I’ve been missing for a bit, but am still around. The frevolution has been kicking it, and I finally pulled the custom built pipe from my derbi race bike off so it doesn’t get destroyed by the streets (and fog) of SF. I got one of those fasmem pipes from treats and had to add a little bracket and trim my transmission cover a tad to get the fit. I had a little electrical issue (read: custom construction = melted headlight) and got a replacement that was creating some gremlins. Some crafty work and now all systems are a go. It doesn’t run nearly as well as it did with the simoni pipe, but a little tuning ought to help out. It does fit on nicely though.

Next up might be a throwback: decking out my clean newport with a gila/phbg ripper setup and mobbing that around town. The details are unclear, but I have a few kits sitting and I want something a little different for the city. I love the start 3 derbi motor but I don’t want to go all crazy with it and unfortunately am limited on gearing by preserving the puch swingarm/wheels. So I’m thinking simple e50 build on a nice base. Should be simple and fun to ride around. With some luck I’ll have a post or two about it.

Oh yeah, got another toy, but it still needs a little work. More on that later.


September 29, 2009, 6:00 am
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So yea, Chappy’s are amazing. There were several different versions sold back in the day with 2 motors and different transmission arrangements. Most common are the LB50’s, which usually have foot pegs, and a 2 speed transmission that has 2 gear ratios (so that means 2 gears of Hi, or 2 gears of Low for hills). There is also the LB50PE which is the same, except it has pedals that are pathetic, but pedals nonetheless. The right pedal arm is also adjustable and can be locked in the forward position to act as footpegs. Yamaha also sold the LB80 (which is actually 72cc’s) with either the 2 gear dual ratio transmission or in very rare cases a 4 speed manual. The 72cc top end apparently isn’t swappable between bottom ends, but I’ve never had one, and I’d guess its like the 75cc puch kits where the skirt is too big for the case.

Stock the 50s are pretty slow. Chappy’s weigh an obscene amount, and the stock carb is tiny, so it really offer much performance wise. When I first got mine it did about 23 mph. Later on before kitting I got it up to a whole 28mph. To do this I did my first pathetic attempt at porting, got new piston rings and cleaned the exhaust.

Internally these are pretty intimidating motors, so beware when you take that transmission cover off. I’ll take a photo next oil change. Luckily everything is awesome yamaha quality, so it is very durable and over-engineered. My bottom end has thus far survived several hundred miles with the polini setup.

Performance wise, there isn’t a ton of stuff available, but at least there is some stuff. Polini makes a 70cc cylinder (45mm, rated at 6 hp), larger intake (for clamp on dellorto PHBG carbs); Ninja makes an exhaust, and Gianelli also makes a pipe. Thats it. If I were to do it again, I’d get some other pipe, maybe an 8p, motobecane ninja, or something else and weld it onto the stock (and MASSIVE) header. The chappy ninja exhaust is pretty, but it has a non-removable restriction and thats a huge bummer. You could cut off the header flange and graft on the one from your stock pipe, but that’s probably more work than most people are going to undertake. The gianelli also has a restrictor washer welded in, but it pops out easy. A derbi Big Muff might be good (too long though). Either Chappy pipe will necessitate the removal of pedals.

My bike has the polini (case matched), the intake, a puch 50cc high-comp head, gilardoni 4 petal reed block (some filing required to make it fit), gianelli exhaust and a 21mm phbg. My oil injection is disabled and I premix in the tank. The NOS and oil injection nipples on the intake are also blocked off.

Unfortunately to make the polini or ninja exhaust work, you need to lose the pedals. To make matters worse, you pretty much need a non-pedal chappy swingarm (narrower to account for smaller rear wheel hub). These are easy to find on ebay, and go on easy, but its just an added hassle. If you have the pedal version, the extra pedal sprocket simply unbolts from the rear wheel hub, narrowing the whole rear wheel so it can fit inside the non-pedal swingarm.

When first kitted I got it up to nearly 50 miles an hour. This is scary for such a small bike that is super squishy. It currently cruises about 40 and can get up to 45 if I want, maybe more, but thats just because the Gianelli has an obscenely long header so its all low end.

As I look back on this all, I now see I omitted discussing the electrical system. Yamaha points are solid, but the biggest issue is non-adjustable timing besides adjusting the point gap itself. The stator just has 2 holes holding it to the case with no room for adjusting. This can likely be fixed with some careful dremel or milling action, but I have no idea what the results would be (well probably faster, but I cannot say for sure without trying). Additionally, no other moped ignition system will fit due to the obscenely large diameter of the crankshaft.

Chappy Resources:
Treatland – Performance Parts
Bike Bandit – NOS replacement parts (select year, then model: e.g. 1978 LB50PE) Most parts cross over between years and models
eBay – any obscure part you may need

If you can’t find it here, France actually has a large number of Chappy’s, so french ebay is a last resort.

I’ll add a photo of the wiring diagram later on.

September 28, 2009, 12:33 am
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For some reason everyone likes to think we blow up an obscene number of bikes. This is false. In 2 years of many fast kitted bikes, the cuperteens as a whole have only killed two cylinders, a 50 tccd (still a mystery, looks like a broken circlip and all associate carnage), and a 75cc derbi metrakit (4 corner seize. Matt was hungover, and fuel line slightly pinched).

That said, I’ve blown 5 pistons. My derbi has done 60% of the damage.

