Posts Tagged 'AMS'

Little A3 Ripper Tomos

My buddy Luke dropped his A3 Tomos by the other day for me to have a look at. The symptoms he was describing sounded like a bad condenser, though it was obvious that he had wired in an external one.
Today I threw it up on my lift and had a look-see.

A3 Tomoses are my favorite. The engine covers and overall styling is so classic.



It turned out that none of the wiring on the bike was very well connected, and the old condenser was still on the stator wired in. I pulled the flywheel and took out the old condenser, replaced a couple twisted together jumper wires with new, proper length wire and soldered it all up.

I took the bike for a good 20min ride and it rips! The Airsal / Proma Circuit combo with the two speed makes for a zippy little guy, and it should be fairly reliable! For a moped anyway.
While out on my ride I ran into a friend of mine that I haven’t seen in ages. He’s got a couple Maxis rotting away somewhere and might be down to unload one on me. I would love to get my hands on a complete bike to build my Tomahawk Cup bike from, so hopefully that works out!

I also played with some Sachs stuff a little bit. I’m excited to finally have some time to get rolling with Austin’s AMS.

I’m converting his 2 speed manual to a 1 speed manual, doing some fun clutch stuff and putting a big boy kit on it. It should be a fun bike, if I ever get it finished.

More later!

General tank vs knockoff General tank

Some time ago a customer had one of those super expensive General knockoff tanks shipped to the shop for a project I was going to build for him. The project fell through and I ended up with the tank at a steeply discounted rate.
Since I have a bunch of legit General tanks kicking around at the moment, I figured I would do a side-by-side comparison of the two, as well as some detail pictures of the knockoff tank.

The OG General tank is from Dirty, my 81 AMS Tahoe. Many companies rebadged General mopeds, AMS was the house brand of Moped Factory out of Reno Nevada back in the 70’s and 80’s.

I kept these pictures super big, that way you can click them and see in high detail the rough finish on the knockoff tank.

I started off by weighing them both on a shipping scale.

As you can see, the knock-off tank weighs in just under a pound and a half MORE than the OG tank. That might not seem like a lot, but when you’re holding the tanks in your hand it sure feels like a lot. Also, take into consideration that Dirty’s tank has probably a quarter pound of varnish in it currently.

The OG tank is your typical stamped sheet metal, seam welded fuel tank, whereas the knockoff tank appears to be made from many pieces of thick sheet metal, cut into shapes and welded together. The welds are then poorly “smoothed” in what seems to be a half-assed attempt at making the tank resemble the original.

Click on these pictures and zoom in on the knockoff and you’ll see little pinholes in the welds at the corners, lots of grind marks and lumpy edges.


The knockoff has balancing tubes which is rad! I think some General tanks have them too, though the three I currently have do not. Not sure I’ve ever seen one in person that does either. Hmm, maybe they don’t? I thought I read somewhere some do. Whatever.

Rather than stamping the tank locating thingies out of a single piece of sheet metal, these guys cut out two different pieces, bent one into a C shape and welded it all together.

That KINDA looks like stamped metal, but it’s actually multiple pieces of metal welded together and grinded into shape. I’ll try and show you the welds inside the tank in a bit.

Another look at one of the balancing tubes. Looks like it shouldn’t leak! I hope! Also, this tank does not use the same petcock as the OG tank, which is too bad – those are cheap.

Grind weld grind weld grind weld

It’s pretty hard to get good pictures of the inside of a gas tank, but I did my best! Here you can kinda see on of the welds that makes up the “bump” on the side of the general tank.

The welds are pretty hard to see in this picture, but they are there. Eventually I’ll get better pictures with a better flashlight.

Or hell, maybe I’ll cut this thing down the middle and get a good look at the inside. I’m planning on putting it on the SR250 and it’s going to need some modification to fit anyway, maybe I might as well.


It looks like a big lump of clay!


It’s pretty rad that someone reproduced this tank, but for $300 or whatever it costs* it’s totally not worth it in my opinion. I mean, the amount of man labor that went into each of these tanks is crazy, but I’m pretty sure the guy who built this tank got nowhere near that amount. Probably more like $30. I hope it wasn’t $3. :/

I’m glad I ended up with one, I wanted to check one out pretty bad and it’ll be awesome on the SR eventually.

