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Yamaha YZ450F

j bjork

1 MW
Joined
Aug 31, 2018
Messages
2,025
Location
Linköping, Sweden
I had a little accident and bought this 😬:

q8Ws80T.jpg


It is a brand new bike without motor, but it is from 2019.
They took the motor for a cross cart, and it has been sitting there in their shop since then.
I thought it would be basically the same as my yz250f 2018, so I could use some of those designs and maybe share batteries.
But I realize the frame is different, so my side covers wont fit. Probably not the batteries either 🙁
 
Well that's a really nice accident.
 
Bad choice of words, it's hard to be a little funny in a second language ;)
I saw an ad for this, and happened to buy it..
Those things are rare, so I felt I better take the chance when it appears.
I think it feels wrong to buy a nice bike in working order and slaughter for a build..

I am not sure I am really ready for a new build, I am rather happy with the one I have.
But at the same time I am curious how a lighter bike would feel.
Maybe get the weight lower in the chassis as well.

I have a lot more power than I can use, so I can definitely go for a smaller motor.
My first thoughts go to qs 138 v3.
And there are 3 of them, all interesting I think.

There is the 70h, the 90h and the watercooled 90h.

I suppose watercooling will add some weight, but could be nice if it turns out the motor would run hot.
It should be possible to start with just filling up the motor and have a small canister to take care of the waters expansion when it gets warm. If it turns out to run hot add radiator and waterpump.

A problem with them seems to be cracked housings over the reduction, seems to happen on both 70h and 90h.
Not sure if it is a problem in enduro, or only in big mx jumps.

Then there is the qs 160, that still is only cnc milled as far as I know.

And maybe those shinwin or sotion motors is something to consider?
Also known as ting tong I think
 
Bad choice of words, it's hard to be a little funny in a second language ;)

OK gotcha 👍
I was thinking something bad happened to your other bike so glad that’s not the case.

Yeah, I hear you on the lighter weight. I really wanted that QS180 as well but as you know it’s super heavy. I’m really happy I went with the QS138v3 70h. Keeps the weight down plus it’s more than enough for trail riding. In your case, I can certainly see where the QS180 would be more desired on a motocross track to keep up with the 450cc’s. So maybe the QS138 90h would be a good happy medium for you.
 
slightly above th QS138 seem to be the SIA155-48 Hairpin motor 5/18kW and 10,5kg weight , they also announced a version with a longer rotor.
 
I have been looking more at the shinwin FW07, it sure looks interesting ;)
As usual the specs is a bit unclear, "rated voltage 72v" "rated speed 6900rpm"
Does that mean 6900rpm @72v? In that case 96kv. Might be possible, they have a map with good efficiency to 10000rpm
I have been 3d printing quite literally the whole week:
s2T84CV.jpg

IjBWaOi.jpg
 

Attachments

  • FW07-72V-15KW.pdf
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That does look interesting, is that for your new bike? I'm planning on building in the next year if I can, had nearly settled on qs138 90h with the reduction, that motor looks to have more potential though?
How does it compare price wise? With a 30s cl1000 should be a good match?
 
With both qs and this there are a lot of maybe and probably.. I think this has more potential, but I cant say I am sure.

Both are 138, but that is diameter of the stator, so it dosent say that much. But it probably means about the same rotor dia too.
I heard something about 100h for this one, in that case it should maybe be able to give a little more torque than the qs.

It seems to have higher kv (rpm per volt), in that case it can hold a higher torque up to a higher rpm=more power.
It also means less torque per amp, so to get the same torque it will take more phase amps=more expensive controller.

According to the specs it should be about 2kg lighter than the qs 138 90h, that could mean less copper..
But from what I can see in the cadfile they seem to have put quite a lot of work in to lighten it, so maybe not.
It also looks better sealed I think, with those proper seals around the wires.

It will be more expensive than the qs, but I am not sure yet how much. Probably about 30%
 
When I started with this I went looking for the engine from the 250. I know I sold the good parts, but I was pretty sure I kept the mid parts and output shaft. I couldent find it though, so I started to fear I had thrown it away.
Then I took a wood box to put the bike on, but it felt a little heavy..
Took a look inside and there it was:

5Z31pLC.jpg


Perfect, then I could take some measurements:

slfw66Q.jpg


I cant get that close to the swing, I think I ended up about 10mm more forward.

ZHJehe8.jpg


Was able to get it in a good position after moving the front housing on the motor 90 degrees. I hope that wont be too hard in reality..
Since then I have struggled with the damn 3d cad to make a test version of the motor mounts :rolleyes:
 
I have managed to make some cad drawings and some prints ;)

TxacCCp.jpg


A few of those..

