ESE's works engine tuner

[TZ350]

I was having a conversation the other day with a friend and he came in conversation that low torque engines like bigger front sproket, this is not about the transmission ratio. He says that bigger cc bikes with high torque like smaller sproket, but low cc with high rpm big front sproket. He showed me a file where it talks about this, but its in Portuguese.

Interesting. I would not have thought so, but I had not thought about it either.

If its true, we might need to look at how the choice of primary gear ratio which affects the torque loading stresses on the clutch has been chosen to see why a particular size front sprocket is needed. As I understand it. If a clutch is prone to slipping then reduce the primary ratio. This spins the clutch faster but reduces the potential torque multiplayer affect of the primary ratio.

A lower primary ratio would suggest a smaller front chain sprocket because the front sprocket would now be spinning faster too. But a high torque motor is usually one the reeves slower than a low cc high rpm low torque one. So the high torque engine would need a proportionally bigger front sprocket. I guess we need to look at the complete picture.

Out of interest, my 250 single road racer that is geared for 110 mph has a 17 front sprocket and a 38 rear 2,2:1. My TZ350 had 14 front and 34 rear 2,4:1. The TZ reeved harder and went faster. I will have to check the primary and top gear ratios to make any sense of it.

[JanBros]

does anyone have the arduino sketch for Adagnes's Ardyno ?
it's no longer available on his site. have mailed him butl no answer (allthough it's only 24h)

[wobbly]

I dont think you can discuss sprocket size in isolation , as in bigger, or smaller is better as a basic premis at all.
First you have the desired acceleration out of the slowest corner , offset by the top speed needed or more likely the amount of power available to generate that top speed.
But in a racebike the other aspect that is highly important is the chain run geometry that generates the squat characteristics out of every corner,
The smaller the front sprocket the greater the anti squat - if its needed.

[Grumph]

I agree with Wob. In addition it's complicated by Rob and I - and several others here - dealing with engines originally intended for dirt bikes.
They tend to have primary ratios chosen to give final drive sprockets that are a comfortable size at the lower gearing needed for off road work.
In the case of the Kawasaki's I remember Cameron when modifying his 350 single having trouble finding clearance for a larger front sprocket to suit the roadrace application.
It looks like my primary belt conversion is going to raise the gearbox speed appreciably - which will help with overall gearing.

[pete376403]

I agree with Wob. In addition it's complicated by Rob and I - and several others here - dealing with engines originally intended for dirt bikes.
They tend to have primary ratios chosen to give final drive sprockets that are a comfortable size at the lower gearing needed for off road work.
In the case of the Kawasaki's I remember Cameron when modifying his 350 single having trouble finding clearance for a larger front sprocket to suit the roadrace application.
It looks like my primary belt conversion is going to raise the gearbox speed appreciably - which will help with overall gearing.

IIRC in Camerons bike the original clutch actuator was a pushrod through the gearbox shaft operated by a bellcrank on the left side. He changed it to a pull operation through the clutch cover on the right side. Wonder what became of that bike?

[lodgernz]

does anyone have the arduino sketch for Adagnes's Ardyno ?
it's no longer available on his site. have mailed him butl no answer (allthough it's only 24h)

Do you mean the Simple Dyno sketch? I don't remember Alex offering a separate Arduino program.
Or do you mean the Ardyno circuit diagram?

[JanBros]

Do you mean the Simple Dyno sketch? I don't remember Alex offering a separate Arduino program.
Or do you mean the Ardyno circuit diagram?

the sketch that needs to be uploaded to the arduino. don't know if it's his own.

on this page : https://ardyno.weebly.com/instructions.html
under software, the second link "Download the Simpledyno zip file from here and unpack it"

[jfn2]

Hello Jan
I have a copy of the simpledyno solfware zip file if that's what you need. I believe it's version 6.5.1
Jeff

[JanBros]

Hello Jan
I have a copy of the simpledyno solfware zip file if that's what you need. I believe it's version 6.5.1
Jeff

I have that too. so it's just the sketch that's whithin the simpledyno software that's alsovused with the ardyno ?

[lodgernz]

I have that too. so it's just the sketch that's whithin the simpledyno software that's alsovused with the ardyno ?

SimpleDyno provides the Arduino sketch that is is used to transfer the Ardyno signals to SD.
The Ardyno board is quite separate from SD and is just one of any number of input devices to SD, but SD requires the engine and roller data to be interpreted and sent to it via the SD sketch, always.

[JanBros]

SimpleDyno provides the Arduino sketch that is is used to transfer the Ardyno signals to SD.
The Ardyno board is quite separate from SD and is just one of any number of input devices to SD, but SD requires the engine and roller data to be interpreted and sent to it via the SD sketch, always.

ok, thanks

[RomeuPT]

I dont think you can discuss sprocket size in isolation , as in bigger, or smaller is better as a basic premis at all.
First you have the desired acceleration out of the slowest corner , offset by the top speed needed or more likely the amount of power available to generate that top speed.
But in a racebike the other aspect that is highly important is the chain run geometry that generates the squat characteristics out of every corner,
The smaller the front sprocket the greater the anti squat - if its needed.

Not sure if I understand what you mean.

Here is the file, but in portuguese.

It seems to be about how much dregress the chain bend per tooth with different sprokets.

[Frits Overmars]

Here it is in Enlish. The only remark I can endorse is that gears with small numbers of teeth have drawbacks. But that is generally true; it has nothing to do with low or high torque.
In the old days (about a hundred years ago), when we had to design a machine, we got a beating if we dared to suggest gears with less than 20 teeth.

[TZ350]

2Stroke Stuffing doing the things I would love to be able to do too.

[RomeuPT]

Here it is in Enlish. The only remark I can endorse is that gears with small numbers of teeth have drawbacks. But that is generally true; it has nothing to do with low or high torque.
In the old days (about a hundred years ago), when we had to design a machine, we got a beating if we dared to suggest gears with less than 20 teeth.

Thanks for the translation!