*Edit – I decided to look up the price, these tanks are now half as much on ebay as they used to be!
Still, at $160 (or best offer) and another $85 for shipping, I don’t think I could ever justify picking one up unless I got them to take a lowball offer.
It’s rad they offer them in aluminum and chrome steel, but dang.. those prices. All in all, I think if I ever have a need for another General tank, I’ll just hit up MA.


Finally got everything from SF. Now to get organized and get busy!








This isn’t all of them, there’s still the Motobecane VLX, Critical Miss, HobBAD Sparkle Butt, Ciao Ciao and the other DR350. But now everything’s more or less in one place and I’ve got my tools. I’m stoked!

gettin dirty – yz80 suspension on dirty general PT4; THE CONCLUSION

last post i kinda showed you my solution to tieing the linked suspension into the general’s frame; a tubesteel loop that mounts to the outside of the swingarm as well as anchors the lower links.

once tieing the lower part of the loop (made from handlebar u-bends and a bit of tube steel i had laying about) into the flat steel swingarm mounts, i needed to figure out a way to mount the lower link to it. after digging around the shop forever i found a pair of generic vespa scooter mirror mounts that did the job well.

after cutting them up a bit they totally worked out perfect.


after welding them on, i cut some more u-bends and tied everything to the frame.

i filled in all the gaps between the handlebar u-bends and the metal plates on the lower half of the loop, and will do the top half later, because i plan to grind everything smooth and make the loop kinda blend into the swingarm mounts. those square plates will get shaped too. it’ll all be smooth and pretty when done.

so the suspension is fully mounted now! that’s exciting.

now to work on getting the engine and transmission all fitted up and worked out.

this is roughly how the hobbit final drive transmission will be mounted in the frame.

i have a brake plate that i shaved all brake related bits and nubs from, though it’s in a box somewhere. for now i’m mocking up with this other brake plate.
as you can see, i have the brake plate inside out from how it would be on a hobbit. i did this because with the brake plate bolted flush to the outside of the frame, it puts the final drive unit right where i want it. i think.


this is one of my ideas, anyway. i have another one kicking around that would put the final drive much more inboard on the frame, but i gotta mess with things some more before i know for sure.
also, i’m waiting on the sprocket adapter i made and sent up to naz in seattle to be shipped back before i can get too serious and start welding up brackets and things.

in the meantime i still need to figure out a steering stop to keep the yz80 forks from smashing the tank and a subframe to support my butt.
hopefully i’ll be able to bust that stuff out in the coming weeks and have this thing ready to roll by 2014! yeah!


gettin dirty – yz80 suspension on dirty general PT3

last post i had a little animated gif with the rear of dirty on in one frame, then chopped off in the next with the yz shock stuffed in there, like so –

since then i’ve set about to get the dumb shock mounted in there proper. i just happened to have some flat steel left over from the dirtbag virago laying around that was exactly what i needed.

i really need a drill press –

after some drilling and chopping and welding, i got the upper mount all sorted. it’s not the prettiest thing i’ve ever made, but then again this bike isn’t really meant to be pretty.

the shock is offset on the swingarm by about 1cm to make room for the drive chain, which put the upper mount flush on one side of the frame.

next, and what i’m still working on, is fabbing up a mounting point for the lower link. you can see it just hanging out here –

i explored many different options of doing this, but what i decided on was to build a loop that supports the outside of the swing arm, simular to the way the yz frame would have, and also ties in the lower link.

i chopped up some bars and some random tubing to make the lower loop. yeah, it’s ugly, but that’s alright.

i cut a couple chunks off my flat stock and drilled the centers for the swingarm pivot bolt. i had measured the width of the swingarm before building the loop, so i knew how wide to make it. i’ll notch the loop so that the flat stock rectangles will slide into them, and then weld the three pieces together. it’ll sit like so –

then i’ll use more handlebar u-bends to tie the tops of those rectangle plates into the frame, and more flat stock to tie the lower link into the lower part of the loop.

