2 speed shifting tranny

[Harold in CR]

I am about to obtain a 1988 Kawasaki Ninja motor-tranny, I am going to try to take the gears and build a shifting 2 speed using Thud's build thread as a reference.

Don't know exactly what the gears look like, but, I'm planning to make the dog clutch by grinding a slot across the face of the gears and having a 2 legged dog that will engage the gears. The dogs will have the edges VERY slightly tapered, so the might engage easier, and the slots on the gears will be slightly wider than the dogs.

I plan to do the grinding on a milling machine, in a pan of water based cutting oil, to keep the gears cool and retain the hardness.

The enclosure will be gasketed, so a gear hugging oil, like the Lucas additive can be inside and thrown around by the gears. Just enough oil to keep the gears from running dry. This will go on a heavy duty Bicycle build.

Anyone see any problems with attempting this build ?? Should be starting this in about 2 weeks, so suggestions pro or con are welcome.

 

[PetriK]

Interesting idea. I have fixed some motorcycle trannies and those are really heavy duty stuff to be able to manage up to a few hudred of horsepower. I dont know how you planned to organize the shifters to move the gears. Somekind onf shifter drum like in the original gearbox ?

If this is the 250cc ninja, maybe then not so heavy ?

Anyway did you consider a variator eg from a moped ? a variator could constantly adjust for best torque and therefore could even to certain degree replace the chain drive. Just an additional idea...

 

[Harold in CR]

HI PetriK

I have other plans for the variator type tranny.

This Kawasaki tranny is FREE. I have never had one apart, so, have no idea what I will find inside. Not sure at this time, what model the Tranny is.

Have you looked at the topic "Thud's First Build " ??? It details exactly what he did. I just want to copy most of what he did for shifting. I'm just trying to get away from chains and sprockets inside his Tranny Build.

Hopefully, I can charge down the hills, and, accelerate back up the other side, and, shift if RPM's drop too much.

This is my first venture into E Bikes, so, I'm trying to use inexpensive, yet strong parts. Adding more batteries and maybe a stronger motor might be required, so, gears sounds better to me.

 

[Danny Mayes]

Hi Harold,

I can't see why this wouldn't work, in fact i think it is a good idea.

Like you say the gears are already hardened, definitely strong enough and the only down side is they are probably heavier than you need. You can always lighten them up on your mill though...

I have had thought of doing what your are attempting so I am keen to see what you achieve with this.

Good luck.

D

 

[Harold in CR]

Time to update this thread. Today, I started mixing and matching gears of the Kawasaki Tranny I got, for free.

I have to mod several things, but, that's something I CAN do. I have a drill press with a surfacing attachment I made up. Today, I surface ground the dogs off of one of the gears I am modding. Then, I cut it in two, in the shifter groove, to make this a single gear. I had to drive 1 bearing off one end of one of the shafts. It had a collar rusted on outside the bearing.

I have the ratios and tooth counts in the shop. Just too tired to go back out there and get the info. Tomorrow, I will take a few photos, and have the gear shots and ratios, so maybe, someone here can give me some insight on what I can expect.

 

[spinningmagnets]

LFP was very adamant that the dogs and the holes/slots they fit into both need to have fairly sharp edges. I seem to remember that the holes can be slightly larger (with a tiny amount of slop in the fit) but the edges still need to avoid having or developing sloped edges.

Dog-shifting needs to be made suddenly and slammed deep into its engagement partner. If that is done properly, the dogs and slots will last a very long time.

 

[Harold in CR]

What I did was, cut a shifter gear-dogs gear, into 2 pieces AT the groove where the fork rides. I also completely ground off ALL signs of the digs. I just made a thinner gear with no dogs.

IT will be a fixed gear on the driven shaft. There are 2 driven gears, same as Thud's tranny. Those gears are running on 2 more gears that are running on sleeves, an, that is where the shifter -dogs will engage hi-low gear. I will show photos, tomorrow. I did NOT touch any part that needs to engage-disengage.

 

[Miles]

Here's another example. Similar design to Thud's but not quite as elegant....

http://www.thepixelpump.com/widdershins/how-to-2speed-transmission.php

 

[bobc]

One of the greenpower cars re-used an old motorbike gearbox. The box has 3 shafts, input shaft, output shaft and a selector drum, all of which could be mounted between 2 ally plates (each with 3 bearings in). So a bit of DIY & you can use all their cogs (the dificult & expensive part) ending up with a compact, massively overrated close ratio sequential dog box. Add some sides so you can run in oil... use sealed bearings to keep the oil in. I had a look at the electric TT possibilities with my brother a couple of years ago & this was the proposed drivetrain, BLDC motor through a normal small motorbike gearbox. No clutch, just crash the box (bike boxes love it...). ICE engine gearboxes are always hugely too strong to take the impact of a bump start so a really small one should be fine (say off a 125)....

 

[Harold in CR]

I took photos. Thanks to Miles for the heads up on posting photos. I thought it was strange because of the lost photo problem.
One photo shows the shaft sets.
Second shows the split gears where I cut them apart.
Third shows how I took off the dogs
Fourth shows the finished gear.

