1e40fm

[joescarola85]

Hey all, Brand new to the forum, I recently acquired a scooter with an 1e40fm
Compression is low and Ive been searching for a replacement head and piston and rings with no luck.

Ive read all the posts available about the 1e40fm I see most say you have to change to a 90cc crank for a bbk due to the 10mm wrist pin, but Ive seen several 70cc bbk with 10mm wrist pin, would that work?
I see the stroke is longer on the 1e40fm
Ive emailed carlos already and Im waiting on a reply.

Any help would be greatly appteciated

Joe

[moofus02]

Congrats the fm motors are basically a set of 90 cases. Crank has a longer stroke with a 10mm pin. The cylinder is longer than a standard 50 and the od is the size of the 90 stuff. You can use a 42 to 45mm 90 crank and 54mm cylinder to make a big motor without any cutting. 70cc BBKs are hard to find

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[joescarola85]

I found a 70cc bbk on amazom, but i fear my connecting rod stroke is 68mm and the 70cc is way shorter, guess i gotta get a 90cc crank.

What exact crank would i need?

[moofus02]

A standard 70cc bbk is like 64mm tall gasket to gasket and the fm is like 68mm these figures are just examples. The od of the fm cylinder where it goes into the cases is also like 2mm bigger.
90 cranks run from a stock 42mm up to about 48mm the most common are 42 to 45 and the cylinders come in 50 to 54mm tall and short depending on the stroke. The guys have had pretty good luck with the short 54mm cylinders and up to a 43.5 stroke crank
What you use depends on what combination of parts you can find. The guys have been getting cranks from AliExpress with ok results. Not sure what is around at the moment in cylinders but Autotech355 on ebay is a good place to check for crank and cylinders. AliExpress PartsforScooters etc. See what's available and ask for advice most of what is out there someone here has run and can give their opinions

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[joescarola85]

Thank you for the quick replies, what crank would i need? Ive looked for jog 90 cranks and they are pretty few and far between, Im waiting for a response from carlos, im hoping he can put together an fm rebuild package for me

Thanks again

[joescarola85]

m.aliexpress.com/item/1565874414.html

thats probably the one huh?

[moofus02]

A few of the guys have used that one

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[2TDave]

Yep that's the one. So far so good in my 103 build. Can't beat the price.

[joescarola85]

thank you all, once I start the project ill post pics and updates. My figures are right around 250 with new carb and variator crank and head and gasket set
the motor is a blessing and curse lol.

Still waiting to hear from carlos hope he has some miracle for the 1e40fm

[joescarola85]

Apr 22, 2015 18:41:26 GMT -5 2TDave said:

Yep that's the one. So far so good in my 103 build. Can't beat the price.

103 build? 103cc? What about seals and bearings that crank just fits right in?

Thanks again.

[2TDave]

Yes cc. I don't have any experience with the fm motor. I opened up my cases for the crank and cylinder. I'd think they're the same as the regular motor but confirm it.

[ryan_ott]

This is where I got mine, nice quality and price.
www.drratvparts.com/crank-full-circle-complete-45-mm-100cc-p-3964.html

[moofus02]

There is a thing in a tech section on the fm motors. It will (or should) list cylinder height, cylinder skirt od etc. The fm should be 90 cases with parts to convert them into 50. So once you verify what you have just look for 90cc stuff. That 45mm stuffer crank combined with one of Autotech355's tall 54mm cylinder kits and you would have a 103. Should be able to use stock variator flywheel carb and even the pipe to start with just need to get the new setup in tune

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[niz76]

49ccscoot.proboards.com/thread/1258/1e40qmb-1e40fm-engine-info

[moofus02]

Thanks niz

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