later on, when i’m mounting my pedal shaft, i’ll probably tie the lower part of the loop into the engine mounts i’ve yet to fabricate. we’ll see how all that goes when i get there.

so here’s dirty sitting pretty much where it’ll be sitting stance wise –


i haven’t had more than maybe two hours a week to work on it lately, so it’s been kinda slow going. i hope to get the swingarm loop done next week, as well as gussetting the frame up near the head tube and fabbing up some kind of steering stop so that the tank doesn’t get beat to death by the fork.

oh yeah! speaking of the tank, i’ve been kinda thinking about what i’m going to do about the gas cap. the stock one is there, but the lock/latch is missing. it’s totally not that important during this part of the build, but it’s something that will need addressing eventually.
last week i bought a box of sachs parts from swoops will d, and he loaded it up with all kinds of random awesomeness, including this! –
the latch/lock for a general gas tank! best part is that it uses the same key as my other general tank. one key for both bikes! that’s awesome.

and that’s it for now. this thing’s a ton of fun to work on, even without access to tools and machines that would make life so much easier. it’s showing me that all i REALLY need to build fun stuff is a welder, a cut off wheel, drill and some c-clamps.

gettin dirty – yz80 suspension on dirty general PT2

my headset reamer/facer showed up and i was finally able to get busy getting my fork on.

i can totally see why bike shops charge so much to do this, IT SUCKS. then again, it’s probably not very often bike shops are cutting the cup seats into fresh tubing, they are more typically just cleaning everything up on an existing cup seat. anyway, yeah. even with a generous amount of tap oil, this probably took me a good 45min to do.

the finished product looks a little rough, but it’s actually quite smooth and the cup presses in nicely.


i then attempted to assemble the fork and realized i didn’t cut the head tube short enough still and had to take another centimeter or so off, then re-ream/face the dumb thing. GAH.

i also discovered the steering stem where the bottom race presses on on the yz80 tripple tree is of a much smaller diameter than any moped fork. it’s the same size/thread at the top for the threaded race/nut, but the bottom race is too small. such a stupid oversight.

so i was left doing a lot of measuring with calipers on 100 different fork, texting back and forth with david at treats about different races they had in stock and getting distracted on the internet when i was trying to research different size bearing races, i decided i was being stupid and ordered a shim bearing from
i found one that once pressed on would allow a race that treats had in stock to press on over it. the whole process took me wailing on my park race installation tool with a 16oz hammer, a copious amount of fire and wanging my left hand with that hammer i mentioned just a second ago before everything was seated nice and tight on the fork. then i had to trim off the excess shim so that it wouldn’t hang on the lower cup and it all went together awesomely. almost.

a little bit ago i said i didn’t trim enough off the head tube on the frame and so i had to cut more off, well as it turns out i cut off about 1mm too much. all of the threaded upper bearing races i had would bottom out on the threaded part of the steering stem before getting tight on the bearing. in the end i used another lower race that fit tightly over the steering stem, locked down with a lock nut. it’s the same way the stock yz80 headset works, and once the upper triple was on with the head tube bolt installed and tightened, the thing was together nice and tight and smooth as butter. smooth butter.


here’s most of the bike roughly laid out where everything will go when it’s together.

erm. something like that. and here it is again, but up on two wheels.

next up, that pesky rear suspension. this is gunna be gooooood.


gettin dirty – yz80 suspension on dirty general

i’ve been putting off posting about this until i got further along, but it’s taking longer than i thought it would due to me having to buy a couple tools to get the job done, so whatever.

firstly, to mount the swingarm to the frame, i needed to ream out the 10mm tube steel to 12mm for the swing arm bolt. the tube steel was thick enough that i would still have plenty of meat, so i wasn’t too worried about it.
i bought a 12mm ream, but there was no way i was going to be able to ream the thing with a hand drill, so i went down to my buddies machine shop to see if i could get him to work it out for me. i left him the frame and the reamer and later that day he called me to tell me he totally goofed and thought i wanted it at 13mm, so he made me a whole new sleeve and tig welded it in for me.
after sanding the weld down on both sides, the swingarm went right on. the suspension link ran into the frame where the kickstand mounts were, as i knew it would, but that’s gunna go anyway.