I have a 13:35 tooth and a 16:36 tooth gear set. If I combine that to a 16" Motorcycle wheel, at 23" outside dia of the tire, and calculate the HP of the motor I will use. Then, I can do the external gearbox gearing from the motor to the driven shaft. I still need to grind off the teeth of the dog gear to reduce weight. Then, cut off and grind down the ends of both shafts, then, have a machine shop true up and fit bearings.

I plan to use Aluminum Plate for the sides, and, some sort of thin sheet to wrap around, so I can put a little synthetic oil in the box for splash lubing the entire insides. I will install deflector washers, so the oil doesn't get direct contact with the bearing seals.

I plan to use the shifting fork to slide the dog into one side of one gear, then, into the other side of the other gear. I can't use the Moto shifting fork like Thud does, in an arc, so, I will just use a sideways push-pull action and bar the fork slides on. .

What I am trying to do, is, get a 30MPH or so, on the nearly flat areas, and, drop into a hill climb mode, that, at times, gets fairly steep.

I have never understood a % hill inclination. I figure ° of rise or fall ???

View attachment 3

View attachment 2

View attachment 1

 

[Miles]

I took photos, but, looks like I need to open a photo account ???

You can upload them to the Endless-sphere server, as an attachment to a post. Click on the Browse button to locate the image on your computer.

 

[John in CR]

I have never understood a % hill inclination. I figure ° of rise or fall ???

We typically use % instead of degrees, so it's just like a roof, ie rise/run. eg 10ft forward and 1ft higher is a 10% grade.

 

[Harold in CR]

OK. That explains how a 20% grade is figured. I was having quite a time, estimating the grade of the hills coming up from Jicarito.

Now I can relate to what y'all are saying. Thanks, John.

 

[acuteaero]

Neat project! I'll be curious to see how it comes together. I've considered a similar project and have got a few questions about your approach-

13:35 tooth and a 16:36 tooth

Did you have an option to go with a larger ratio difference? Seems like these ratios are going to be very close- maybe closer than would be most advantageous--

Are you using the dogs that the gears already have on them? Or are you going to machine all new ones in?

Seems like it'd require a fair amount of machine work to get the shafts much shorter, but it would pay off in overall size reduction very much. What do you expect the finished overall size to be?

How will you determine the shaft center-to-center distance? Is it feasible to measure it off the old gearbox case?

Again, will be looking forward to watching it come together. Looks like a very good start! I wish you luck machining those hard steel gears!

 

[Harold in CR]

Acuteaero
There will be no need to machine any gears. They cut real easy with a 4½" angle grinder. Well, not REAL easy. I just want to take the teeth off the dog gear in the middle of the bottom shaft in the photo. I want to lighten this up as much as possible. I also did not want to use chains and sprockets. We have read about what happens when a chain breaks and binds up. I'm too damn old for a face plant and broken bones. I have better things to do, than sit around, healing.

Ground off the dogs with my drill press and cross feed vise. Didn't take long, considering. I kept dabbing the parts with a wet rag, to keep the metal temps down.

I tried every possible combination of gears. Problem is, to keep the shafts in line and parallel. That doesn't leave much. As I am not looking for top end speed, I'm concentrating on hill climbing. I have some very steep, short hills, at the end of my rides.

I plan to cut the shafts with that same angle grinder and thin cutoff wheels. I also need to cut grooves in the shafts for snap rings to hold the gears in line.

I have to say, this is as much a practice in machining, as it is an experiment in getting the feel for gearing things.

I'm not a machinist or an engineer, or a Physicist. I'm just a guy with some different ideas, and, will share what I do, no matter if I get laughed at or not. It's called learning and experimenting. Just WISH I knew electronics.

 

[Thud]

Hello Harold,
I am following along with interest looking at how you are adressing the the re-application of existing parts. I have a ton of motor cycle trannys laying about, but never gave more than a passing thought to attempting what your doing. more for the reasons of the splined shfts & the space required to get everything figured out.

I do have concern with the gearing chioces as you only have a 4% step in ratio. For EV use I am finding that 80% is a good starting point for starting out & also "bailing out" to climb a steep hill. I love what you have acomplished so far & if you could figure a way to use the maybe 2nd & 5th gears from the tranny (1st gear is normaly machined directly into the mainshaft) you would be much better off.

Other than that I wish I had some better insight to help you along, I have mentioned before about the complexity of gears in machines & a lot of racing trannys are optomised for ratios on the track & use real wacked pitch #s to maintain shaft spacings.
good Luck,
T

 

[Harold in CR]

Thanks Thud
Any input from you I value highly.

The biggest problem I have, is, the 2 shafts are different diameters.

IF I had several shafts and gears lying around, this would be a piece of cake. I originally wanted to use the shaft ground gear for the low speed. Unfortunately, that is also the shaft with the larger gears I need as a match up. As you are well aware, keeping shafts parallel is the toughest part of doing what I want.

One option is, grind out the center of one of the larger gears, including filing the spaces for the splined shaft. It's not impossible, and, it costs me nothing but time, so, I may look at doing that. Only need to do 1 gear, maybe. :lol:

I used to be pretty sharp with figuring ratios and power in and out, but, I just don't function as well as I used to.

