Need instructions on how to replace timing chain

[eprovenzano]

I'm going to replace the timing chain on our 99 400ex over the wnter months. Last winter I did the top end, bored 2 over, replaced piston, rings, valve seals and a few minor things. But, in the back of my mind I wish I'd replaced the timing chain, timing chain guide, and chain adjuster. So I'd like to take care of that this winter.

Is there a video or step by step instruction manual anywhere? I looked at the repair manual I have, and it was not real specific. I do plan on replacing the chain with that of the CRF, but with CRF 250 or 450, and for which year?

thanks

[honda400ex2003]

02 crf450 chain will work. take your head cover off, and right side cover(one with the clutch in it) you will have to unbolt clutch and basket, along with a couple of other bolts that hold the gear on behind that. the cam can get lifted up to take the tension off of it and you should be able to drop the chain out. when installing make sure you take the tensioner out or at least get the little tool that goes in it to lock it closed so there wont be any tension on it when buttoning everything up. once it is all back in enough to have tension on the chain when it is back on the sprockets with the head cover back on you can release the tensioner to put the correct tension on it. if you dont have the correct locking tool you can use a small flat head to move it in. i would recommend taking it out though since you can look at it, work it and inspect it while it is out. make sure you have new gaskets cause the side cover one(if never off before)will be torn and need replacing. torque it all down and you will be all set! steve

[eprovenzano]

Thanks Steve, I didn't think it was too difficult, but I wanted to be sure before I tore into her...

[CJM]

Got any more issues feel free to ask, Im usually around and have replace a few chains. its not that hard, just time consuming.

some key points fyi:
Biggest thing is scraping of the old side cover gasket-its like baked on and took me FOREVER using scrapers and razor blades. Make sure you get one of these before you start!!!

Also the clutch detent can be kinda tricky, gotta align it just right and the cover will go back on and the clutch will engage properly.

Lastly, make sure you dont over tighten the clutch bolts that hold the clutch basket cover on. They just get snugged and you should do this in a star like pattern.

Also, since the clutch basket will need to come off, you really need a clutch holding tool to do it. i got mine form rocky mtn for like 20 bucks. Also need a 1 1/8 socket iirc to remove the large staked on nut. I used an impact gun and it makes the job soooo much easier.

Manual will show you how to do the entire job btw.

[eprovenzano]

When I help a friend rebuild the lower end in his KX125 we just used an impact gun while I held the clutch basket, but I think its time to spend $20 for the proper tool.

Will I need to remove the bottom timing gear, or will be able to slip the new chain into place?

Thanks for the help, I appreciate it.

[CJM]

I cant recall if it actually has to come off, but it doesnt matter it doesnt line up with anything. The most important part is aligning the cam gear.

[togup]

Im trying to remember , but seems like you have to take the oil pump off too ,anybody ?

[CJM]

Originally posted by togup
Im trying to remember , but seems like you have to take the oil pump off too ,anybody ?

Makes two of us, but even so it all goes together fine-there are no marks you gotta line up at all for them and several of the gears can only go on one way thank god.

[hocman123]

u don't need to remove the oil pump

[eprovenzano]

Thanks for the info guys, my plans are to replace the timing chain once the snow flys. So if I'm not mistaken, its not difficult, just time consuming. One thing I've learned the hard way is to take pictures as I dismantle the bike.. it sure helps when trying to figure out how to put it back together.

I'll add this to my list of winter projects. Right now the list looks like new cam bearing, upgraded timing chain, new timing chain tensioner, maybe a stage 1 hot cam...

[honda400ex2003]

that can all be done at the same time so they will be done quicker. :D get yourself a manual and review it a bit before doing the procedure. ahaha sound like a doctor now. :D steve:devil:

[togup]

Originally posted by hocman123
u don't need to remove the oil pump

so how do you get the chain out from behind the oil pump?

[rubbersdown]

Just remove the clutch cover, then the clutch assembly as a whole as you cant get the gear out without doing this and then Just remove the big nut above the oil pump that holds the oil pump drive, main and timing gears. Oil pump can stay in place.

[togup]

Also watch out not to loose the little linked o-ring it will either stick to the case or the pump,then fall off when your not looking, then you find it when your done. While were on that subject pay attention to how the oil pump shim goes too (when you take the pump off).

[togup]

Originally posted by rubbersdown
Just remove the clutch cover, then the clutch assembly as a whole as you cant get the gear out without doing this and then Just remove the big nut above the oil pump that holds the oil pump drive, main and timing gears. Oil pump can stay in place.

The nut on the end of the crank?

[rubbersdown]

Originally posted by togup
Also watch out not to loose the little linked o-ring it will either stick to the case or the pump,then fall off when your not looking, then you find it when your done. While were on that subject pay attention to how the oil pump shim goes too (when you take the pump off).

You dont take the pump off, just the gears above it. See the oil pump in this pic, after you take the clutch off you just take off the big nut above it and the oil pump drive gear, main gear and timing chain gear will all come right off.

http://i31.photobucket.com/albums/c368/rubbersdown/DSCN3388.jpg

[togup]

sweet that makes more sense than the 3 bolts for the pump well that proves it ,you gotta be smarter than what your workin with!

[togup]

What the recomended torque for that nut is it listed in the manual?

[rubbersdown]

Main gear nut is 65lbs and the clutch nut is 80lb's but you will never get it that tight with a torque wrench without a clutch holding tool and a very strong friend to hold it. So while I have one (clutch holding tool) I dont often use it. I just hit it with an electric impact that I know is damn close enough to those specs.

[CJM]

^ agreed, I use a cordless snap on 1/2 impact gun and its good to about 300ft lbs so a few light taps on it with the gun and its good to go.