Re: Derbi RD-50 adventures

Brandon Weiss (Detective brandon to you) /

Hmm....there seems to be some wobble in the front variator. I don't think it's the bell, and its definitely not the crank. I'll have to verify it tonight, was too late in the shop last night to bother.

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Re: Derbi RD-50 adventures

Brandon Weiss (Detective brandon to you) /

Ok ok, we're back! Made a lot of progress, especially with the pipe. All that's left is to route the stinger/mount the baffle, and then the finishing touches like the tail light, pedals, the little things.

I'm VERY happy with the way this pipe turned out. Dimensionally, it's a perfect fit. The chamber matches the natural lines of the bike's frame, and it sits really nicely with good clearance all around (theres a good 1/4inch between the pipe and the gas tank) Given all the cutting and rotating I had to do, it turned out super well considering a lot had the potential to go wrong.

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One thing that I have to consider with the stinger is how it may affect my ability to remove the pipe from the bike. It will cross over to the left side through a part of the frame, so I may have to make the stinger 2 parts, joined by some silicone hose. My hope is that it will be cool enough at that point upstream where the silicone/rubber hose won't burn.

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Re: Derbi RD-50 adventures

Brandon Weiss (Detective brandon to you) /

Yes, I went with a left side mount for this pipe, it was easier as it fit slightly better and I could utilize the factory mount.

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My friend had a genius idea to use a shaft collar instead of welding anything to the frame. I bought some 13/16ths steel shaft collars and welded some steel flat bar to it, worked great!

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Re: Derbi RD-50 adventures

Dirty30 Dillon /

Absolutely great work

Re: Derbi RD-50 adventures

That pipe looks pretty awesome! Can’t wait to see it mounted!

Re: Derbi RD-50 adventures

Brandon Weiss (Detective brandon to you) /

Here's a better shot of the header, made with scraps of header from the pipes I've cut up over the years

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Re: Derbi RD-50 adventures

Gasoline ignites at 500 so you should be fine, but that paint on the tank might be screwed up after a while

Re: Derbi RD-50 adventures

Brandon Weiss (Detective brandon to you) /

> MPB Dylan Wrote:

> -------------------------------------------------------

> Gasoline ignites at 500 so you should be fine, but that paint on the

> tank might be screwed up after a while

Yes, the vapors are flammable (not the liquid itself), but not without oxygen, and an actual ignition source. Without physical contact, even the lip of the tank right next to the pipe will never get hot. And even if it was touching, there would never be enough heat transfer to heat the tank sufficiently to pose any danger, especially not when the tank is filled with gasoline that acts as a huge heat sink.

I'd wager a lot of black painted gas tanks out there get hotter on a hot sunny day than my tank would even if it was touching the pipe.

TLDR; I thought about it a lot before making the thing and concluded there really isn't anything to worry about

Re: Derbi RD-50 adventures

Ya that’s true and the wind on the pipe and tank will help cool everything down

Re: Derbi RD-50 adventures

Could wrap that part of the pipe or get some of that heat foil and stick it on the underside of the tank.

Re: Derbi RD-50 adventures

Brandon Weiss (Detective brandon to you) /

This exhaust baffle is huge, figuring out how to brace it might be a challenge. Dont want it snapping off! May switch to a smaller baffle at some point. I cut and pieced together a curvy bit of stinger to exit from between the shock and the fender at an angle so that the large diameter baffle would clear.

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Just need to make them meet in the middle! There has to be a split at some point too, I wouldn't be able to remove/mount the pipe if it was one long piece

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Re: Derbi RD-50 adventures

Brandon Weiss (Detective brandon to you) /

Finished up the stinger last night! Took a lot of finessing to get the slip joint to slide right in as some of the pieces inevitably moved/warped during welding, but it's on there and it comes on and off easy. I still do need to figure out a brace for the baffle, it's big and I have no doubt it will snap off eventually if I don't.

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Re: Derbi RD-50 adventures

Brandon Weiss (Detective brandon to you) /

And here's the first start, fired right up! I re-lined the starter shoes, they seem to work great. Once the bike is tuned I have a bell with a one way bearing to swap over, but for now the starter shoes make starting this tall bike easy.

I have a 95 main and a 20 idle in the vm18, seemed like a good place to start. I think I'll jump up to a 100 though and go from there.

Re: Derbi RD-50 adventures

Oh yeah , is right .

Sounds as good as it looks . ;)

Re: Derbi RD-50 adventures

Nice!! Real snappy. Slick job dude. For the baffle You could strap it with a hose clamp, weld the clamp to a bracket and attach to the frame. Don't wanna soil your thread but here's a pic of what I mean.

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Re: Derbi RD-50 adventures

Brandon Weiss (Detective brandon to you) /

> Alex hernandez Wrote:

> -------------------------------------------------------

> Nice!! Real snappy. Slick job dude. For the baffle You could strap it

> with a hose clamp, weld the clamp to a bracket and attach to the frame.

> Don't wanna soil your thread but here's a pic of what I mean.

Love your AD build!

