Air Cooled 103 70cc Cylinder Tuning (video)

I received a few emails and PM's asking about the Zeros Shop video series, we are still making them! Just in smaller versions! In a few of those emails/PM's I was asked about tuning 70cc French cylinders and the issues related to heating, so in response I tuned up one of my 50cc 103's with a 70cc Malossi cylinder, check out the video below and let me know what else you'd like to see

PS: the sound is not wonderful in a few spots, sadly its still cold and our heat is loud!

Re: Air Cooled 103 70cc Cylinder Tuning (video)

coooooooooooool

i made some heads back in the day that really helped with the 70 air cooled kits, they don't have enough fin surface area for the power they make and they have such a bad chamber with the decomp valve and shit in there that they burn really inconsistent. they are slow to burn off the pipe and once they are on the pipe they detonate like shit.

there are only a couple 70cc heads on the market that *look* good IMO, i haven't run them because i always make my own but the malossi no-decomp head for 70 and the doppler for 50cc are the only two that look halfway decent.

i dunno what to make of that polini but the one i built a few years ago had big casting boogers all up inside it and no real quench area.

the problem with all of them (including the two mentioned above) are they have WAY too much squish area for the pistons that come in these kits. Maybe if you had a flat top piston but you really need to have more combustion chamber volume to keep them cool with a big french pipe.

i'm not a french expert by any stretch of the imagination but my conclusion is: 70 cc with a stock pipe, low rpm, low compression, big torque and cruise OR 50cc balls to the wall high rpm big pipe and do everything you can to keep it cool/alive, there is no in between.

i actually kept the stock pipe on my TSM with a 70cc airsal kit, SHA, stock variator. Dont' have a lot of miles on it but feels good.

Re: Air Cooled 103 70cc Cylinder Tuning (video)

Ilia Edouardovich /

Graham hit the nail on the head with the two best types of setups for Peugeot. Although, being a sadist, I love torturing myself with the MLM thread-in circuit pipe on my 70cc Malossi Kit. Seems like it needs more reinforcing after every ride, but it’s so much damn fun with a 70 kit. Pulls so hard out of the hole and throughout its range, but keeps me restricted below 50mph with 11/52 gearing. I love it for the city. Great low end pipe!

FYI A guy I know recently ran it on a Doppler kit and reported nearly identical results. It just stops working in your favor around 8k rpm regardless of displacement size.

Enough typing. I should probably watch the video!

Re: Air Cooled 103 70cc Cylinder Tuning (video)

Circuit pipes usually stop around 7500-8k, and that MlM circuit is just a techno circuit, aka terrible pipes.

Toss some cool French specific pipe on there and you’ll see some real gains

Re: Air Cooled 103 70cc Cylinder Tuning (video)

Oh I should also give a “it’s 20+ degrees warmer then when I tuned the bike update”

Dropped down to an 88, went for a ride today, didn’t get on the throttle to hard and had to push a dead Garelli with rider home, I hit 320 degrees while doing 28mph up a hill, this thing sheds heat like that’s it’s job (cough cough take notice all my dumb air cooled AV10’s), anyhow I also went from a 13t front sprocket to a 12r, better bottom end, with out letting the front wheel get loose under torque, doing a solid 45mph, I’m pleased with this bike, pleased AF

Re: Air Cooled 103 70cc Cylinder Tuning (video)

Ilia Edouardovich /

I already own and have ran most of the Peugeot pipes that are on the market and seriously love the performance I get from the MLM circuit pipe. Sure it’s poorly made and lacks topend, but the build can be improved with a few welds as well as brackets/gussets. Plus I didn’t build this bike for topend. With 70cc it’s the best pipe for stop light to stop sign riding here in SF while still letting me cruise easily at 45mph. No pipe I’ve found comes even close to pulling this hard at low end (no clutch pulleys anymore for my city builds). This is on the aluminum Malossi kit with matching head. It rarely passes 330F when riding on flat streets.

Re: Air Cooled 103 70cc Cylinder Tuning (video)

Jack Rutherford /

What kind of microphone input do you have on that camera? I think you need a mic in that huge boomy space because your voice kind of gets lost in the void.

Re: Air Cooled 103 70cc Cylinder Tuning (video)

> Jack Rutherford Wrote:

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

> What kind of microphone input do you have on that camera? I think you

> need a mic in that huge boomy space because your voice kind of gets lost

> in the void.

I have a nice mic, but your right. The issue is our heat during the winter, it’s a really loud 30ft long natural gas snake heater with 4 fans blowing the heat down. I try to shut it off while filming but can always do so, those are the sections where you have a hard time hearing me. It’s warming up here in Ohio so that should help my next video sound better! Apologies for the meantime’s filming!

Re: Air Cooled 103 70cc Cylinder Tuning (video)

you would look good with one of these

britneymic.jpg

the microphone, but yeah the top would be cool too. please and thanks.

Re: Air Cooled 103 70cc Cylinder Tuning (video)

> Graham Motzing Wrote:

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

> you would look good with one of these

>

> the microphone, but yeah the top would be cool too. please and thanks.

For you Graham, anything

Re: Air Cooled 103 70cc Cylinder Tuning (video)

> Graham Motzing Wrote:

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

> you would look good with one of these

>

> the microphone, but yeah the top would be cool too. please and thanks.

He might not mind what's in that top , either . ;)

Re: Air Cooled 103 70cc Cylinder Tuning (video)

nice! finally had a chance to listen to this. i like the shorter vids, makes it easier to catch them on a lunch break or something. the long ones just make me feel bad that i'm not out in the shop myself working.

definitely got me sold on the 3d printed SHA slide, i was on the fence but i'm gonna check it out.

i got that dakar with the adjustable jet on my TSM right now, seems to be working pretty well but i still have a lot more tuning to go after i finish paint, wiring, cables.

Re: Air Cooled 103 70cc Cylinder Tuning (video)

> Graham Motzing Wrote:

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

> nice! finally had a chance to listen to this. i like the shorter vids,

> makes it easier to catch them on a lunch break or something. the long

> ones just make me feel bad that i'm not out in the shop myself working.

>

> definitely got me sold on the 3d printed SHA slide, i was on the fence

> but i'm gonna check it out.

>

> i got that dakar with the adjustable jet on my TSM right now, seems to

> be working pretty well but i still have a lot more tuning to go after i

> finish paint, wiring, cables.

Thanks for the feedback!

Ya dude those sha slides rock, we have them in several bikes around the shop, each one shows improvement

And the Dakar Sha clones have an air mixture screw ya? I remember Davidde from MCR championing them a few years back, I have one that I got from Sal Smog (good seller btw) and I could just never get it to run right, maybe you’ll have better luck then me!

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