so i sliced the bottom of the frame off under the swing arm. i will be welding in a mount for the lower link, but before i do that i have to figure where the front will sit, as the lower link mount will dictate the height of the rear of the bike.


i mean, this might look like a mess
but i’ve done more with less in the past.

as you can see, the rear shock is going to want to go right through the rear of the frame there. the plan at the moment is to chop that curved square steel out of the altogether and replace it with two tube steel pieces on either side of the shock, like your typical motorcycle subframe.
that will come later. first i gotta get the fork on this thing.

the problem with the yz80 fork is that the steer tube is too short for the general frame. originally i was planning on pressing the steer tube out of the lower fork triple and press in a longer bicycle steer tube, both the yz80 and the general frame use a steer tube the same diameter as your typical 1″ bicycle headset.
i decided this was more work than it was worth.
the head tube on the general frame is super long, however there is a large gusset supporting most of it. i figured i could cut the gusset off, shorten the head tube and modify the gusset and weld it back in. it should look pretty stock except, perhaps, with nicer welds than the boogery stock welds. hopefully. that’s on me, though.
so yeah, off with that gusset!


then i put the fork triple trees together with the general’s headset cups on the steer tube, measured about how long the head tube needed to be, scored an even line around the bottom of the head tube and then chopped that sucker off.

the only issue with this is that the inside of both ends of the head tube are machined for the bearing cups. except it’s not on the bottom, not any more.
this is the part that makes or breaks this whole project. not only is it super tricky (nearly impossible) to cut a steer tube perfectly parallel with the fancy machines currently at my disposal (pipe cutter, hacksaw and a cut off disk on an air drill), but i have nothing to machine the inside of the tube for the bearing cup.

knowing some bicycle shops have head tube facing/reaming tools that will make sure the head tube is flat on both sides and reams a nice little machined surface inside for your bearing cup, i called around to a half dozen shops here in the city to get some quotes. of the seven shops i called, only four had the tool, and only one of the four had the bits to do 1″ head tubes as 1 1/8″ is the “standard” for most bikes these days.
the one shop that had the tool quoted me $75.
that might be fair but the tool can be had for around $300, and i have at least two other general frames that will be getting this same front end once i’ve worked out the kinks, so i decided it would be worthwhile to just buy the dumb thing.

so that’s where i’m at. once the tool shows up, i’ll ream/face the head tube, trim up the gusset and weld it back on, install the fork with the general’s stock headset, figure out where the swing arm’s lower link is going to go and build a bracket for it. then i get to build a subframe for the thing! yay!
and once all THAT is done, it’s finally time to start figuring out how i’m going to put my engine on this dumb thing.

you guys, this is going to be awesome.

swing arm showed up, shock should be here any day.
IMG_20130214_175526seriously. i’ve never been this excited about a moped build.

new front for dirty

man, ebay is so rad. click for big!
dirty fork

if you used to visit the destroymopeds blog, you probably remember dirty, the 2-speed sachs powered AMS moped i picked up for $30 from a hillbilly at a small engine shop a couple years ago.

this bike is getting my vx4 engine, hooked to a hobbit final drive mounted mid-frame with a chain and sprocket final-final drive to the rear wheel, kinda like a derbi moped, but way better.

the intention all along was to make dirty a kind of dirt-ped, one that could run laps around pretty much any other moped out there (on or off road — lookin at you, dan k., with you’re pretty little diablo), and if i can get it done in time i might just have the chance at 77’s 2013 dirtped challenge! some off road race thing dan is dreaming up.

the hydraulic ebr moped forks are great for road going bikes, but i need something taller with more travel for what i want to do with this bike, so i figure i should try out some small displacement dirtbike forks and see how i like them, and for less than $50 shipped i won’t be too bummed if these 86 yz80 forks end up not working out.

the shop is supposed to be getting a mig welder soon, so i’ll be able to finally finish up the frame. or, if i end up leaving town before we get a welder, i’ll just have to finish up when i get situated back in sac.


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