KX Guru Racing

Here's a thread on KDXRider.net with some suggestions on getting this tiny bearing out.

Just tried heating the case, putting some cold compressed air on the bearing, then tapping it out with a deadblow (while holding case). No dice.

Will try to fab up another edge do that again. After that I don't know what to try (without damaging the case).

http://www.kdxrider.net/forums/viewtopi ... 77&t=11982

Second time was a charm.

Didn't make the lip of my second tool as wide. put a little more heat around the bearing (and on the back side of it).
Now to clean these case halves up a little more.

What caused (causes?) the pitting I'm showing on one of my case halves? Is this something to worry about? None of the divits are very deep, and the case thickness is not at all in danger.

Curious to know what these are exactly, and if it is something I need to be especially concerned about.

Foxx4Beaver

that could be a combination of/from corrosion...and just plain ole porosity from a s**ty cast from the factory....if it's held up this long, I wouldn't be too concerned....providing the bearing journal is still good.

sandblaster

Looks to me like there was a bit of water that sat in there for a while.
As long as the mating surfaces are good, you should be ok.

Using good glass media in the Vapor or water blaster is the way to go.
If the metal is really bad you will have to glass blast it first.
The Vapor or water blaster will remove the impregnated media so I have been told.
I will of course test that theory when I get mine

queen of spodes

as rare as parts are for this old bike, I probably won't use it as a guinea pig. From all I've read, the glass media will partially lodge itself in softer metals (AL) and work its way out later.. causing cylinder scoring, premature wear, ect. Maybe the water/glass slurry makes the difference.. maybe. I guess one way to test is to blast a broken case, then literally grab a microscope to check for evidence.

queen of spodes

An airplane mechanic acquaintance of mine had this to say about the photos above:

Quote
Motorcycle parts are notorious for casting pits, so my guess is that's what this is. You can use 80 grit by hand, maybe 120 with Dremel on slow, to evenly remove material and see if pits diminish. If you start seeing more then STOP as it's definitely casting voids. If you manage to get it cleared up with the 80 or 120 then finish out with progressively finer grits until the finish you want. You can apply an alodine or similar solution to further protect the surface.

Foxx4Beaver

yup...porosity.

queen of spodes

I'm less concerned about how the inside of the crankcase looks.. don't need it to be purty. but do want to stop the corrosion if it is ongoing.

sandblaster

It's not going to corrode any further as long as you don't mix water with your fuel.

queen of spodes

Think I'm going to bail on this right side engine case. Crank seal surface is corroded - see the big hole where the tool tip is? Not sure I want to chance this engine on a suspect seal surface.
Ugh. Getting burned out with the nonstop hiccups and unexpected expenses.

queen of spodes

While the original matched case is at a shop being repaired (oil drain plug collar broken), I'm gathering stuff I'll need to assemble the lower end.

Kawasaki doesn't offer 57001-1174 anymore but there is an alternate on Ebay:
http://www.ebay.com/itm/CRANKSHAFT-JIG- ... 0888811855

Before I dump $80 on this tool I'll likely only use a few times in my lifetime, do I absolutely need this tool or can I make something for cheap that does the same thing? I don't want to mess with the crank balance, so if I have to get it, I have to get it.

Setting out bottom end bits on the workbench so I can go through what I have, and see what needs to be replaced. Obviously the broken gears in the pics have to go.

motojason

Quote from: queen of spodes on September 22, 2014, 03:06:24 PM
Before I dump $80 on this tool I'll likely only use a few times in my lifetime, do I absolutely need this tool or can I make something for cheap that does the same thing?

