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Got everything cleaned up and new seals in: crank, output shaft, kick-start, shifter.


Going back together
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I used the Loctite 518 (see previous post). First step is to spray the clear activator on the mating surfaces and then a thin layer of the red 518 onto one surface.


Red flange sealer

After carefully lining everything up (and wedging the crank opposite the crank pin with a chisel), the pressing went smooth and easy.


Pressing the engine together

Torqued the cases (new hex head screws make this 10 times more enjoyable :-). Just a bit of red sealer squeezed out - great! The stuff stays gooey when exposed to air, really does not solidify like silicone, but it is always better to avoid too much and leaving blobs on the inside

Thin layer, not much squeezes out

I was ready to button up the clutch side but had to wait for a few more screws, It looked like the old Philips head screws had been in and out a couple of times and were pretty rounded - I had to fight a little to get the shifter mechanism screws out. While waiting for the screws, I will jump back and try the Barkeeper's Friend cleanser on the carb and lap the needle valve.

Any reason you went with that instead of Kawabond 5 or other ThreeBond equivalents (Permatex MotoSeal, etc.)?

Keep up the good work.

Any reason you went with that instead of Kawabond 5 or other ThreeBond equivalents (Permatex MotoSeal, etc.)?

Actually, I am not familiar with Kawabond or ThreeBond - I am happy to learn tho I have used Yamabond years ago and it seemed fine. I have a leaning towards Loctite products and like to use them when possible. This seemed like a good application of 518, I had some on the shelf and couldn't resist. I think it will work well and, if not, I will be investigating Kawabond (hopefully nice and green :-)

I think Kawabond and Yamabond are the same thing.

Nice etching of the dates on the inside!

Nice etching of the dates on the inside!

I figure I have room for another 30-60 years - and I think parts are hard to find now!

The last few hex-headed screws came in so I did some more engine assembly. Some of the old screws look like they have been in and out one time to many.


New screws!
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A couple of the screws in the kick-start and shifter components have shoulders that replacements would not have - the originals were in good shape so I re-used them.


Shifter assembly

Using a torque wrench (instead of an impact driver) is really nice


Screws were torqued to 6.3 lb-ft

The generator side has a total of 21 screws


Generator side

The clutch side has a total of 15 screws.


I will make a chart of the screws on the next post. I am trying to think of anything else for the engine while it is on the bench. So far, I have new seals, o-rings, gaskets, piston circlips, kick-start spring, reeds, clutch friction plates and most screws. Work performed last century, but never run, includes new Nikasil and piston/rings, bearings as needed and studs as needed. I will do a leak-down test once everything is buttoned up. Hopefully, no leaks, and then a little bit of safety wire should do it.

Looking good but if any of those internal hex bolts stand more proud than the original bolt make sure they don’t cause any interference. A bit of test fitting during assembly may prevent a lot of grief. I’m sure you’ve considered this but just thought I would mention it.

You’re gonna have a fine running 175 when you get this done!

Were those JIS or Phillips?

Whew, finally got some kdx time in the shop :-)

Were those JIS or Phillips?

JIS, I think (the blunt nosed bits fit best).

Next up, a screw chart for the KDX175.

KDX175 Engine Case Screws

I replaced the original engine case screws (Phillips or JIS) with hex head screws where possible for two reasons, 1) some of the old screw had stripped heads, and, 2) the hex head allows the use of a torque wrench. Plus, stainless steel screws just look nice

I replaced 13 screws on the clutch side and 21 screws on the generator side for a total of 34 screws. I kept a couple of the original shift pivot screws (shown in the picture) because they looked to have an extra shoulder that new screws would lack and they were in good shape.

All but two screws are socket cap Metric Socket Screws. The Stopper Assembly Change Drum takes two screws ( number 11 on the Partzilla diagram ) that are socket flat head Metric Socket Screws. Note that the length of the flat head screw is the complete length and not just the shank length (see following diagram) - I found this out when the new ones were too short. The flat head screws also have a taper which was plenty close to the original.

All of the case screws I replaced were 6mm and I went for stainless 18-8 which is common and cheap. The cost was well under $20 including shipping ( BoltDepot.com ).


