Case splitting.

[Tedh98]

However, I made a boneheaded mistake which I hope to help others avoid--I left 2nd gear off the input shaft and pressed the case crankcase together. When checking the trans through all the gears afterward, 2nd acted like neutral (no kidding!) and several gears seemed to be the same ratio. Without that gear in place, the input shaft could slide left and right within the cases.

To help others who are using a puller to put the cases back together, don't install the left seal and bearing in the left case. Install the right seal and bearing and pull the crank into the right case. Install the transmission and since you don't have a bearing in the left case, you can slide the left case in place and snug down a few case bolts. Now you can run through the gears and test to make sure the transmission is installed properly.

Once you verify that, install the left seal and crank bearing then use your puller to bring the cases together.

[Tedh98]

I'm currently searching for a press to get the right side crank case out of mine

I think you are saying the crank and bearing stayed in the right case half. If so you could heat up the case around the bearing and it should come right out.

[Friedom]

Without damaging the seal(new seals were put in everywhere ~20 hrs ago)?
I was hoping to not need to redo every seal again.
"Good job, guys. "

[Tedh98]

When I put bearings in the cases, I put the cases in a 230 degree oven with no damage to the seals.

I got to ask - why are you having to split the cases if all the seals were recently replaced?

[Friedom]

There's a thread around here somewhere... shortly after rebuild my head bolts and plug came loose. Somewhere between that and detonation from low octane gas in the desert left me with no coolant and a hole in my piston.

"Good job, guys. "

[Onlyinawillys]

i had the spare time, lathe, and mill. I made my crank installer rather than spending the money. worked like a charm (on my friends yz125, havent used it on my kdx yet, probably this winter).

I would like to make my own also what size tube did you use? Thanks

[bazwalton]

As people are talking about home made. Here's a link to the crankcase splitter I made for the E series. Might save someone a few ££

https://www.facebook.com/Enduromotorcyc ... 7178616219

[Tilts]

A few taps on the crank pin with a copper [HAMMER] does the job easy enough!

Sent from my S60 using Tapatalk

[Racer73]

Great article. Woud an automotive Harmonic Balancer puller work in place of the case splitter? Looks like the same concept.

[SS109]

Great article. Woud an automotive Harmonic Balancer puller work in place of the case splitter? Looks like the same concept.

Same kind of concept but, no, it won't work. They just don't have the spread to attach one properly.

[penniar]

The automotive harmonic balancer puller can be used to split the cases if you make an adapter plate. I made one from 1/8 steel plate. The plate will be bolted to the left case where the stator cover bolts up. Drill a hole in the center to fit over the crank. Last, drill a hole on either side of the center hole to bolt the puller to. Didn't cost me anything but time as I had everything already. I have used it twice. Works great. I have used just the puller on some Honda engines, but it will not work on the KDX without the adapter plate.

[Chuck78]

Great write-up @rbates9!
I came here looking to see what type of case splitter tool was needed, and found a VAST wealth of knowledge.
THANK YOU!

great write up
I might have to split my case too and wondered what special tools are a MUST have and can't really be "home made" one way or another?

Tusk Crank Puller/Installer Tool? (1177380002 $59.99)
Tusk Flywheel Puller 27 mm? (1179010002 $10.99)
Tusk Crankcase Splitter/Separator? (1177390001 $59.99)

Thanks for posting the splitter and crank tool!


Good tips I thought I'd highlight / aggregate here:

I thought I'd read this part IN this post before..don't see it..but this might be a repeat:

When installing the transmission parts, make sure to secure the output shaft through the RH case. If it is not clipped in place, it WILL move when you squeeze the case halves together. You will end up with some bent forks.

Also, after the cases are together, DO make sure the transmission shifts as it should. AFTER the engine is completely assembled is NOT the time to find out there's a bind somewhere.

To help others who are using a puller to put the cases back together, don't install the left seal and bearing in the left case. Install the right seal and bearing and pull the crank into the right case. Install the transmission and since you don't have a bearing in the left case, you can slide the left case in place and snug down a few case bolts. Now you can run through the gears and test to make sure the transmission is installed properly.

Once you verify that, install the left seal and crank bearing then use your puller to bring the cases together.

Regarding installing crank and cases and finding crank to be offset slightly and not perfectly centered in the cases, and a slight bit of resistance in the bearings:

Put the case splitter on the left side and whack it with a mallet until its centered. Pour some 2T oil down those two holes by the crank. Those orifices go between the crank and seals so the bearings are already lubed when you start it. Also, the crank should spin so freely that the rod/journal weight causes it to settle at the bottom.

Good that you posted about this, it's not normal and the resistance is not from your new bearings, your bearings have side load on them which is a really bad thing, you need to pull the crank to the centre then give it a little tap back the other way with a nylon hammer, you will feel the bearings free up, remember to add a few tablespoons of oil to the crankcase before putting the cylinder on

[jaunt]

This thread is awesome, much thanks. I just found out one of my crank seals is leaking... so this is in my near future.

[Corndog26j]

So I can replace crank seals without splitting cases and pulling the crank out??

[KDXGarage]

Only if you grind out the three holding tabs. Normally, no, the cases must be split on about every KDX and KX.

Which bike do you have??

[Chuck78]

I don't know if this was ever mentioned in this thread in particular, but I have talked to a few other KDX owners including reading one guy's build thread of his hybrid on an Australian trials forum, he is also a member here, where people have found some casting porosity in the thin casting area around the crank seals where there are a couple of slotted arcing "window" shaped areas, curved ovalized slots or rounded end curved slots around the boss or casting, which they determined needed filled with epoxy in the recessed areas, in order to fix some very minor crankcase pressure leaks that they had found. If you're looking at the crankcase around the seal area on the exterior of the cases, it will be plain to see these slotted areas recessed into the casting which are what has been discussed as thin enough to cause crankcase leaks in a slightly porous casting.

[KDXGarage]

That is shown in the Eric Gorr 2-stroke performance book from 2000 and 2004 on the KX60. The E model KDX's can use the same thing. He used to have that page on his site and I linked to it a few times. Now, it just goes to his main page. Oh well.