Yamaha YZ250F

Hi

Just found this forum and this thread. This build looks awesome!

I'm in the fantasy/planning stage of a (prototype) build of my own so just trying to learn stuff and see what engines/batterys/controllers you guys are using.
I'm located some 120km northwest of you so if possible I would really appreciate a field trip to see your bikes and pick your brain a bit

//Jocke

Jocke_D said:

Hi

Just found this forum and this thread. This build looks awesome!

I'm in the fantasy/planning stage of a (prototype) build of my own so just trying to learn stuff and see what engines/batterys/controllers you guys are using.
I'm located some 120km northwest of you so if possible I would really appreciate a field trip to see your bikes and pick your brain a bit

//Jocke

Click to expand...

Sure, I saw in in the ktm thread that you are an experienced rider. So I guess you have all the gear? Bring it, and we can take the ktm out for a test ride.
Either just here in the woods, not very challenging but you get a feel for how it is at least.
Or when when it is open at prästtomta, that track is very good for testing.

I have started with some kind of side covers:



Something like that I think, hard to get the right shape and "flow" in the lines.



This is where I am now. It is hard to see in the pictures, but there is already a lot of filler and more to come
Some parts will be pretty thick. It doesn't really matter for the result, but it would have been a good idea to have glued on peaces of wood or something to save filler..
I have already cut it up and changed some angles and shapes, it will probably be more.

Love your part-making skills using anything that is nearby to help get fairings built!

Any reason why not some type of foam? or is it the obvious that it is quicker using materials nearby? (or maybe a kink for hot glue) :lol:

I'm just about to start working on some fender repair and making some new body panels so your posts have been a great resource of knowledge on processes!

i can't help but looking at those wires coming out of the motor.
if they won't have some sort of a strong cover, they will be kicked off in no time when riding a track.
also have you thought about this bike will be covered in mud ,are all those components really waterproof, for a power washer?

L.E.S said:

Any reason why not some type of foam? or is it the obvious that it is quicker using materials nearby? (or maybe a kink for hot glue) :lol:

Click to expand...

Thank you, I haven't really looked in to how to use foam for something like this. And I don't hove any experience in it. I have seen it used when a guy made his own car body from scratch.
I think my way is easier for small parts like this, and when I have a few given points where it should fit. But I don't really know.
I think it will be hard to get a good surface on foam?

hannesd said:

i can't help but looking at those wires coming out of the motor.
if they won't have some sort of a strong cover, they will be kicked off in no time when riding a track.
also have you thought about this bike will be covered in mud ,are all those components really waterproof, for a power washer?

Click to expand...

There will be a cover for the wires, I just haven't got to that point yet.

Yes, I am expecting it to be covered in mud and power washed regularly.
Thats part of why I put every electric part possible in the battery box. I will probably drill small drain holes in the bottom of the battery box, so it will be possible for water to get out if I get some in there. There will be holes for a few wires, a button and some screws so I am not sure if everything will be absolutely water tight. And then there is the joint between the bottom and top to get water tight too.

I have small drain holes in both the batteries, the box with the bms and the box with the display on the ktm. And that has been covered in mud and power washed for two seasons so far. It has been more or less under water once without problems with any of that. However, I haven't opened up the batteries so I dont know how they look inside.

I have gotten water in the motor on the ktm, but I think that will be less likely on this. Here the shaft seal will be protected because I have the primary reduction in oil where the shaft ends.
With a cover over the wires to the motor they will be protected from direct hits with the power washer. The rest of the motor seems to be well sealed.
I expect the controller to be well protected, it is ip66 classed. It will also be protected with a cover over the wires, so that will help with direct hits from the power washer too.

I expect to have some problems with switches, I have that on the ktm. I havent found any good, waterproof ones.
But I haven't chosen switches for this bike yet.
Is there something in particular that you think wont take some mud and a power wash?

i personally have no experience in builing e-motorbikes but maybe you could try to find the same (kind of) switches other dirtbikes use. those are powerwash resistant too.

"Explosion proof" switches are so sealed up, they prevent a spark at the switch from igniting a flammable gas environment.

Just an option...

brilliant build!

been thinking about building a motorcross/enduro bike quite a bit.
to replace my ktm 2015 exc but. after reading this tread i am going to back that idea off

good luck with the build i am folowing!

j bjork said:

L.E.S said:

Any reason why not some type of foam? or is it the obvious that it is quicker using materials nearby? (or maybe a kink for hot glue) :lol:

Click to expand...

Thank you, I haven't really looked in to how to use foam for something like this. And I don't hove any experience in it. I have seen it used when a guy made his own car body from scratch.
I think my way is easier for small parts like this, and when I have a few given points where it should fit. But I don't really know.
I think it will be hard to get a good surface on foam?

Click to expand...

I believe clay is used to get a smooth surface, after gelcoat etc.. I don't think any wet sanding is necc. for a very smooth topcoat

Also random question but are you using jackshafts on both of your bikes?

louis raaijmakers said:

brilliant build!

after reading this tread i am going to back that idea off

Click to expand...

Thank you
But why dont you want to build a dirtbike after reading this thread?

