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400EX oil cooler with fan

12436 Views 18 Replies 4 Participants Last post by  BigBuck
Here is a pic of a fan on my oil cooler. I will post more info later for people that may be interested in adding one to theres.


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more details? Were do u get the fan and how did you mount it up? im having a problem kepping mine cool.
The deleted thread from 2013 said: "Spal makes a 4" fan that fits perfectly on the factory cooler."

Why are you having a heat problem? Keep the cooler clean and as long as the oil does not get over 300 degrees F it's not a problem - I was racing and pushing the oil to near 300 degrees, so I switched to a 15w50 full synthetic oil - the temp stayed the same, but mineral oil starts to break down at around 300* and the synthetic is good to about 350*. What temp is your oil getting to?
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Got bike and immediately replaced piston, rings and gasket due to leaking. I also installed full dg exhaust and rejetted carb. Haven't temp checked oil but noticed it burns a significant amount and seems much hotter than my previous bikes ran. I'm switching to amsoil full synthetic 4 stroke formula to see if it stops burning so much
Generally, synthetic will get past the rings easier than mineral oil. so oil consumption might increase with synthetic - only time will tell.
Any recommendations then? Like I said I just replaced rings that's why I'm a little confused on what it could be

When you replaced the piston and rings, what size piston did it have in it? What was the piston to cylinder clearance of the old piston? What was the ring end gap of the old rings? What is the ring end gap of the new rings? How was the cylinder honed before assembly? Did you replace the valve seals?
Yes I guess I should have been more clear. I got a stock (397cc) top end kit. Cylinder and all looked and felt as they should but honestly I've never measured the rings or got that into detail with it and maybe that is my problem
If you got a std piston and put it in a .020 overbore cyl, it will run and burn oil

Still got the old piston? Clean the top of it and look for markings
It is standard piston and cylinder, all came in a single kit
Oh - OK - then all should be well - now the only thing I can think of is valve seals or the rings didn't seat as they should have - how have you been running the engine? Let sit and idle to break-in, went racing the day after assembly, rode ten miles down a road at a steady speed?
I took it out for about an hour just around some trails running it at pretty high rpm but not maxed out and never idled more then necessary or low rpm in any gear.
Maybe just give it some time - I rebuilt the engine in my 65 Mustang and was dejected that it was still burning about a qt of oil every 1000 miles. A veteran mechanic asked me what kind of oil I was running and I told him Pennzoil 10w40 - he suggested the oil was too slick to break in the double moly TRW rings I had installed and suggested switching to Quaker State 5w straight weight oil until the rings seated and the oil consumption decreased then switch back to Pennzoil. It worked - after about 3000 miles the engine quit burning oil and I got another 100K out of the engine before the next rebuild.
I seen in the manual that the oil filter has o- rings for the cover to seal properly and recommend changing with every filter. Do all filters come with these rings or know where to find them?
The 400EX only has one on the cover and it does not come with the filter - it has to be purchased separately

Part # 91302-KF0-003 @ $3 (54 x 2.4 mm)

I do not replace it every time - I keep one on hand in case it is needed and reuse it as many times as possible.
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Ok I asked on another forum and they said fram ch6015 filter comes with the ring so I'll have to check it out but thank you for that part number
Yeah - that might be true - Fram is so cheap, they can afford to include o-rings - I won't use Fram - I use HiFlo almost exclusively - I will use K&N (they are made by HiFlo and use the same numbering - a HiFlo HF113 is a K&N KN113) - Fram is $8.50, K&N is $8 and HiFlo is $4 - Fram has been proven to come apart in use and damage engines, so I simply won't use them - won't use Champion spark plugs either.
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