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02 300ex build thread

86K views 512 replies 16 participants last post by  Dj300EX 
#1 · (Edited)
Hey guys,


Well thanks to TRX (a mod on here), and others, I have got my 300ex re-jetted, and running right.

I have many plans for this 300ex to make it better and last longer, so I figured I'd make a build thread to not only share, but get help as I go.

Plans:
Spare set of DWT red label 9x8's for rear. got em
add oil cooler done
400ex front suspension swap done, also got Urethane bushings
450R front shocks. Done
Rear grab bar change-done
headlight delete/rewire of existing led lights. Done
Rear axle rebuild/upgrade - even though it's perfectly fine right now. Done
Throttle cable/clutch. Done
Reverse mod. done
ASV F3 shorty clutch perch/lever in Red Done
01 Raptor 660 rear shock. Done
tires for spare rims
UNI filter/K&N bag Done
Possibly different handle bars.... More low profile?
sand down plastic, make look new.
new chain/sprockets done
new front rims/tires
Front end steering Stabilizer Done


And a couple other things as I go, like tires, rims, and hand guards.

Basically for this quad, I'm shooting for a ride that I can go through the trail normally, then if I see a pack, I can whomp the throttle and have the power and suspension to compete.

Current mods:

400ex carb jetted to a 175 main, and 42 slow.
FMF full exhaust with powercore4 slip on muffler
Parking brake BOP
twin LED lights on a DG front bumper
Razor2's on rear racing rims, with razors on the front racing rims.
Rear carry rack
winch capabilities on the front suspension. (Not on right now)

Here's a pic of her as is.


Thanks for looking/fallowing.

Dj
 
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#2 · (Edited)
Parts came in today:)

I got the spare 02 300ex clutch side cover to do the drilling for the return oil line.

It also appears that on the underside, it is ready to except a return oil line.

This is what I want to replicate with the 300ex cover.

I also got the Honda 350X oil lines.

And I also got the oil filter cover from a 350X that you can see on the clutch side cover pics.

All I'm waiting on now, is a 400ex oil cooler that I ordered up, also got to go get transmission line O at some point.

Now I have researched this a little on my own, with the help of TRX and the set-up that he has done on his quad.

As far as I can see, there should be no problem with oil pressure lose, but does anyone else think it could be a problem?

This is a diagram of the 02 300ex oil passages.

To me it just seems that making the oil go out the oil filter would cause the system to lose some oil pressure, and would require a oil pump that can bump up the pressure to make up for the lose?
 
#4 ·
I've been running this for almost a year . . . make sure you bleed off the oil lines. . Pressure shouldn't be an issue the 350x is setup from the factory thisway
 
#5 ·
Okay, that's kinda what I was thinking, that the 350X runs this system, and from looking at diagrams, the 400ex almost runs a similar set-up to this.

But how do I measure oil now though?


And my pops is going to do the mod to the clutch cover for the return line, any advice to give him when going to drill the hole through? I know you(TRX) said you had a shop do it, but maybe someone else has done this as a CNC machinist?
 
#7 ·
Okay, that's kinda what I was thinking, that the 350X runs this system, and from looking at diagrams, the 400ex almost runs a similar set-up to this.

But how do I measure oil now though?
the 400ex is a dry sump engine totally different. what do you mean how do you measure the oil now?
 
#6 ·
I do not recommend drilling this yourself unless you're a machinist. . that line that fits there must not leak
 
#8 ·
My father is a CNC machinist of almost 40 years. Do you happen to know the size of the screws for the return line? The one I bought didn't come with them.


And how do I measure the oil for my motor now with the oil cooler on?


Is it as simple as fill the cooler up till it comes out the return line, then add more into the motor until its hitting its mark on the stick?
 
#9 ·
I think I added about a 1/4 more oil. . . I can't remember right off. If pops is a machinist that great. the filter cover screws are the same thread pitch as the housing screws(where it attaches to the case) the other line you can use whatever will work. I used an allen headed screw
 
#10 ·
Okay cool, I feel much more secure now about adding this oil cooler. Hopefully it will prolong the life of my great running motor for years to come.

I will probably also add a small cooling fan to this mod list, as I do not want it to get hot if I idle for a few moments. Sometimes the summers around here get hot too.
 
#11 ·
I wished I had of added mine sooner myself. . . I wouldn't be going in it now. . . but I will be back on the trails by spring I hope
 
#14 ·
Incase you haven't. . .excuse the dirt I haven't cleaned it.
 

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#16 ·
Nah is protected better than you think. ..and I know it looks like it's leaking but it's not. . I checked it that's gloss black and I polished the clutch cover and filter cover
 
#23 ·
Mine came on the cooler I just got lucky that they fit where the fender stay bracket mount
 
#24 ·
Update: Well check off the throttle cable, but I think I might want to do the other two now too, clutch and reverse cable.


On the other hand, I went to both autozone and advance auto parts looking for transmission hose in 3/8th inner diameter, and no one had it? Might have to order it online, or find a trans shop near by.
 
#25 · (Edited)
Okay I got a question.

There are two black box's in the front suspension that take up a lot of room where the oil cooler would go, I believe one is the CDI box, and the other is ignition control?

Anyways, where is a good relocation point for these?

Started to make the brackets for the oil cooler, and ran into this problem^.

Couldn't mark where I wanted to bend the brackets with those box's in the way, and I'm kinda just fishing for a clue to a good spot to relocate them to otherwise?
 
#27 · (Edited)
I am going to mount mine like yours, and I need to get it up higher then I can right now, and those boxes are in the way.


Even when I look at the pics of how/where yours is mounted(on page 21'ish of your thread), you had to move those box's to get it up high enough to attach to the lines coming off the motor?

But I can't see where you moved them to in your pics.

 
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