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09-15-2001, 12:27 PM
Does anyone out there know a good way to check oil pressure on a 400EX. Finding a guage is no problem. I just looking for a way to plumb it up. Also for anyone with a "Honda" service manual, is there a spec. listed. Thanks.

Leo
09-19-2001, 06:59 PM
There is no spec listed in the shop manual, nor do they list a place to check it..

Taking a quick look at the oil flow diagram it appears it goes from the pump to the filter.. You could drill and tap the oil filter cover for a pressure gauge (which I have considered doing).. If you didn't want to leave the gauge in you could always install a plug...

It's diffucult to say for sure though, as the diagram is a bit vauge at best..

Leo

Leo
09-19-2001, 07:11 PM
OK.. Just spent a few more minutes looking through the shop manual...

and I have to admit that I'm even more confused than I was before.. :(

I still think that a pressure tap on the filter cover would work, but I'm not sure of that ...

Leo

09-19-2001, 08:04 PM
Thats basically what I was thinking, either at the filter or somewhere close to the pump dowmstream. If one was able to check the oil pressure on a stock bike then compare that to adding on another/or larger cooler. They would be able to tell if there was any drop or extream rise in oil pressure. If I'm thinking right the oil would flow from the tank-crankcase-pump-filter-interal oil passages of the engine-cooler and back to the tank. Does that sound right?

09-20-2001, 09:34 PM
Well I did it, bit the bullet and drilled/tapped the filter cover. I installed a quick connect pressure tap(1/8 pipe thread). Cranked the quad and let the engine warm. Took it for a bisk 20 min ride, returned home and attached a 0-50psi guage. Restarted the engine and looked into the guage and what I saw was scary to say the least. To my dismay the 400EX was only making about 2-4 psi oil pressure with the engine idleing. I then had to tell myself, ok the engine is completely stock and well maintained and has always ran flawlessly. After calming my nerves I then took the quad for a little ride. What I read from the guage during the ride made me feel ALOT better. At 1/4 throttle the bike would jump up to about 10psi. Without a place to really stretch it out I did the best I could. With the quad in 3rd gear full throttle on a slight uphill grade the iol pressure jumped up to just under 20psi. It seems that Honda did a great job designing the oil pump on the 400 because anytime that engine rpm was raised oil pressure followed right behind without much delay either. Oil pressure was even maintained when the throttle is chopped off until engine compression slowed the oil pump. Just as stated earlier the engine is completely stock and running 15/50 weight oil. The outside air temp was about 75-80 degrees. After checking the pressure I simply removed the pressure tap and installed an allen head plug the plug sets flush with the outside of the cover. Everything turned out well and if nothing else I've got a base line for future. If anyone is able to find a pressure spec. even if it's for a streetbike, it would be great just to compare.:)

Leo
09-24-2001, 05:12 AM
2-4 psi doesn't really suprise me...

with virtually everything rotating part in the motor on needle/roller bearings the oil is there as much for coolling as it is for lubrication.. I would also be curious to see some specs.

I would think Honda would list the specs + give you a way to check it in the service manual, but they don't..

Leo

09-24-2001, 02:09 PM
bama,can you post some pics of it

09-24-2001, 04:51 PM
I will try, I havn't posted a pic before but now is the time to learn I guess. Bro-in-law has a nice digetal camera so I'll see what I can do.