Motobecane ER3 Doppler Variator - School Me

Hey guys

I ripped the moby apart for several reasons and installed a Mikuni Vm18 and an ER3 variator. I wanted to first tune the carb on stock variator, but that variator is a pain to take off, so I installed the ER3 while I had the motor on the bench.

I'm running the airsal 74CC Kit.

I got the moped to idle on the Minkuni, and started to tune the ER3.

I started with very light weights and worked my way up. Maybe I didn't work my way up slowly enough. When it was super light, I was going nowhere the moped was loud as hell and I was barely moving. I ended up at the heaviest possible, with still terrible performance. With the heaviest weights, it won't even full variate on the stand. Once im on the moped, forget about it, just doesn't seem to variate.

I'm using the stock spring.

Now that I think about it, it didn't seem like it would even rev up to the usual RPMS I used to get. I have a trail tech vapor and I used to see at least 8K. Wasnt seeing more than 4-5k rpm. I'd have to verify to be sure

This is on the stand with maximum weight. 16.15 g on each arm.

(edited)

Re: Motobecane ER3 Doppler Variator - School Me

I don't think I was getting to the RPMs I needed.

Just took a video of the Mikuni slide "no throttle to full throttle positions" are shown in the video.

Does the slide need to come up all the way?

If so, I might need a new throttle handle, I dont think it gives me enough throttle travel.

Re: Motobecane ER3 Doppler Variator - School Me

Yes the slide definitely needs to go all the way up.

Re: Motobecane ER3 Doppler Variator - School Me

> Stephen Simmons Wrote:

> -------------------------------------------------------

> Yes the slide definitely needs to go all the way up.

Hi Stephen,

Assuming that my throttle cable is tight and perfect at 0% throttle, then I twist to 100% throttle, and it doesn't open all the way, that means I need to find a new throttle handle/system?

I don't see how I can pull the slide up anymore with my current system, without making the slide higher than resting position at 0% throttle.

Bummer.

Re: Motobecane ER3 Doppler Variator - School Me

A moby 50v throttle needs to be modified to open a sha all the way. There is no way it will open a vm18

Re: Motobecane ER3 Doppler Variator - School Me

> Daniel '' Wrote:

> -------------------------------------------------------

> A moby 50v throttle needs to be modified to open a sha all the way.

> There is no way it will open a vm18

LOL!

Wow, well, that is interesting. Too late to check now if my Sha was ever running properly lol...

I ditched the sha 15.15 cus the only way I was staying within cool temps at high speeds was with a 78 Jet, with terrible rich acceleration. Wanted to try the Vm18.

I'm running this throttle, it has one of those spiral grooves. I'll see if I can modify it.

https://www.treatland.tv/motobecane-throttle-assembly-with-dual-lever-p/motobecane-throttle-assembly.htm

Will report back, found a wiki, but I figure I can use my brain to make it work.

https://www.mopedarmy.com/wiki/Adapting_Your_Motobecane_Throttle_for_a_Larger_Carburetor (edited)

Re: Motobecane ER3 Doppler Variator - School Me

I don't know if you can modify the stock throttle to get that much more pull, but whatever throttle you end up with, you want it to pull just even with the top of the carb bore, too high will create an undesirable "swirl" at high rpms.

Re: Motobecane ER3 Doppler Variator - School Me

> Kenneth Hill Wrote:

> -------------------------------------------------------

> I don't know if you can modify the stock throttle to get that much more

> pull, but whatever throttle you end up with, you want it to pull just

> even with the top of the carb bore, too high will create an undesirable

> "swirl" at high rpms.

Yooooo Kenneth.

I been working long hours and got triggered with the moped, I pulled the throttle off and broke it haha. It wouldn't have worked even modified, but I coulda at least given it to someone. I got a magura, and it opens her right up.

I also installed an ER3. IDK if its the carb or both, but the acceleration on the moped has tripled or even quadrupled. Makes me wonder if the Sha was 80% open.

Now I'm dealing with the carb flying off.

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account