I would be much better off to use a Variator, but, I live and maintain our small tree farm on $750.00 per month. That is why all my projects are way behind schedule.

The economy of the world has put selling my portable sawmill to achieve sufficient funds, right in the toilet.

I have given serious thought into selling our 4 acre tree farm, but, then what ?? Ay 68, I'm getting too old to make yet again, another start over in life. I thought I had a good game plan when I came down here, until the economy took a HUGE dump.

 

[Harold in CR]

Have an update. Looks like I missed one combination. The absolute best ratios I can get with these gears is 13-35 drive and 21-23 driven.

I have a 16" Motorcycle front wheel for the bikes drive wheel. Outside dia of the tire is 23". I have a 400-450 Watt Kollmorgan motor, OR a 2HP, 90V Brushed motor. It's heavy and longer than I like.

I have, as the steepest hill, approx. 40% at 200 feet of run, until it start to flatten out. I do get a short run at it, so that should help some. The hills are a step stair type thing. Run down the longest and back up the other side higher than what I just left. A short over the top and down again, and back up higher than that last hilltop. Then, it's a long steady climb, maybe 25% until I swing right and get to that 40%. It could be even steeper, and, about200' total, until it flattens out. Then around a bend and up another 20%, then run down 10% and back up 30% or more, for about 300 feet or more. From there, it's a walk in the park. :lol: :lol: :lol:

I just have to use what I have. Any rough guesses as to the ratio from the motor(s) to the drive shaft on the Tranny ??

I hope to use regen, so, I might just keep the batteries from getting too low before I reach the top. Just have to play with it.

 

[Miles]

Have an update. Looks like I missed one combination. The absolute best ratios I can get with these gears is 13-35 drive and 21-23 driven.

That gives 1:2.45 ratio difference. Probably too much the other way, Harold.

I think you may have got your % gradients wrong...? [40% = 22degrees] If not, ignore my comment above..

http://www.greenbeltconsulting.com/articles/relationships.html

 

[Harold in CR]

Thanks Miles. All input is appreciated.
I think I have the gearing ratios screwed up.

Low gear is 13T-35t
Higher gear is 21t-23t

Don't forget, I'm also gearing the drive shaft seriously low.

That 40% hill angle might not be correct. All I know, is, even walking slowly, it makes the old pump really hammer and you breath like a race horse. The 1.2 Litre Diesel Pickups have to drop back to 1st gear to top out on this steepest hill. I know how to charge hills and drop gears as I get slower.

I wish John in CR would take a stab at the angles of these hills. He drove up in a minivan.

One day, soon, I will take my 4' level and my line level and string, and tape measure and a couple stakes, and do a line of sight level, and measure the steepest hill.

It's very difficult to take photos and show grades.

That's why I use the ° degrees instead of %.

 

[Harold in CR]

OK. Nother update.

The toughest part of my climb up to the house, is, 6' of rise in 46' of distance. This is right near the top, after about 8' of incline for about 250'.

This means I have to climb 6' within 46" of distance, after climbing 8' in 250' of distance. Hope this makes sense. I can't seem to explain it, any better.

Had a few tragedies to take care of, so now, I can get back to machining (Hand Grinding) some more weight off the gears. :lol:

I used to build reproduction Early Spanish Arms. These were octagonal tapered match lock "Carbine" types, circa 1557.
These were the ones with the smoking string hanging from the gun. They were very crude. They shot round balls. This was way before the Flintlock design. The original was found in a well in St. Augustine, during an Archeological processing of the Fort site. Photos at the bottom of this post.

I also have a Denso Motorcycle Alternator, I may try to get running. It would be a better size for the drive motor.

I'm thinking 36 or 48 volts to start out. I have a 36V 120A controller. Just need to get something variable for the rotor voltage adjustment.

 

[Miles]

The toughest part of my climb up to the house, is, 6' of rise in 46' of distance.

I make that 13% gradient (7.4 degrees).

 

[Harold in CR]

I just don't get it. It's VERY difficult to walk up, if you are on wet grass. On the pavement, I get about 25 steps and have to stop and rest a bit. I'm not in THAT bad of shape.

Guess I need to figure on trying the treadmill motor. It's rated at 2Hp at 90 volts, 2200 RPM's. Measures 4 1/4" X 7 3/4 ".

That should be 800watts or so, at 48V ??

 

[Miles]

How did you measure it?

13% is a steepish hill. The hill to my house is 15% and that's quite steep. The most extreme gradient seen on navigable roads is around 1 in 3 (33%).

 

[Harold in CR]

I used my 4' level as a rifle scope, picked out a spot on the roadway, at level height with my eye, then stepped it off.

As I wrote earlier, the 1.4 Litre Toyota Diesel pickups, empty, get back into 1st gear to top out on this run. That's with charging the hill.

I'm going back out to the shop, after I have my afternoon cup of coffee, and the lightning abates, and take a couple photos of my "surfacing machine", showing how I just took off some dogs off one of the gears in the Tranny build. :lol: