Gearbox oil

I have been told that the 02 CRF gearbox oil check bolt hole was drilled to low. Is that also the case on the 03? should I use 590cc or go by the check hole?

put in 590cc don,t use the hole and you will know that it has oil in it that it needs

I believe that the tranny holds 690cc instead of 590cc

I drain my oil completely and re-fill with 700cc and never worry about it again till the next change! Over 200 hrs on mine now! :)


Motocross Action Magazine needs to be punked. MXA has stated the oil level check bolt is wrong...they are ignorant and spreading mis-information.

If the idiots there would Read The F#$%$G Manual (RTFM) then they would see it is not.

Go read your owners manual, it specifically tells you how to check and set the tranny oil level. If you do it by the book, it is perfect.

However, if you drain it completely, 700cc of oil works every time as well :)

yes you are right it holds 690 not 590 it was to cold last night to go ck



What are you guys doing, it's 590cc!:)

-Transmission oil level-

"In addition to having separate engine oil and transmission oil cavities, the 2002 CRF450R uses new transmission oil distribution/leveling technology. In order to reduce overall drag, the CRF450R designers incorporated slightly lower oil level in the clutch cavity than in the gearbox cavity. This is a performance enhancing design, but it can create some confusion when changing and checking the transmission oil level.

There are three small oil catch basins on the clutch side of the right crankcase. These catch basins transfer oil that is slung from the primary gears into the gearbox cavity. As the engine runs and the oil level in the gearbox cavity rises, oil begins to spill back over into the clutch cavity through a transfer hold. The oil continues this circulation process, much like a pump, transferring back and forth between the two cavities.

The overall transmission oil capacity is 670cc at disassembly and 590cc at draining. Because oil is added to the transmission throuth the filler cap on the right crankcase cover (clutch cover), you will only be able to add about 400cc before oil begins to run out of the check hold. Once the engine is started and the pumping process begins, oil will transfer in to the gearbox cavity, but the overall level will now be too low.

The Owner's manual and Service Manual both state to start the engine, let it run for three minutes, shut it off, and let it sit for three minutes before checking and adding oil, but if you are unfamiliar with this technology an under-fill condition will result. the easiest and sure way to set the proper transmission oil level is to use a graduated measuring cup (ratio-rite) and add 590cc to the transmission after draining."

If you want to put 690cc in your gonna end up with problems :D

I guess the White Brothers mechanics for Spud Walters and Paul Carpenter don't know what they are doing. They put 700cc in the transmission and 800cc in the crankcase. I am mystified by the comments saying you will cause damage by putting in 100cc extra. I suppose I've already ruined my bike. Funny how it starts and runs perfect all the time though. Come to think of it, I'll stick with what the factory teams are doing after all.

If it were over full, would it not overflow out of the front sprocket seal? I could see a problem then. I just 700 in everytime. I kick the kickstarter a few times to dump the rest out before I seal it back up.

ditto again. 700 and 800 every time. no problems here.

The guys trying to use the check bolt and the 590cc refills were probably the same ones with clutch bearings and kick starter ratchets going out! And also problems with starting in gear ect..


if youlook you will see that i wrote back that it was 690 not 590 seeing that it was about 12 deg. last night i did not ck untill the next day and no i don't have any of thethings you said my bike has had nothing go wrong

Ok, not to sound like too much of an idiot, I just got my bike, and I know LHS and RHS...which is the Crankcase left??? I put in 700 on the left and 600 - 650 on the that ok, or what should I be doing, thanks in advance!!! DINGA :)

I am with LowCo and the others i just mesure out 650mm and put it in. I never check levels in the gearbox, i change oil fairly often though.

Actually now i have an EFM clutch i add an extra 100mm to the gearbox to allow for the spacer

I measure it out from the manual and dump it it. Bothside.


I'm no mechanic, but in the tranny side since their is not engine pressure (I wouldn't think so anyway) and the oil is just in there to bathe the gears and clutch, it seems to me that it wouldn't matter if you put an extra 100cc in there. Seems like a little more in this case could be a good thing.

With that being said, you have to wonder why the honda engineers didn't recommend 700? I don't think they are stupid and since I don't know any better I am sticking with what the manual says.

My reasoning: I know some have quoted Pro Race mechanics that put a little extra in there, BUT, They also rebuild those machines all the freaking time (anywhere from every race to every 2 weeks (honestly I don't remember exactly what it is, but it's a lot) depending on the part of the bike you are talking about). I can see that a little more oil might be good for heat disapation and maybe better clutch action, but then after the race or maybe two of them, the gut the tranny and start over.

How many of us are rebuilding our trannies after 2 races or however often they do it?

I pose this as a question not as a flame. I know what I do, and it has worked for me, I just have to wonder if over filling will have adverse affects in the long run?

As previously stated, I HAVE NO IDEA if it will, but why wouldn't the engineers at honda recommend 590 instead of 690, if there was no real reason for it? Maybe there is no reason, maybe that is just a recommended minimum amount? Who knows?

Anyway, I thought I would post my thoughts and see what all of you have to say, since I certainly don't know the answer, and if adding an extra 100cc's won't hurt anything in the long run, then I'm all over it.


I don't know if I'm checking the tranny oil properly, but when I put in 590cc, I can't get the oil to drain from the little screw on the side. I wait the 3 min. and then check and nothing comes out. So I add a little until it starts to run out, which usually adds up to about 690 or 700 cc. So, I just started putting in 690 to 700 cc and not checking the bolt. JED

A little extra gear oil won't hurt. I put in what the manual says to at oil change (plus an extra ounce or two).

I went through the whole check bolt thing on the first couple of changes just to make sure I had it right (even then I added an extra ounce to be sure). Note: The check bolt is RIGHT ON for my 2003 if you follow the manual. It's just easier to measure the correct amount and go ride.

A few months back I read a post here from a guy who has been putting a full quart (about 950cc) in the gear side at every change for over a year - No problems.

A little more is better then not enough!

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