Another "stealth bomber" build.

[Dung]

Hi j bjork

How big is your rear brake disc? I have same frame but seems like my disc touch the rear swingarm. My disc are 200 mm. And how do you protect the motor wires?

 

[j bjork]

My disc is 203mm I think. I just looked, I have a few mm between the disc and swing arm. But as you can see I have modified my swing arm, so I have a little more room on the brake side.
I dont really protect the wiring, but I have made some extra room in the swing arm. I am pretty sure I have posted pictures of it.
It is still really tight between the brake disc and wires.
And I clamp the motor axle so it dosent move at all.

 

[Dung]

I have seen you have modified your swingarm. My disc is 200 mm but looks bigger than yours. If I want to use my current disc I have to move the wheel more to the right side and the wheel will not be centered. I made a picture to illustrate how it looks like.

 

[j bjork]

I took out this bike recently for some testing.
When I was charging it I made a mistake that I think I should share so others can avoid it.

I have my battery set up as 2 10s packs, that is series connected with automatic fuses.
When I charge I turn off the fuses, and charge as 2 10s packs with an icharger 4010 duo.
I usually do this with the controller on, so it discharge the caps.
But I didnt this time..
When I connected the charger it went out, the display got dark and the input shorted.

It seems like I didnt get much pictures but I have a few that shows most of the problems.

This is how it looks.

Nuxland had a similar problem, and blew 2 diodes when it happened.
At first it seemed like it was the same problem on mine, when I measured they seemed shorted.
But when I unsoldered them it was still shorted :?

I found that I had blown all the mosfets on the positive side on one of the channels:

Here I have dismounted them.
For some reason there were 2 models:

They seem very similar to me, but I got the same models anyway.

I also blew a row of fuses.
Now it is back together again, and seem to work.
But the design sure is not fool proof. I used to think that the only thing was to not forget to turn off the fuse, but I didnt think about that charged caps is a problem too.

 

[j bjork]

I made some changes recently.
I havent really used this bike since I built the ktm.
It has only been used to test a controller a few times.

I decided to simplify the use by adding a bms:

So now it only has a 3 pole charging plug, for either charging through the controller or directly to the battery (trough the bms).

Test charged and test ridden, it is a little scary at full settings when you are not used to it.
It has a way of just gently keep lifting the front wheel in a way that feels unexpected somehow :lol:

I have ordered some psu:s so I have one to include with this bike, then I can sell it.

 

[kenbrasensei]

First I want to say Great Job. You have a lot of great shills and talents. I have an 8000w Chinese version stealth bomber like yours.
I have two questions first could you tell me where you bought that rear fender? Second would you consider selling me a completed rear fender like yours?
Also it looks like you did ok on the brakes I’m currently looking into upgrading to dirt bike brakes. But my first choice in bike brakes is the Magura MT7e there amazing. Of course if I were rich the best brakes in the world are the Trickstuff Maximum. But I’m not. Best of luck, even though with your talent and skills I don’t think you need luck, with you e-bike it will be a blast.

 

[kenbrasensei]

I have to do some work on my suspention, it is way too soft.
For the fork there was no problem to find different springs, they come in 5 options.
From extra soft to extra firm. No info on spring rate, but the stiffest is recomended for riders 90+kg, no mention of bike weight.
But I am almost 90kg, and my bike is about 60kg.. So I think the stiffest is what I want

I didn´t think finding a stiffer rear spring would be a problem, but it seems it is not so obvious as I thought.
I have a dnm burner rcp-2s, 200mm with 550lbs spring. I think I have seen those with 750lbs spring, but I have´nt found that now.
I looked at some other springs, but the stiffest was about 600lbs.
Does anyone here know of a suitable spring?