L.E.S said:

Also random question but are you using jackshafts on both of your bikes?

Click to expand...

No, not on the ktm.

Ah ok I just wanted to make sure I wasn't crazy to trying a direct drive!

It seems almost all of the other conversion I have seen either use a jackshaft or stock transmission, so it is reassuring knowing someone has made it work especially if it is an electric dirt nut like you

Well, I wouldn't do it again now when the v3 of the qs 138 70h with built in gear reduction is available.

If I started over with this build I would probably go with that on this one too. It would save a lot of time, money and weight.
And I think hit with a big enough stick (high A and V) it would probably be capable of more power than I need.

j bjork said:

Jocke_D said:

Hi

Just found this forum and this thread. This build looks awesome!

I'm in the fantasy/planning stage of a (prototype) build of my own so just trying to learn stuff and see what engines/batterys/controllers you guys are using.
I'm located some 120km northwest of you so if possible I would really appreciate a field trip to see your bikes and pick your brain a bit

//Jocke

Click to expand...

Sure, I saw in in the ktm thread that you are an experienced rider. So I guess you have all the gear? Bring it, and we can take the ktm out for a test ride.
Either just here in the woods, not very challenging but you get a feel for how it is at least.
Or when when it is open at prästtomta, that track is very good for testing.

I have started with some kind of side covers:

Something like that I think, hard to get the right shape and "flow" in the lines.

This is where I am now. It is hard to see in the pictures, but there is already a lot of filler and more to come
Some parts will be pretty thick. It doesn't really matter for the result, but it would have been a good idea to have glued on peaces of wood or something to save filler..
I have already cut it up and changed some angles and shapes, it will probably be more.

Click to expand...

Thanks. I'll do that for sure.
I've been so close in buying both donor bikes and motors many times but I chicken out every time
Seeing not oen but two bikes in the flesh will, hopefully, push me over the edge.

I've seen both car builders ans sound builders using fleece blankets to create sort of the shapes you are looking for. Just attach the blanket looking like the fairing you want and start saturating it with epoxy. The fleece is some sort of fibre glass so it works really well together.

Step one of the models done:





Now it is time to start rounding edges..

Beautiful custom plastics work as usual out of you!
I hope I can make mine look as OE as yours!!

Thanks, I havent got much more done on the bike unfortunately.

At least I have rounded the edges, starting with an angle:





The plan was to get it painted last weekend, I was just going to make a cover for the controller first.
I started with it, it should be rather easy to make:



But then something got in the way, this:



Now I'm thinking that I might as well 3D print the controller cover. It is not very critical when it comes to strength, and shouldn't be too difficult to draw I think. So it would be a good start.
I just have to learn to set up the printer properly, and draw 3D cad first

Not much progress, but at least I have painted the models for side covers and in front of the seat.
I am trying to decide the color, so the white I used was interesting to see:



It dosent look bad. I'm not sure how black would work, but I kind of think the white would probably be better.
I have a blue gelcoat too, but I dont know how it matches the other blue.

Making molds:



It will be interesting to see how they turn out, I didnt notice any serious problem.
Except that the first layer of gelcoat started gelling before I was finished, but I dont think it led to any defects on the surface.

This model proved hard to get out:



I made a mistake with the extra edges I made, so I got a "bump" in a bad position.
That model dosent look the same anymore



Some adjustments and ready to start waxing.
I bought a blue gelcoat to see how it would look, but it was a bad match to the more purple blue on the bike.
It works very well for molds though :wink:

Side covers fresh out of the molds:



I bought the brightest white gelcoat I found, and it turned out pretty good I think.



Basically in place on the bike, some small fitting here and there left.

I went with black top cover in front of the seat, I will see how I like that.
I am considering a 3d printed version with a built in display, but I need to learn a lot of cad before that could be a possibility..
There is not a strait line anywhere, well actually in the front there is a little strait. But I would probably change most of that.

I wish i had your molding skills! Great work.

Thank you, I just took this top part for battery 2 out of my not so good mold:



There is a lot of sanding and polishing to get good surface on that, and after a few rides it wont even matter..

Finally an important piece of the puzzle have arrived:



Well, it actually arrived last week and is mounted but anyway :wink:

j bjork said:

Finally an important piece of the puzzle have arrived:

Well, it actually arrived last week and is mounted but anyway :wink:

Click to expand...

And you don't show us?! [emoji30]

cheers
Tyler

Sorry, I haven't really gone in to detail lately. The interest seemed pretty low, so I haven't bothered.





Made some sleeves and mounted the sprockets.
I also finished one of the watercut front sprockets, I wonder how it will last though.
I asked for hard materials but got normal steel.



Working on the wiring, it will be something like this. Most of it will be behind the sidecover, but some will have to go under the frame rail to get past the battery. It is that or under the motor, and I choose this because I think it would be more exposed to damage and I worry about the magnetic field from the motor if I go that way.
Throttle signals for the sevcon seems very sensitive to interference.

It would look better the other way though, and I wouldn't have to worry about the wiring getting in the way when changing batteries.



I have started building the second battery, still a long way to go.
I dont have any pictures so far, and it is basically a copy of the other one.