Wondering how many have rebuilt this motor top to bottom?

[rocky_mtn_honda]

title says it all...chime in if you think your "certified"...got a few rebuild questions
thanks guys!

[drew416ex]

I had mine totally torn down when I stroked it two years ago. If its been going that long I must have done something right :macho

[rocky_mtn_honda]

cool...yeah i've been talkin to quite a few super sharp guys on here...but all of them are like "i've never actually been in my bottom end yet"...which is cool, wish that was the case for me.
but when it won't shift into 5th at all...its time to tear it apart.
so whats the poor mans way of getting the main bearing off the crankshaft on the side its pressed onto? this poor man doesnt have a bearing puller...or any other puller for that matter.
also, does anyone think its hack to use two crankcase halves from two diff. machines? is it really nessecary to replace all the bearings? they all feel brand new still...seriously
and if anyones interested, i now have a couple spare items laying around that i ordered before i got my gasket kit, and it came with a couple extra things i already ordered...valve seals...oil pump o- ring

[Ryanwolfe911]

I've done it several times, ona 400ex and 300ex (especially the 300ex, as I've had to replace broken case halves a few times)

THey're not that difficult as long as you have the manual, and patience. The trick I use for the gear set it to use big zip ties to hold the main/countershafts together with the gears, with the shift forks attatched as well, so that you don't get confused as to how they go back together.

The main bearings on the crankshaft come off rather easily, if you have the right tools. You need at least a bearing cup puller (a 2 piece set that places each half under the bearing) and a really tall set of wood blocks. You can then hit the crankshaft with a rubber mallet and it will drive it out of the bearing. SOmetimes you get lucky and the crank bearings stay stuck in the case halves.

On using 2 different case halves? They say they're a matched set, and I beleive Honda, but I've used 2 different halves (almost 10 years apart in age!) with all new bearings, and had no adverse affects whatsoever. THe guy I sold my 300ex to still has it and beats the hell out of it. So, I say F it and go ahead and do it. The way I see it, they all have to be machined to a certain standard, and are all similar, so it's not THAT big of a deal.

[drew416ex]

I dont see how you would get the main bearing off without a tool and not tear something up. And as long as the bearings feel good (smooth with no play) you dont have to replace them. I replaced my main bearings while I had it apart, but those were the only ones. And if it were me, I would have no problem using a case half from another machine as long as its in good shape.

[rocky_mtn_honda]

good idea...but im not sure i mentioned the gears...lol but that was a great helpful suggestion...just got my gaskets today...machine shop called and my jug is done...freakin two weeks later
im about ready to start the reassembly, just need to finish cleaning up the inner cases and get this damn bearing off the crankshaft

[Ryanwolfe911]

http://www.madxj.com/MADXJ/technical/technicalfiles/ARrearD44ox/images/large/OXREA022.jpg

That is the tool you need

I have rebuilt completely 3 400ex motors so far and watched maybe another 5 rebuilds? Sad thing about me leaving the 400ex is the abundance of knowledge and parts I have for them. If you gave me a frame, a-arms, swingarm, and steering stem I could have another complete 400ex in my garage. I have a complete motor just as a backup and half of another motor for parts. If your doing anything yourself I recommend buying the Clymer 400ex book.

[mmbintn]

Originally posted by rocky_mtn_honda
cool...yeah i've been talkin to quite a few super sharp guys on here...but all of them are like "i've never actually been in my bottom end yet"...which is cool, wish that was the case for me.
but when it won't shift into 5th at all...its time to tear it apart.
so whats the poor mans way of getting the main bearing off the crankshaft on the side its pressed onto? this poor man doesnt have a bearing puller...or any other puller for that matter.
also, does anyone think its hack to use two crankcase halves from two diff. machines? is it really nessecary to replace all the bearings? they all feel brand new still...seriously
and if anyones interested, i now have a couple spare items laying around that i ordered before i got my gasket kit, and it came with a couple extra things i already ordered...valve seals...oil pump o- ring

I sent you a PM.

