Peugeot belt length: Malossi Multivar

Ok, so I swapped out my stock variator for a Multivar, and the belt was looooose. I’m running both a Polini engine spring, and a stock spring, the belt was a hair loose, like sometimes when the clutch was catching I could feel it slip a tad bit, I’m running a 50cc LC Airsal, 15 sha, Simo Circuit pipe, le partie timed at 1.3mm btdc? Can’t remember the timing off the top of my head, but you get the point. Anyhow I put a spare Multivar I had laying around on it, and damn that Gates ax32 was loose! I had a Gates ax31 belt on my shelf from who knows what, and it works perfect, variated fully, not to tight, but no more slippage, so ya am I fine? I’m fine right?

AE9E5557-794F-4B18-9262-A661B5A037A1.jpeg

Re: Peugeot belt length: Malossi Multivar

It'll probably be fine, I've only seen belt tension shear a crankshaft once...

P.S. Sell me that caterpillar seat for my Motobecane VLX pls

Re: Peugeot belt length: Malossi Multivar

> Nick MBC wrote:

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

> It'll probably be fine, I've only seen belt tension shear a crankshaft

> once...

>

> P.S. Sell me that caterpillar seat for my Motobecane VLX pls

Pretty sure I have a spare

Re: Peugeot belt length: Malossi Multivar

is this with a stock length conrod or the longer conrod cause 1.3mm btdc would be different if it was the 75mm conrod vs the 85mm conrod.

Re: Peugeot belt length: Malossi Multivar

> Toledo Riot wrote:

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

> > Nick MBC wrote:

>

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

>

> > It'll probably be fine, I've only seen belt tension shear a crankshaft

>

> > once...

>

> >

>

> > P.S. Sell me that caterpillar seat for my Motobecane VLX pls

>

> Pretty sure I have a spare

I'll trade you this ugly Mondial I got sitting in my garage for it

Re: Peugeot belt length: Malossi Multivar

> LSLB RXb wrote:

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

> is this with a stock length conrod or the longer conrod cause 1.3mm btdc

> would be different if it was the 75mm conrod vs the 85mm conrod.

this has an Artek crank which should be the same length as stock? I have 3 of them, and one did have spacing issues, never gave that much thought, do they sometimes have different conrods?

Re: Peugeot belt length: Malossi Multivar

> Nick MBC wrote:

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

> > Toledo Riot wrote:

>

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

>

> > > Nick MBC wrote:

>

> >

>

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

>

> >

>

> > > It'll probably be fine, I've only seen belt tension shear a

> crankshaft

>

> >

>

> > > once...

>

> >

>

> > >

>

> >

>

> > > P.S. Sell me that caterpillar seat for my Motobecane VLX pls

>

> >

>

> > Pretty sure I have a spare

>

> I'll trade you this ugly Mondial I got sitting in my garage for it

Ohhhh my baby is so close!

Re: Peugeot belt length: Malossi Multivar

Multivars have a smaller OD shaft.

Stock:

Diameter = 1.340"

Circumference = 4.210"

1/2 stock circumference (approx belt contact) = 2.105"

Multivar:

D = .825"

C = 2.592"

1/2C = 1.296"

2.105 - 1.296 = .809"

so theoretically you have almost an extra inch in your belt for the multivar.

you either/both bring the belt in (shorter belt as you have done) or swing the motor out into the belt run. I don't think you can top out on the polini spring, but you can top out the nut/bolt that goes through the stock spring - preventing full extension -- until something hits, like the motor mount stop, or the head on the frame, carb on swingarm etc. so you could take off the belt and see what is preventing it from swinging forward. but if it works, it works. there is no spec position.

> LSLB RXb wrote:

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

> is this with a stock length conrod or the longer conrod cause 1.3mm btdc

> would be different if it was the 75mm conrod vs the 85mm conrod.

rod length should not affect timing in a significant way.

http://www.torqsoft.net/piston-position.html

crank angle difference between 75mm and 85mm rod with 40mm stroke @ 1.3mm btdc is .23 degrees.

piston position difference @ 18.5 deg is 1.302mm - 1.271mm = .031 mm aka .0012"

Re: Peugeot belt length: Malossi Multivar

> jumpsuit steve wrote:

>

> > LSLB RXb wrote:

>

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

>

> > is this with a stock length conrod or the longer conrod cause 1.3mm

> btdc

>

> > would be different if it was the 75mm conrod vs the 85mm conrod.

>

> rod length should not affect timing in a significant way.