Quick list
May 5, 2021

--------
Individual Screws
6mm socket cap Metric Socket Screws except as noted

   diagram number
(see diagram below)     Size     Quantity             Description                  
-------------------- ----------  --------  ---------------------------------------    
        1 .......... 6mm x 12mm      2      socket flat head Metric Socket Screws
        2 .......... 6mm x 14mm      5      socket cap Metric Socket Screws
        3 .......... 6mm x 30mm     11      socket cap Metric Socket Screws
        4 .......... 6mm x 40mm      2      socket cap Metric Socket Screws
        5 .......... 6mm x 45mm      4      socket cap Metric Socket Screws
        6 .......... 6mm x 55mm      2      socket cap Metric Socket Screws
        7 .......... 6mm x 60mm      3      socket cap Metric Socket Screws
        8 .......... 6mm x 70mm      5      socket cap Metric Socket Screws
 

Clutch side, case screws
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Generator side, case screws
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Hopefully enough about screws!

Starting on clutch re-assembly, I noticed a tab was missing on the washer (left side).


Made a new tab
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A couple of cuts and a little hammering produced a new tab. All set, time to pack the disks. The outer disks (friction) were binding slightly in the slots until I used the wire wheel to remove some kind of conformal coating (anti-rust?) from the edges of the tabs. Assembly proceeded but, then, while tightening the clutch hub nut to 35 lbs-ft - snap! - and nut and shaft were turning freely


Torquing the clutch hub nut

I got lucky with this before pic I happened to take - it shows that I did something wrong and there is a big gap between the top friction disks and the top hat.


Clutch disks were not seated

After un-doing everything, I could see that my new tab was sheared off from the washer - that must have been the snap (much relief :-)

I cut a (another) new, slightly larger, tab in the washer and assembly try number two was normal.

In retrospect, is seems like I did two things wrong. 1) I cut the first tab too small (narrow) and it sheared off, and, 2) I failed to notice that something was hanging up and the clutch pack was not fully compressing. There was enough friction to hold but only up to about 10-15 lbs-ft at which point there was nothing to keep the shaft from rotating.

All seems well now and the shifting into each gear feels fine.


Clutch is on.

I followed up with putting on the piston on and torquing down the cylinder. The way things went today, I figure I had better do that leakdown check next

Man! That was a lot less costly SNAP than I feared, thankfully.

As always, thanks for taking us along for the ride on your VERY well documented rebuild.

I did a leakdown test and failed

No psi (?) was achievable but I think I see why. I can hear air escaping as fast as I pump it in. Listening around led me to the crank gear - and then I remembered: while cleaning the engine case halves some time back, I noticed three small holes (1/8" or so) under the crank bearing on the clutch side. I scraped out the RTV and forgot about them. This seems to be where the air is coming from. These two pics show the holes:


Mystery holes
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Digging through the KDXRider archives (invaluable resource - much appreciated!), it seems similar to this page that KDXGarage referred to in a different thread.


Kawasaki KX oval plugs

I wonder if these holes are ever useful for anything? My inclination is to clean them and then fill with JB Weld.

Pretty please tell me some jackass did not drill them and use them to push out the bearing.

It appears that KDXGarage is correct and someone drilled it to remove the bearing and used RTV to seal it back up.

Ideally it would have been addressed before reassembly but you should be able to get a good seal with your JB Weld strategy.

It’s always gotta be something. You’re doing a great job bringing this bike back to life and your ability and patience to document this build are very much appreciated. I’ve photographed and explained step by step repairs on other forums and I know how much time it takes. You’ve made me feel like a slacker. lol

Thanks KDXGarage and Goofaroo! Documentation seems to be my second nature And, with the usual numerous projects lined up in the wings, I am working on fine tuning how to create usable docs with minimal effort. Right now, I am rolling around in my mind ideas on how to make docs better organized, portable and searchable. A taxonomy for projects may be in order (just a fancy way of saying: a hierarchical list of main topics :-)

On those holes, I think you are right; a previous owner must have drilled the holes for bearing removal. JB Weld coming up!

JB Weld applied in three places:


Mystery holes plugged
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A quick check indicates that the force on the JB Weld plugs is under 1/4 lb.


Worst case force estimation

I think it will hold!

Don't come up on here doing no math now. :-)

You are welcome on all previous suggestions.