No, you do not need that tool. I don't like the idea of pressing on the crank to assemble the bottom end. That tool only acts as a crank spacer to keep the flywheels parallel while you press the cases onto the crank. I put my crank in the freezer and my cases in the oven. Then I use some threaded plumbing fittings from the hardware store to pull the crank into the cases if it needs some additional tweaking. Use 1-1/4 to 1-1/2" black iron couplings and 3/4 reducer. Use the fittings as a spacer between the crank's ends and the case, use washers between spacers and nut on the crank's primary side or bolt on the ignition side. When you tighten the nut or bolt onto the crank it draws it into the case without putting stress on the crank pin. The plumbing parts and big washers cost me about $6-7 at Ace and I have used them on KXs, YZs, and CR cranks with no problems

motojason

And... Awesome job on the restoration! That is a great bike and its nice to see the care and quality that you are putting into the project. What do you plan on doing with it when you are done?

dinkyguitar

I didn't use any special tools either when I closed my cases on my 87 KX250.
I used a barbecue to heat my cases to about 170 deg, and also froze the crank.
Once the case heated I quickly got the crank and dropped it in. I had to use a piece of 2x4 to tap the crank in because the coldness of the crank hitting the heated case will sometimes stop it from sliding in.
Then, I quickly applied yamabond to the case, got the other half of the case and installed it.....you have to work quickly, but it can be done. Just have everything ready and planned and make a dry run first.
With heat and freezing parts, you can put or removed just about every bearing in the motor without buying special tools.

dinky,

queen of spodes

Quote from: motojason
When you tighten the nut or bolt onto the crank it draws it into the case without putting stress on the crank pin. The plumbing parts and big washers cost me about $6-7 at Ace
Just the workaround I was hoping for.
Quote from: motojason on September 25, 2014, 01:57:53 AM
And... Awesome job on the restoration! That is a great bike and its nice to see the care and quality that you are putting into the project. What do you plan on doing with it when you are done?
Thanks! I will have well over two grand in it by the time its done, maybe closer to 2500 after tires, bars, ect. I am not going to finish the wheels at this time - had them soda blasted clean but will leave the wheelsets to the next owner. Hope they remain silver per stock.
My hope is to sell it to someone who will put it away and not ride it much if at all. Parts are extremely scarce for this machine. Would love to see it in a museum eventually. It won't be museum ready when I'm done but close.

motojason

Quote from: queen of spodes on September 25, 2014, 03:47:47 AM
My hope is to sell it to someone who will put it away and not ride it much if at all.
I would have a hard time parting with it if I had done all that work. I wouldn't be able to keep from riding it either! That is half the fun for me, the building is just the prelude to the riding. Love the character of 80s KXs.
Looking forward to finishing my 85 500 this winter and plan to rebuild my 88 250 sometime next year. Then I might be done for awhile. Well, unless a 79 125 turns up... grin
Good luck with finding your 125 a good home.
Please keep posting till it's done, this is a great thread!

queen of spodes

Rest assured this bike will be ridden a little if/when I finish with it.

queen of spodes

I've ordered the replacements but am curious to see what others think. How important is it to replace the shaft snap-rings when disassembling?

Foxx4Beaver

Quote from: queen of spodes on September 27, 2014, 12:40:48 AM
How important is it to replace the shaft snap-rings when disassembling?
look at it this way...how are ya gonna feel when you take it for that 1st good ride and it starts jumping outa gears on that 1st good ride...then it's tear the whole thing down again and start from scratch just to replace a $2 snap ring that broke.
For the "pocket change" they cost...replace EVERY one, not just the tranny ones either...all of them.

sandblaster

When I bought a donor bike for my SM project, I bought one that 3rd gear was bad in.
When I tore the engine down this is what I found;
As it turns out, all the gears including 3rd were good (Yes, even the dogs).
Lesson learned.... if you are splitting the cases, replace the snap rings...

queen of spodes

Even on a shaft I'm not disassembling? Isn't there more stress put on them during installation than simply letting them remain in place?
What size tip are you using on your pliers?

Foxx4Beaver

replace them regardless....it's extremely cheap insurance getting new ones, rather than rolling the dice with old ones....unless of course you don't mind yanking out the motor again and starting all over.

queen of spodes

What size tips are needed for these snap rings/circlips? I had a devil of a time getting these off.. ending up mangling a few of them. The snap ring ends kept popping off the tips. I tried a smaller diameter pair and those bent.

queen of spodes

First two OEM bearings installed in the left side crank case.
Still waiting for the tig guy to finish welding the right side case. Hope to get that next week.