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Clutch Oil / Fluid Level

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Can someone please tell me the proper way to check the transmission fluid. I have read the manual and for some reason cannot figure it out. Then when I asked a number of people at the track today, i got a different technique or no idea response. Also, is it bad to have too much oil in the clutch side?

:)

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03' manual calls for 590cc or mL in transmission. I put in 600cc. The general method discussed in the manuals is to add oil, run at idle for 3 minutes, let sit for 3 minutes, check oil level. The problem people have is when they just add oil until it comes out of the check bolt hole on the transmission without the idle 3/ sit 3 steps. In this case the oil level will be too low.

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Got this off of MXA's website. This seems to be the best method. This is the one that I use and I have seen lots of others post the same method. IBTW the second part of what should you do is the one I use.

WRENCH TECH/HONDA CRF450 TRANSMISSION UPDATE

One of the nifty features on the 2002 Honda CRF450 four-stroke is the separated oil cavities. Unlike a normal engine, the Honda has distinctly different oil compartments for top-end oil and transmission oil. This is a great idea, although by no means new. By separating engine oil from tranny oil, a CRF450 owner can use specialized fluids for each task. There is no cross contamination from sheared-off clutch particles, gear flashing and valve seats.

What’s the downside? The available pool of oil is greatly reduced. Instead of having 1500cc of oil running through the engine, filters, frame and pumps, the CRF450 has 650cc of oil in the engine and 670cc of oil in the transmission. Both quantities are more than adequate for the job at hand, but lower volumes demand increased vigilance by the owner. Normal blow-by on a YZ426 will not make much of a dent in the overall volume of oil, but careless maintenance will allow the smaller volume of CRF oil to become critically contaminated.

THE CRITICAL TRANNY INTERFACE

In addition to having separate oil cavities, the 2002 Honda CRF450 also uses a new method of oil distribution for the clutch and transmission gears. In order to reduce overall gearbox drag, Honda engineers incorporated a lower oil cavity for the clutch than for the gearbox. The idea, from a layman’s point of view, is to bathe the clutch in oil while only dipping the gearbox’s feet in it. Thus, the transmission gears are raised up onto an elevated platform in relationship to the clutch. There is no doubt that this is a performance-enhancing idea, because it keeps the spinning gears from having to slog through a giant pool of oil—and less drag equals more power.

There are three small catch basins on the clutch side of the CRF450 engine. These catch basins transfer oil from the clutch to the primary gears and then into the transmission cavity. The source of transfer is the paddle wheel effect of the clutch. Since the clutch is submerged in oil, when it spins, the oil is slung into the other cavities where it lubricates the gears and then spills back to the clutch basin through a transfer hole. As the engine runs, the oil in the clutch cavity is slung up to the transmission basin and the process repeats itself.

SO WHAT’S THE PROBLEM?

It is possible for the transmission cavity to come up short on its oil allotment. How so? The CRF450’s total oil capacity is 670cc at assembly and 590cc at draining (some oil stays in the gearbox). Since oil is added to the transmission through the filler cap on the clutch cover, the CRF engine will only accept 400cc of oil before the oil runs out of the CRF’s check hole. If you stop filling the CRF when the oil runs out of the check hole, it will only have 400cc of oil in it instead of 590cc. Once the engine is started, the oil will be slung up to the tranny, but it will not be enough oil. What will happen? In a worst-case scenario, a gearbox failure. In a best-case scenario, failure of the kickstart idler gears.

SO WHAT SHOULD YOU DO?

So, what should you do? Here is a possible solution. When you are changing the CRF’s transmission oil, fill the clutch up to the check hole and then start the engine and let it run for three minutes (on the stand). Turn the engine off and wait three more minutes. Now, refill the clutch cavity with the additional oil.

A better fix would be to measure out at least 600cc of oil into a graduated beaker and then not ride your CRF450 until you get all 600cc into the tranny. If you have split the cases or cleaned the cases out with solvent, use 670cc.

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Well, OK... :D

Can't believe that your the only one that called me on this!

Not quite a whole quart in each side, but I'm only partially kidding. I have a 3/8" spacer on the clutch cover for my EFM clutch that allows me to put 800cc's in without trouble. The spacer is made of lexan, so you can see your fluid level at all times, it's great for peace of mind :)

JR

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so when checking the fluid before / during /or after riding, how do I know that there is enough oil in the transmission. When riding on Sunday, after a couple of moto's (I did let the bike sit for a few minutes) I checked the level as per the manual and a ton of oil came out. I believe the manual indicated that it should just trickle / drip out. If this is the case, am I to assume that I put too much in?

Thanks to everybody for the info so far. I must admit I am pretty much an idiot when it comes to mechanics.

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even if you had the correct amount it will still come out after a ride. The oil is still hot and airated(sp?) and will show a highter reading. I put 700cc and leave it alone. unless you have a leak you do not need to check it between changes. I change mine every 4-5 rides.

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