>

> http://www.torqsoft.net/piston-position.html

>

> crank angle difference between 75mm and 85mm rod with 40mm stroke @

> 1.3mm btdc is .23 degrees.

>

> piston position difference @ 18.5 deg is 1.302mm - 1.271mm = .031 mm

> aka .0012"

still makes a difference :)

I just really am lobbying for people to report timing on setups in degrees so the information can be compared across platforms. we can start to make gains on timing approximation from setup to setup if we use like terminology.

so to say:

If an adequately aircooled 10,000 rpm 40mm cylinder/pipe setup on a 40mm stroke need to be timed at 15º BTDC, does an adequately aircooled 10,000rpm 38mm cylinder/pipe setup on a 43mm stroke need to be timed the same?

and what about

if an adequately aircooled 10,000 rpm 47mm cylinder/pipe setup on a 40mm stroke need to be timed at 13º BTDC, does an adequately aircooled 10,000 rpm 45mm cylinder/pipe setup on a 43mm stroke need to be timed the same?

if you aren't reporting in degrees, it just sort of makes it harder to ask those semi-difficult questions.

thanks for that calculator tho, that thing rocks.

Re: Peugeot belt length: Malossi Multivar

> LSLB RXb wrote:

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

>

> > piston position difference @ 18.5 deg is 1.302mm - 1.271mm = .031 mm

>

> > aka .0012"

>

> still makes a difference :)

While you could measure the difference, I think this is well below the accuracy with which any of us can place a flywheel on a crank. Unless there's some super secret trick I'm not aware of. :-)

Re: Peugeot belt length: Malossi Multivar

> jumpsuit steve wrote:

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

> Multivars have a smaller OD shaft.

>

> Stock:

>

> Diameter = 1.340"

>

> Circumference = 4.210"

>

> 1/2 stock circumference (approx belt contact) = 2.105"

>

> Multivar:

>

> D = .825"

>

> C = 2.592"

>

> 1/2C = 1.296"

>

> 2.105 - 1.296 = .809"

>

> so theoretically you have almost an extra inch in your belt for the

> multivar.

>

> you either/both bring the belt in (shorter belt as you have done) or

> swing the motor out into the belt run. I don't think you can top out on

> the polini spring, but you can top out the nut/bolt that goes through

> the stock spring - preventing full extension -- until something hits,

> like the motor mount stop, or the head on the frame, carb on swingarm

> etc. so you could take off the belt and see what is preventing it from

> swinging forward. but if it works, it works. there is no spec position.

>

> > LSLB RXb wrote:

>

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

>

> > is this with a stock length conrod or the longer conrod cause 1.3mm

> btdc

>

> > would be different if it was the 75mm conrod vs the 85mm conrod.

>

> rod length should not affect timing in a significant way.

>

> http://www.torqsoft.net/piston-position.html

>

> crank angle difference between 75mm and 85mm rod with 40mm stroke @

> 1.3mm btdc is .23 degrees.

>

> piston position difference @ 18.5 deg is 1.302mm - 1.271mm = .031 mm

> aka .0012"

Boom, the math to prove my caveman esc test and try theory, thank you for the help!

Re: Peugeot belt length: Malossi Multivar

> b to the eff wrote:

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

> > LSLB RXb wrote:

>

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

>

> >

>

> > > piston position difference @ 18.5 deg is 1.302mm - 1.271mm = .031

> mm

>

> >

>

> > > aka .0012"

>

> >

>

> > still makes a difference :)

>

> While you could measure the difference, I think this is well below the

> accuracy with which any of us can place a flywheel on a crank. Unless

> there's some super secret trick I'm not aware of. :-)

with French bikes the stator is not movable, but if you are running say a Pietcard you would set the flywheel then move the stator plate for the fine fine adjustments, but I still agree, accuracy to that extent is beyond most of us, myself included

Re: Peugeot belt length: Malossi Multivar

> LSLB RXb wrote:

> I just really am lobbying for people to report timing on setups in

> degrees so the information can be compared across platforms. we can

> start to make gains on timing approximation from setup to setup if we

> use like terminology.

degrees work for me! but to do any cross platform comparison, you still need to know stroke and rod length. in which case, piston position is just as useful.

> so to say:

>

> If an adequately aircooled 10,000 rpm 40mm cylinder/pipe setup on a 40mm

> stroke need to be timed at 15º BTDC, does an adequately aircooled

> 10,000rpm 38mm cylinder/pipe setup on a 43mm stroke need to be timed the

> same?

