Friday, April 9, 2010


Recently I bought this bike and brought it home from LA:

I was really excited to finally have a derbi to play with and this was to be my first foray into variated bikes. Lucky for me the Mosquito Fleet has some really talented and helpful people. Within a few days of me returning from the Latebirds invitational Michael Mike and I had done the following improvements:
-I had naz lathe off the restricting collar on the variator cheek
-he turned some lighter weights out of delron
-we welded a nut onto the wheel adjuster that was stripped
-we cut the header on the pipe and rotated it so that the pedals clear and the stinger kicks up at a radical angle like a simonini
-I swapped the stock 12-12 carb for a 15 SHA
-we properly spaced the front axle so that the bearings weren't just floating from side to side
-took off the crazy stock handlebars with the welded on perches and made a neat little handlebar bridge (This is one thing that drives me nuts about Derbis, the triple tree is so long that the top plate is wavy shaped and it's difficult to replace the bad stock handlebars with new nice handlebars, also, what if these forks give out? What forks have the same length head tube?)

I've been slowly going over the bike finding sketchy things and making them ultra solid so that when I'm wheelie-ing down the road with rosanna on the back I won't have to worry about whether or not the front wheel is going to fall off or if the variator is going to spin off into my leg.

Today I made some really nice aesthetic and functional improvements to the bike:
I put on some neat low rise handlebars and some new red grips, and during the process decided to simplify the wiring.

I HATE messy handlebars and the bane of my existence is ugly switches and a snarl of wires. So I had the great idea to put little switches on the riser that Michael Mike made me:

As you'll notice, there is a red switch for killing the bike and a yellow one for going into ninja mode (lights out). The caveat to ninja mode is that with the lightened variator weights when this thing is running reved (revved? rev'd?) out it is very loud. It sounds like an angry weed wacker fighting a cheetah.

Last but not least of my favorite things about this bike, the sweet ass pipe.

This was a Metrakit pipe that was right in the way of the pedals. I've always like the swept up angle that simonini's have so while Michael Mike and I were refitting this pipe to clear the pedals I positioned it in such a way that it looks really nice and aggressive. I love it. I couldn't be happier.

Further possible improvements on the way:
-New Seat. I love the stitching and the logo on this stock seat but alas it is rusted through and won't last much longer. I'm thinking about putting on either a Brooks saddle or that neat futuristic cafe seat from polini. NOT. Actually I'm thinking more along the lines of this:

-Install foot pegs so my boo can ride doubles
-Powdercoat. But what color?
-New shocks
-New Forks?
-Puch Reed kit? I have a polini four petal and a kit just sitting here. Oh the possibibilities!


  1. woah, awesome stuff. more pics of the pipe please! i've got the same one and have been looking at it trying to figure out the best way to cut, rotate and weld it back up for a different angle.

  2. This bike is pretty awesome, and I rode it last night. For a lightly modded stock bike, this is stupid fast. 50cc stock jug with a slight carb upgrade, pipe and some know-how. Also, I'm glad you have such a sweet ass-pipe.

  3. missed that this was on a stock cylinder. awesome! those metrakit pipes are amazing. mine might also end up on my stock piston port cylinder. twinzies!

  4. it was actually a pretty simple modification. I cut it at the weld where the header meets the first cone, then we held it like we wanted it to sit. I marked it with a sharpy to roughly grind the angle of the pipe and then we welded it up. Done. I'll post some pics of the pipe in another post.

  5. Thats exactly the seat I plan on making. Maybe a little more comfortable than a banana seat. :(

  6. that'd be great! if i did this it'd probably be friday afternoon and could also just implore some of phil's insight on the spot. handy handy. also really dig the handlebar mount. simple/clean fix to an ugly derbi problem.