There is a dmn shock just like yours in AliExpress that has a 750lb spring, the shortest it comes is 220mm.
I’m new to this forum I posted a previous post asking you a couple questions, I might not have put it in the right place. Again good luck Ken

 

[kenbrasensei]

This is what I meant with that I had to offset the clamping bolts on the sprocket side:

And how it looks on the other side:

It looks a lot better after a little finishing work, a little sand blasting and some paint:

Great work

 

[kenbrasensei]

Man, you guys are making my buyers remorse even worse! lol I mean, I don't have the means to make an entire new swingarm...how much do you think a fabricator would charge me for something like that?

18" Tire isn't an option with them apparently. I tried asking the company to put a 21" on the front and a 19" on the back, and they're telling me no, the bike will not function, and I'm like say what? I don't see any hub rims that are cross laced in an 18" either. Should I go with both 19" and worry about getting a 21" later down the road? Maybe put a shinko 241 3.5x19 on the back? I guess I could ask them to ship an extra 21" wheel if they refuse to put it on themselves. I just don't get why they're saying no to that.

Also, do you know what the crank bracket size on these frames are? The crank they're putting is total garbage with a shimano touring tensioner. I was gonna take all that out and make it fixed with a 32T front sprocket. Does it need a chain tensioner?

My stealth bomber Chinese model 8000w has 21” motorcycle time front and rear. So it does work, at least on mine it does.

 

[j bjork]

First I want to say Great Job. You have a lot of great shills and talents. I have an 8000w Chinese version stealth bomber like yours.
I have two questions first could you tell me where you bought that rear fender? Second would you consider selling me a completed rear fender like yours?
Also it looks like you did ok on the brakes I’m currently looking into upgrading to dirt bike brakes. But my first choice in bike brakes is the Magura MT7e there amazing. Of course if I were rich the best brakes in the world are the Trickstuff Maximum. But I’m not. Best of luck, even though with your talent and skills I don’t think you need luck, with you e-bike it will be a blast.

Thanks, I bought the rear fender at some shop for vintage moped parts. I dont remember what it was for, maybe I have posted something about it in the thread?
I wont build another one, I think it would be better for you to find a solution locally
I sold the bike 2-3 years ago, so I dont have anything to test it on anyway.

The brakes were not great from what I remember, I think they lost a lot of stopping power after a few brakes from high speed. Maybe new, different pads would have helped, but I think a better solution would have been beefier front brakes.
The regen was all that was needed in the rear, the mechanic brake was just for emergency.

 

[Esar42]

I have to do some work on my suspention, it is way too soft.
For the fork there was no problem to find different springs, they come in 5 options.
From extra soft to extra firm. No info on spring rate, but the stiffest is recomended for riders 90+kg, no mention of bike weight.
But I am almost 90kg, and my bike is about 60kg.. So I think the stiffest is what I want

I didn´t think finding a stiffer rear spring would be a problem, but it seems it is not so obvious as I thought.
I have a dnm burner rcp-2s, 200mm with 550lbs spring. I think I have seen those with 750lbs spring, but I have´nt found that now.
I looked at some other springs, but the stiffest was about 600lbs.
Does anyone here know of a suitable spring?

A lot of people are missing the most important thing regarding these stealth bomer clone frames concerning the rear suspension and achieving a decent level of off road handling anyway
I have the same frame swingarm. I use my bike for offroad only and it has to be able to go anywhere my KX125 can go . Even though its not possible to emulate the handling off the 125 although it possible to vastly improve on the next to useless rear shock/swingarm rear suspension setup it comes with (totally fine for road and light fire trail use) but if you want to ride hard offroad then you need to modify swingarm suspension mounts relocate the mounts to slacken the head angle a couple of degrees and change the leverage ratio to something similar to the original stealth bomber B52s rear suspension. You must modify rear of the frame/swingarm so that you can fit the largest shock absorber possible.
Im using the shock off the genuine stealth B52 but am upgrading to a KTM 85 rear shock. you want a bike that has 200-250 mm of plush rear suspension that never bottoms out even when landing from 2 metres to flat. Then you have to do these mods. Im going to be uploading photos of all the Bomer clone frame bracing/strengthing and rear suspension mods shortly