confused.....crank case oil/tran oil 03 CRF450R

manual says 10w-40 for crank case but not very clear on trans oil. but the way i read it . it's the same in both.

Make sure for the tranny you use the no moly oil. I can't remember off the top of my head the weight of the tranny oil but I know the manual says no moly. I use the honda tranny fluid w/o moly

Without MOLY is key. I use Honda 2 smoke trans oil, but any oil that meets the spec. listed in the manual is fine.

Be sure to follow the Tranny fill procedure in the manual...add the recomended the bike 3 minutes....wait 3... THEN pull the oil level bolt and add oil until it comes out the hole.

I use 10W40 Castrol in the tranny and 15w50 Mobil 1 in the engine.

Another thing that I have picked up from TT is to measure the tranny fluid in a cylinder etc so you have the mfg specified amount and then add all of the fluid. The reason I don't use the check bolt is that I have heard it is not that accurate. If you buy a funnel for 2 or 3 dollars at the auto part store you can measure the exact amount and add the correct amount without using the check bolt. This way you know for sure you have all the oil you need.

I've been told the transmission is basically the same as a two stroke tranny. I'm curious why most 2 stroke tranny oil is around 75/85 weight and the manual says it's okay to run 10/40 in the CRF. So, this must mean that it would be fine to run 10/40 engine oil in any two stroke transmission?

I run Golden Specto 10/40 in my engine side and the Honda (HP4?)85W tranny fluid in the transmission.

Your right, I used to run 10w40 in my RM125 case. The manual said to us 10w40. On my 450 I use Mobil 1 15w50 in the engine and valvoline 10w40 in the tranny. By the way, my tranny oil in my '03 is a lot cleaner than the '02 was by comparison.

So all this time I was wasting money on buying the expensive gear lube when regular engine oil would've worked. :)

In my YZ400F, I ran the Mobile 1 15w50 and never had a problem, even though the tranny is not seperate from the engine. I had heard on TT that Mobile had added the dreaded friction modifiers to their 15w50 and did not suggest using it in wet clutches. The other day I was at Autozone and picked up a bottle and started reading the back and didn't see anything that looked different from when I was using it in the YZ. Is that why you are using Valvoline in your tranny, antman? Also, are you using the regular Valvoline that you buy off the shelf at your local auto store?

The reason I don't use the check bolt is that I have heard it is not that accurate.

You heard from people that didn't read their manual! :)

The check bolt works PERFECT if you follow the instructions in the manual. When the CRF first came out, some folks thought it worked just like any other bike...pulled the bolt, added oil...stopped when it came out the hole.... WRONG If you follow the procedure in the manual ( where have I heard that before?hmmmm) it works fine! :D

The crankcase oil capacity is .62 qt....drain out all your oil, fill up a bottle with .62 of a quart of oil and start pouring it in. See how much oil is left in the bottle when it starts flowing out of the oil check hole. Theoretically there shouldn't be any.....I bet there will be some left in there.

I have been using Amsoil in my bikes for a few years now with great resaults. I talked to the tech department at Amsoil and they recomend the 10-40 AMF motor oil. This is great for your motor and wet clutches. This is what Mike Larocco uses. If you want any information on becoming an amsoil dealer please let me know as this is what I did and now sell at the races to help support my habit. You can change your oil less with the full synthetic oils so It saves $$.

Good luck and have fun riding.

I stopped using Mobil 1 in my tranny due to the changed formulation. Supposedly they just lowered the levels of zinc and phosphorus according to a tech at Mobil 1 who I called personally. He did say that I should use a motorcycle specific oil (bullshi**). The 15w50 worked great both sides before. I wish they would not have changed it. I don't have the balls to chance it so I just use regular valvoline 10w40 in the tranny now. I know that Mobil 1 will be fine in the engine. I just started using it this past weekend on my '03 (after break in). I change the oil real often anyway, so I am not going to sweat it. By the way, my tranny oil is a lot cleaner in my '03 than my '02 was after two rides. I think the clutch bushings are made of a different material for '03. Cheers!

this is from the artical in MX action

i guess i will do what manual says. run for 3 min. then add.


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. "

anyway, as long as i use 10w 40 without the molly stuff i'm ok. right?

Yes, no moly in the Trans side.

I use pro honda on both sides and ive had almost 3 good years of HARD racing and no problems. they both use the same oil.

the post before your's was the day i bought my 03!!!!!!!!!crazy!!!!!!....this thread is nearly six years old!!!!!!!!

Anybody used Torco oils in CRF450R?? My mechanic guy likes gold Honda oil (no moly) in the tranny...............and says its ok for the crankcase too. so I've been keeping it on both sides. My kid wants to switch to Torco.

I've been told the transmission is basically the same as a two stroke tranny. I'm curious why most 2 stroke tranny oil is around 75/85 weight and the manual says it's okay to run 10/40 in the CRF. So, this must mean that it would be fine to run 10/40 engine oil in any two stroke transmission?

I run Golden Specto 10/40 in my engine side and the Honda (HP4?)85W tranny fluid in the transmission.

It would be fine to run 10w40 in a two-smoker!

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