Trx300FW - Oil Cooler Mod (Tutorial)

[Fishfiles 20,145]

2 minutes ago, Orvis25 said:

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.

 

I can tell you from experience , the cooler does practically nothing without the fan blowing thru the coils , and that is with double stacked coolers and relocated to unobstructed flow of air on top the rack 

 

I know this cause with the coolers relocated I can grab the upper hose with my hand while I am riding , untiI I  hit the fan switch , there is very little cooling going on , then within seconds of turn the fan on , the hose gets cool 

[jeepwm69 7,605]

46 minutes ago, Orvis25 said:

Why not above a 317 top? any particular reason? 

 

It's a 350 rancher cylinder installed in the 300 fin section, so when (not if, but when) you need to do a rebuild, you order an oversized 350 Rancher piston and have the cylinder bored oversized.

 

If you do any of the other big block kits you're looking at all custom stuff.

 

It's about $400 last time I checked.  Once you buy it, you can get replacement 350 Rancher pistons, and when the cylinder gets too far gone to bore, you can put in a new 350 Rancher sleeve and start over again.

 

@Mac102004 at one time had stuff to put a 4 valve 350 Foreman top end on a 300 bottom end.  Don't remember what all was involved but it was $$$$ and a lot of work.

[Orvis25 108]

16 minutes ago, jeepwm69 said:

 

It's a 350 rancher cylinder installed in the 300 fin section, so when (not if, but when) you need to do a rebuild, you order an oversized 350 Rancher piston and have the cylinder bored oversized.

 

If you do any of the other big block kits you're looking at all custom stuff.

 

It's about $400 last time I checked.  Once you buy it, you can get replacement 350 Rancher pistons, and when the cylinder gets too far gone to bore, you can put in a new 350 Rancher sleeve and start over again.

 

@Mac102004 at one time had stuff to put a 4 valve 350 Foreman top end on a 300 bottom end.  Don't remember what all was involved but it was $$$$ and a lot of work.

So the OEM 350 rancher cylinder head a direct swap bolt on with a new piston for a 300 lower? 

Might look into that when I have to do a piston replacement when mine starts to go. 

I know to do some other "cheaper" bbk options you need like reverse ground cams and stuff (like 300ex  BBK head swaps) . 

Edited August 5, 2021 by Orvis25

[Orvis25 108]

30 minutes ago, Fishfiles said:

 

I can tell you from experience , the cooler does practically nothing without the fan blowing thru the coils , and that is with double stacked coolers and relocated to unobstructed flow of air on top the rack 

 

I know this cause with the coolers relocated I can grab the upper hose with my hand while I am riding , untiI I  hit the fan switch , there is very little cooling going on , then within seconds of turn the fan on , the hose gets cool 

Iv never owned a bike or atv with cooler fans. Are they all "over sized" or do they also sell like side by side units to meet the length of the radiator? 

[Mac102004 426]

5 hours ago, Orvis25 said:

So the OEM 350 rancher cylinder head a direct swap bolt on with a new piston for a 300 lower? 

Might look into that when I have to do a piston replacement when mine starts to go. 

I know to do some other "cheaper" bbk options you need like reverse ground cams and stuff (like 300ex  BBK head swaps) . 

not the 350 Rancher head, that wouldn’t work. The older 350 Foreman head and cylinder will swap as an assembly, you do need a reverse grind cam and will have to custom build an exhaust and top motor mount. It’s much the same as swapping over a 300EX head. The whole thing is quite involved and I think there are some new big bore kits on the market now that are probably a better option. Although you wouldn’t be getting that 4 valve head. 

[Orvis25 108]

10 minutes ago, Mac102004 said:

not the 350 Rancher head, that wouldn’t work. The older 350 Foreman head and cylinder will swap as an assembly, you do need a reverse grind cam and will have to custom build an exhaust and top motor mount. It’s much the same as swapping over a 300EX head. The whole thing is quite involved and I think there are some new big bore kits on the market now that are probably a better option. Although you wouldn’t be getting that 4 valve head. 

Ah, ok good to know info. 
Forman 350 head on trx300fw is not compatible without accommodating modifications. 

[toodeep 1,758]

13 minutes ago, Mac102004 said:

not the 350 Rancher head, that wouldn’t work. The older 350 Foreman head and cylinder will swap as an assembly, you do need a reverse grind cam and will have to custom build an exhaust and top motor mount. It’s much the same as swapping over a 300EX head. The whole thing is quite involved and I think there are some new big bore kits on the market now that are probably a better option. Although you wouldn’t be getting that 4 valve head. 

 

I didn't even get my 350 build 300 completely done and I was tired of replacing all the other parts of the machine. It did win a lot of mud races though. I'm glad those days are behind me on now it's the kids problem to spend all that money.

 

On topic: Nice job, simple but does the purpose. All I ever ran was a cooling fan but most of the time the motor was under water so it was "water cooled".

[Orvis25 108]

Just now, toodeep said:

 

I didn't even get my 350 build 300 completely done and I was tired of replacing all the other parts of the machine. It did win a lot of mud races though. I'm glad those days are behind me on now it's the kids problem to spend all that money.

 

On topic: Nice job, simple but does the purpose. All I ever ran was a cooling fan but most of the time the motor was under water so it was "water cooled".

"water cooled" hehe 😛 
Thanks though, glad you liked the write up. 

[_Wilson_™ 6,564]

@Orvis25 sent you a PM.... mines not working good so let me know if you get it. 

Edited August 6, 2021 by _Wilson_™

[Orvis25 108]

4 hours ago, _Wilson_™ said:

@Orvis25 sent you a PM.... mines not working good so let me know if you get it. 

