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Split the cases - DIY or send it out?

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It's finally time to send the head in to Ron Hamp for my first valve job. I'll be throwing in a JE 12.5:1 piston, possibly a Hot Cams stage 1 cam and MRD pipe too.

I've had a Baja Designs wide ratio gear set sitting on the shelf for a year or so. I guess this would be the time to split the cases and install it. My question is, should I do it myself of send it out? I've got no problem doing the top end but never split the cases before. Are there special tools required?

Any advise would be greatly appreciated :thumbsup:

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It's finally time to send the head in to Ron Hamp for my first valve job. I'll be throwing in a JE 12.5:1 piston, possibly a Hot Cams stage 1 cam and MRD pipe too.

I've had a Baja Designs wide ratio gear set sitting on the shelf for a year or so. I guess this would be the time to split the cases and install it. My question is, should I do it myself of send it out? I've got no problem doing the top end but never split the cases before. Are there special tools required?

Any advise would be greatly appreciated :ride:

you should know the answer to that yourself. you know your abilities we don't. if you have a clean place and the room it's no big deal. if you have no problem with the top end intimidating you,your more than likely good to go :thumbsup:

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Thats what I was thinking. I was just checking to see if anyone jumped into the cases and got in over their heads and wished that they had taken it to a shop.

I guess there are no special tools required other than a flywheel puller, which I already have. I'll print out the gearbox section of the manual and start pulling it apart this weekend. Thanks for the reply.

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You need a special tool to undo the round nut on the clutch side (crank or balancer) and a rattle gun helps with othe shaft nuts. It is relatively easy to split the cases, but prior experience reassembling a gearbox is a help - to install the Baja kit you need to disassemble the transmission shaft, and there is a few traps there - thrust washers, circlips etc - if you go ahead with diy, when you reassemble the cases, put it together dry and only use 3 or 4 of the case bolts - make sure you can easily spin both shafts, select neutral, first through to fifth then down again. Then you can open it up, check/correct any errors, lube the appropriate bearings and do the final assembly.

You will need a clutch hub holder to correctly torque the clutch nut.

Dont hurry through it and dont force anything. Good luck

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It's finally time to send the head in to Ron Hamp for my first valve job. I'll be throwing in a JE 12.5:1 piston, possibly a Hot Cams stage 1 cam and MRD pipe too.

I've had a Baja Designs wide ratio gear set sitting on the shelf for a year or so. I guess this would be the time to split the cases and install it. My question is, should I do it myself of send it out? I've got no problem doing the top end but never split the cases before. Are there special tools required?

Any advise would be greatly appreciated :thumbsup:

I'm curious...are you doing the Baja kit for top end purposes only? I would like a taller 5th gear too but I would also like a lower 1st and it appears that the Baja design kit only affects 3rd, 4th, and 5th. Any thoughts?

Oh, and keep us posted on your rebuild progress...I definitely want to do it all myself at the next rebuild. :ride:

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It's not that hard, I just would caution against it without a manual in your hand...once you start shuffling the gear shafts, it's easy to get confused....and don't forget the case splitting tool ! Motion Pro makes a nice one.

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You need a special tool to undo the round nut on the clutch side (crank or balancer)

You can take a 19mm socket and make one with a dremel, just hold the socket up to the nut, mark where to make the cut outs with a sharpie, only took about 10 minutes :thumbsup:

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Usually you need a puller to seperate cases evenly, at least on 2 strokes. Ive made a few in the past but you can buy them from Honda. If you are capable of doing the top end you are capable of doing the bottom end. You may also need circlip pliers etc..

My advice.

1. Buy the Service Manual from Honda (Read the whole process through before you start)

2. Mark and keep everything in order and make sure you know which side touches what, a lot of the parts in transmissions have steps for clearance(use zip ties or whatever it takes)(Digital pictures would have been worth there weight in gold more than once in my experience)

3. Keep everything clean

4. Dirty threads don't torque properly (non chlorinated brake cleaner is cheap and effective)

Good luck

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I'm curious...are you doing the Baja kit for top end purposes only?

I'm putting the WR gear set in for a few reasons:

1. Because I can. I have one on the shelf.

2. I ride mostly desert, sometimes when I'm topped out in 5th I'm still looking for more.

3. I do a Baja trip 1 or 2 times a year and its a pain trying to keep up with the KTM's, WR's and Huskies on the pavement.

4. The bike is plated. I bolt on the dual sport kit in the summer when the desert is frying and ride in the mountains and around town.

I'm keeping this bike for off road/dual sport and hopfully pick up a new bike whenever the next big chage is (insert year and color here)

I pulled the top end off Saturday. I was suprised how good the cylinder looked after more that 200 hours. the only real wear on the cylinder is at both sides from the pistion skirt, otherwise it looks pretty clean with visable cross hatching everywhere else. I took some photos, maybe I'll post some later. I'll be printing out the manual today and start reading up before I crack the cases soon. Is the case splitter mandatory or can I get by without it. I'm sure the manual will list the tools required.

Oops, anybody know the password for the pdf. manual? I know, I know, I'll do a search!

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Is the case splitter mandatory or can I get by without it. I'm sure the manual will list the tools required.

I've never been a big fan of prying the cases apart with a tire iron , I'm sure everyone will have an opinion, but I'd think for $ 150.00 a nice Motion Pro case splitter would be money well spent...You can also get a pretty good one from Honda for less than $ 100.00, you just have to find your own really long 6mm bolts and stuff to make it work.

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Those parts look great! Im stoked iv'e got a honda after seeing that. My 2003 ktm 450sx motor looked like bloody hell with 40 hours on it compaired to yours.

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