[rocky_mtn_honda]

i've got the genuine honda service manual...it seems to be perfect for everything i've needed it for

[F-16Guy]

Originally posted by rocky_mtn_honda
...so whats the poor mans way of getting the main bearing off the crankshaft on the side its pressed onto? this poor man doesnt have a bearing puller...or any other puller for that matter.

The crank is out and you need to get the bearing off of the crank, right? Put the crank in the freezer for a few hours and then use a propane torch to carefully heat up the bearing race. The race will heat up and expand more quickly than the cold crank, and it should slide off fairly easily. To install the new ones, freeze the crank again and heat the new bearings in the oven until they're very warm to the touch, and then quickly install them. When the temps equalize, the bearings will be locked into place.

[rocky_mtn_honda]

allright...sounds kinda sketchy...but ill give it a shot
thanks for the info...got my jug today...cam chain... i will be reassembling this weekend
might start on it tonight...depending how many friday night beers i drink :huh

[Ryanwolfe911]

Just go take it down to a local automotive garage and have them pull it off. I bet if you pulled one of the techs aside and offered him $10 he'd probably do it.

[rocky_mtn_honda]

i just pressed the crank into the case with the bearing on it...worked like a charm with my tusk crank puller/installer...but takin it down to a shop was my next option...thanks Ryan

[rocky_mtn_honda]

success! runs like a sewing machine...gotta love the self reward of your own personal blood sweat and tears going into a rebuild like this....thanks for everyones help!

[Pipeless416]

congrats! sorry i missed your IM before.. long day haha.

[rocky_mtn_honda]

its cool...i know how it goes...but i did have a little trouble, which is why i IM'ed you earlier... couldnt get the cam lines to match up exactly with the top of the head...its either one tooth high on the left or the right...i know it has to be something to do with this crf450 chain i put on it...but i never got it lined up perfect...i messed with it a lot...i could get it to line up when i released the chain tensioner, but then the gear was sitting too low to attach to the cam flanges...i dunno, pretty depressing, but it does run great...and its got that new motor smell..love that :cool:

now i've got pretty much a complete bottom end, minus the left inner crankcase, and the crank...so if anyone needs any tranny parts or whatever, let me know

[Pipeless416]

Originally posted by rocky_mtn_honda
its cool...i know how it goes...but i did have a little trouble, which is why i IM'ed you earlier... couldnt get the cam lines to match up exactly with the top of the head...its either one tooth high on the left or the right...i know it has to be something to do with this crf450 chain i put on it...but i never got it lined up perfect...i messed with it a lot...i could get it to line up when i released the chain tensioner, but then the gear was sitting too low to attach to the cam flanges...i dunno, pretty depressing, but it does run great...and its got that new motor smell..love that :cool:

now i've got pretty much a complete bottom end, minus the left inner crankcase, and the crank...so if anyone needs any tranny parts or whatever, let me know

did you use the original TDC mark with the sparks key?

[rocky_mtn_honda]

sparks racing had a backlog from the machine shop...so they didnt ship it till thursday...wont have it for the "break-in" period...o well, but no i didnt to answer your question...stock woodruff key used

[rocky_mtn_honda]

it just seems a little cold blooded...hard to keep running at the cold start...it will start fine and run for around 5-10 seconds, then just die, unless you punch the throttle quickly a couple times...i just rebuilt it to a 407, same cam, HD cam chain, and thats about it as far as modifying it goes...im thinking maybe its starving for fuel a little bit? im not even sure what jets are in it...i forgot to look when i had it apart, but ill for sure check that because i live in colorado anyhow
it used to start and purr without any throttle whatsoever...i never have used the choke, and i still dont...the first time it was fired up was last saturday the 26th, about a week ago, and since then ive started it about 10 times when its cold and it does it everytime...if its been started within a few hours, the problem is non-existent
any suggestions would be greatly appreciated...