The pipe came with a band/clamp for the baffle designed to mount onto a gpr/aprilia, but to fit this rd50 I'll need to anchor it the frame tube under the seat. I'll need to make a bracket similar to the front pipe mount with a shaft collar

Re: Derbi RD-50 adventures

Where'd you get those shaft collars? Those could come in handy for lots of things of the sort.

Re: Derbi RD-50 adventures

Brandon Weiss (Detective brandon to you) /

> Alex hernandez Wrote:

> -------------------------------------------------------

> Where'd you get those shaft collars? Those could come in handy for lots

> of things of the sort.

I just went on amazon and searched for 2 piece steel shaft collars, mine are 13/16ths, they come in all bore sizes! My friend Dibble's idea

Re: Derbi RD-50 adventures

DrGeorgeTompson (Alan) /

> Brandon Weiss (Detective brandon to you) Wrote:

> -------------------------------------------------------

> Hmm....there seems to be some wobble in the front variator. I don't

> think it's the bell, and its definitely not the crank. I'll have to

> verify it tonight, was too late in the shop last night to bother.

My flatreed had this wobble, so i swapped the crank and it still wobbles so i just dont care anymore. It's been like 1500 miles yolo

also it goes without saying that this build is fucking awesome (edited)

Re: Derbi RD-50 adventures

If I ever find myself in NYC, I wanna hang out in your garage!

Re: Derbi RD-50 adventures

Brandon Weiss (Detective brandon to you) /

> Ryan Graeme Wrote:

> -------------------------------------------------------

> If I ever find myself in NYC, I wanna hang out in your garage!

Thanks, but it's kinda cramped in there haha

Re: Derbi RD-50 adventures

Looks great dude. It’s wild how big these things are. We have one at our shop now and my DT50 is like, 85% the size.

HPI would be a nice finishing touch.

Re: Derbi RD-50 adventures

Brandon Weiss (Detective brandon to you) /

> c k Wrote:

> -------------------------------------------------------

> Looks great dude. It’s wild how big these things are. We have one at our

> shop now and my DT50 is like, 85% the size.

>

> HPI would be a nice finishing touch.

Yeah! I'm 6'2 and it's a a little awkward even for me haha.

Maybe I'm wrong, but I thought I read somewhere that super lightweight ignitions are really rough on PP/PR engines? I bough pietcard stuff for this bike to run if I needed to keep cooler than points would allow. But I do have an HPI with a weight on my maxi that maybe i would steal haha. I think I'll just run points for now though

Re: Derbi RD-50 adventures

So tall, like 125 size! We were trying to figure out the target market for these things and couldn’t come up with one. Campers maybe?

“Do you have the money for a small cc enduro but want a slow big dirt bike thing with pedals? Well, we have the bike for you!”

Re: Derbi RD-50 adventures

> Brandon Weiss (Detective brandon to you) Wrote:

> -------------------------------------------------------

> > Ryan Graeme Wrote:

>

> > -------------------------------------------------------

>

> > If I ever find myself in NYC, I wanna hang out in your garage!

>

> Thanks, but it's kinda cramped in there haha

That's it, let me down gently!

Re: Derbi RD-50 adventures

> c k Wrote:

> -------------------------------------------------------

> So tall, like 125 size! We were trying to figure out the target market

> for these things and couldn’t come up with one. Campers maybe?

>

> “Do you have the money for a small cc enduro but want a slow big dirt

> t bike thing with pedals? Well, we have the bike for you!”

50cc single track races/ enduro races. Only way to get 50cc motorpickles into the us was to install pedals is what I have heard

Re: Derbi RD-50 adventures

Brandon Weiss (Detective brandon to you) /

Little bump....tried to get this thing registered by mail at the one DMV that's open for mail-in services, and they hit me with this bullshit. Of all the mopeds I've registered, I've never been asked for or needed a "certified weight slip", and nowhere in any of the online documentation or fine print does it say anything about it, except for trailers and trucks. Where the heck am I supposed to go now to even get one? Might have to go the Vermont route if all else fails.

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Re: Derbi RD-50 adventures

Brandon Weiss (Detective brandon to you) /

The reason there hasn't been any further progress is because Its not registered. I dont dare ride more than a few blocks from my home, so I have no place to open it up.. probably the worst time to get something impounded.

Re: Derbi RD-50 adventures

DrGeorgeTompson (Alan) /

It's funny. I think it's a derbi problem and the lack of information. When I registered my ds50, the DMV guy spent like 20 minutes trying to find a weight for it on the internet. Eventually he gave up and just took my word for it.

Just a guess idk

Re: Derbi RD-50 adventures

> Brandon Weiss (Detective brandon to you) Wrote:

> -------------------------------------------------------

> Little bump....tried to get this thing registered by mail at the one DMV

> that's open for mail-in services, and they hit me with this bullshit. Of

> all the mopeds I've registered, I've never been asked for or needed a

> "certified weight slip", and nowhere in any of the online documentation

> or fine print does it say anything about it, except for trailers and

> trucks. Where the heck am I supposed to go now to even get one? Might

> have to go the Vermont route if all else fails.

> >

Mabye go to a gravel pit or something that has a scale and ha e them weigh it. I wonder if that will be good enough? Mabye take a pic of it on the scale? Most pits will give you a print out of weight. Worth a try?

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