some 300ex questions

[dsmlover]

ok i have a few questions about my 300ex
and by the way im new here, hi

ok i am trying to keep up with or beat a z400 with exhaust, intake, cdi box and of corse jets so im planning on boring it to a 330, 350 or 390, i dont want much overkill so my other mods will be full exhaust, intake, cdi box, cams, oil cooler maybe, and all that good stuff... so which should i do to keep up but read the rest before you answer

also planning head work, i think i may send it into mickey at fst but i would rather find a more local place, anyone know a place around wisconsin here?

i will have a local shop bore the block by the way

cams, what cam should i get? and what size valves should i go to?

exhaust, i need it to be less than 92 db's in wisconsin here to go on the trails so i need a full exhaust system OTHER THAN STOCK that will be close, i dont want any looney dual crap neather i dont have that kind of money. I know i will need a silencer too w/ a spark arrestor so which one?
ive heard good about wb e2 and some others

who, other than mickey does motor work like that EX: who has the 350 kit?

thanks again guys

[hard one]

from messing around with my 300 i have gone threw many mods and have figured out what works and what almost does.

-go with 20 rear tires for take off but still are tall enough to keep top speed.
-gearing 14 front 36 rear
-white bros e -seires meg with header
-bore kits, fst 330, duncan,330, www.hetrickracing.com 313 or 390,
a 330 kit will put you at about the same power as a stock z-400
- head work big valves port and polish dosent do much( dont bead blast your head it will mess it up seen plenty of people do it)
- open air box with uni filter( not K and N it lets dirt threw into the carb)
-jet kit 140-145 main jet works well
-cut front fenders creats less drag but brings more mud
-also if you are going to make your 300ex fast as a z-400 make shure you upgrade thr front suspension, go to www.diamondjcustoms.com they have some cool effective and cheap ways to widden and increase your travel.
DONT let freind buy cobra products they poorly made.

[spartacus]

By the time you spend the money to build up the EX to even get close to the zuke it will cost about the same price as a quad that is faster. If i had the money to do the motor work that you are talking about to build up your EX run with a zuke I'd just sell it and buy a 250r or something like that. Thats just me, but I think by the time you add it all up youll probably be over the price of a used zuke with all the mods and the price of the 02' ex you got. Im not trying to knock the EX, hell ive got one and its great. But im going to build up an R instead of spending any more on my EX that will never compare to a quad like a 250r, Z400, 450r, Z450, yfz 450, or even a 400ex. So if i were you id save your money and get a bigger quad, thats what I'm doing. (or you could always drop in a cr500 motor and never be touched by anything haha)

[humblesquirel21]

i agree with with hard one


i personaly liek sparks powroll and fst for engine work

i recomend a yosh pipe

i love my edle brock carb but many people feel they are to expensive

the gearing he quoted should be perfect its what i jsut purchased i can tell you in a week what i think

i disagree about the air filter though i have considered swtching to a uni filter but i haev my k@n and i love it i jsut tore my engine down after riding with my k@n for 2 years and there is no sign of that filter leting any dirt through my darb is also clean you jsut have to keep it oiled

20 inch rear tires are the best handling imo id recomend razr 2s all around

everybody has a different idea for suspension i like my elka's they have been supurbed performers aixs pep ohlins fox and others are good brands the only brand i wouldnt ever buy is works they are inexpensive though

maier is good middle of the way plastic between cheap stuff and full bore i like mine

srp metals (only found on magic racing) makes great products at a very good price i have loved every one of their parts so far I honestly wish i wouldnt have bought the higher priced brands on afew things and stuck with srp they make good stuff at fair prices

[TOfunk2drunk]

i didnt even bother readin your whole post.

ive owned a 300ex for five years. wicked reliable. the least expensive mods i did , was put 22-12-9 kenda rampages on, great tire all around and taller = more top speed. put a disc exhaust on...i used dg, thyre great u can tune for more top end or less by amount of discs. u can actaully notice it too. and last but not least i put 1 more tooth bigger front sprocket on it. almost felt like another gear was added.


