all kinds of 300EX info!
i know me and others have answered many of the same questions over a short period of time, so i figured if there is one reference chart with a majority of 300ex frequently asked questions, in theory this could save everyone some time, i will keep adding to the list feel free to add something useful!
ok, here we go remember this all 300ex info, some corresponds to the 250x some doesn't.
stock valve lash =.004
Stock jetting = 122 main , 120 main (high alttitude), 38 pilot, stock needle position - 3rd groove
Wheel offsets - front = 4/144 rear =4/110
Stock gearing = 13 / 38
stock spark plug # - DR8ES-L
stock carb 32mm keihin with accelerator pump.
Ignition: CD with electronic advance
(300ex CDI will not work on 250x)
Ground Clearance : 4.6 in. (stock)
Will 400ex a-arms work?
yes, you will need a-arms, tie rods, and 400ex length shocks (16.25), and a shock relocator bracket, 400ex spindles are not neccessary but are an improvement with this set-up,and yes stock brakelines will stretch far enough.
will a 400ex steering stem work?
yes, stops on bottom need cut off beacuse there 180* off, and the little washer about 3/4 will need removed, it is roughly 1'' longer
will a 400ex carb work?
yes, i recomend it for engines that have atleast the basic mods, such as pipe. filter, ect.. stock boots will stretch, all you need to do is rejet, and i recomend a 42 pilot jet
Hardweld rockers are only necessary for a hard weld cam -
EX. web cam, billet cams such as hot cams do not require hard weld rockers, they will actually cause damage to your cam
What is max. compression piston on 93 octane. - 11:1
any thing over is pushing and detonation could result.
engine idle speed = 1,400 +/- 100 rpm
stock pilot screw setting = 2 1/4 out from closed
engine compression with stock piston - 171 - 200 PSI
engine oil capacity -
oil change only - 1.6 quarts
oil and filter change - 1.7 quarts
totally engine dissambly - 2.11 quarts
*if you run a oil cooler about 2 quarts even on basic oil and filter change*
Suspension
Front: Independent double-wishbone with dual hydraulic shocks, 5-position spring-preload adjustability; 7.1 in. travel
Rear: Swingarm with single shock, 5-position spring-preload adjustability; 7.9 in. travel
Fuel Capacity- 2.2 gallons, with a .5-gallon reserve
chain free play - 1 3/4 in. at most
heres a gearing calculator to show how variables such as rev-limit, tire size and gearing affect speed
gearing calculator
here is the link from the tech section on how to rig your reverse set-up, used when you use a aftermarket clutch lever & perch or if you are just tired of hurting yourself when you try to engage reverse
reverse bypass
quad clicks when start botton is engaged -
its can usually be narrowed down to 2 things, assuming your battery has a proper charge, and it putting out correct voltage at (100% it should be reading about 13 volts)
now, its either your solenoid, or contact brushes in your starter
Common Rear end Swaps:
A 01 raptor rear shock will work but they are famous for blowing bladders on the 300ex
a 450R swingarm will also work, how ever this set-up requires tabs to be welded or bolted to the frame to accept the linkage. You WILL have to use a 250R rear shock, linkage is up to you, the 250r or the 450r linkage will work, carrier and axle, and rear brakeline will also be needed. the swingarm is around 3 inches longer
the 350x rear end will also work
same as 250r
more info will be added by me constantly,, don't be shy feel free to add anything you think would be useful
QUAD BOGS WHEN IN WATER?
alot of times it is your carb vent tube. the one that hangs down behind the motor. the problem is this tube gets submerged, you can either trim the tube shorter, or put a T splittler on it and add a different length hose.
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