your rear wheel torque, and basically make you quicker through the trails like you say you want. but it will noticably lower your top speed.
also, smaller tires will obviously lose you some ground clearance, but in my book, its worth it.

now with me, im the opposite, i like higher speeds in the open feilds even if it does sacrifice some grunt. if you look in my sig, im running 14 teeth up front and a 33 tooth sprocket in the back. this setup is for high speeds, with less bottom end grunt. so you would do the opposite...

damn that was a lot lol

ok good luck... :)

[Braff1]

zoe17, the 300ex is a good woods bike. My daughter just blew up her 330 kit in the middle of the local xc season and TC racing was dragging their feet about getting me a new piston and sleeve so we went back to a stock bore .20 over with 11:1. Her bike already had a TC race cam in it and a 400ex carb which is suppose to be close to stock. We are still in the process of trying to get it jetted but her is what we have: 38 pilot with a 160 mh, 2.5 turns out on the mix. I know when I had a 300 ex and I put a new head pipe and silencer with modded air box I had to put a 40 pilot and about a 140 range mj. But the best thing to do is let the bike be the judge about the jetting, do a couple plug readings and see what it says.

Now for tires. The 22's will give you more ground clearance but the also require alot more power to turn those big things. You say it had 18" tires on it when you got it. I would say check the gearing, stock is 13/38. If you go to 20" tires there are a couple options to run 13/35 and 14/38. Both these combos will put you gearing close to stock but will give you just a slight bit more bottom end than stock.

From the way it sounds with "the bike being slower now" with the 22's I would say you were geared for the 18" tires. Your bike is prolly geared so low you should be able to take off in second without any probs? Try the new sprockets and I think you will have a new bike that you like.

[zoe17]

Thanks for the replies. I still have the red labels and 18" holeshots. I will try bolting them back on. I like the little taller ground clearance as I ride woods,rocky terrain at a sometimes too fast of a clip.

Thanks