you will never be able to beat your friends Z.....i was in the same situation as you once. the only thing to beat him was a raptor at top end only, but my friend with a cannondale beat his has all around from bottom to top! save for a new quad cuase in the end thats what your gonna do anyways as most people do.

o ya if u take off ur front fenders you will gain a about 1 mph, friend with warrior did it nver seen it done on a 300ex thou

[dsmlover]

thanks for the links

[spartacus]

It'll take a lot of work to get it to dominate a Z. and yes a 400ex carb will work on your 300ex. ....if you can get $2000 out of your quad you could pick up a 250r or used 400ex for around $3000, or even less if you get one thats a little rough. Look on Ebay, I bought my 02' 300EX on there in jan or 03 for only $3000 and it still had tire hair. Im not trying to talk you out of your 300, its just that after you put all that motor work in it your still going to want more power, and it wont be there. So its just better to upgrade to a bigger quad if you plan on making some big HP numbers and running with the 400+cc 4stroke quads.

[humblesquirel21]

i was in the same situation new quad or mod the 300 and i wsa reluctant to trade so i didnt and now im almsot done with my rebuild and im kind wishing i woulda held back cause i wana sell my little beast but ill never get my momeny back at all so im gona ride her till she drops dont get me worng i love that quad its jsut not a 400. I did make the smart desision to not go big bore i jsut rebuilt with a higher comp piston and high lift cam


my honest advice is to go easy on the modds on the 300 and pursue a 400ex or sometihng bigger

the 300 is so deceptive cause its a blast to ride and its got all hte fundamentals right it jsut coems up alittle short in every department compared to its big brothers

a coment i would liek to make for the simpel reason of defending a great quad is with elka front shocks on stock a arms and a works in the rear i have never bottomed out even on some considerable jumps

[Cody_300ex]

Check this thread out, lots of useful info there.... http://www.exriders.com/vbb/showthread.php?s=&threadid=195797&highlight=Engine+build

[bwamos]

Originally posted by dsmlover
ok guys thanks alot for the feedback... keep it comming

now part of the reason i posted this is im still contemplating selling it, but i figure i could get 2000 for my quad, he just got the z for 4000 so 2000 in parts is alot of stuff, and i will have a sweet quad too but i could just buy a new one too but i am so used to mine, i mean i weigh 130lbs i control this bike like i control the women (j/k, i wish) so its just right for me but i dont know


I'd sell it and upgrade.

Honestly.. for $2000 of aftermarket you're not going to be even close to competitive with the z400. For 2K you could "almost" keep up to a stock z400.. but then it blows you away in the suspension department.

I'd get a 400ex for about $3k and put $1k of mods on it. You'll have a quad that is much faster than the 300ex.. and have a better suspension package to work with. And it's air cooled like the 300ex, so less things to go wrong. ;)

I'd seek out a 400ex w/ suspension upgrades.. then upgrade the motor. (I'd stay stock bore w/ HighComp piston, cam, pipe, filter)

[exkid300]

no no no if u want the best gearing 4 the 300ex call sidewinder sprockets and ask them if they have a 33 tooth 300ex rear sprocket and they will have it.. i warn u its a lil pricey but my friend has it on his 300ex and he stays with the z400 thats has a yoshi exhaust and a k&N airfilter. but heres the number to sidewinder trust me you will not go wrong and just make sure you are running a 14 tooth front and u will haul som 300ex *****... heres the number and it sounds like one hell of a bike.. well when you are done let me know how urs runs..


Sidewinder sprockets- 630-513-1000

[humblesquirel21]

heydsmlover does does your friend have any low end left after he put that sproket on ?

[dsmlover]

thanks again guys

[dsmlover]

ok and another thing to get a 330cc is it a stroker crank and a .08 piston or a big *** piston?

[bwamos]

Generally on a 300ex a 330cc kit is a +.240" (+6mm) 80mm piston with a stock stroke. Requires a big bore sleeve. So yes it is a much larger piston about 17% larger surface area on the face of the piston. A stock piston is 74mm.


Sparks Racing has a 350 kit. 82mm piston. Which is actually 346cc's so it is below the 350cc sport class limit most places. (some places like MHSC has a 300cc limit)

[redrider9045]

Ride Better

[dsmlover]

thanks again guys