reepicheep

Member
Apr 3, 2009
670
2
My first vintage restore project! (Unless you count the 1985 KLR-250 I restored, or my 1995 KDX-200 I rebuilt from the ground up)...

Got it cheap from a sympathetic seller, a bike enthusiast who was happy to see (a) more space in his garage and (b) somebody who looked like they were actually going to restore the bike and put it back on the road. So he made me a deal I couldn't refuse.

It's missing a carb cover (the carb goes under the engine cover on this bike, probably breathes lousy, but looks really cool) and missing a carb (Mikuni VM30, so no problem there). most of the rest of the bike is there and intact.

It also needs chain guards (which I can probably fabricate) and a front fender (which I bet is unobtanium, so I'll have to leave it off or find something else I can put on there that looks reasonable) and tail lights and turn signals.

The motor is locked up... so I am probably looking at a new piston and possibly a new cylinder liner. And lots of nuts and bolts need cleaned, replaced, reworked, etc.

Also, oddly, the shifter is currently set up on the right, and the brake on the left. Looks easy to swap back around, but I wonder why somebody had it rigged that way...

Looks like a fun project! Anyone have any experience with a rotary valve two stroke Kawasaki?
 

reepicheep

Member
Apr 3, 2009
670
2
Lets see if this works...


44232_1431088984761_1458971072_31074244_6886366_n.jpg


Can people other than me see that picture?
 

dirt bike dave

Sponsoring Member
May 3, 2000
5,349
3
Pic looks good!

As for the shifter being moved, the previous owner must have been used to Euro bikes, or raced the bike as a flat tracker (which may be why the front fender was removed).
 

2strokerfun

Member
May 19, 2006
1,500
1
Try pouring type F ATF on top of the piston and let it sit for a few days. (I've never had the patience to wait a few days, myself).
 

reepicheep

Member
Apr 3, 2009
670
2
Thanks, have some out in the garage, I'll try it next. So far it's had WD-40, brake fluid, and acetone. This afternoon it's getting some kind of "as seen on TV" penetrating oil, and I'll give it ATF type F also.

Then it gets a bigger hammer. :)
 

reepicheep

Member
Apr 3, 2009
670
2
I thought about that after I had been pounding for 10 minutes or so. :) It is somewhere in the middle... Exhaust port is covered by the piston, but it still holds a decent amount of brake fluid in the cylinder. :)
 

reepicheep

Member
Apr 3, 2009
670
2
Got it out. Hard to tell for sure yet, but the bore actually looks pretty good (if I can get through all the goo).

ATF type F seemed to do really well.
 

dirt bike dave

Sponsoring Member
May 3, 2000
5,349
3
Congratulations on getting the jug off!

Does the crank spin freely?

Is the rotary valve intact and original? In hopes of more performance, some people would widen the opening in the rotary valve.
 

reepicheep

Member
Apr 3, 2009
670
2
Amazingly, the crank spins beautifully and has no alarming play. But it does burp up an oily goo that I have to get out. I suspect it's old gas, and stuff that has been poured in the cylinder over the years to try and loosen it up, and stuff I had soaking in there as well (ATF, brake fluid, etc). This is my first rotary valve, so I'm not even sure what it should look like, but I'm pretty sure I am the first person in this motor (2k miles on the bike). I think it is all stock (yay!). Hopefully the goo actually has been in there a long time, and was keeping things from rusting while it sat all these years.

What are the odds that the crank seals are still good? I would have thought zero for an original 40 year old bike, but the more parts I pull off this bike and clean up, the better they look. For example the carb boots (all three on this bike) look as good as new. Far better than the cracked junk from the 1995 KDX-200 I restored.

I'll clean up the cylinder and see if it is ringed from where the piston was stuck (looks like it could be OK at first glance, but there is a lot of goo left to remove). Then get that off to be rehoned. Then pop off the primary and clutch covers and look and see what surprises are under there (and check the crank bearings then).

Factory this supposedly has a Mikuni VM-30 carb (now missing). Good news, as that is a really cheap and easy to find and maintain carb, and there are lots of new ones on ebay. Anybody know if every VM-30 is the same? Or if the older ones for these bikes had special controls or mounting points? This carb mounts in the engine under a cover, which looks totally cool, but I wonder if that could make it fussy for anything but the original carb.

On the other hand, why would Kawasaki make a special version of a standard carb, and once Mikuni has a well established carb with well established tooling, why change it and mess things up?
 

reepicheep

Member
Apr 3, 2009
670
2
Ok, more questions for people that may have experience with these bikes...

1) The bore actually looks good, but is now covered with surface oxidation and carbon, and has non trivial scaling that I am guessing is aluminum from the piston. I could probably get it out, but I'm guessing its simpler and better just to machine the bore. It's steel sleeved in aluminum, probably original from the factory (67.77mm bore based on my cheap harbor freight calipers). Is reboring these things trivial in that any local motor shop can do it in their sleep, or should I be looking for an expert? Eric Gorr did my KDX cylinder and did a great job, but that was sleeveless and needed the tungsten deposition removed and nickisil added, so it was a serious job. This one feels a lot simpler. I'm looking for the $50 option here, not the $400 one. :)

2) This bike still has the factory automatic oiling system. I hope to use it as a fun street bike, not a dirt bike. I have a nice KDX-200 for that. If I was going to beat the thing to death I would probably eliminate the oil pump and just run premix (one less thing to go wrong). But for the street bike, I like the idea of an automatic oiler. Are they reliable? Any downsides to using them? I never had a bike with one of them before.
 

_JOE_

~SPONSOR~
May 10, 2007
4,697
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None of us can tell you if the local guy can do a decent job with the cylinder. Maybe some locals could point you in a good direction......or call Eric and ask him what he'd charge you to clean it up?

