Posts Tagged 'two stroke'


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!

dirtbag challenge 2013 bike – critical miss v1

ryan and i dragged out the kawasaki roadrunner we tried to build a few years ago and made it our 2013 dirtbag build. everything we did all those years ago had to be done over, but in the end it turned out to be a fun little ripper.
well, until the piston melted down on the dirtbag ride. as it turns out, taking a 46 year old 120cc two stroke trail bike with stock gearing out on the freeway for miles isn’t a great idea. who would have thought?
obviously we didn’t “finish” it, but with ~$300 and probably ~15-20 hours invested, we didn’t do that bad. the bike had been sitting in a guy’s back yard for 20 years or more when we got it and i had to break up the stock piston with a hammer to get it out of the cylinder. we are pretty stoked we even got it running in time for the dbc.
we have a new piston and ryan will be rehashing it next year for his dirtbag 2014 bike and i’ll be building something new, so i figured i’d get some shitty pictures of version one before that happens.

video of the first start at the bottom!


























moto guzzi trotter engine rebuild

since the trotter’s going to be my main rally squeeze for the landsquid rally later this month, i decided i should maybe tear into the engine a little just to have a look to make sure everything’s good.
i could get the engine to start up ok, but it wouldn’t idle and the crank seemed a little too hard to turn by hand. i figured worse case scenario the crank would be trashed and then i’d have to hack some other engine onto the frame. part of me thought it would be hilarious to graft a crazy big-boy kitted e50 or something into that little frame, but if the engine was ok, i wanted to just leave it alone and ride it stock.

first things, i wanted to check out the top end and make sure the piston and cylinder looked fine.




the piston’s in great shape, though there’s quite a bit of carbon. i figure it’s probably from the old school oil from forever ago that it probably ran last.

look at the tiny intake port, it’s so cute!

the exhaust is pretty tiny too, and also has some carbon to scrape out.




once i had the clyinder off and the piston off the crank, i could tell something wasn’t right in the crankcase. the crank would spin, but not easily at all. the connecting rod bearing is in great shape and there’s no excessive movement anywhere, so there’s some good news at least.
the trotter engine has the same flywheel taper as puch, and uses the same electronics, though this stuff’s a bit older than you see on most maxis. the points still have a lot of life and i was getting great spark from the coil, so i’m just going to replace the sparkplug wire and leave the rest alone for now.


if all else fails i’ll just stuff something else in here.

the right side crankcase half came off pretty easy, and i was able to see why the crank was kinda hard to turn right away; the main bearing has siezed and the crank was spinning in it.

fucker bearing rusted solid.
no big deal though, turns out this engine uses your standard 6203 main bearing, same as puch and a bunch of other guys.

also, can we take a second to just look at how weird this engine is? so weird.

last time i removed the clutch i noticed the bell doesn’t just come off and i didn’t have time then to explore it more. turns out under that top hat seal thingy there is a snap ring that holds it on the crank.

crank out, thing’s a weirdo.

the crank has a nice sized oil groove in the big end of the conrod, and really wide triangle spacer washers between the conrod and the lobes, allowing lots of oil to get up in there.


so i got this far planning to just replace the bearings, make a new gasket for the case halves and put it all back together, but i figured i might as well pull it all the way apart and replace all of the bearings and seals.
actually, i didn’t replace any of the roller bearings in the transmission as they were all in great shape so i just did all of the big bearings. i’m getting ahead of myself here.

before tearing into the transmission, i decided to make sure the crank was salvageable. since it spun in the seized bearing, the new bearing would slide right on. not having access to a new trotter crank, i decided to go the hillbilly rout and dimple the bearing surface.
i’ve done this before on vespa large frame clutches when they would spin the brass bushing and the customer was too cheap to replace anything, but i’ve not done this on a crank before.
but whatever, it’s a moped. plus i have a set of e50 cases sitting on a shelf just asking for an 80 kit.

i went around the whole crank and made a bunch of dimples with my center punch. a bunch of them.

i totally didn’t take any pictures of the new bearings on the crank, but they pressed on nice and tight.

since the crank is fine, i tore into the transmission.
the sprocket on this thing really needs replaced but i’ll never find a new one. oh well!


i kind of really sucked at getting pictures of this stage. whatever, if you ever end up with a trotter and need help rebuilding it just email me.

