Saturday, May 29, 2010

One of these is not like the other.

I'm nearly done with Rosanna's bike. I finished the fuel system and I was able to get it to idle.
makeshift fuel valve
All I need now is a throttle cable and we'll be ready to go.

Here is a picture of the derbi clutch that is missing all of the material on one arm:
derbi clutch
Travis was kind enough to give me a hobbit clutch that is nearly identical.
Hobbit clutch
But there is one major difference... can you spot it?
Hobbit clutches spin the opposite direction so I had to modify the derbi clutch plate a little and I had to drill out the hobbit clutch arm because the mounting post is slightly larger on a derbi. Once I had that done, I put some TJT's on and I think this thing is ready.
TJT springs

I'm pretty excited for these projects to get done, though solving problems and working on these things is pretty fun too.

In completely unrelated news, someone posted this video in the members forum of mopedarmy and I remembered what an amazing summer song it is. When I was growing up my family was totally into waterskiing and Alan Jackson's goofy revelry in '80s/'90s cheesiness really takes me back. Enjoy.

Friday, May 28, 2010

Working on Derbi Too

So rosanna's new bike needed some love so every day I've been putting in a couple hours of wrenching before I head off to work. Apparently the cracked petcock is a chronic issue with derbis because when I looked into the body I noticed that the petcock on this bike had been replaced with a rubber grommet and just straight fuel line. Fuel line that was too big for any of the carb banjos I have. Finding myself covered in gas is becoming a disconcerting trend.
Here is the solution I (really Michael Mike) came up with:
makeshift petcock
I lathed a piece of delron to 16mm and then tapped it to fit this barb fitting. I'm going to get an inline fuel valve and then we should be good to go.

I should also mention that this last wednesday I had an opportunity to head to the Responsible Naz's Shop of Wonders. I worked like crazy trying to make progress on as many projects as possible. I was able to make seat supports for the pintos, lathe the above fuel adapter, lathe some lighter variator weights, Naz welded me a big intake for Rosanna's bike, and I discovered that one of her clutch pads has no mo material.

Here is the intake we made:
18mm derbi intake
And here it is in the frame with a nice little air filter. Also, you can see the fuel solution the previous owner came up with and how I had to use a socket to cut off the fuel flow:
phbg mounted in a piston port derbi

In related news, Rosanna got some new parts in the mail. We decided to try out this pipe made by Zen. So far it looks like a really quality pipe, spring mounted, hydroformed, and really solid construction.
Once we weld on a support brace it will be ready to rip.
Derbi Zen 65cc pipe
Spring Mount
Check out this support brace at the stinger, it's just one nice quality detail of this pipe:
Zen pipe lower re-enforcement

That's all for now! More later I'm sure.

Sunday, May 23, 2010

Gila kits are crazy. and awesome.

The dual Kvernmo Pinto projects are coming along slowly but surely, every day a little closer.
Recently I bought a Gilardoni kit. These things really are beautiful. They have a HUGE reed cage and just really nice finishing all around.
Gila Reed hole
gila reed cage
gila ports

And look at the difference between the gila reeds and the 4 petal polini:
polini reed cage, gila reed cage

I took these photos this morning with the intention that the crappy pictures on the moped army wiki of puch kits could be updated, do you have a puch kit and the ability to take pictures that aren't blurry? Help me, help the wiki.

Friday, May 14, 2010

I'm an idiot.

So, it turns out that the Derbi was out of gas. the stock Derbi petcock looks like this:

The tank of a derbi variant is plastic and so rather than having a petcock that threads on, the petcock slips inside the outlet a the base of the tank and then a hose clamp secures it in place.

Now, if this petcock had been made with metal it would have been great. The problem is that every time someone needs to change the jetting in the carb, you have to push the petcock out of the way and eventually all of this tweaking just makes the plastic valve portion of the petcock crack and leak and then drain all of your gas out. I'm working on a solution right now but since I currently working, I don't have much time for moped work.
Here is where the crack is on my petcock:

One idea that I came up with was to take a pinto petcock (12mm) and adapt it to fit the 16mm opening of the tank. I called my dad and asked for his advice and he suggested wrapping the pinto petcock in teflon tape.

It didn't work.
So, Jona from the Ghostriders is sending me a replacement stock petcock and hopefully that will do me just fine.

In other news, I did get some TJT clutch springs.

Travis has been telling me that these particular springs are a necessity and in the brief test ride I took I have to agree. From a dead stop they really rev up nice and high before engaging which creates a sensation like popping the clutch on a manual transmission. Rooooom!!! BraaaaaaaaaaaaaaaaaAAAAAAAAAAAAAAAAAAAAAAAAAH! That's what it sounds like.

Update: Rosanna just traded old Red and Gold for this...

Monday, May 10, 2010

This one is for my baby boo.

So the derbi is still a little sick. Not pooping your pants sick, just like a cold that won't go away.
Specifically, everything is running good, the jetting is pretty much right on, the timing is extra nice, and the bike goes at a pretty good clip, however, right about when I get up to top speed and I'm thinking, "Yeah! Finally this thing is solid." And then it goes, "Baaaaaaaaaaaaaaaaaah." If you can't figure out what that onomatopoeia means, basically it's like I run out of gas instantly. Not the zing noise like a seize, or a sputter noise like a fouled plug, no this is like I just cut the kill switch or ran the tank dry instantly. I have a theory that involves fuel flow but I can't be sure.
So in the meantime while I try to figure out the inexplicable, I'm improving the things that I DO know how to fix.

1) 12mm x 220mm Super Strong 10.9 axle.

This is 20mm longer than the stock axle. I really wanted the low-end power and long seat of the derbi to be put to good use so I bought some buddy pegs and this longer heavy duty axle so my boo can ride on the back. I'm really excited, we'll see how excited Rosanna is.

2)M6 set screws for my variator weights.

So Naz in his infinite handiness turned some weights for me out of a plastic material called Delron. Isn't Delron a mans name? Anyway, this material is pretty much perfect for variator weights if not just a tiny little bit too light. Hmmm how to increase the weight just a tiny little bit... Ah HAH! By tapping those delron weights with a tiny M6 set screw I can incrementally increase the weight. (By the way this was in no way my brilliant idea. This is all Naz, all the time.) So I bought two sets, M6 x 6mm and M6 x 8mm. Hopefully they should do the trick.

3)TJT Clutch Springs

I haven't been home to look at these things yet but I should have these fancy lads sitting on my desk when I get home.


While googling for the pictures above, I found these pictures from the netherrealm of Cupertino:

What the What?!
Well apparently the cuperteens have already done the EXACT same pipe modification that I did but they beat me by about 10 months. Dang. Well, good job gentlemen, you reign supreme in the land of Derbi.