OK now we are talking about actually changing the stroke, not the rod length. so, yes, changing the stroke would change the relative piston position. but by how much?

according to that calculator, with a constant 75mm rod:

40mm stroke @ 15° BTDC = .860mm

43mm stroke @ 15° BTDC = .939mm

difference in piston position is .079mm or .003"

> and what about

> if an adequately aircooled 10,000 rpm 47mm cylinder/pipe setup on a 40mm

> stroke need to be timed at 13º BTDC, does an adequately aircooled 10,000

> rpm 45mm cylinder/pipe setup on a 43mm stroke need to be timed the same?

40mm @ 13°BTDC = .648mm

43mm @ 13°BTDC = .707mm

difference is .059mm or .002"

in these examples, a degree of crank rotation is approximately .1mm ~ .004" piston travel.

so even when splitting a tenth mm is possible with a dial indicator, or a half a degree on the wheel, you still face visual aid timing mark alignment, and - with points- firing inconsistency. and even so, spec timing is often a range of a couple tenths mm or degrees.

with a 10" wheel and a sharp pointer, I can confidently degree cam and relative ignition timing in within .5° . It only really matters if you have a way to measure the effect of your changes, which is where having a dyno is a big help.

so i guess a question i have is - how do you know when something is timed where it "needs" to be? like how can you tell the difference between 13° and 13.5° ignition advance?

Re: Peugeot belt length: Malossi Multivar

A 100mm flywheel (like the le partie CDI) has a circumference of ~314mm; which means that 1° is ~0.87mm at the outer edge of the flywheel; that's about half the thickness of a US quarter.

So +/- 0.5° is probably about as close as most folks can get.

Re: Peugeot belt length: Malossi Multivar

errrr i knew i forgot the part where the conrod is 90mm on the 43mm stroke setup...just like a puch/tomos.

Which honestly works towards your argument because 13 degrees for 43mm stroke with a 90mm conrod is .681mm, or only .033mm different. The dial gauge micrometer I use for setting timing without a woodruff key totally measures up to .01mm, so I can dial in that close, but you are correct, timing is all just a loose construct based on how many RPMs you are spinning, what type of cooling you have, how much over-rev you'd like and other factors.

but OK, for me, timing something means starting EXTRA low for timing (closer to TDC) and gearing. Once I verify I'm making all of the RPMs I should be (thank you exhaust nomograph, tuned length calculating and port timing maps) then I can start to add the gearing back. Once I'm geared where i wanted to be, I verify that my set up can pull that gearing and still hit all of my RPMs with temps being in check. Then I can start add timing back (farther away from TDC) while rejetting and watching my head temps. It can be kinda hard to do long WOT pulls here in Boston, but there are a few big main drags where I can hold WOT for like 5 to 10 minutes and usually get some true readings.

that all being said, I honestly don't know what my tomos is timed at because of the parmakit box, but I can tell you I never saw temps over 270ºF - 280ºF when I had my temp sensor on and my take off is more than adequate, so I haven't really had any need to bumped up my timing yet.

but yea, I sorta have wondered if extremely oversquare setups need less timing then closer to square setups. anyways, I'll stop jacking this thread with my timing talk :)

Re: Peugeot belt length: Malossi Multivar

BUMP

So here is an amalgamation of info gleamed from a few sources/ trial and error

reference this thread from Mars in which he finds the proper belt for the Multivar

and further this thread which has some more belt info

But hers the long and the short

for the Malossi multivar you want to run this belt as it has a deeper V that fits the cheek angles of the variator

you can also run a Gates BX32 belt as it will match one cheek of the variator perfectly, not so great on the other, it will work, but it will break down qucikly

If you are insistent on an AX belt, aka you wanna do wheelies, you need the Gates AX31 as the inner diameter of the variator is smaller then stock resulting in the need for a 31 not a 32

This is JUST for the Multivar, not the ER2/ER3, those work best with a good old Gates AX32 or the special toothed Malossi belt (I still prefer the Gates)

Re: Peugeot belt length: Malossi Multivar

Yooo you're the man!

I found this thread but no conclusion, just Adam nerding it up worrying about .0012" of piston travel.

Re: Peugeot belt length: Malossi Multivar

Hell yea

Good info Andy

Re: Peugeot belt length: Malossi Multivar

> L e e wrote:

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

> Hell yea

>

> Good info Andy

Lee was the one who found the info from Mars I tested it, so thank you bud

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