Moby vs 103 50cc’s: your thoughts?

Ok here is my deal, I’ve got 2 av10 set ups, liquid cooled 50 Doppler and a 50 air cooled Doppler, both of these bikes get it off the line, they are both using er3’s with a normal pulley

Now I’ve got the same with 103’s, one air cooled the other liquid, but bikes rip, but build slowly off the line. One has a modified stock vario (m6 nuts for weights/3 balls/2 star washers/lightened starter shoes) and a normal pulley, the other has the same vario with a clutch pulley, both are ok off the line, then rip

What’s the deal? Are Mobys just better down low?

Re: Moby vs 103 50cc’s: your thoughts?

are you double clutching with the second 103?

Re: Moby vs 103 50cc’s: your thoughts?

Longer stroke on moby

Re: Moby vs 103 50cc’s: your thoughts?

> jumpsuit steve Wrote:

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

> are you double clutching with the second 103?

at the moment I have a stock clutch up front, so yes. However I do have an er3 to swap in and try. Shane Johnson and I we're talking about this over on "lovers of french mopeds" I just love the stock 103 vario so I left it on to test, it worked very well, but like I said im gonna swap that er3 on and give it a go. Im waiting for a longer Doppler pedal shaft to arrive from Treats so I can have my pedals back and feel a bit more confident while testing, not to mention the fucking snow, Ill upload the video, I was testing in an empty area of the building my shop is in

Re: Moby vs 103 50cc’s: your thoughts?

Re: Moby vs 103 50cc’s: your thoughts?

Can’t you do something like weld the plates together to remove the clutch part of the front 103 Vairo so it only used the clutch pulley? I think that would be interesting.

Re: Moby vs 103 50cc’s: your thoughts?

> EH FCC of the QCB Wrote:

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

> Can’t you do something like weld the plates together to remove the

> clutch part of the front 103 Vairo so it only used the clutch pulley? I

> think that would be interesting.

yeah you could modify it to always be engaged. you could get rid of the balls and save some weight on the crank.

Andy - My instinct was to guess you were slipping too much, but it really sound like you maybe aren't slipping enough? I would put a tach on it and see where the clutch is hitting relative to your powerband.

or eliminate some variables (like the crank clutch) and tune the doppler and see how it feels. I lightened my shoes and made stiffer springs to get a higher rev engagement.

final drive ratios would be a factor too.

Re: Moby vs 103 50cc’s: your thoughts?

> EH FCC of the QCB Wrote:

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

> Can’t you do something like weld the plates together to remove the

> clutch part of the front 103 Vairo so it only used the clutch pulley? I

> think that would be interesting.

you can remove the starter clutch arms to save weight then flip that one washer that sits behind the fixed cheek, that will lock the stock vario so it no longer works in a "clutch'd" manner, Im going to try this, and the ER3 on Sunday, see which set up works best

> jumpsuit steve Wrote:

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

>

> Andy - My instinct was to guess you were slipping too much, but it

> really sound like you maybe aren't slipping enough? I would put a tach

> on it and see where the clutch is hitting relative to your powerband.

>

You could be right, but I was also holding a phone, using one hand for brakes and throttle in a small space, so it may not be the perfect example of how its really reving, regardless I take your point and will keep it in mind when tuning further!

Re: Moby vs 103 50cc’s: your thoughts?

Other thing to consider is gearing related to tire size.

I was running a 50cc setup on a shorter tire and it ripped. Swapped the tire to a diff brand but same size with a higher rounded profile and I lost off the line gusto. 50cc is super sensitive to gearing as far as takeoff is concerned.

As well....,pulley size, and belt depth at zero variation is critical.

I swapped my stock moby pulley to an aluminum one that was slightly larger and the bike had much better launch

Re: Moby vs 103 50cc’s: your thoughts?

Travis King /

Andy, jumpsuit gave you a good path forward.

And Jbots point about stroke difference is highly relevant as well.

That being said, this is where that range difference could come into play between the er3 and the stock variator.

If you had two peugeots with exact same setups, except the variator, the one with the ER3 is gonna get off the line and into the power quicker because of that smaller diameter to begin with on the ER3.

Re: Moby vs 103 50cc’s: your thoughts?

Travis King /

That last point is with the caveat that Jbot pointed out in his last post: This assumes that your belt is getting down far enough between the cheeks.

Re: Moby vs 103 50cc’s: your thoughts?

I'm not a big time engine powerhouse kinda guy. I make a decent engine but tuning variation is my fucking thing. It's all about gearing (sprockets vs tire height) and belt height above the boss at rest, belt thickness (Bx are never your friend) and believe it or not...the steepness of the cheeks. Very steep variator cheeks really make a bike rip dicks even off the line . Like surprisingly so

Re: Moby vs 103 50cc’s: your thoughts?

I’m using a Gates ax32 belt, anything wider sucks hard, even on my 70cc bikes

I have lots of parts to play around with and tune the bike, I was mostly fishing for other people’s thoughts and attempts on the matter, I’m not racing these bikes, just dicking around and having fun. But it always seems, no matter how well I tune em, my 50 Mobys kick their ass. Now when it comes to 70cc cylinders the pendulum swings in the other direction, and I’m all about that stock gearing!

Re: Moby vs 103 50cc’s: your thoughts?

Ok I tried some variations

First test was stock vario, no clutch shoes, m6 nuts for weights, one star washer, no balls, so the variator was essentially clutch-less, it performed about as well as the same vario with a clutch function, maybe slightly slightly better due to the lower weight

For the second test I used a clutch-less er3 from a Moby, spaced it out to get the belt alignment proper, and boom fucking screams off the line, I doubt this motor will last long with these rpms off the line, buuuut it will be fun while it lasts

Re: Moby vs 103 50cc’s: your thoughts?

