ESE's works engine tuner

[Vannik]

Thanks Jan

http://www.cimaingranaggi.it/en

Michael,

Why do you not just make a closer ratio 5th gear? That is what we used to do years ago on another project.

[peewee]

i would use the latest ktm sx trans. if 5th gear doesnt suit then make a new one. 125 version would be even better since theres 6gears

[guyhockley]

Michael, if you search for kart homologation pdf some of them will give you information like gear teeth numbers, centre distances etc, but it's a bit of a lottery. Maybe include engine or motor and, probably, kz to avoid all the carb and chassis stuff. I have a load but I'm away from my computer for a few days.
Check out VM Motors, their production part prices seem way better than the Italian ones (they are Czech).
They also were at a Motorsport trade show a while back saying they would do custom work.

[guyhockley]

https://www.vmmotor.com/www/vmmotor/...5-m02-beng.pdf

[Michael Moore]

Gear making is one of those many subjects where I've read a bit about it but I've never attempted it (other than one small oil pump drive gear in machineable wax CNCd as a test to see how it would come out). If the shaft center distances don't match what my software says is appropriate for a standard gear then I'm at sea on how to proceed on modifying gear profiles. It appears there are a lot of non-standard gears in use in motorcycles. I've already got experience with subjects where I've uttered the phrase "how hard could it be?" and I suspect gear making could easily supply the same answer as the other subjects: "wow, that was pretty hard."



I'm going to pick up a Ducati lower end (offered at a very low price as the person has a literal heap of them) tomorrow for inspection.

I've also got a new 2017 250 crank and a set of lightly used matching counterbalancer and dual pinion primary gear coming and I'll be interested to see how the balance factor is done.

thanks,
Michael

[jato]

Years ago i measured a 95 RS125 crank for its balance factor and from memory it was 47% - i was expecting 50% but i used the top half of the rod as reciprocating although people often use just the top third. I didn't have the balance shaft to measure but surely it would equal the crank.

[husaberg]

Gear making is one of those many subjects where I've read a bit about it but I've never attempted it (other than one small oil pump drive gear in machineable wax CNCd as a test to see how it would come out). If the shaft center distances don't match what my software says is appropriate for a standard gear then I'm at sea on how to proceed on modifying gear profiles. It appears there are a lot of non-standard gears in use in motorcycles. I've already got experience with subjects where I've uttered the phrase "how hard could it be?" and I suspect gear making could easily supply the same answer as the other subjects: "wow, that was pretty hard."



I'm going to pick up a Ducati lower end (offered at a very low price as the person has a literal heap of them) tomorrow for inspection.

I've also got a new 2017 250 crank and a set of lightly used matching counterbalancer and dual pinion primary gear coming and I'll be interested to see how the balance factor is done.

thanks,
Michael

Michael talk to flet and also read Bradleys First book it explains it all.

[Michael Moore]

husaberg, as John's former North American distributor for Volumes 1 & 2 I have read his short chapter (with photos) on gears, but I'm sure John would agree there's only so far he can go in approx 10-15 pages, and he finishes with the admonition that once things have been modified seeking specialist help is probably needed. I've got three "home shop machinist" books of 50-150 pages each on gear making and Machinerys Handbook has 211 pages on gears and I have two different gear software packages that allow some pretty strange looking gears to be made, and if it were dead simple people wouldn't spend entire apprenticeships learning about it.

If every gear in use was an unmodified and completely "standard" gear things might be a bit different, but I've been assured by someone who did an apprenticeship as a gear maker that is not the case in the motorcycle industry. Some manufacturers are "pretty good" on using standard Module gears as long as they fit the job, others mix and match DP and Module as they see a need, and others do whatever they please when they please to get what they want.

It is a complicated subject and while I could probably make a basic gear for some application with not very stringent requirements (like the Honda oil pump drive gear I machined from wax that seems pretty close to what Honda did, though it was not a "standard" gear by the time I got things to match under magnification), motorsports transmission gears are likely to be a different kettle of fish. Maybe the KTM gears that would be changed to improve ratios are dead standard unmodified gear forms that can easily be slightly changed on total tooth count for a pair (one up, one down so the total number of teeth remain the same). But on the XC ratios I see total tooth counts for the pairs of 46, 41, 45, 45, 47 and 46 so I'm pretty doubtful everything there is an ideal "standard" gear.

Frames seem easy by comparison.

cheers,
Michael

[husaberg]

husaberg, as John's former North American distributor for Volumes 1 & 2 I have read his short chapter (with photos) on gears, but I'm sure John would agree there's only so far he can go in approx 10-15 pages, and he finishes with the admonition that once things have been modified seeking specialist help is probably needed. I've got three "home shop machinist" books of 50-150 pages each on gear making and Machinerys Handbook has 211 pages on gears and I have two different gear software packages that allow some pretty strange looking gears to be made, and if it were dead simple people wouldn't spend entire apprenticeships learning about it.

If every gear in use was an unmodified and completely "standard" gear things might be a bit different, but I've been assured by someone who did an apprenticeship as a gear maker that is not the case in the motorcycle industry. Some manufacturers are "pretty good" on using standard Module gears as long as they fit the job, others mix and match DP and Module as they see a need, and others do whatever they please when they please to get what they want.

