Replica KX 125's.

[larryg]

           Found this Image on the web several months ago, I only saved it for the Strange Exhaust mounted on what appears to be a KE or KS 125.  BTW; the exhaust looks Very Similar to the CZ 516 Pipe Kit that Marmax's Karts and Parts sells?

Interesting Story; back in 1974-5 a good frend that worked in a large San Diego Area Motorcycle Shop that sold Kawa's, CZ's and Other Brands.  He once mentioned where they would get several KS 125's and strip them down, port them, install a 26mm carb from another Kawasaki, and build there own expansion chambers in-house, and then change the gearing and fenders to build very quick 125cc MX'ers.

They had no option but to do this from the high demand from track results and the lack of KX 125's for each Dealer.  This tells me that some Shops did have Very Good Results building KX Replica Bikes back in the day.   It will be interesting to see how many Replica KX 125's pop-up in the next few years.  BTW; the KS and KE 125's have a Cast Iron Liner which was easy to port and re-bore.   Larry

[Retrowerx]

I've seen a few KS/KE vintage racers over the past 20 years. Never paid enough attention to see if they were running modded KS/KE or transplanted KX (or mix and match) motors. There was a lady out here running a very fast KE-based 125 for quite awhile. Of course, she was a darn good rider and would have been quick on a KE100. Pretty sure she had a KX top end on that one. But, yes, it most definitely (as also shown by the above photo) can be done. Hmmm...a fast true KS125--now there's a whole new challenge, eh? Actually, the only real shortcoming of the KS/KE is the small, non-bridged, oval exhaust port. But, those can be made to flow pretty darn well, too.

[kidkawie]

Not sure about the 125's, but the KE/KD 100's have a crappy transmission. Huuuge gap between 1st and 2nd. You'd have to gear it to eliminate 1st to stay on the pipe.

[larryg]

Some Interesting Videos of the KS, KE, and KD 125's in action.
The Videos might give you a hint on how the Gear/Trans Spacing looks and sounds like while the bikes are running. Larry

www.youtube.com/watch?v=MZAMTdfEf4I

www.youtube.com/watch?v=NBLOyRVFs-M

www.youtube.com/watch?=gh2Nrvpp_no

[Retrowerx]

Speaking of replica KX125s...here's what $135 on eBay and a 200 mile round trip to pick up netted me this weekend. Pretty much a complete KD125 minus the tank (didn't need that). Going to be my mule for testing things like the long rod motor, my version of the Skunk tube, some different pipes, etc. Funny thing about the KDs (and KE/KS) is the difference in the rear of the frame. Conventional full width swingarm and motor mounts (like CR, YZ, RM, etc.) rather than the rear engine cradle and separate bushing heads on the swingarm of the KX setup. I can see reasons to do it (especially on the KX), but don't know why Kawasaki built such similar bikes with one big difference. Seems much more cost effective to stick with one method for all. 

[racerclam]

It worked for Hodaka Larry, they were the small block chevy of motorcycles. Hey I did have a Kawasaki trail boss at one time , it was a great bike I wish I still had one. My Dad let me sell it to bbuy my first Hodaka . The Kawasaki was actually His bike.. Besides that looks like you have a good find.

Rich

[larryg]

Doug; that is a Smokin Deal. Lots of nice rust-free parts. Will also make an Excellent Base for a ISDT-R Type Bike. Someday they will have Event in Socal. LG

[Retrowerx]

Yep...I was quite happy with the deal. Was cruisin' eBay last week and found a guy parting out the entire complete KD. Seems there isn't a lot of interest in them, as I got every part I bid on for the opening bid of $5.00. I had emailed the seller to ask--as he was only 100 miles away--if I could just drive down and pick things up if I bid and won. He agreed, which made the deal worthwhile as instead of a fortune in shipping (which would have been a deal breaker), it only cost me a little over 1/2 a tank in the car. With it stripped down, I didn't even have to take the truck--just folded the rear seats forward in the Fusion and loaded her all up. The only thing he sold to someone else was the tank (it hit $10.00 so I let it go...LOL), so when I got there he offered all the rest to me for $20 extra. Works for me. 

Then, at work today, I got the package I've been waiting for with my other eBay find from a few weeks ago. Complete KS125 lowend in great shape. Only things gone are the engine covers and ignition--which I now have thanks to the KD purchase. Got the motor for the whopping sum of $23.95. There was shipping, of course--which came to $40, all the way from Canada. I'm kind of getting hooked on this cheap KS/KE/KD stuff. I believe there could be a whole untapped VMX source there--too bad they aren't old enough to fit into Classic 125 class. But, frankly, with the attrition rate and gate size shrinkage in the Sportsman 125 class, a good running KS/KE/KD might not be a bad choice. If the rod thing works, they could be built and run fairly cheaply. I think even the cylinders could be made to put out decent power for a fun ride. But--I did confirm what I had suspected from looking at pics closely. The KS/KE/KD pistons are taller than the KX pistons. The cylinders are built taller, too (by almost exactly 4mm...hmmm). Port timing is different by quite a bit (to be suspected, of course). I will have to get some time to really look at things and see what the possibilities are. Right off the top, I'm thinking, hmm...what about a long rod with KX piston in KD cylinder? Almost a perfect fit with no spacer necessary. Play with port/rotary timing to pull it in line. As I said, I do see some potential in those KE/KS/KD cylinders. Could make a fun little budget VMX ride. Still don't know what Kawasaki was thinking when the designed two swingarms/rear frame sections for the KX and KS/KE/KD, though. Strange.