IGzvuFx.jpg


Got the motor in place

6J2UUXY.jpg


I tried to get it tight, I got it maybe too tight.
It fits nice there, but the sprocket is a little high.
I cant help that it ends up a little far from the pivot. The center of the shaft is about 60mm in front of the swing arm, vs about 45mm with the original engine.
I think I will be better off with the shaft a little lower than original , to save the underside of the swing at the pivot from chainrub.
I dont know how much, but maybe about 5mm I would guess.
 
Is there any size/configuration calibrators for battery building? Like what can you fit in that shape, what would be a decent layout of the paralell/series connections etc. I kind of thought I have seen something like that, but I cant seem to find it now.
Are you gonna use the same cells as in the other builds?
 
Unfortunately yes it does seem that way. I know I saw a battery design app . this isn't it but you can design by shape it is a web based tool.
later floyd
 
Is there any size/configuration calibrators for battery building? Like what can you fit in that shape, what would be a decent layout of the paralell/series connections etc. I kind of thought I have seen something like that, but I cant seem to find it now.
I've been trying to build something in Fusion360 that would fill any shape with cells, that'll be finished in about 10 years from now ;)

There is this one (kindly shared on the Electric Dirt Bike Open Source Design Discord)
Lithium Battery Pack Designer - Cell Saviors

there's also this pack generator script from esk8 Forum that can be used with Fusion360

And if anyone is good at Fusion360 then these steps should work to fill an irregular shaped area with cells
I tried to follow it but couldn't get it to fill the space, much learning to do!
 
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Thanks, that cell saviors site hanged every time I tried to change cell size.
I went back to the old fashioned cardboard models with some 3d printed cell holders to find the shape ;)

You could always buy a few 21700 cells to start with and build the shape of your battery with the cell spacers. That’s what I did, built many different configurations before I settled for the final version. think I bought around 10 Molicel cells and was able to build and figure out what shape worked best.

Edit: i’m curious to see how the performance turns out with your motor. I can’t believe you left QS 🥲😂
 
This is how it looks at the moment:

uxpP7Zg.jpg


I have some 3d printed cells and cell holders to play with.
I need to figure out a height and how much cells I can and want to fit.
I think as a "base number" 30s10p. With molicell p45b that would mean 4.86kwh and a decent current handling.

Each extra p group means 486wh and 2.1kg more in cells, I wonder if a total of 2.5kg with connections etc. is enough?
I suppose the more cells I fit, the higher in the chassis they will end up
With 13p I get about the same capacity as the varg, with 6.3kwh, which could be a good thing when (if) competing in future electric classes that might be customized to that runtime.

I plan to build 2 batteries and hopefully be able to develop the system from the other bike to faster changes, therefore Im leaning more towards smaller batteries (10p)
But then there is the question of weight distribution, should I mount some cells further back? Like over or behind the rear shock.
Hard to know before the stuff are in place..
 
This is how it looks at the moment:
I have some 3d printed cells and cell holders to play with.
Oh nice! I didn’t realize you printed the cells as well 👍
But then there is the question of weight distribution, should I mount some cells further back? Like over or behind the rear shock.
Keeping the majority of the weight of the battery where the combustion engine used to be, it’s going to give you the best handling. The engineers designed these frame around the weight of that motor to be positioned exactly where it’s at for best handling, jumping, etc., so if we can mimic the weight of our battery to be in a similar position the motor was this should give us the best handling.
 
Ok, I made a decision to go with 30s10p..and ordered the cells:oop:
I am a little worried now, 600 cells from china.. I can only hope they turn up in good shape and genuine😰
That should mean pretty small and light batteries, and I have a first layout:

uDuzRcq.jpg


It might still change, but it is somewhere to start.

I found this picture of an interesting build:

1vCmCp1.jpg


It is a kit from electro and co I think?
I planned something like that to hold the battery too, hopefully be able to change battery without tools.
They managed to fit the battery without a bend in the middle, but it sits higher than mine.
And it looks like it expands through the original fuel tank.

I wonder if they made it to be quick to change batteries, or if things is just mounted on top of it so you have to take it off part by part?
 
It looks like this in the bike:

8PJL8PH.jpg


The problem is to the front:

51pCMtM.jpg


To be able to have a strait "box" battery I have to either angle it forward, and then it has to sit higher. Or make it narrower, I made it 16cm wide. I think that will be needed. 14cm for just the cells. Then there are the connections, box itself etc.
 
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