Trx300FW - Oil Cooler Mod (Tutorial)

[Orvis25 108]

OK guys, 
Got another write up for you guys! 

This one is how to do make and install an oil cooler on your trx300fw. 
Special thanks to @Wheeler for the core idea of this mod.

OK, here we go
__________________________________________________________

Tools: 
Hack saw

Flathead screwdriver
Pipe reamer 
Metal file

Items:
CB650 Oil cooler w/ hoses (other coolers should work similarly)
OEM oil line from filter to rocker box

Hose clamps/clips
(2) sections of 3/8" oil cooler hose
(2) sections of 1/4" hose (I used fuel injector) 
(2) 3/8" to 1/4" barbed adapter

__________________________________________________________

 

Step 1) 

Cut the oil cooler hoses and the oil line. 
Be sure to ream the inside smooth, and file the outside. 
Flush any metal shaving out of the lines. 

 

 

Step 2) 

Attach the 3/8" hose to the metal lines of the oil cooler. 
Insert the 3/8" to 1/4" barb adapter into the 3/8" hose.
Insert the 1/4" hose on to the 1/4" barb. 
Secure everything with hose clips/clamps.  
 

 

Step 3) 
Insist the OEM oil line into the 1/4" hose ends. 
Secure in place with hose clamps. 
* the 1/4" will be a loose fit so I used multiple clamps to be safe. Using 3/16" oil cooler hose would be a better option, but I could not find any locally, so I used fuel injector hosing in 1/4 as my next best option *
 

 

Step 4) 
Install the feed line part of the radiator to the engine (above the filter housing), leave the return (on rocker box) un-bolted for now.
 
Start engine and let it idle to pump oil into the radiator and flow out the return hose, then cut engine.  
(This should only take 15-20 seconds from starting the engine)

! Make sure to ensure oil is flowing out the return line before reinstalling onto the rocker box, else you risk blowing the engine from no oil flow !

 

One oil has filled the radiator, and you verify the pump is pushing it out the return hose, bolt the return line on to the rocker box. 

* Another option is if you have the tools, inject oil into the radiator system before hand *

 

Step 5) 
Mount the radiator to the frame. 
I used plastics zips for test fitting (as seen in photo's), but for long term use and reliability I recommend doing metal wire or metal zip ties. 
@Wheeler produced his own bracket using U-bolts and L bracket metal. this would be another option.

Run the engine again, and listen for any abnormal sounds (since we messed with oil feed systems). 
As it warms up, check the radiators temperature to ensure its warming up (signaling oil is flowing). 

Check all connections for leaks, especially around where the metal OEM line fits into the 1/4" hose held on my clamps (as that's the weakest link in the system)

 

 

Step 6)
Reinstall all external components
 

__________________________________________________________

And that's it! 

Other than sourcing some of the parts (specifically for me the hose and barb adapter) this is an easy mod to do. 

I recommend buying a spare metal OEM oil line just in case something ever goes wrong, or you want to convert it back. 

 

Best use case for this mod would be BBK users (like @Wheeler) or for people who live in hot climates and what to keep their engine cooler.
The mod does not do a a lot for making the riders comfort better (does not reduce hot leg syndrome) by much, but it will make your engine happier.

If you do this mod, let me know how it goes for you and what you did differently! 
Hope it helps guys! 

______________
Disclaimer:
I am not responsible for any damages to your equipment or vehicle, nor for injuries to yourself or others. This mod write up is for educational purposes, do it at your own risk. 

 

Edited August 5, 2021 by Orvis25
Re-wrote everything (posting it glitched and deleted all text)

[Orvis25 108]

Something when wrong with posting (all the text is gone but pictures stayed). 

goin back and re-writing it all.......

Edit:
Took a few attempts and an extra hour, but I got her re-written. IDK why it was giving me such a hard time posting text and photos'. 

Edited August 5, 2021 by Orvis25
update

[Fishfiles 20,147]

Banjo fitting  to #6 ANS /JIC to #6  hose barb and do away with the steel tube and hose clamps ---  or go with the oil filter cover plate 

[Orvis25 108]

Ya i consider going directly from he cooler threads to a barbed fitting to eliminate a lot of conversion and clamps, but even a 3/8" flaired fitting would not screw in properly to the CB650 cooler and mount flushly, so I went with the cut the line method like @Wheeler to preserver the OEM fiaired fitting so I have proper pressure throughout the system with no "whirlpool" points in the line from gaps on the internal parts of the line. 

I considered the oil cooler plate method, but its a much more expensive method (I got this whole thing done for under $30 us) and would position the oil lines closer to the riders legs (something I did not want). 

But ya that is a mean looking setup @Fishfiles ! 

OOC: what is your oil cooler from originally? 

Edited August 5, 2021 by Orvis25

[jeepwm69 7,752]

I might do this as some point.  Have a couple of extra 500 Foreman oil coolers, and your writeup would make plumbing that in pretty easy.  I like the fan Fish has there too.  

 

Of course, I need to build a monster 300 first......or I wouldn't really need it.

[Orvis25 108]

2 minutes ago, jeepwm69 said:

I might do this as some point.  Have a couple of extra 500 Foreman oil coolers, and your writeup would make plumbing that in pretty easy.  I like the fan Fish has there too.  

 

Of course, I need to build a monster 300 first......or I wouldn't really need it.

Well hope it helps in the long run. 
I'm sure your engine would be happy, even if no BBK is installed (like mine). 

I was considering a fan, but I think its a bit overkill given my engine is stock.

[jeepwm69 7,752]

My only running 300 now is bone stock with 26's.

