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CRF450X Transmission failure...please help.

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I bought an 05 450x that has been converted to motard. I know the previous owner and he NEVER(less than two hours) rode it....so I got a good deal...however, the transmission locked on me this weekend. I did some research and have found that the problem is relatively common. I see that the most common fix is to over fill the trans with oil...My real question here is this:

Will using a full quart of oil completely solve my transmission problems or simply delay another failure? Have any of you guys had a failure, rebuilt the trans and run a high oil capacity for a long time with no problems? I need to know what the longevity of this trans can be, because if it is just goint to lock again, I need to sell the bike and get something more reliable.

Any help is greatly appreciated.....THANKS!!!!

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I'm surprised at how relaxed you sound in your post. If that shit happend to my bike I would be pissed! Welcome to the community.

I hate to tell ya, and I dont know too much about bikes, but honda has been building tranmissions for dirt bikes pretty much the same way for years. I have not seen a cut-away of the design, but I'm sure its similar to almost every other honda and every other dirt bike for that matter. Having said that I doubt it's a flaw in the design but rather you probably didn't follow the correct procedure for checking your oil level.

This problem is not common and you should really look at how your maintaining your bike. I've got a 250X and my transmission works so good it feels like I could put water in there and it would still work.

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Sorry, but no improper procedures here....been riding off road for 24yrs...bike had the OE recommended 750cc of HP4. Honda doesn't run a bushing or bearing under the gear so it's just steel on steel. When you are in fifth gear, third is spinning really fast, and apparently the stock oil level is not enough to lubricate third gear, it then welds itself to the countershaft. I just want to know if running the oil overage is a true solution or just delays the problem.

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Sorry, but no improper procedures here....been riding off road for 24yrs...bike had the OE recommended 750cc of HP4. Honda doesn't run a bushing or bearing under the gear so it's just steel on steel. When you are in fifth gear, third is spinning really fast, and apparently the stock oil level is not enough to lubricate third gear, it then welds itself to the countershaft. I just want to know if running the oil overage is a true solution or just delays the problem.

Honda did not design the 450X to be ridden on the road, therein lies most of these transmission related problems.

The solution to the problem is simple....run a full quart in the Transmission. on or off road.

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OK, I know the full quart is the solution, but once again, my question is:

How reliable is the full quart solution? Has anyone had failure after running the full quart? How many miles/hours do people have on their transmissions without failure?

I'm on the street, getting run over when my tranny locks really isn't an option, nor is having it fire off mid corner and pitch me off of a mountain.

Again, I know I need to run a full quart, but, is this the real fix??????

Thanks guys!!!!

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OK, I know the full quart is the solution, but once again, my question is:

How reliable is the full quart solution? Has anyone had failure after running the full quart? How many miles/hours do people have on their transmissions without failure?

I'm on the street, getting run over when my tranny locks really isn't an option, nor is having it fire off mid corner and pitch me off of a mountain.

Again, I know I need to run a full quart, but, is this the real fix??????

Thanks guys!!!!

Right now it's the only fix so the question is moot....but to answer "your suestion" I think one guy has had a 3rd gear tranny sieze after running the full quart. He was a desert rider and agreed that he flogged the bikeand rode it hard at high speed constantly. He was happy with the time he got out of the tranny (several thousand miles if I remember right) and did not complain.

It is a bike and tranny designed for offroad use...competition use actually, competitions like the R was designed for. short high speed runs on dirt, If you want a road bike for every day use get an XR650R and SM it.

check the maintenance specs. Do you think a road use bike have a piston that is spec'd to be replaced after 15 hours of use? 5-10 hours on an oil change? You would be ripping the motor apart every month and changing the oil every 2-3 days.

I'm not talking down it's just not a street bike and if you SM it then it should be looked at as a race only SM not a street/sm hybrid.

Good luck.

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Someone Chime in at let me know if I am right, but didn't Ron H. cut a notch or something in some gears were it would throw up oil? I think if you have your motor apart you might what Ron H. to do the work. If you are supermotoing it you might just want to have him do his tricks to it. From what I have read HE IS THE MAN if you want power.

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Sorry, but no improper procedures here....been riding off road for 24yrs...bike had the OE recommended 750cc of HP4. Honda doesn't run a bushing or bearing under the gear so it's just steel on steel. When you are in fifth gear, third is spinning really fast, and apparently the stock oil level is not enough to lubricate third gear, it then welds itself to the countershaft. I just want to know if running the oil overage is a true solution or just delays the problem.

