Hi Guys - Newbie - Engine ID request

[zenriddles]

I don't remember what this critter is anymore. I have had it for over 30 years after a truly epic wipeout by a buddy of mine.
As I recall, it was a 'small wheel' bike. Broke the forks off - bike was trashed. I saved the drivetrain for a future project with my son that never happened.

Fast forward to the twenty-first century. What is it? Complete carb to tailpipe all original.

 

[Midnightpromises]

There should be a serial number down on the lower left crankcase. Good chance it'll have the bike model number to start .

 

[airblazer]

Looks likely to be a ST90 motor to me

 

[Midnightpromises]

Looks likely to be a ST90 motor to me

Not even close bro, ST90s got three engine mounting holes.. that motor is a 70cc or smaller

 

[MiniBike Mike’s Garage]

Looks like a Honda CM90 engine.

 

[zenriddles]

There should be a serial number down on the lower left crankcase. Good chance it'll have the bike model number to start .

I will dig into this to see if we can uncover some breadcrumbs.

I love a good mystery.

 

[Midnightpromises]

I will dig into this to see if we can uncover some breadcrumbs.

I love a good mystery.

 

[zenriddles]

CM91E
Looks like late 1960's stuff.
Carb forward and dual pedal shifter kind of dial it in according to pictures I just looked at..

What think ya'll ?

 

[airblazer]

Well, I got the 90cc part right lol

 

[zenriddles]

Well, I'll be darned - There it is !

Next question - Is this motor worth anything to anybody?

 

[Midnightpromises]

One of the largest selling Honda models ever produced. I think around 20 million worldwide, that started the Honda explosion with the you meet the nicest people on the Honda commercials that being said probably parting out on eBay or something get a couple hundred maybe. I've got an old Fuji engine that I'm doing the same thing with and a few S90 and ST90 motors . The cost to ship those things will make it cost prohibitive for someone to buy the entire engine or they'll eat away any profits you might make by paying for the shipping yourself.

 

[Midnightpromises]

Use the information from this website and it's part listing to see interchangeability and pricing to give you an idea of what you might ask for when you're trying to sell parts off that motor https://www.cmsnl.com/honda-cm91-1966-usa_model1042/partslist/

 

[zenriddles]

I have no interest in parting it out.

Anybody in the Chicago area want this? I will let it go for a song but I am not shipping.

 

[Midnightpromises]

Was that the actual serial number of the engine you have that you showed the picture?
How far from Rockford are you?

 

[zenriddles]

107115.
See picture further down in the thread. I think that is it, no?

I am in Lombard, Illinois. Spitting distance from 355 and 88.

About 1 hour from Rockford.

 

[OldGuy]

I have a '66 CM91. Lots of similarity to your pics. But I don't recognize the 2 "bracket like" items attached to the lower sides of the carb. They might be for the leg shroud panels that I don't have on my Rat-Bike version of the original. And my CM91, like your later pics (purple one) is not what I'd call a Small Wheel bike. But the serial tag doesn't lie... it's a CM91 motor.

 

[MiniBike Mike’s Garage]

I have a '66 CM91. Lots of similarity to your pics. But I don't recognize the 2 "bracket like" items attached to the lower sides of the carb. They might be for the leg shroud panels that I don't have on my Rat-Bike version of the original. And my CM91, like your later pics (purple one) is not what I'd call a Small Wheel bike. But the serial tag doesn't lie... it's a CM91 motor.

I could be wrong, but I don’t think the carb in his pic is original to the engine.

 

[62pcup]

I'm interested in your CM91E motor, what's the price, thanks.

 

[Blaine]

That’s a very old Tillotson boat motor carb.

 

[OldGuy]

Per the commenters above... That's a CM91 motor, but the carb is nothing like my original.
I just went through the carb on my CM91 this winter. Definitely different.