ESE's works engine tuner

[yatasaki]

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.

Used to work on hobbing mill in secondary school, ten times, at least, faster than milling with index head and module cutter

[DoldGuy]

I've got a 2015 KTM 250SX engine and the 5 speed has a larger, instead of smaller, % drop from 4->5. I can put an entire 6 speed from an XC (not the XC-W) in and it would be an improvement but the 3rd through 6th % drops are kind of wide, all of them more than the typical Ducati (and 5->6 looks to be about 25-30% wider than would be appropriate for higher speed track use).

A complete new XC box is about US$900 for the gears/shafts/clips/shims plus the drum/forks add another $100-200. I looked at the 2013 250 SX-F fiche and that 6 speed seems possible on the ratios but it has a few bushings and I don't know if it is a drop in. The 2T 250/350 share transmissions with the 350 4T but I can't find any significant interchange with the 250-F, and later Fs are 5 speed.

FWIW, the 250SX 5 speed drops are 20, 16.7, 14.3 and 16.5% from bottom to top.
A 350 Bultaco/AJR is 25, 17, 15 and 8.
The XC has 24.4, 20, 16.4, 15.8 and 12.6% so 6th could be closer to 5th.
The "small" Duc standard street 6 speed (not the high first gear Corse) is 32.3, 20, 15.2, 11.5 and 7.7. The Duc Corse is pretty much the same but with a 28% drop when shifting to 2nd.
I have a 2003 TZ250 as 25.6, 16.1, 11.9, 8.3 and 7.4%

Those Ducati ratios look pretty good to me and are used in a good 10+ years of recent models and are plentiful on eBay. But that means making new crank cases, which could be a fun project and also let me see about adding a balance shaft, but it pushes a running bike even farther into the already hazy future.


Yes, it may well be that for the few times it gets run as a track day bike (if I get it built) the 5 speed with a fairly standard MX tune (I bought a Pro Circuit chamber that is supposed to maintain the 50 hp peak for another 1000-1500 RPM) will be fine for my mediocre riding skills, and the XC would be better. But even though I'm transitioning to "former racer" I still like to have things the way I think they ought to be. I wish I'd known more about KTM when I bought this engine, and was clairvoyant so I could see that they'd be adding an effective balance shaft in the major engine redesign for 2017. Neil's transfer port injection which is on some new KTMs would be nice to have too.

Greg, I was surprised when I looked at late Yam/Kawa/Suzuki 600 part fiches as they were my first though on possible donors. Not only are the idlers generally running on a bush (separate from the gear) but some of those bushes have internal splines to keep them from spinning on the shafts, which I'd never seen before. I looked at some photos of the parts on eBay to verify it wasn't just needle bearing details being left off the drawing. In some you can see the internal oil grooves and drillings to let oil get out to the bush/gear interface.

The TT Industries parts do have a good reputation, but isn't everything they do for pre-unit British stuff?

An XC 6 speed with tighter custom 5th and 6th gears would most likely be fine, if it was possible to get those gears designed and made at an affordable price. But for the price of those gears (and probably for less) I can get a complete Duc lower end and have clutch and primary gears too, as well as no special replacement parts.

A pal sent some primary gear parts to Ellis Moore at Moore Engineering in England to get some parts made but he told me that Ellis had a race crash last year that left him paralyzed from the chest down and he's closed his shop and his parts are coming back. Ellis was keen on one-off stuff (which Nova is not) and appears to have supplied high-quality parts at reasonable prices so his accident is a loss to the industry (as well as being tragic, I know other racers who've ended up in wheelchairs).

A friend who purchased a TZ125 last year has been telling me of some major parts that aren't to be found as NOS, and now that I'm done with vintage bikes I'd like my remaining projects to not involve massive part searches. It is difficult enough to finish things without getting hung up on "wish I could find a new one of these" issues.

So when I saw various cool 125-250 shifter kart motors of modern manufacture it had me wondering what they are doing for gearboxes, and this seemed like the place mostly likely to have someone who knows.

cheers,
Michael

Michael,

I have a 300xc 6 speed & a 250sx 5 speed. I prefer the 6 speed ratios & feel the 5 speed is limited to just moto and have collected most components to convert it over to a 6 speed. Have spent a bit of time researching what fits (I’m Cheap), if I can help, let me know.