 

I do plan to build a big boy one of these days, but it's a ways down the list.

[_Wilson_™ 6,593]

why would you think a fan is over kill when honda offered them as as option for that model  ? just asking.... 

[Orvis25 108]

Just now, _Wilson_™ said:

why would you think a fan is over kill when honda offered them as as option for that model  ? just asking.... 

Fan for the oil cooler, not for the engine (idk if that was misunderstood)  
I never had overheating issues to begin with, so having an oil cooler already is reducing the chance of a non-existent problem for me, I deemed the fan unnecessary. 

Pretty much just that. 

[Wheeler 2,530]

7 minutes ago, _Wilson_™ said:

why would you think a fan is over kill when honda offered them as as option for that model  ? just asking.... 

 

Ive always contemplated tossing a fan on mine!!

Edited August 5, 2021 by Wheeler

[Orvis25 108]

5 minutes ago, jeepwm69 said:

My only running 300 now is bone stock with 26's.

 

I do plan to build a big boy one of these days, but it's a ways down the list.

well, best of luck with the "big boy" build. 

I saw the cost of doing a BBK build and nearly s,h@,t myself (I got a price for a kit + the boring work at $800 before tax and shipping costs both ways).
I would not need the extra HP as all I do is pull mulch and logs, and plow in the winter, so I will stay stock.

Edited August 5, 2021 by Orvis25

[Wheeler 2,530]

3 minutes ago, Orvis25 said:

well, best of luck with the "big boy" build. 

I saw the cost of doing a BBK build and nearly s,h@,t myself (I got a price for a kit + the boring work at $800 before tax and shipping costs both ways).
I would not need the extra HP as all I do is pull mulch and logs, and plow in the winter, so I will stay stock.

 

I’ve spent over 10k on my 300 lol! 
 

TRUE STORY!

 

[Orvis25 108]

3 minutes ago, Wheeler said:

 

I’ve spent over 10k on my 300 lol! 
 

TRUE STORY!

 

Well I bet its a beast and a ! of a lot "better" than mine.
But.... I'm not putting 1/3 of my yearly income (before tax) into my near 30 year old ATV to pull some mulch around and plow in the winter 😛 

I might consider the BBK when i need to do top end engine work though since id have to spend money regardless. 

Edited August 5, 2021 by Orvis25

[_Wilson_™ 6,593]

that doesn't shock me at all...wheeler. most likely that fastest 300 fourtrax here... lol! ram air works wanders for cooling an air cooled engine, eh ? 

[Wheeler 2,530]

I was just sayin… yup Orvis a bbk & major mods will NOT be cheap like u said. I’m just half mental lol 

 

(Canadian costs are like over double the states though ug too!!:)

[Orvis25 108]

1 minute ago, Wheeler said:

I was just sayin… yup Orvis a bbk & major mods will NOT be cheap like u said. I’m just half mental lol 

 

(Canadian costs are like over double the states though ug too!!:)

brutal. 

But as long as your happy right? 

OOC: what mods do you have on yours? Iv never seen like a list of everything you done to yours. 

[jeepwm69 7,752]

Oh I don't have any intentions of going Wheeler with mine.

 

I just plan on a 317 top end with a 54 or 62% GR and some 29.5's.

[Wheeler 2,530]

355bbk

40B Cam with Hardened Rockers & stiffened valve springs

300ex carb & full SS FMF exhaust

HL Outlaw Springs

EBC DRC 

K&N Filter

Torq Locker

424 kick out

Rear Brake Delete

HL Disc Conversion

Terra 3500 Winch

LED Pods & 22” light bar

HL Lift

Bronco Shocks

VIP Fairing & Mirrors

Oil Cooler

Heat Demon Hand/Thumb Warmers

 

 

just to name a few lol

Edited August 5, 2021 by Wheeler

[Orvis25 108]

2 minutes ago, Wheeler said:

355bbk

40B Cam with Hardened Rockers & stiffened valve springs

300ex carb & full SS FMF exhaust

HL Outlaw Springs

EBC DRC 

K&N Filter

Torq Locker

424 kick out

Rear Brake Delete

HL Disc Conversion

Terra 3500 Winch

LED Pods & 22” light bar

 

just to name a few lol

Well you can read my signature for my mod list 😛 
Not even approaching 10k like yours, but hey, i do some stuff >.< 

[Orvis25 108]

4 minutes ago, jeepwm69 said:

Oh I don't have any intentions of going Wheeler with mine.

 

I just plan on a 317 top end with a 54 or 62% GR and some 29.5's.

Why not above a 317 top? any particular reason? 

[_Wilson_™ 6,593]

300ex carb! thank you, i had been thinking about which sport carb you were running. 

[Wheeler 2,530]

Back on topic, this was a great write up. The oil cooler mod works perfect. Cools the oil down, but only at speed really. I would mount the cooler solid to the frame though. & like mentioned a fan would totally compliment this mod! 

[Orvis25 108]

17 minutes ago, Wheeler said:

Back on topic, this was a great write up. The oil cooler mod works perfect. Cools the oil down, but only at speed really. I would mount the cooler solid to the frame though. & like mentioned a fan would totally compliment this mod! 

OOC, do you know of a fan system that mounts to the sb650 radiator, or would you be doing it via retrofitting? 
Didn't see anything via google. 

[Wheeler 2,530]

I’d just fab my own..

 

[Orvis25 108]

1 minute ago, Wheeler said:

I’d just fab my own..

 

Ya, kind of figured, let me know if you do though, would like to see how you come up with it.