CRF Transmission Oil Change Drill

[Woody_393]

This info is from www.offroad.com concerning changing the transmission oil in a CRF. This applies to both '02 & '03 models. This info is good, since there have been many people that have ruined their transmission because they didn't put the proper amount of oil in the transmission.

Here is what they had to say about it:

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."

Hope that helps.

[Clark]

590 cc's are correct for an 04 crf450 also woody?

[Woody_KDub]

Check your book to make sure, but it should be. Not sure though as I have an '03. but it is the same for '02 & '03

[Frakke]

Good info

[Yardpro393]

yep, volumes are the same

[Woody_393]

This info applies to all CRF's up to and including those released at the date of this posting.

[kjjz28]

Woody....glad I found your "post from the past". Just wish I'd seen it yesterday before I changed the tranny oil on my CRF250. I think this may answer the question I had this a.m. when I walked into the garage on my way to work and noticed a fairly good size puddle of oil under my bike.

I filled a little too much yesterday and a substantial amount of oil came out of the "check bolt" hole. After it had stopped, I tightened the bolt but didn't start it as I hadn't refilled the engine oil yet (I noticed the engine oil drain bolt washer was missing and the dealer was closed yesterday and today). I don't have a ratio rite so I didn't measure how much trans oil went in.

My question....is there a transmission oil overflow somewhere (other than the check bolt) that the excess trans oil could've come out last night? I didn't have to time to really look at it this a.m. but it looks like it came out somewhere under the bike (and not the check bolt).

BTW...how often is it recommended to change the tranny oil? I don't race it, just trail ride. Thanks again for your help!

[Woody_393]

I had an hour meter on my bike (very handy) so I changed it every 5 hours at the longest, Prior to that or if I was feeling lazy, I'd change it every 5 gallons of fuel, or when it shifted goofy (if would get notchy after a while).

As far as other ways of getting out, besides a crack would be the crank bolt cover, the drain bolt hole or the seep hole (the one you used to check it). Otherwise I don't know.

I'm sure you'll find the answer when you have additional time to look at it.

[brokenbonze]

hi i know this goin to sound silly but how many cc's does the left side take in an 08 450?i just got one and it never came with a manual and the first thing i want to do is change the oil. thanks

[Woody_393]

I'm not sure it's the same or not? Motoman has one, maybe he'll see this thread and can reply.

[Darin]

Why do cars go practically for ever on tranny oil and and months on an oil change and run for a hundred thousand + miles when a dirt bike is supposed to be changes every 5 hours? That would be half a day of driving in a car. Racers? perhaps I can see the oils getting trashed under high revs and heat. But the casual trail rider? I just don't buy it.

[Woody_393]

I do not understand all the details either but I know this.

Cars with clutches are typically not wet clutches (in fact, I don't know of any that are -- I guess automatic transmission are wet, but they are quite a bit different than a motorcycle). Wet clutches produce a LOT of debris that gets trapped in the oil. That debris is not good for the gear box (and if the engine and trans are sharing the same oil, this is even worse -- do you want clutch debris in your valve train?)

The gears in a constant mesh gear box are very hard on oil. Especially oil with a lot of polymers. The gears literally tear the polymers to bits, which causes a loss in viscosity.

Since we typically don't run normal car transmission oil, you really can't compare the two. It's apples to oranges.

I can also tell you that I can tell when my trans oil is shot. My shifting would become notchy and hence not shift as smoothly.

It is of course your call. Go a head and run your oil for 100,000 miles or even 20 hours and see how it does. But make sure you report back. I'm pretty sure the oil will look pretty bad, and your shifting will be pretty poor. Some bikes aren't as sensitive, but CRF sure was, and so is my RMZ.

I also do not agree with you about the trail rider vs the racer. I've ridden plenty of trails in my day and slipping the clutch and constant gear changes were par for the course. I change gears and use my clutch a lot less on an MX track than I ever did riding trails. My point being that I don't see it being any more or less worse. The gears are moving as long as the motor is running and clutch slippage/usage happens in all riding.

As stated, to each his own -- but for me I can tell when it needs changing and it's almost always right around 5 hours (and yes I run an hour meter).

Hope that helps.

[Darin]

Originally Posted by Woody_393

(and if the engine and trans are sharing the same oil, this is even worse -- do you want clutch debris in your valve train?)

Don't the oil filters catch that stuff?


As far as "trail riding" I'm not talking about the guy that rips around trails jumpin tree stumps and logs. I'm talking about the average guy that casually rides trails. I guess your argument makes sense. I just thought they made oil better than that. For what they charge, you sure don't get much in return.

[Woody_393]

Yes, the oil filter does catch a lot of that stuff. In fact hopefully all of it that's above the oil filter micron rating.

However, unless you change the oil and filter pretty often it wouldn't take much for that filter to get clogged and reduce oil flow -- that's not something anyone wants.

Oil is expensive, but motors are even more expensive -- and that doesn't count the cost of the down time either.

Now having said that, not all oils are created equal, so picking a good oil that has fewer polymers (or none at all in the case of some synthetics) than the next is a great way to help your oil to last longer in the gear box. Though synthetics oils are typically better, it's been argued that synthetics are not very good for clutch plates (too slick) so that's up to you to decide. The key is to know what your using and use it within it's expected life in a given situation -- and in my case always err on the side of caution.

Again, though to get back to your main point, extended drain intervals on a motorcycle gear box is not a good idea. In any bike of mine 5 hours would be the max, and I can always tell when it's exceeded it's useful life.

[JoyrideCRF450]

I really agree with woody you also got to put in the point of how much is really going into these bikes 590cc's thats really not that much oil so cycling and breaking down that oil only takes the matters of hours. I change my oils both sides and filter on my 03CRF450 5hours max or couple gallons of fuel. Nothing feels more relieving to me when going on a long ride and knowing i have fresh oils and filter in my bike. Also the price of oils, well when running HP gold or Honda oil products i can see your end of the argument but now running Rottela T from a suggestion from a few Well Knowledge based guys on here is turning out to be much cheaper and buying it by the gallons makes me want to change my oil sooner. But remember this is all in cheap insurance your bike is going to last for as long as the owner allows it to. Take car of her and she will take care of you..