Curious, did you get the EngMod file from Wobbly? If so, how far off is the later model cylinders?

[Michael Moore]

Michael,

I have a 300xc 6 speed & a 250sx 5 speed. I prefer the 6 speed ratios & feel the 5 speed is limited to just moto and have collected most components to convert it over to a 6 speed. Have spent a bit of time researching what fits (I’m Cheap), if I can help, let me know.

Curious, did you get the EngMod file from Wobbly? If so, how far off is the later model cylinders?

Thanks for the offer, I've got all the part numbers for the XC recorded. Online parts fiche are sooooo useful, and the "where does this part fit?" searches often give some interesting information.

I've not taken the SX engine apart so wobbly's EndMod info is sitting, ready to spring to action at some point, and I'll rope Jeff Henise in on the EngMod stuff (he has a 300XC of the Husky flavor).

I now have a 2009 M696 Ducati lower end assembly (crankcase damaged by the side stand) sitting in the garage and I'll start cleaning/disassembling/modeling transmission/clutch/primary drive bits soon. FWIW the dry clutch uses 4 more plates than the SX wet clutch but the friction plates are twice the thickness so the 52.4mm stack is 25mm thicker than the KTM.

I looked at that PowerCDI site mentioned in the Speeduino thread and read some reviews by people who tried it and it sounds interesting, especially since there's going to be (or is) one for the TPI engines. I've got a new 38mm PWK Stryker (which I understand isn't universally liked) on hand but going to Neil's TPI system sounds appealing and I could see buying a PowerCDI if it proves out as I will not be surprised if I have to spend money anyway to get a different ignition curve from the SX for paved track use.

cheers,
Michael

[TZ350]

.
Flettner originally suggested this approach to me.

The 2S-MAP changes from about 0.4bar to 1.40bar, but not very smoothly. As the motor is not running that great. So at this point I can't tell how useful the two stroke pseudo MAP results are going to be.

Still it is great to have something to continue working with and I will know more in a few days hopefully. With any luck I will be able to get the motor running better and be able to log some data. That should tell me if I am on the right track with my ideas about getting a usable two stroke MAP value that indicates real airflow through the motor. It is such hard work making "reality" conform to "theory" ...........


Ok ...... I now claim for Myself and Flettner this working 2S MAP indication of air flow for 2S EFI, as a world first.
Happy to be proved wrong about being first, but you will have to show a link that includes technical details, and a picture(s).


The difference between high/low 2S crankcase pressure displayed/used as a MAP value for 2S EFI. Time will tell if this is a good useful indicator of air flow like a 4S manifold MAP sensor is for 4S EFI.




A big thanks to Flettner as I managed to get to here by following a path he suggested.

More on this 2S EFI project can be found here:- https://www.kiwibiker.co.nz/forums/s...2T-EFI-Project
.

[husaberg]

Thanks for the offer, I've got all the part numbers for the XC recorded. Online parts fiche are sooooo useful, and the "where does this part fit?" searches often give some interesting information.

I've not taken the SX engine apart so wobbly's EndMod info is sitting, ready to spring to action at some point, and I'll rope Jeff Henise in on the EngMod stuff (he has a 300XC of the Husky flavor).

I now have a 2009 M696 Ducati lower end assembly (crankcase damaged by the side stand) sitting in the garage and I'll start cleaning/disassembling/modeling transmission/clutch/primary drive bits soon. FWIW the dry clutch uses 4 more plates than the SX wet clutch but the friction plates are twice the thickness so the 52.4mm stack is 25mm thicker than the KTM.

I looked at that PowerCDI site mentioned in the Speeduino thread and read some reviews by people who tried it and it sounds interesting, especially since there's going to be (or is) one for the TPI engines. I've got a new 38mm PWK Stryker (which I understand isn't universally liked) on hand but going to Neil's TPI system sounds appealing and I could see buying a PowerCDI if it proves out as I will not be surprised if I have to spend money anyway to get a different ignition curve from the SX for paved track use.

cheers,
Michael

Ian Cramp used a 851/916 gearbox on Loinheart i know he had the tooth pattern deciphered for the primary drive it was some oddball pressure angle only Ducati used i have his email somewhere,
I think i have the company's name that made the primary gear for Lionheart but i recall it was very spendy even back then. i believe they had to make the tooling to make the gear. I doubt Ducati would have changed the gear designs in the interim.