Be sure to clean the entire oil injection system out very well before running it. If there was a bunch of goo in the motor it's in the pump and lines too.
 

reepicheep

Member
Apr 3, 2009
670
2
Thanks! I have a contact for one local guy that did a good job for a friend with an XR-650 that needed rebored... and the guy is a triumph guy, so he should know the techology for that era. I'll talk to him and see what kind of vibe I get, and if it's not good just call Eric.

Thanks for the ongoing help all!

Now I have to decide if I want to split the cases. The transmission cavity looks pristine. The stuff that came out of the crankcase was a brown goo, but was mostly petroleum of some kind. I think it was mainly stuff all of us were using to try and loosen up the cylinder. The crank now spins free and reasonably smooth, and after flushing the crankcase 3 or 4 times with gasoline and foaming engine degreaser it is starting to come out pretty clean. Soaking in diesel overnight right now.

I know the safe option is to split the cases and have a look in there, but I wish I could find some reason somewhere to really know I have to split the cases first. So far everything in there (aside from being really dirty) looks fine. The only hint of a problem I have found so far (besides the brown goo that pumped out) was very minor pitting on the small end crank roller bearing. But that poor guy was stuck up in that piston for maybe 30 years.

I don't mind splitting the case, but I worry about creating a problem finding a bearing or seal that was discontinued 40 years ago. I guess the crank bearings are the only ones that really get damaged in the process of doing a split, so if I can source those bearings and seals I should probably just split it and replace them.

Maybe I'll find evidence of a crank seal when I pull the primary and clutch covers.

I did notice a little right to left play along the direction of rotation on the disc valve. Was that normal for these motors?
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
Have you tried resourcing parts for this bike yet? Try typing year make and model in the google bar? A bison only web site? This is why my yellow old bikes sit, no rods available. There is a company or 2 that will make a 10 minimum run, 10 guys who like old rm 370's,anywhere? And it seems it was like 200 dollars a rod! BUT, all the bearings and seals are available! Pitting in the bearing will lead to a really short life, and take out something else with it. Now if it was a boat, it might last a few years! Egay and get a manual/parts, no parts fiche online, Service Honda? Nothing? Kaw was the only ones that tried the rotor induction that I recall, up until around 76, in the dirt?
 

reepicheep

Member
Apr 3, 2009
670
2
Sourced a 2mm over Weisco with rings for under $50 on ebay... so that will do fine, but thats a big overbore. Probably the last overbore this thing will get without re-sleeving (which I am guessing would be even harder to find then a piston). A 1mm over would be better, that would give me more margin for future overbores, but this is after all a $100 rat bike project.

So $100 for the bike, $120 for piston and rebore and small end crank bearing, $40 for missing carb cover (in the engine on this bike), $90 for new VM30, and $75 or so for new cables. That should give me a runner for under $500. Another $200 for tires and chain, but as those are wear items, those don't really count. I am wearing those out no matter what I am riding. Figure another $100 in bearings and seals if I decide to split the cases (I was going to, but the thing is turning over awfully smothly now that I am getting the goo out of the crank case, so the jury is still out).
 

_JOE_

~SPONSOR~
May 10, 2007
4,697
3
I probably wouldn't chance the crank bearings if you don't have room for another overbore. If you can find a 1mm over I'd say it was a crap shoot and might try it? Is it really worth another piston, sleeve and bore/finish?
 

reepicheep

Member
Apr 3, 2009
670
2
As these things are prone to play out, I now have 4 Weisco pistons on the way. The first was complete (rings and circlips) but WAY oversize. So it would do. Then another auction popped up with three other pistons (one 1mm over, two 1.5mm over) but that had various missing bits (rings, circlips). Enough to get one of the three pistons going though, and I'll start hunting matching rings. The price was right even if I only end up using one of the pistons... and now my cylinder guy can just cut until he is down to bare metal everywhere and start with the smallest possible piston.

I got the stator (well, rotor) off as well, and that was where a lot of the rumbly noises were coming from. Little metal shavings were bumping the steel cores the stator coils are around. No damage fortunately. I'll pop off the clutch gear on the other side, and see if it still rumbles then, and look at the seals. No play anywhere, so I might not have to split the cases yet.

There was a little oily residue under the stator cover. More just oily dirt stuck to the bottom, no puddle, and not slung all over the chamber. So if there is a leak in that seal, it's a little one. And based on the inside of those covers, this bike really does only have about 2000 miles on it. It's just a baby! :)

Any suggestions for cheap front fenders for the thing? I don't mind fabricating or welding parts up, I just want something cheap that looks reasonably period correct. Though perhaps with those metal fenders, "period correct" meant ripped off and rusting in the woods somewhere, which is how it's set up now! :)
 

dirt bike dave

Sponsoring Member
May 3, 2000
5,349
3
Stock metal or fiberglass fenders on so many bikes were not well suited for dirt duty.

I'd go with Preston Petty plastic fenders which are 'period correct' for about 1974, which is close enough if you intend to ride it.

I googled them and this Hodaka site may have a later, wider design Petty fender (the Tony D model) from about '78+- available.

http://www.strictlyhodaka.com/
 

holeshot

Crazy Russian
LIFETIME SPONSOR
Jan 25, 2000
1,823
0
reepicheep said:
What are the odds that the crank seals are still good? I would have thought zero for an original 40 year old bike, but the more parts I pull off this bike and clean up, the better they look.


It's possible that they are still good. I've just finished pressure testing a '79 Husky two stroke, and it was air tight (after I replaced a blown base gasket). I had imagined leaky, rotten old seals, but this wasn't the case. I don't know how long the old seals will hold up though.
 

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