Anyway...here's my $54 eBay motor...

 

[larryg]

       Now thats real interesting about the Piston Differences.   My KX 125 currently has a KE Lower-End and a KX Top-End.   I will need to check things out in the future.

BTW; the Hodaka 125's feature a Non-Bridged Exhaust Port and Rich can really make them work using a Unique and Wider Shape.   The same proven Port Shape E.C. Birt uesd back in the day.   Rich can also make the rest of the KE-KS-KD 125 Cylinder really perform.   Check out his website for some Small-Bore Hodaka Cylinder Images.
    Rich's Taylored Porting.

One Very Interesting Fact I found out is that the Late 1970's-Early 1980's KE 125's have 4 Main Transfer Ports just like the 1975 Works SR/KX 125 Cylinder.  The cool part is, the port shape at the base-gasket looks the same as the early KX 125.  If the Late 125 Cylinder works on the Earlier KX Lower-End, I bet that Cylinder can be made to Work the Best
using Rich's Porting Knowledge.   Time will tell.

I am going to start collecting some Low Cost KS-KE-KD 125 Stuff now that the prices are still low.  LG 

[Retrowerx]

Yes, the low ends are essentially the same so you can put a complete (cylinder and piston) KX top end on the KS/KE/KD lowend easily. The taller piston for the KS/KE/KD motors matches up to the taller cylinders for those motors. You're fine as long as don't mix and match things. A KS piston in a KX cylinder (with the common 96mm rod) would protrude approximately 4mm out of the bore at TDC. Conversely, a KX piston in a KS cylinder will be about 4mm below the deck at TDC. I mocked up both scenarios last night. 

I like the split transfers on the KS cylinders, and the boost port is fine, too. Quite frankly, the boost port is close to identical to KX, and the transfers I think could be better than KX with a little work. They don't match the cases as well (easily fixed) but could direct fuel charge flow much more efficiently. The exhaust port (and timing) is small and lazy. Closes very early, most likely to reduce emissions on the little dual-purpose bikes. But yes, that port could be massaged to flow quite well, so there is potential there. Definitely worth looking into. Not many KX cylinders come up for sale, but KS/KE/KD stuff is pretty common.

So, Larry, here's a question--how does your bike pull the two top gears? If you still have the KE trans, 5th and 6th are both overdrive (with a .75 top gear vs. .89 on KX). If the motor pulls it, I could see a top end advantage over the KX trans. KXs were down on top end from the other 125s in the day due to gearing, so the taller KE trans could be a benefit (after fixing the gap between 1st and 2nd...).

[larryg]

             Doug; the Bike currently runs a 13T Counter and 60T Sprocket.   First is too low to use but 2nd thru 6th works pretty good.   The area I last rode at did not have a long enough straight to stay in 6th long enough to feel any real advantage.   The Bike also has a KX 125 Ignition and the engine spools-up pretty quick with the funky gearing.

If you want the Free/Donation KX 125 Rotor, Stator, and HT Coil like me know off-line.   Just cover the 7 bucks for shipping.  LG  

[Retrowerx]

Hey Larry--I will definitely take you up on the generous offer--thanks. I have a few CDIs but no stator/rotor spares for a mule motor. I'll get in touch.

Question--you said you have the KX ignition on your bike, but also that you still have the KE lowend. Did someone change the crank? The KX rotor is not a direct swap for the KE components, as the KX is an internal rotor and the KE has an external rotor. The flywheel shaft has external threads for a retainer nut on the KE and internal threads for a retainer bolt on the KX. The tapers are different as well. Pics below have KX on left and KS/KE/KD on right.

I believe the KS/KE/KD trans could be a good deal--maybe better than the KX for some tracks--by simply doing away with the 1st-2nd gap. How to do that? Well, swap out the KE drive shaft and the first gear driven gear with those robbed from a donor dead KX (or pricey NOS ones...). Then you have 2.27 (KX) low; 1.69 (same for KE/KX) second; 1.25 (taller than the 1.33 of KX, so a gap, but not huge) third; 1.00 (slightly taller than KX 1.14) fourth; .84 (taller than KX 1.00) fifth; and .75 (taller than KX .89)sixth. So a gap between second and third, but not huge and the torquey KX motor can pull it as you are doing it on yours now. The other gaps are not bad at all. In other words, it's the same trans your bike is pulling now except without the huge first/second gap. Should be very workable. Best of both worlds, in a manner of speaking. And, if a guy can round up the KX parts cheap enough, a pretty cheap alternative.

[kidkawie]

check the transmission shafts. You guys might be able to mix/match Kx/KE gearing for a sweet trans. A friend of mine built a wide ratio trans for a moden woods KX250 using KDX 3,4,5th gears. His project was a little more involved being a totally different trans though.

[Retrowerx]

That was exactly what I was referring to doing, kidkawie. Swap out the drive shaft and first driven gear with KX items to get the 2.27 low gear instead of the enduro bikes' 2.60. I suppose if you wanted a little better and want to work a little more--and had a complete donor KX trans (or bought NOS parts of the auction site or from an old dealer)--you could also swap out third gear (the 1.33 fits a little better in the curve than the 1.25 of the KE/KS/KD). You would then have 2.27/1.69/1.33/1.00/.84/.75 for the six gears. Not bad at all.

[larryg]

Doug; It looks like my KE Lower-End has a Mixed-Bag of Parts. Makes me wounder if a past owner destroyed the KX Trans and Center-Cases and then just swithched-over his good KX Parts onto
the KE Lower-End. LG