Here you go
assuming its the same 2.25 modulus 15 degree pressure angle and i guess he might still have the tool still. seeing it was about $800 USD then plus about 1500 us for the two complete small primary gears
Tay Tool work analysed it
M&B gears made them.
Let me know if you want his email


another to talk to would be The V Two people which i guess Ken will know.
They made primary gears for bevel racing Ducatis but i suspect they might have used a more traditional gear.

[Michael Moore]

This 696 is a wet clutch motor.

The Duc primary pinion gear OD matches a standard Mod 2.32(ish) which seems an unlikely number.

The basket uses 3 rivets to attach it to the clutch primary gear, and that gear has a bearing that runs on the mainshaft. So it might be that the KTM (or other) gear could be substituted as seems appropriate. I haven't gotten the KTM primary pinion in yet so I haven't been able to compare it to the Ducati. If the Duc clutch gear needs to be retained then maybe the KTM and Ducati pinions can be grafted together, or since I think the KTM is a straight plain bore with a key to drive the crank, a straight bore/tapered OD with key slot sleeve (which might be a straight-foward lathe part) could be used between the KTM crank and the Ducati pinion.

Once I pull a KTM clutch plate I'll be able to compare that to the Ducati for effective radius (including the changed primary ratio) to see if the Ducati clutch could be modified to use fewer plates which would narrow it up and save a little weight. The Ducati primary gears might be narrowed up a lot too, the dual gear (cam drive) pinion is a hefty chunk of steel.

There's lots of investigation still to happen.

cheers,
Michael

[_____]

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

Aw cheez! That are great news! I will buy the third one right away. Thanks a lot!

[Flettner]

Gears, yes, hardening is an issue.
I pre machine the blanks close to size then get them stress relieved
Then cut the teeth to a finished size minus about 0.02mm, in hardening process the blank will grow approx 0.02mm.
If the carborising is done properly ( along with the stress relieveing) the distortion will be very little in the hardening process. Finish is, clock the teeth concentric in the cylindrical grinder then grind to finished size, be it shaft or bore. This is for EN39B, hardness 60 Rockwell.
Or to put in technical terms, fucken hard.

Good to see TZ has cracked the EFI nut, FAB.

[yatasaki]

Flettner, do you use gas or salt? We always use to go in plus for the blanks for outer diameter/gears, then exceed carburising over that plus into the material core, and, after stress relieving grinding to final measure.
We used sodium cyanide.

[Flettner]

don't know if there would be any cyanide baths in NZ still, you know, health and safety.
Carborising done by gas.

[flyonly]

I am interested in people’s opinion on 10mm spark plugs for a 50cc. I was thinking Brisk Silver racing.


Sent from my iPhone using Tapatalk

[husaberg]

don't know if there would be any cyanide baths in NZ still, you know, health and safety.
Carborising done by gas.

There is a great story in George Beggs book about Bert Munro and the Cyanide baths at some engineering firm in Invergiggle
they warned him it had to be 100% dry before he put it back in. Even pointed to the sign that said just that.
he just nodded . As he he used to often call in and use their gear they left him to it
But Bert i guess was in a Hurry
They heard the bang but couldn't find Bert they looked in the toilets here he was in the stink trying desperately to put his on still on fire hair out.

I dont think he quite understood the belts and braces safety philosophy.
He got rid of the belt drive in the 1930's and the braces were for holding up his pants

[yatasaki]

Baths were switched off in 1998, for health reasons, salt went solid, chiseled out ,and thrown away...so sad story...
Flettner, do you quench imediatelly after carburising?

[dutchpower]

Neels (vannik )

Can you tell me more about how de design in Engmot of the exhaust pipe calculate ( simulate )
Everytime this shape appear 25 / 50 / 65 / 125 etc. as the best !!!!

[Vannik]

Neels (vannik )

Can you tell me more about how de design in Engmot of the exhaust pipe calculate ( simulate )
Everytime this shape appear 25 / 50/ 65 / 125 etc. as the best !!!!

DutchPower, I do not fully understand your question:

1. Do you ask why, after a number of simulation runs and development, the best pipe looks like the picture,
2. Or do you ask why Dat2T always gives the same starting pipe?