Ok, I plan to have my '96 300Ex full race ready by the end of summer. I think that all I really need to do that is a cam, suspension, a big bore kit, a high compression piston and maybe some porting or something like that. I already hvae a pipe and tires/wheels, air filter and stuff like that
but not any of the "major" engine or chassis mods. Which do you think would be most important to do first out of WEB cam, bore .20 over/wiseco high compression piston(this is 11:1 so I am also gonna have the starter re-done), and suspension?

And with the suspension, I am planning to get a fox rear shock and maybe works dual rate fronts. Do you think that I should get the cans on them? How much difference do they make? I raced this weekend and never bottomed my stock suspension, but I didnt get very aggressive with it. Thanks

 

I had a 300 ex for a season...I really liked the machine... It was not my banshee, but was not meant to be either....

I have the triple rates up front on the banshee and they work really great for me....I don't bottom at all. Since this was my first set of works shocks, I have not been able to compare against the ones w/o the cans.

Never seen a fox shock on a quad, except on a few local polaris' machines. They (polaris) seem to bottom all the time. (they weigh a ton though)

If I had the money to spend on building a 300ex...I would get extended arms (at least 2" out/1" forward), An extended axel, of course shocks all around, an adjustable cdi box, cam, push the jug to at least 330, carb, port/polish, I could go on forever. But after you spend that kind of money...You better be planning on keeping the bike forever. Cause I don't know too many people that will spend 10+ grand on a 300ex.

For your application, I would probably have to say that suspension would be a good place to start... I only weigh 160-165 lbs. and I had no problem bottoming the 300ex most of the time.... My opinion is that it is too narrow and tall for high speed racing (tippy) But....Even with a stock motor (just pipe)...you should have enough power to keep up pretty good.

 

What size carb would you recommend for the 300EX after I have it bored and add a piston? (I am only boring it .20 over, not sure how much that will make the CC's but I dont wanna go to far the first time. That way I can always do more when I feel its necessary.) I was keeping up well, in fact was one of the fastest quads on the track during my race, but like any ATV enthusiast I just want more! Where I race, there is only one quad class so I was up against banshees and 250r's. It was real muddy so they just didnt really have the bottom end to get through that stuff. (they werent built, mostly stock though)

 

I would get works shocks up front and get my rear shock revalve and put dual rate springs on it. it would be cheaper than a new rear shock. once I get my new works on my 300ex in a few weeks I'll let everyone know what I think about them. later

 

I have heard that only going .20 over won't really make too much of difference. Unless your quad burns oil and really needs bored over-- stick with the cam and a higher compression piston
Keep in mind you may need to run higher octane fuel when you bump up the compression. If you haven't already-- vent the lid of your airbox and rejet the carb. A 350x intake boot will also inprove airflow. Be sure to go with a new higher rev cdi box to take advantage of your new cam. A one tooth larger front sprocket (14) will also help your buggy make the most of it's new found power.

 

Tires......

 

Unless you go really crazy with the jug size/compression...the stock carb should provide plenty of gas...even with a cam.

Your talking alot of money for the work you want to do.

Good luck

 

ok, i had a 300ex and raced it for 3 years, i know everything about a 300ex you need to know.I just sold it buy i had everything done to this thing. Firt off, i had works shocks on the front with canisters and plus 2 a arms, and i hated them, i rode very aggressive and bottom them out off of almost every jump.i wound up buying the weld on kit it from atvracing that converts it to a 250r front end cause the travel on a 300ex sucks and it don't matter how good of shocks you buy for a 300 the travel still sucks and there is no potential. with the kit you use a 250r shock and a arm then if u still have problems bottoming u can buy a set of aftermarket shocks for a 250r and slap them on there. For the rear, your never gonna find a fox rear shock for that. and you cant revalve a rear shock on a 300ex. go with a works ultracross its a great shock for that bike. as for the motor, where i race they have a seperate 4 stroke class and you wouldnt believe the bikes those guys got. so to be competitive i had to send my motor to TC racing the top 4 stroke motor builder around, i had it bored and stoked, camed, ported, big valves 38mm carb, pipe, unlimited rev cdi.it was then a 405cc and pumped out 50 horse power when stock puts 18, You will never have to get your starter redone.for the mods your doin, you will never in a million years have trouble startin that thing. i would go with the biggest possible upgrade for the motor now and not to move up later cause you will wind up spending alot.and they don't make an adjustable cdi for that, u have to send it out to get fixed to unlimited rev. if u have any questions email me at steve300ex@aol.com. honestly i lost alot of money hooking that bike up and i wound up selling it for a 250r. i wouldn't put to much money into, seeya

 

Put the 250r front end on it. Put a new high compression piston. A cam ,talk to Lauri at webcam she is a big help. New valve springs, revlimiter mod, and a 400ex carb.