3 were in my Gilardoni on my derbi (Matt did one of them). The cylinder is a bit rough, but still works fine. The first one was in LA. I was flying down La Tuna Canyon, my bike was backfiring, piston was hitting the head, and more, and it locked up at about 50. Lost the lower ring, but it ran the rest of the day, and the first practice day of the polini cup. The next one was the first race at polini cup, not sure, I think jetting was off. The last one was the 3rd polini cup. I believe this was due to poor jetting (fuck OKO’s). No biggie.

One was a polini piston in portland; the ring got hot, snagged the exhaust port, and managed to destroy the piston while doing zero damage to the polini. This happened due to an exhaust leak because I was chasing terry dean down the freeway at 62 mph, lost the rear bolt, then ghetto rigged some safety wire to hold the pipe on which subsequently didn’t work, I got an exhaust leak, and yea, broke a ring.

The last one is an elusive korado piston. I’m not exactly sure how this happened, but it developed some ring noise, started acting funny, then finally died right by tom’s house. Of course this happened the first day I ever rode to work, so it was a bummer.

But yea, thats pretty much it. We’ve had a handful of soft seizes, but nothing catastrophic. Tom’s seized a derbi crank at the races (HOT!), and Matt exploded a big end bearing on a top crank on his gila monstermagnum (paced at 68-69mph at sacramento).

So yep, fast bikes but relatively little destruction. Pretty sweet. That said, this is just about ready. I’ll give some specs later. Its quick, but not insane. If anyone going to atwater this weekend has mikuni jets between 205-220, I’ll be your bff.:

derbi, attempt 4
August 20, 2009, 2:56 am
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racer renditions:
1-gila, 24 oko, metra bendy pipe. Seized in the canyon in LA, got it running, matt raced it, seized it again.
2-gila, 24 mikuni, metra bendy. seized by matt again.
3-gila, 24 oko, puch cdi, zen. seized racing
4-current build.

so the previous builds all had their own issues. I thought number three was solid, and it ran well, but super noob jetting made me seize it. So yea, now its being done better, maybe not perfect, but better no less.

I wanted to run a metra 80, but those pistons are not available, so I’m going to run my polini instead. New intake, ported the exhaust and transfers a bit more, cleaned up the case matching, milled stock head ghetto polished, and its going to run a 24 mikuni. I got the selettra cdi just cause, so we’ll see what that does. The zen has been re-angled too many times, and it needs to be done once more. Hopefully everything together will equal a sweet blaster. I need to get a piston tomorrow, fix the pipe, and it should basically be good to go after double checking the timing. I don’t know if it will be crazy fast, I doubt it, but it should run well. I just want a shit ton of midrange like tom’s bike so its quick through the turns. I’d like to change clutch springs too, but we’ll see about that later. Paired with amazing brakes, I should be able to get some decent lap times.

check out these sweet bikes:

cuperteens race-prep

so while all the other teams seem to be doing all this crazy stuff, we’ve been keeping it pretty low key. I’m just going to accept derbi how it is. I know I could get a lot more out of it with a little porting, but I want to make sure it survives the weekend before I tear into it further. I also would like to mod the clutch more, but can’t afford another broken shoe, so that will also wait. The cdi and zen pipe paired with the disks already make it a fair amount faster than its last appearance in may (in which it earned the 3rd fastest lap time), so maybe it will be alright.

MagnumX is also going to be coming along and has received its own upgrades. 64cc of piston port magic make for some amazing torque. The pipe we made totally limits its top end, but its loud, and pulls pretty well throughout. I’ll probably ride it in at least one practice just for fun.

My brother is upgrading his tomos as I type, polini, 4 petal, etc. Again, won’t be the fastest bike, but it should rip pretty hard.

Justin (blasto) is riding the polini maxi which has a polini kit on it. I think its slow, and his pipe is going to scrape, but it has some amazing throttle response. Tom (broke dan’s arms) I think is just going to be riding speed racer again, but this time better tuned and a tad faster. He has some other builds in the works, but he’s all hush hush and I don’t know whats happening with them. Matt should just be riding his garelli/derbi monster. HPI, zen pipe, 75cc metrakit and a lomat 4 petal with a 24 mikuni makes a super blaster. My bike has more low end, but his mid-range/top end is insane. True blaster steez. No kinked fuel lines this time.

So thats it, no super hobbit/derbi/puch builds or whatever, although I kinda wish we were. I think Tommy and Jimmy should be ripping, but i know choke is working on some stuff too, so we’ll see. Everyone is upgrading and adapting very quickly. I do have leathers and plan to race as long as I’m healthy. I couldn’t walk yesterday, but spent most the day wrenching today, so I should be fine by friday. Either way, I’m super excited for the weekend. A long lost cuperteen returns!

good and bad
May 30, 2009, 5:53 pm
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derbi was running well, then I decided I wanted it to be better. This didn’t work as well as I imagined. It’ll be fine tomorrow, but its annoying today. Some sweet upgrades over racer version one.

this is the rest of the current running fleet. 2 will be gone soonish.

derbi dreams?
May 22, 2009, 5:42 am
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Its been a tough day. 2 amazing mopeds so close yet so far. We will see what happens with them, but probably out of reach right now.

Gilarderbi is almost alive again. Well it is, but I had some not fun today with ignition, so I go back to stock tomorrow. I also need bigger balls and more patience. Stoppies! I’m also really good at using a timing light now, so thats cool. Matt’s bike is really fast, its going to rip. The polini ciao is really awesome… I’m looking forward to a 12 year old in moped class.

I bought leathers today. I hope that means what you think it does.