engine cases all stripped down. well, except the studs. they were kinda stuck and i didn’t have a good rease really to pull them so i left them.

most of the rest of the engine in a bucket.

so i grab all four of my old seals and the two big bearings from the transmission and hit up the internet to see what i can find.
i am able to find three of the four seals on amazon and get them on their way, but one of the crank seals is a weird size that is apparently impossible to find on u.s. soil. i forget what sizes everything was, and everything’s at the shop 80 miles from here so i’ll leave a comment on this post tomorrow with bearing and seal sizes on the off chance of anyone ever needing to know.

i find my weirdo seal on this awesome website out of great brittan called, not only do they find it, but they have it super cheap, and shipping was like $3 or something! i went ahead and ordered it, not knowing how long it would take to get here.

fast forward a week and my two transmission bearings arrive along with both my crank seals, one from some warehouse here in california, the other from engineersmate! that seal got here before my two transmission seals had even shipped!
with everything needed to put the crankcase half of the engine back together, i decide to go for it. also, i cleaned everything up a bit.

not only were they super cheap and super quick, engineersmate also has a super rad seal on the baggy! a seal! GET IT??? ok, that’s enough.



popped the crank in and bolted it all together. i don’t realize it yet, but i totally put the crank in upside down. even though i checked it before i put it together, i still managed to goof it up. i realize it later and pull it apart and put it back together proper.

my transmission seals still haven’t shipped at this point, so i check engineersmate again and, sure enough, they have them for a lot less than the ones on amazon. i cancelled my amazon order and gave those britts my money and i expect i’ll probably have them sometime this week.

in the meantime i decided to go ahead and rebuild the transmission. the seals go in from the outside, so i figured it’s better to put the thing together rather than just have a bunch of parts in a bucket.



TA-DAAA! again, total fail on getting step-by-step photos. whatever.

the carb needed a good cleaning and a rebuild, so i did that next. you know how to rebuild a sha i’m sure, so here’s it after. pretty!

decomp got tore down, lapped in and put back together. new copper gasket.

the cylinder cleaned up nice! so did the head, but no photos of that i guess.


stock, the piston covered almost a quarter of the port windows in the cylinder at bdc. had i more time, i would have gotten some alum plate and made a ship to get the cylinder up to where it should be, and then deck the cylinder down to get the compression back to normal. i just want to get this thing on the road right now, though, so i just made myself a thick base gasket. it helped a lot, but the piston still doesn’t totally clear the windows. it’s hard to see, but here are some pictures.

if this thing ends up being a reliable runner, i’ll pull the top end off and do some work to it.

oh hey, there’s the head all cleaned up!

reinstalled the electrics and the clutch junk. also loosely installed the sprocket and other bits that go on the outside so that i don’t lose anything. once the transmission seals show up, i’ll pull that stuff back off, slap those seals in and button everything back up for good.

then i’ll throw it back in the bike and do a compression test. if it’s lower than i’d like, i’ll pull the cylinder again and take some more meat off the top (so far i’ve only done a little, mostly to make sure the cylinder and head were square to each other). it’s a stock moped, though, so it’s not like i’m going for super high compression.

once the engine’s in and i’m happy, i’m going to ride the crap out of it and see what else it’s going to need before the rally. i have already replaced all the cables (less decomp, but i’ll do it when i put the engine back in) and both chains. wish i could do sprockets, but those are weird and i’m not going to be able to find them. i’m thinking maybe tires, but i don’t know if i have the cash right now. if i do end up doing tires, i’m going to rebuild the wheel bearings while i have the wheels off. i’m thinking about dropping the fork and doing the headset bearings too, just to do them.

i should also think about registering it before the rally maybe. hmm.
it should make a fun rally bike!
i hope it can blast stock ciaos.

oh, and here are those rear pulley pics i took forever ago and never posted! such a weird bike.