It is a complicated subject and while I could probably make a basic gear for some application with not very stringent requirements (like the Honda oil pump drive gear I machined from wax that seems pretty close to what Honda did, though it was not a "standard" gear by the time I got things to match under magnification), motorsports transmission gears are likely to be a different kettle of fish. Maybe the KTM gears that would be changed to improve ratios are dead standard unmodified gear forms that can easily be slightly changed on total tooth count for a pair (one up, one down so the total number of teeth remain the same). But on the XC ratios I see total tooth counts for the pairs of 46, 41, 45, 45, 47 and 46 so I'm pretty doubtful everything there is an ideal "standard" gear.

Frames seem easy by comparison.

cheers,
Michael

I didn't mean to be flippent What i was meaning is it covers the multiple use common ones used and the way to calculate forms.
Flettner here makes gearboxs for a living, i guess that kind of makes him qualified. But as far as i know he sticks to simple is best. and mostly uses a ready made gearbox
The book includes examples like Honda 750 using 4 diferent modules and the KR1 the same
as you said to lose a tooth or two they mod the profile but often they just use a totally different module,

But using the Nova T20 first gear conversion as an example its possible to go even further.

The first gear, which is too low for racing anyway, I replaced with a brand new higher ratio gear. This can be done quite easily. All you do is replace the 36t gear with a 33t one! The cut angle is different so it allows for only one gear to be changed! Engineers out there will be telling me that this is impossible, but it is a common conversion, it works, and I've done it! These are manufactured in batches of 10 by Nova Racing. Martin Crooks is always prepared to order a new batch to be made up, if he gets sufficient orders (5 or 6). Through this site, we managed to get enough orders (I bought two - one for each engine) and this is now fitted and working.

I spent a fair bit of time once going through Kawaski parts fiches looking for gear ratios for KE/KS 125 there were about 30 or more combinations just through model changes and updates
Bradleys 15 pages is better than anything available on the Net i have ever found.

There was another place that used to do the mix and match gears in the UK but i think Nova took over them.

EDIT i think it was Nova trading as G Dyson previously.

Mr Francis Payart posts occasionally and i assume he makes his own gearboxs you could try him.

i did find this though
https://grabcad.com/library/involute...from-scratch-1

https://khkgears.net/new/gear_knowle...imensions.html
https://khkgears.net/new/gear_calculator.html
Toothed belt drive primary and CVT is far more appealing by the minute

here is a KTM125SX i found on Ebay plus the tooth count

[_____]

.. as John's former North American distributor for Volumes 1 & 2...
Michael

Hi Michael,
is there any chance that there will be a reprint of the series? I am happy enough to own Volume 1 & 2 and was recommending it to friends.
Since they are not available anymore the prices on amazon have been skyrocketing. They are billing ten times higher than what I have paid (was ~50-80, cant recall. Now 600€! Each!)

On topic of changing a single gear: That works. I know that from a friend of mine who does Vespa tuning.
They change the primary gear ratio with up to four different small teeth numbers with the same pinion and it works. Profile shift is the keyword.

Cheers
Chris

[Flettner]

I cut my own gears, here a plastic oil pump / water pump drive gear.
A David Brown gear hobb.
Some I make in 4140 and get them nitrided, counter balance drives etc.
Others I do in EN39B and get them case hardened, mostly heavily loaded gears, gearbox and the like.

[fpayart]

Hello,

Indeed, Flettner seems to know what he's talking about.
The design and manufacture of gears, is a very specific job.
We are starting to have a good experience in this activity.

We outsource a part of the production of our gears.
But we buy most of the different ratios at ROTAX.

One of the main difficulties, when designing a gearbox, is that the center distance of the shafts, is contant.
To change the ratio, it is necessary to change the number of teeth and the module and most of the time, to apply a teeth correction factor.
Care must be taken to maintain a sufficient driving rate and to balance the specific sliding of each gear.
Specific software is welcome ...

Then, during manufacture, the painful problem of heat treatments arises.
This is the most difficult point to master.
We had a lot of problems with our subcontractors.

Cheers,
Francis.

[OopsClunkThud]

On topic of changing a single gear: That works. I know that from a friend of mine who does Vespa tuning.
They change the primary gear ratio with up to four different small teeth numbers with the same pinion and it works. Profile shift is the keyword.

Changing a single gear in a set will still mesh, but it changes the angle the teeth contact at and all the forces related to that. Yes many vespa tuners do it, and then when the cases crack they take that as proof of power output...

[lohring]

We solved a variable ratio gearing problem with rear differential quick change gear sets. They are inexpensive and come in various ratios. We used it to increase the motor rpm from around 5,000 to 10,000 rpm that our prop liked. We played with the ratio for the best speed. The electric hydro went 98+ mph in 2008, still the fastest electric boat official record.

Lohring Miller

[Michael Moore]

Thanks for the examples of gears not being a trivial thing the typical home machinist (and I'm not a particularly good one) just knocks out.

Chris, your friends could help John's volumes 1 and 2 get back into print by purchasing a copy of volume 3

http://www.broadlandleisure.com/

John is aware of the demand for the earlier books, but since the printer who did them went bust and the plates were destroyed he's got a fair amount of work in order to do to reprint. Right now he's staying busy selling/packing/shipping the new book, and money from sales of that (and a reduction in the pallets of books cluttering up his house) will be needed for a final print of the other books.

Volume 3 easily equals the quality of the first two books, but it demonstrates that, as with gears, if you want to set up a bike at a "pro" level you need to be prepared to do some study and put in the work.

cheers,
Michael