Chinese BROS 400

[Forcerouge]

Hello everyone,

Time to start a build thread!
I purchased my BROS 400 in 2012. It was a really beat up bike, the engine was not starting, the ignition wiring was completely melted, CDI burned and also the fuel pump was dead.
Put it back together, enjoyed it for a couple of weeks... then ruined the fun by destroying the oil pump while working on the water pump seals.

I opened the motor, tried to replace the cranck bearings and that's where things got really sideways: I couldn't find a crank bearing replacement.
Tried many, none fit well. Took me about 10 years but finally found a couple of original Honda bearings last month, so finally, after ten years, I was able to reassemble the engine!

Cranck bushing back in place, ready to be reassembled:
IMG_20221016_213704.jpg

The whole jigsaw puzzle just before I closed the lid (hopefully for a long time) I realized later I've been a bit too generous with the sealant...:

IMG_20221016_231435.jpg

Then it was time to make it look a bit cleaner, so first I removed the old paint with chemical paint remover and elbow grease, then spent a while masking everything:

IMG_20221026_165304.jpg

Then I gave it a fresh coat of nice 2K engine paint:

IMG_20221027_191130.jpg


Reassembled the valvetrain:
IMG_20221026_135619.jpg

[Forcerouge]

Finally got the whole engine back together:


IMG_20221027_225912.bak.jpg

Put it back on the frame (or more accurately, put the frame back onto the engine ):


Then I started working on putting back all the piping, wiring and other accessories:

IMG_20221107_234732.jpg

At this point I got the engine to start, using the 10 years old fuel that came with it... This is how the old fuel looked like, next to the fresh fuel I got a few days later. I'm still surprized it even started:

IMG_20221108_183637.jpg

It managed to start and run, but I had a dead cylinder. Took me 3 days to find out that it was just bad spark plugs (they were making decent spark out of the cylinder, but for some reason they didn't work while inside the cylinder, it was difficult to troubleshoot).

[Forcerouge]

As I've lost all the pedal/rearset system, I couldn't go out for a test ride, so I thought that I could work on a bunch of other stuff while waiting for new pedals to arrive.
So this weekend I decided to quicly restaure everything I could. It's not proper restauration, more some kind of quick and dirty job so it looks a bit cleaner.
Starting with the handlebars.

My master cylinder was badly corroded, so I replaced it with another one I had collecting dust in a drawer.
Then I ordered what was supposed to be direct replacement lhandlebars switches. As usual with chinese stuff it did not fit at all, the wires were 40 cm too short and the plug wasn't even the same one.
So I spent 2 hours removing the wiring harness from the new switch housings, and then soldering the old harness to the new switches. Kind of a Frankenstein switch with both old and new stuff together.

IMG_20221111_203244.jpg

That was a lot of work, but it turned out well so no biggie.
Reassembled the handlebars, gages and levers.
Too bad my speedo looks like crap now, I did fully restaure it years ago and it looked better than new, but it didn't really like spending the last 5 years outside...anyway, at least it looks cleaner now:

IMG_20221112_234701.jpg

Dropped a new chain, and then quickly realized I am missing the bottom chain slider. I will have to find a solution for that soon because it rubs on the frame. I'll probably start with something 3D printed, I'm not a big fan of the giant rollers with skateboard wheels so I'll keep that as a last resort option in case the 3D printed one doesn't work.
IMG_20221112_193144.jpg

I also sanded and repainted all the rusty screws and changed the old hardware wherever I could. Hopefully it'll stay nice for a while.
Next I removed the subframe, wire brushed it and painted it with mate black:
IMG_20221112_225016.jpg


Then worked on the front: I rebuilt the caliper but one of the piston is leaking, I probably messed up a seal while reinstalling so I'll have to take another look at it.
Also painted the front fender quickly, I'll do a cleaner job later. Painted the screws also because they were very rusted. I still have to rebuild the forks because the seals didn't really like the outside storage. Will do that last, once I'll be sure the bike runs decently, cuz it's a bit of a pain to do:
IMG_20221112_234750.jpg

[Forcerouge]

Did also a whole bunch of other stuff this weekend, like wiring harness cleaning, testing the temperature sensors, basic setup of the carburetors, rebuilding the fuel lines, installing a new headlight, cleaning the tires with acetone, installing a new ignition key switch, repainting the stands, etc. It was a busy weekend
So far it is almost ready, I'm just missing the rearsets before I can ride it:
IMG_20221113_121809.jpg

I'm very happy so far, it looks a lot better than it did last month....

Now i'm waiting for the rearsets to arrive in the mail and hopefully I should be able to make the first ride this week. Let's just hope it won't blow up...
Also the radiator leaks quite a lot, I'm trying to temporarily seal it with silicon, but I don't expect it to hold for long. I'll get a replacement soon if the bike works well.


Cheers!
(edit: it's only after spending an hour writing this post that I had the dipleasure to realise that only 5 attachments are allowed by post....Don't know why this rule exists, people love pictures!
Anyway, I had to cut the story in several posts, sorry.)

[squirrelman]

acetone on tyres is a really, really bad idea

it's obvious that you're not native chinese, so what's your real story ?

