Engine S/N Question

Oldhenry1

Oldhenry1

Member
I have an engine serial number question. The engine I got for my '68 project bike has a very high 6 digit S/N that from all the reading I've done must be from late '71 as near as I can tell. It's higher than the supposed ending number for the '71 model year.

Sorry for the crappy picture.

Z50AE-639962 ??
Mini Eng SN 639962.jpg

The '72 swing arm S/N's look to have started with 7 digit's.

I'm not into the non-Honda clone engines and unless I can find another engine with a lower S/N closer to my frame(no luck so far), this one will get freshened up and installed.

Anybody have any thoughts?
 
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kirrbby

kirrbby

Well-Known Member
OLD CT said:
I have a Z50AE-419800 core bottom end someone is picking up soon. What is this out of Kirrbby?
Click to expand...
I think that is a K3...1972 engine Pat. Does it have the manual cam chain adjuster? I think K2 engines might have ended in the high 300s. Any of the 400s would likely be K3s
 
OLD CT

OLD CT

Well-Known Member
Thank you Kirb! I am not savvy with Z50's. It does have the manual cam adjuster. I actually prefer that style when building a stroker engine. I had it listed on facebook. Mike from North Carolina is going to pick it up soon. He said he is a member here. He does have a lot of cool mini's also... I have to get him to post up some pics he shared.
 
Oldhenry1

Oldhenry1

Member
Now knowing it's a K2 engine, is it possible to hook up the 1968 On/Off toggle switch style ignition to this engine? The '68 had a one wire toggle switch I'd like to retain that style if possible(not a stock Honda switch, those are out of my reach). Did I mention I'm no electrician? I'm seeing 4 wires on the engine plug(2 of which are broken out of the plastic of the plug itself). Could a guy hook up a modern toggle switch?

'71 Engine electrical.jpg


The wires look to be in decent shape below the terminals.
 
Tripod

Tripod

Well-Known Member
You could if you wanted to. You could also get a stator from a 79 up z50r.

What is your frame number you're trying to get close to?
 
Oldhenry1

Oldhenry1

Member
Correct me if I'm wrong but wouldn't a stator assembly from a ' 79 z50r be for a 12v set-up?

This one is 6v so far, with no battery provision in the frame, no tail light bracket(I do have the rear fender, it's kinda ugly). Front fender is long gone). The forks appear to be '71 vintage or so I'm told. It has home welded (I think) headlight brackets and side reflector provisions.

The frame number is 109xxx. It's a Non-Slant guard frame with the plug restrictor in whats left of the(rusty) muffler instead of the later year longer tailpipe.
 
C

CLEC66

Active Member
K3 bikes had 7 digit vin numbers, Polson’s z50 book mentions k2 bikes vins starting with a 4 but only have 6 digits. I’m sure it’s a grey transition area to 7 digit.
 
C

CLEC66

Active Member
That’s what his book shows so I would think late k2. I was confused about the 4 number myself so did a little digging cause I ain’t no expert!
 

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kirrbby

kirrbby

Well-Known Member
Engine numbers on Z50 s didn't go to 7 digits until long after the frame vin did...sama as CT70's. K3 Z50s definitely have 6 digit vins.
I'll look at polsons book...but I would think he knows that.
But K2 engines ALL have the auto cam chain adjuster, as best I know. BUT, that IS a K2 carburetor on that engine..?
 
Z50nut

Z50nut

Active Member
OLD CT said:
I have a Z50AE-419800 core bottom end someone is picking up soon. What is this out of Kirrbby?
Click to expand...
Hey Pat, hope all is well! Just another opinion here on your engine. I did quite a bit of researching K3s and K4s way back when. They're odd balls in that they have 7-digit frames, and non-corresponding 6-digit engines. As Kirby notes, those engines differ from the earlier K0, K1 and K2s with the manual cam chain adjuster. My notes from back then indicate K4s had engines in the range of 39xxxx to 43xxxx. Regards.
 
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