L’s magnum and some laguna stuff!

a while ago i got L’s magnum up on my lift to pull apart the transmission and check out the shift pucks. the bike has 201 miles on it, but it has been sitting for many years and i didn’t want to just assume they were still in good shape.

well, they totally were.

everything in there was in great shape. totally not suprised, the whole bike is clean and in good shape. it was just one of those better-safe-than-sorry things.

besides, i still had the low mile PAZ pucks that were removed from sparkle butt when the prototype atomic pucks went in. since i had this thing opened up, i figured i’d throw them in.

i threw on a new clutch cover gasket and sealed everything back up and topped it off with atf.

since i’m putting this thing back on the road for L, and this is pretty much her first real 2 wheeled ride out side of bicycles and the hobbit she rode around for a bit, i am making it as little and compact as possible. i decided the rack had to go (though i’m keeping it so that it can be thrown back on for possible camping adventures or whatever) and the rear fended needed bobbed so that the tire was the thing that stuck out the furthest.

first pulled the carb to run it through our ultrasonic cleaner. it’s always a good idea to get that going while you’re doing other stuff to minimize sitting around time. while the carb’s cooking, i can take care of little stuff.

new fuel line, fuel filter. stuck a drill to the crank and turned it over enough to make sure the oil pump is pumping as it should. replaced the starting cable.

pulled the rear fender off and removed the tail light, then kinda eyeballed where i wanted the fender to end, rolled the fender back and chopped off the front of it to retain the stock lip on the rear (and keep that sweet ‘the marvelous moped’ sticker intact).
the carb was done by this point, so i rebuilt and reinstalled it.

i picked up a little led tail light for the rear. i think the stock lighting coil should run it ok? we’ll see. i haven’t mounted it up yet, because i’m still trying to decide if i want to drill holes in that perfect trunk or not. i did run the wires for it, though.


with the carb reinstalled, pump working as it should and a new sparkplug thrown in, i hooked up a fuel iv and fired it up with my drill. the thing started right up and proceeded to smoke out the whole 2nd floor of our building. it was awesome.

i’ve since installed a new petcock after unsuccessfully rebuilding the stock tap (i can’t find a proper rubber piece for it) and replaced the left hand grip. i also pulled the pipe apart and cleaned it out as best as i could, but it’s still pretty smokey.
i need to get some brake knarps, trim up the stock brake cables and then i can go ride the thing around and hopefully burn out the rest of the junk in the pipe.
then it’s a matter of wiring it up proper and getting the plate for it and L can finally start ripping it around sacramento!

in other news, the kickstart guts for the laguna’s gpr engine finally showed up from europe!
so i pulled the clutch cover on that engine and went to work installing the parts.
it required me to remove the clutch itself, which i wanted to do while i was in there anyway. the clutch pads look alright, maybe a tiny bit worn. i think they will be fine for now. also, it’s got yellow springs in the clutch, i have no idea if those are stock or not.

everything where it goes.

i don’t have a replacement clutch cover gasket just yet, so it’s not quite ready to go all back together, plus i need to fix some shady stuff the previous owner did to this engine. for example, see those marks on the clutch’s face plate? they are from the oil level bolt being replace with one that was too long, it was dragging on the clutch. how do you not notice that?

i also remembered that the previous owner had said the cylinder had some porting done to it. i figured now was as good a time as any to pop the top off and have a look. the porting is actually pretty ok. everything looks clean and nothing looks horrible. i’ll run it as is.

i bolted the engine back together loosely until i get new gaskets for everything, and put it aside. i hope to be able to afford to get the parts sometime soon, it would be awesome to have that bike on the road this summer at some point.

but then, i have so many project sitting up here..

sparkle butt maxi

a couple weeks ago i got sparkle but to sac thanks to my buddy ryan. it’s been super nice on the weekends lately and i’ve gotten to go out on a couple rides. this is such a fun bike!
i think i’ll probably be out on it again this weekend, i’ll see if i can’t setup my gopro and get some fun video.

i really wish i could capture the color on this thing, it’s so rad.

this bike is doug’s west coast rally bike now, and after all the trouble he had with the laguna i’m going to keep riding it now and again to make sure it’s in great shape for him the next time he’s here.

oh, and sorry about not updating this as often as i was for a while there. i’ve been working on dirty and a few other bikes, taking pictures for big updates and stuff, i just haven’t posted anything in a bit.
i do upload pictures a bunch to my instagram, though. follow me there if you want more stuff more often!