[Forcerouge]

acetone on tyres is a really, really bad idea

You are correct, but tbh I've been doing that for years on all my bikes and never seen any issue with it.
It works great to remove the grease and bad gunk that accumulated, usually after that the tires grip a whole lot better.
It's been said that it isn't great for tires, which I believe is probably true, but so far I honestly never seen any disadvantage of doing it. I don't soak it in acetone, I just pour a bit on a paper towel and wipe the tire to remove all the crap. Also I do that very rarely, only when the tire is covered of oils or like in this case, when it sat for a very long time outside.

In this specific case, it is to be noted that the tire isn't rubber but it is nylon, which is not sensitive to acetone.
The tires will be changed anyway, they've been sitting there for ten years plus I don't know how many years before I bought the bike, they are toast. But I need to make sure the bike runs decently before I invest in expensive new tires...

it's obvious that you're not native chinese, so what's your real story ?

I'm a French dude living in China, been here for 15 years now

[Forcerouge]

I received my footpegs yesterday, yay!

They were completely trashed...
IMG_20221114_183218.jpg

They were all buried inside a thick layer of rust and gunk. Also, the pedals were badly bent. I was expecting them to come in a slightly better condition, they looked like absolute garbage.

But with a bit of elbow grease magic:

IMG_20221114_234840.jpg

IMG_20221114_233517.jpg
IMG_20221114_235635.jpg

With the final piece of the puzzle in place, it was finally time to try the bike, I just couldn't wait for one second.

So I jumped on the bike, put it in gear and went for a little tour of the block!

The bike works well but the transmission is rough, I think I might be missing the dampers in the rear sprocket because there is a huge transmission lag when changing from deceleration to acceleration and vice versa. Quite uncomfortable.
Anyone knows if these dampers are compatible with other bikes? Or even if these can be DIYed (I suppose I could make a mold and cast them out of some material)? I'm pretty sure it will be very hard to find the original part from Honda here and I don't think the scrapyard bikes will have dampers in good condition...

I'm sure the gurus here have a great suggestion for that

Anyway, for now the bike is semi finished. I will ride it for a while, make sure everything is fine, and maybe later give it a proper restauration, especially redoing the rear because it looks sad with this garbage saddle and naked subframe.
Also I bought an other tank because mine is in really poor condition... it seems like the bike fell at some point, denting the tank quite deeply. Instead of repairing it properly they filled the dent with a 3cm thick coat of bondo. Great job. Plus the insides are entirely rusted. Hopefully he other tank might be a bit better.

I've temporaryly fixed the (many) leaks in the radiator using silicone sealant. Not a proper repair, obviously, but it seems to hold so far, so at least I should be able to make a few dozen km to test the engine before replacing it. Right now the only supplier I found in China for a new radiator is in lockdown so he cannot send anything...

Anyway, here is how the bike looks like now. I'm so happy to see it look like that, it was a pile of rusty garbage just three weeks ago and now it looks almost clean!
IMG_20221115_001954.jpg

I'm eager to see which is faster, the hawk or my emotorcycles/escooters? If I had to guess I would say that the electric bikes will win, especially from 30 to 100 km/h, but I'm not sure yet, maybe the Bros will put a good fight.
One thing for sure: the Bros wins in the smell of gasoline and engine sound category!

[ParcNHawk]

https://www.hawkgtforum.com/forum/multimedia/videos/824628-hawk-gt-forum-video-library?p=828925#post828925

[ParcNHawk]

And the chain looks a bit tight. These bikes want a lot of chain slack. If everybody tells you it's about to fall off then it's probably okay.

[Forcerouge]

https://www.hawkgtforum.com/forum/mu...925#post828925

Lol this dude in the video has no problem at all compared to what I am experiencing on my bike, I can turn it almost 1/5 turn freely!
I think there is no damper at all inside mine.
Thanks for the link, is there any way to make these dampers or to buy ones from another bike that you are aware of?

[Forcerouge]

And the chain looks a bit tight. These bikes want a lot of chain slack. If everybody tells you it's about to fall off then it's probably okay.

I set it up according to the method described in the video just above the one you posted, but yeah I agree it looks a lot tighter than his bike for some reason. I'll make a slider first and then readjust the chain, thanks

[ParcNHawk]

Lol this dude in the video has no problem at all compared to what I am experiencing on my bike, I can turn it almost 1/5 turn freely!
I think there is no damper at all inside mine.
Thanks for the link, is there any way to make these dampers or to buy ones from another bike that you are aware of?

Any play is too much. If you can rotate it 1/5 then your rubbers are gone.

Continuing to ride it will crack the castings and you'll be in serious trouble.

As far as I know, the rubbers are still available from Honda.

[Forcerouge]

As far as I know, the rubbers are still available from Honda.

In the US maybe, in China nothing is ever available haha
That's why I always have to find workarounds, everything that isn't made here is hard to come by.

[ParcNHawk]

That's ironic because the attitude out here is that everything is made in China.

[Forcerouge]

That's ironic because the attitude out here is that everything is made in China.

Haha yeah, it is easy for stuff to get out of China but not so easy to get in, the customs are very tight.
I'll have to find an alternative solution and get creative.