That video sounds like very low rpm engagement.

With high rpm 50cc setups you want like 7-8k engagement if you can get it. My 50cc hobbit clutch hits at 8k, then big power at 9k.

With a clutch pulley it will help, but that would probably require malossi blacks and shoe lightening depending on the weight of the arms

Re: Moby vs 103 50cc’s: your thoughts?

Eh for most of the 50cc Peugeot kits if you didn’t port it or space the cylinder the stock clutch pulley springs are almost too stiff. Getting the belt all the way into the front pulley and the gearing right is the biggest thing. Typically on high revving kits if you have too much gear you end up not reaching max rpm or full variation. If you go fucking with the spring tension and increase it too much it makes the engagement super violent and will make your variator unthread itself, if you fix that it will break the blue piece or at worst the crank will go snappy snappy and send your fancy variator into a ravine.

Re: Moby vs 103 50cc’s: your thoughts?

its not the greatest example in the video, again stupid snow, it is probably catching around 7k right now, absolutely needs tuning, but its heading in the right direction, the er3 is clearly a better choice over a stock moded vario

Im also running stock gearing

and a Polini spring, the gearing will probably stay stock, the spring will be tuned when the weather cooperates

Re: Moby vs 103 50cc’s: your thoughts?

> Daniel '' Wrote:

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

> snappy and send your fancy variator into a ravine.

lucky for us we live in the midwest = no ravines.

Re: Moby vs 103 50cc’s: your thoughts?

Are there no hardened pug cranks to stop this breakage?

Re: Moby vs 103 50cc’s: your thoughts?

> Graham Motzing Wrote:

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

> > Daniel '' Wrote:

>

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

>

> > snappy and send your fancy variator into a ravine.

>

> lucky for us we live in the midwest = no ravines.

just endlessly flat roads for it to disappear over the horizon into

Re: Moby vs 103 50cc’s: your thoughts?

Nope, there really isn’t a reinforced Peugeot crank. The doppler endurance is the best we get, they’re fine. The problem isn’t the crank, it’s the way the var attaches to the crank. It is only held on by a nut, no taper, no key, just the nut torqued. So basically it’s just your hopes and dreams are holding it on there. I have one that is “keyed” to the crank, and uses set screws for the blue piece on my flipped er3. It works great and never had given me issue. But after seeing Matt sheer his crank, collapse his clutch pulley, shoot his variator 250 feet and get left 20 miles outside of the city I decided high stall with lots of h.p. can be fun, but also very very not fun.

Re: Moby vs 103 50cc’s: your thoughts?

> Daniel '' Wrote:

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

> Nope, there really isn’t a reinforced Peugeot crank. The doppler

> endurance is the best we get, they’re fine. The problem isn’t the crank,

> it’s the way the var attaches to the crank. It is only held on by a nut,

> no taper, no key, just the nut torqued. So basically it’s just your

> hopes and dreams are holding it on there. I have one that is “keyed” to

> the crank, and uses set screws for the blue piece on my flipped er3. It

> works great and never had given me issue. But after seeing Matt sheer

> his crank, collapse his clutch pulley, shoot his variator 250 feet and

> get left 20 miles outside of the city I decided high stall with lots of

> h.p. can be fun, but also very very not fun.

you have a good point with the 1 nut thing, I dont like how the Peugeot version of the er3 fits on the crank, so I used a Moby version, I spaced out the keyed part of the crank with those strange rectangular washers, then used the part of the stock vario that the balls rest in brace against the back of the er3, then used the Moby version of the vario nut to secure it properly, wish my crank luck

Re: Moby vs 103 50cc’s: your thoughts?

Ive concluded that I’m just to fat for 50cc 103’s lol, I’m about 210 dry

After a few days of tuning and some positive results, my best configuration being a clutch’d er3 on a stock pulley, it did pretty well, I had to put a good bit of tension on the Polini spring to prevent the engine from slipping, and with a lighter rider it ripped. But hey I’m just more to love.

So fuck it, this is my only completely air cooled 103, this is just my excuse to switch to a 70 kit, I’m going to run the cast iron Malossi

Re: Moby vs 103 50cc’s: your thoughts?

Try a bigger sprocket. Most 50 kits won’t move until you get at least a 56.

Re: Moby vs 103 50cc’s: your thoughts?

> Daniel '' Wrote:

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

> Try a bigger sprocket. Most 50 kits won’t move until you get at least a

> 56.

I was running stock gearing so what’s that 11x54? Maybe 11x56 depending?

Re: Moby vs 103 50cc’s: your thoughts?

I think stock Peugeot is 11x52, moby is 56? I can’t remember actually. I bet myrons lists them based on speed designation.

Re: Moby vs 103 50cc’s: your thoughts?

> Daniel '' Wrote:

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

> I think stock Peugeot is 11x52, moby is 56? I can’t remember actually. I

> bet myrons lists them based on speed designation.

ya, I feel like im mixing moby up in there

Re: Moby vs 103 50cc’s: your thoughts?

I'm pretty sure my 103 Lvs-u3 was 11/54 stock

Re: Moby vs 103 50cc’s: your thoughts?

7BB97475-DE2A-469C-ADB3-551230180D54.jpeg

Found it.

Re: Moby vs 103 50cc’s: your thoughts?

I stand corrected

Cool chart!

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