1E40QMB-A / 1E40FM Engine Info

[90GTVert]

This information was provided by drawkward.

It's (1E40QMB-A) basically a 90cc minarelli bottom end, with 50cc parts attached to it.

- The stroke is longer.

- The carter's opening for the cylinder is larger,

- The CVT cover is vented much like a 90cc's cover.

- The CVT cover for the 1E40QMB-A will NOT work with a 1E40QMB, and vice versa, unless of course you want to lose the kick starter.

- The stock cylinder is about 69mm tall, and the head has larger fins on it - which means that the shrouds for the 1E40QMB-A are similar to that of a 90cc minarelli (larger).

Now if you want to build yourself a 90cc, I'd say this is one hell of a deal, but if you just want to buy a 1E40QMB bottom end, and bolt on a cylinder meant for a 1E40QMB, then this is not the engine for you - unless you want to do some custom cylinder spacing fab work.

[90GTVert]

This information was provided by drawkward.

I decided to do some checking on this cylinder I was using. The 71mm tall cylinder that Carlos sent me to replace the order I made for a regular 1E40QMB 48mm cylinder, which didn't fit due to stroke issues. I started to wonder, after reading about other 1E40FM engine tuners about how they could just bolt up 50mm+ kits without carter modifications. I wondered, what is my carter?

Did some measuring and comparing on three different cylinders to come up with an solution to my problem of untunability.



From left to right.

Autotech Cylinder
- 71mm tall
- 51mm carter bore
Stock 1E40FM Cylinder
- 68mm tall
- 57mm carter bore
Stock 1E40QMB Cylinder
- 64mm tall
- 51mm carter bore

[90GTVert]

Here are the measurements for one of Autotech's 54mm kits.




Here's a gasket for the above cylinder on a 70cc cylinder just to show how things are lining up.


I don't believe these kits will bolt right on. Most 90cc stuff has a 12mm wrist pin and I believe the FM has a 10mm so a crank swap is necessary to work with the BIG bore stuff, but the FM cases should fit most replacement cranks up to 45mm stroke without the costly machine work required for the typical 49cc 1E40QMB.

[90GTVert]

This information was provided by drawkward.




Stock FM 52cc Cylinder


Stock 1E40QMB 49cc Cylinder wearing a gasket that fits the FM cylinder.

[90GTVert]

This information was provided by drawkward.

On a side note, I decided to check out my gears on the 1E40QMB-A (1E40FM) and see what the count is. I'm hoping to swap them into the 1E40QMB for the time being.



13/52 (4:1) and 13/44 (3.38:1) are your gear ratios. 13/52 is primary and 13/44 is secondary.

[90GTVert]

This information was provided by dude.

I have one of them but short case. The gears interchange with my Vento Zip. I did not count the teeth but the over all ratio. Vento 11 1/4 turns Linhai Power Max 10 1/2 turns. I CCed the head it was like 6.6cc compared to a Zuma 5.5cc.