No pm in my inbox. 

[Fishfiles 20,145]

16 hours ago, Orvis25 said:

No pm in my inbox. 

 

 

He sent a couple of PM for you to me by mistake 

[Orvis25 108]

Just now, Fishfiles said:

 

 

He sent a couple of PM for you to me by mistake 

Ah. 
Well if you can forward them on to me that'd be nice. 

Least I know where they went 😛 

[Fishfiles 20,145]

I was talking with a guy that knows the 300 mods well , asked about the 350D side cover as far as the oil lines go , he was telling me :

 

"  I have a 350d case and was looking at it next to my 300.  All the bolt holes don't line up. I read awhile back that , for it to work the bottom section needs to be modified where the screen slides in with some welding and grinding  I also wouldn't mind  the factory oil cooler lines that the 350 has.  Have also read you have to use two gaskets to get proper  clearance ,which is a good chance of a leak " 

[Orvis25 108]

1 minute ago, Fishfiles said:

I was talking with a guy that knows the 300 mods well , asked about the 350D side cover as far as the oil lines go , he was telling me :

 

"  I have a 350d case and was looking at it next to my 300.  All the bolt holes don't line up. I read awhile back that , for it to work the bottom section needs to be modified where the screen slides in with some welding and grinding  I also wouldn't mind  the factory oil cooler lines that the 350 has.  Have also read you have to use two gaskets to get proper  clearance ,which is a good chance of a leak " 

Ah thanks. 
Ya he mentioned something about someone mounting a 350 crankcase to a 300 for oil cooler lines instead of doing the mod, and I asked for the source.
Guess it was word of mouth type thing. 

Appreciate the forwarding. 

[Fishfiles 20,145]

I would say , an oil cooler without a fan blowing over the fins is about as useful as nipples on a bull hog ----  

[Orvis25 108]

Just now, Fishfiles said:

I would say , an oil cooler without a fan blowing over the fins is about as useful as nipples on a bull hog ----  

Well, I agree and disagree. 

It will help dissipate heat better than no oil cooler, but certainly not as effectively. 
With no fan on them, its effectiveness curve would be all about the speed, your going (and airflow obv) just like on bikes. 

As far as i know @Wheeler also does not run a fan, but it benefits his rig.

[_Wilson_™ 6,564]

17 hours ago, Orvis25 said:

No pm in my inbox. 

 

i did send them to you orvis, said you had left the convo, I'm in chat on a new phone now... lol, i think my PM was acting up, which it's done before... sigh. 

[_Wilson_™ 6,564]

52 minutes ago, Orvis25 said:

Well, I agree and disagree. 

It will help dissipate heat better than no oil cooler, but certainly not as effectively. 
With no fan on them, its effectiveness curve would be all about the speed, your going (and airflow obv) just like on bikes. 

As far as i know @Wheeler also does not run a fan, but it benefits his rig.

 

dont forget he's got (probably) the fastest 300 foutrax here...... right around 55-60 mph, at least i think thats right ? big defrence from from a gear reduction mod, compaired to a fast bike, I'd say there IS  a benifit ... to having one without a fan because the trx350 has a fan plus oil cooler, and the fan on mine hardly ever came on, as a matter of fact just one time while i was dragging a dead cow off, if i recall right the oil temp light also came on ? might need shade or goober to correct me on this... but you also get cooling from the oil lines to and from the cooler, that's why i thought metal lines would be a better choice, just my thinking. 

[Fishfiles 20,145]

Like I said , if you put your hand on the cooler without the fan being on ,  it will be HOT , I don't care if your doing 75mph ,  once the fan kicks on the temperature drops within seconds and dramatically  -------  once I finish the installation of Retro's GIZMO , I can give exact temperatures   ----- not that it even makes a big difference , having a fast bike doesn't do much good  running wide open all the time to creative air flow , it still isn't the same as a fan blowing over the coils ---- I tell you hear some stupid things , don't believe everything you read

[_Wilson_™ 6,564]

13 hours ago, Orvis25 said:

Well, I agree and disagree. 

It will help dissipate heat better than no oil cooler, but certainly not as effectively. 
With no fan on them, its effectiveness curve would be all about the speed, your going (and airflow obv) just like on bikes. 

As far as i know @Wheeler also does not run a fan, but it benefits his rig.

 

i believe that's right, but i think he might be planning to add a fan, i don't think he ever mentioned anything about an over heating issue, even with that bbk. 

[JR_TRX 22]

On 8/5/2021 at 2:42 PM, Fishfiles said:

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 

Are those oil filter covers custom fab or for sale? I need one in my life.

Edited August 18, 2021 by JR_TRX

[jeepwm69 7,605]

Custom fab.  Guy named Jake Janacek makes them. Think he lives in Texas.  He was on bookface before I got off of there.

[Fishfiles 20,145]

Yep , Jake Janecek ,  here is his facebook link , he gets $85 

 

https://www.facebook.com/commerce/listing/369944673731594/?ref=share_attachment

[_Wilson_™ 6,564]

i had a video of a guy who drilled and tapped his oem fourtrax 300 oil filter cap, but heck if i can find it, i might have posted that in the old forums, but the mod didnt cost him much at all sept the elbow fittings line, and cooler, plus a cooling fan, wire, and toggle switch, @jeepwm69 does that hand (jake) make those from the oem filter cap, or ? i can't find anything online about him, and i don't mess with Facebook. 

[jeepwm69 7,605]

I think it's a new cover he makes.  Not sure.  I just saw them for sale and thought they looked interesting.