1971 moto guzzi trotter

i totally got the guys at the shop today. i was like “GUYS! I’M BUYING A MOTO GUZZI!” they were all “OH NICE WHAT IS IT” and i was like “YOU’LL HAVE TO WAIT AND SEEEEE!”
like an hour later my little trotter shows up in the back of this girl’s truck and it was fun to watch everyone’s reactions. it was a lot of PPPFFFSSHHH’s and HAHAHAHA’s. it was great.



after work i put it up on my lift to see what i could see. the first thing i did was check for spark and found none. i popped the fly wheel off, filed the points and sanded the rust off the little internal hi-tension coil. slapped the flywheel back on and it had awesome spark.



i figured the carb was going to need to be cleaned, but i thought i would put some premix in it to see if it would start up. it was stuck in bicycle mode and took a some work and lubrication to get the lever that switched it from moped and bicycle mode to function, but i got it. however, it was a bitch trying to pedal start the thing while working the decomp and pulling on throttle cable, so i quickly gave that up. i put it back into bicycle mode and grabbed the drill.

dr. rob was visiting and he took a video of it firing up.

that’s about as far as i got with it tonight. i need to pull the carb and clean it so it will idle on it’s own and replace every cable before i can ride it around at all.
i did learn some things about it when i was researching it the other night. this is the special M model, which means it’s the single speed version. there is also a special V model version of the trotter with the same engine, only rather than two fixed pulleys it has a variator up front with a spring loaded rear pulley. it would have been RAD if this was a V but it’s an M so it’s only rad.
i learned a bit more about the trotters but nothing that’s really relevant to mine so i’ll not bother talking about it.
here are some photos!

happy rob



it’s not a runner, a sprinter or a galloper, it’s a trotter.

raaad tail light



so yeah! another project! great!


1975 vespa rally 200 restoration

well i’m not doing a full restoration, more like a freshening up. stripping it down, doing a little body work, installing a left side trunk cowl from a 150 sprint, sending it out to paint. should be a fun project! i’m doing this one for a first kick customer, figured i might as well post about it since it’ll be on my lift a bit.




i also finally got myself a camera! picked up a canon s100. still trying to figure it out, but photo quality should be a bit better from here on out!


so it’s time for the laguna’s piston port to go.
every bolt holding that engine in was loose and covered in oil. the pipe was barely on there. this bike has had issues in the past with loosing exhaust nuts and i can see why, there’s not much room in there to get a wrench on anything! i would use those long allen nuts on this thing if i were going to keep the engine.

having never removed the engine from a laguna, i didn’t realize the swing arm pivot bolt had to come out, and that the kickstand/rear engine bracket thing was all together. kinda neat? anyway, it all came out easy enough.

new lump next to old lump. the gpr engine is quite a bit shorter.

i set the engine in the frame to get a look at things. it fits nicely! this is going to be a piece of cake! with some simple plate brackets welded to the frame the engine will go right in. sprockets line up perfect.


the engine is sitting in there a bit more forward than it will when it’s mounted i think, i have a ton of room to put it where i want to.

so yeah, the engine with the puch gila kit, custom atomic mopeds intake and derbi pipe modified to fit the gila are all up for grabs. i’ll probably post it in the buy/sell on moped army soon, but friends get dibs (if you reading this i consider you my friend! probably).
also up for grabs are the laguna plastics. the left hand side plastic has the bottom tab broken off, but i think the tab is still bolted to the bike, so one could possibly plastic weld them back together.

the engine looks right at home in the laguna. i love that it says derbi all over it too, once it’s all mounted it’ll look like it came this way from spain.

derbi laguna gpr

i moved my tool box upstairs into the moped shop area which allowed me to finally rip the engine out of the gpr. i didn’t get any pictures of that, but it was a bitch. remember the first time you tried to re-install the engine in a ciao? how frustrating and impossible that was? this was like that, but worse.
then i realized i was doing it wrong and the dumb thing came right out.

i put the gpr in the corner and put the laguna up on my lift. that’s where things sit at the moment, but i think i’ll go in tomorrow and pull the engine out of it. it’ll be up for grabs if someone wants it, along with the pipe and probably a few other laguna goodies! get at me and we’ll talk money!

the piston port moped engine is quite a bit longer than the gpr 6 speed lump, which means it should go in relatively easy with extra room inside the frame for the radiator.

some preliminary plans include a hand made sheet metal tail section that may include the exhaust baffle, possibly hand made sheet metal tins for the sides, and maybe even a mini fairing, similar to what it already has, but not broken and awkward.
a nice fork will be in the works, with a better front brake, maybe some handle bars instead of clip-ons. we’ll see!

oh man, i have so many fun projects going on!

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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