Street legaled 450X, around 8000 miles, no problems. I run a quart and change it when I feel like and/or get around to it. I habitually ride on AZ 2 lane hwy bumping against the rev limiter, for hours on end. If you rebuild it right, it should last just fine.

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He was a desert rider and agreed that he flogged the bikeand rode it hard at high speed constantly.

Nope, that guy would never answer repeated questions about whether he ran a full quart or not.

I have never then read anything about anybody having a transmission failure running a full quart of oil. Doug

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cant help you a whole lot in telling you whether or not a full quart will be a permanet solution because I simply dont know, but I can tell you that I have run a full quart in mine for around 150 hours and I havent had any tranny issues as of yet. I ride 50/50 track and desert, I have been out on a dry lake bed bouncing the revs in 5th gear for multiple miles, and other high speed fire type roads and I have yet to have a problem. I havent had this tranny apart but once you get yours apart, you might be able to make some oiling mods, whether you can cut a oil slinger in the gears or something I dunno. :devil: Sorry wish I could be more help but I dont believe these bikes have tranny problems if you run a full quart.

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Nope, that guy would never answer repeated questions about whether he ran a full quart or not.

I have never then read anything about anybody having a transmission failure running a full quart of oil. Doug

Doug, your right..now that I go back and reread the thread he never does answer that Q. I stand corrected...

but thats the closest any thread has gotten to answering his question i think. everyone else has ponied up to NOT running a full quart.

course he's in dubai..it gets hot enough over there that you should drysump about 3 quarts on the bike

Hey maybe the SM guys could run a dry sump piped into the top of the tranny case...just a thought.

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I thought about an auxiliary tank, kinda like the baja designs aux. oil tank for the crank case....but what would pump the oil?? The trans. doesn't have an oil pump, and I'm not an engine designer so I don't really know what to do on that point.

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Maybe When You Have The Gearbox Apart For Repairs You Could Have A Machine Shop Cut The Hole And You Could Install A Needle Bearing In Place...

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I thought about an auxiliary tank, kinda like the baja designs aux. oil tank for the crank case....but what would pump the oil?? The trans. doesn't have an oil pump, and I'm not an engine designer so I don't really know what to do on that point.

Not necessary. After you fix the welded 3rd gear just run a full quart of tranny oil and change it frequently. You won't have any tranny problems then. :devil::thumbsdn:

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....but what would pump the oil??

You hit the nail on the head for the cause of the X (or R) transmission problems. As an ex Honda tech, I used to see an average of 3 welded up trannys per year. The main reason (other than extended high speed riding) is the twin sump oiling system combined with the four-stroke engine.

In a traditional single sump system, the oil is pumped up to the head, and then it can flow DOWN over the tranny. In a twin sump setup as seen on an X or R, the oil is only moved by the spinning gears: no pressurized oiling system. At higher shaft speeds, the centifugal force of the spinning gears flings the oil off, obviously causing less lubrication. This can be prevented by running very high quality oils and the aformentioned over-filling.

Now you may wonder why your old two strokes didn't suffer the same fate. The reason for that is the operational temperature of the engine. The bottom end of a two stroke is cooled by the incoming air/fuel charge which results in a much cooler operating temperature for the tranny. In an X or R the tranny temperature is much higher due to the hotter engine operating temperatures.

Although that is not to say that the two stroke is immune. I also saw a kid do the same thing to a YZ 125 the day he took it home. It leaned out while he was tapped in 5th gear on the highway; he was wound out in 5th for over three miles. Fused 3 and 4 to the mainshaft. He left a black mark on the pavement that was around 150 feet long!

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Mine locked up going about 70-75mph....I left a darky on Hwy 64 in NC that had to be well over 200ft.....And I forgot to take a picture of it!!!!! I was just glad it didn't come out from under me....though it did try.

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Hi there,

This is the guy from Dubai with the locked up tranny, yes it was running a full quart. Finally got it rebuilt and guess what it seized again, I was running a new bashplate (incl. 2 liter water reserve) which is mandatory for rally's. Riding down a straight (sand track 9.8km long) topped out in 5th (14t x 48t) then my carbon yoshi blew to bits(This is when I suspect the damage was done. The next ride 10km's in the tranny seized. Our calculated guess is that not only does the amount of oil play a role also the airflow around the engine. Back to square one and another 18 days untill the rally starts. ps this is a stage of the world rally championship and I guess around 10-15 450X will be competing against a bunch of KTM's 660 Rally and the 2007 KTM 700 Rally. No the X will not win against these boys in the desert. Beleive me, a KTM can top out at 180 km/h in the sand but I reckon you will see one or two Honda's in the top 10. (no not me).

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