After riding my friends 400ex today for the first time, I was greatly impressed. I then hopped back onto my stock '98 300ex and was wanting more out of my bike. So my question is, What are the best mods I could do to my 300ex to get it some what close to a 400ex for under $1000?
Thank you in advance
-Justin

 

I have never ridden a 300EX, but we had a 250X for a couple years, back in the early 90's. Your post isnt exact in saying what part of your machine you want to improve the most. Because, you can say I want my machine to be more like a 400EX, but it is always going to be a modified 300EX. The 400EX is wider, has better suspension, better suspension, handles better, and has a more race oriented frame geometry.

If you put $1000 into just your motor. I would have to say you would get up with a stock 400EX. If you go with a good engine builder you might even be able to outrun a stock 400EX. However, there is more to life than drag racing. So you would still have a machine that lacked the sweet ride that the 400EX has.

I would think some good places to start would be a complete exhaust system. I have a Curtis Sparks on my 400EX and from what I hear he can do miracles for the 250X/300EX. Maybe a cam, stiffer valve springs, and a rev override kit. Of course an aftermarket air filter and jet kit would be good too, and would compliment the other engine mods significantly. If you really want to get crazy you can get a big bore kit, but that might put you over budget. However, it would give you alot more power throughout your revs.

If you still have some money left over after all that. I would suggest some aftermarket front shocks. I have never purchased any, but from what I have heard from others I ride with the Works performance are a good value, and will perform to what most riders need. Good, luck.

Adam Smith
99 400EX

 

Justin

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Put the 400EX front end on your 300EX. That's about $700 but it greatly improves the handling.

See Ya,

Darrin Talbott

 

Put the 400ex front end on the 300ex. Sounds righteous. Do you mean re-locating the shock mounts and using longer shocks, changing over to the 400ex A-arms (is this possible?), or both. Is there a "kit" available for this. Just curious....

 

You need a shock relocation kit from ATV Racing. Then you can use the 400EX a-arms, shocks, and tie-rods. It is easy to do and everything fits nicely.

See Ya,

Darrin Talbott

 

If you put a high-performance cam in a 300ex do you have to get stiffer valve springs? I often see someone suggest those two together. Is it nessary? Will it help the cam?

Cason Simmons

 

In one of my 4-wheeler magazines Jeremy Schnell took a 300ex motor put a 350x head on it and bored it out 8mm to make it 398cc. I am going to get a 300ex soon and I want to do that to it. The hard part is making it cost less that a $1000. You can also put headers, high compression piston, racing cam, and after market exhaust and that will give you at least 5 more horses. With the money left over you can buy a black box which costs $79 and eliminates the rev-limiter.

 

I just got done installing 4ooex shocks,a-arms,on my sons 300ex by relocating the shock tower and making it myself out of stock steel and the end result is awesome.The next thing is to put the 400ex swing arm and axle on it.I only have appox. $150 invested on the front end by going through ebay...

 

The rev box is definatly a waste of money. By the time you hit your rev limiter you are loosing power and not gaining so thhere is not point in reving higher. You run the chance of blowing up your motor too, not a good idea. POWROLcan help you out with kits for your motor. Get some good tires like Razrs or Holeshots to improve handling. Shocks help out ALOT.