DRP: Derbi Reactivation Project

[toratora]

Road it out to the D-StoreSF to watch the MotoGP race (great race if you've not seen it yet). The bike is way better, but not really there yet. After the race I took a trip across the Bay Bridge to Oakland. Not very fun at all!

The pipe seal doesn't seem to have held all that well. I really am bumming that the Voca action didn't work out. Plus there seems to be more vibration. I'm wondering if the pinion gear slipped again. The bike is better, but it's still a handful to ride. And it's fucking loud. Not enjoying the loudness at all!

Still it's going to have to do because I'm out of time. I've got to work on the other bikes to get them ready for GPR Camp.

The brakes are amazing thought.

[toratora]

Speedy did some stills with his chin cam at GPR Camp. He sent me this one.

[toratora]

very cool bike looks fun

What a road! I would kill to ride there.

believe me it will try to kill you too, I learned firsthand, and am still limping...

Matt, I thought you said you didn't get hurt?

haha I sprained my ankle! lol. it's almost better now but still a pain.

Glad to hear that you are healing up.

Looking at these photos really reinforces how lucky we are to have roads like these. I'm surprised it took us so long to do a camp out there, but I'm sure glad we finally did it.

[toratora]

This week we had our GPR Camp. It was awesome. I've posted some photos already. Speedy got a bunch with the ChinCam™ which I'll be posting up. A few of us ran video. We are in the process of uploading and sharing. Then we'll do edits. Hopefully we will have something fun to post. But it's hard to get proper videos when all sources are on-bike. To really get good videos we needed some off bike cameras.

We are super lucky with regards to the roads here. Ultimately that was a huge part of why we chose to do GPR Camp here, although Deals Gap was high up in the running.

There's talk of doing a fall GPR Camp, but it's probably going to be next year if we do it again. However, I do organize a monthly one day ride. Matt was here for Derbi de Mayo. Currently I'm working on plans for our next ride.

[toratora]

From the department of hilarity Airsal, after over a year, finally sent me a head for the Xtreme kit. But guess what—this one has the right bolt pattern, but it's the head for the 45 mm stroke kit, and not the 40 mm stroke kit. Really?

The part number and description on the box is correct, but I can tell from visual inspection that if I were to put this kit on an engine with this head that the piston would hit the head. This is clearly the head for the 45 mm kit.

It's a damn good thing I gave up on them and fitted a Metrakit to the bike.

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[toratora]

Okay I found out something really cool tonight, because Scotty has been asking me questions. At some point Derbi did a major upgrade to the clutch on the D50B0 engine (also know as Euro3). Early version of it, the Euro2, and Euro3 clutch used a bushing on the primary shaft. MetraKit made (makes?) and upgrade to replace the bushing with two roller bearings. I have this installed on one of my engines. To me the major advantage of the Bidalot clutch (on the Derbi engine) is the bearing upgrade. The other features are nice, but not as important (well the gearing could be argued).

Here's what the current clutch basket looks like. Those of you with keen eyes will notice a couple of roller bearings. At this point I don't know if you could retrofit this to a Euro2 engine.

Here's what the older set up looks like with the bushing.

There are also a number of companies selling five disc clutch sects for the Derbi engines. MVT, Polini, Conti, and maybe some others. With this you are getting very close to the Bidalot setup.

[toratora]

Oh man this is a cool read Tora! Love the detail you go through when sharing your project. I've been away from the forum as the last year and a half been building my electric scooter so all my gas bikes have been chilling out! Now that the electric bike is running well and the next upgrade is new batteries perhaps mid 2017 I figured it's time to get back to the gas stuff. So will get playing with the Malossi GPR 2008 model with the Euro 2 BRK 50 x 45 setup.

Tora so need to share something I found when tuning the Euro 3 engine with the Airsal 50mm block. I was running a 24mm carb on it, pipe and a few minor bits and found the jetting to be a nightmare! I was getting so frustrated that I finally just left the airbox off. At that point holy cow was did it suddenly all work out and the top end was impressive! I had the 125cc air intake plug fitted but it seems the stock airbox just doesn't work so well, though obviously it works for the 125. So I did a test and cut a few large dia holes in the box and sure enough the jetting issues went away and the power increased.

The only issue is the sound was now throaty which I'm not a fan of. So what I have done is designed new airbox intakes that I can bolt or rivet into place. They have trumpet inlets with curved outlets to help keep the noise trapped within. I can't remember if I had my own post going on in the past, but if so will try to get back on it.

Hey Scott,

I actually bought the 125 air box for this bike. But yeah the jetting has been slightly more than difficult!

I need to do a bunch of updates to this thread. I have photos, just haven't had time. ¯\_(ツ)_/¯

I have the 125 airbox on mine and yup it needs to be tweaked! Will show a picture of the intake design, not test out yet. Will have to modify an airbox first to accept them.

Can see the design I went with below. The idea is to have them fitted on the sides and even the front on the filter side. The curved bits aiming down or upright depending on what traps the sound better. Will use aluminium pop rivets to hold them in place.

[toratora]

I think if you have modified engine with 20 hp plus then you definitely should uprage your clutch. On derbi it is not that bad but on minarelli am6- it wont hold the power... I have the Bida clutch set and it is really nice! The only problem is where to buy 6 disc for derbi engine. Everybody sales only 4-5.... I will contact Derbi and hopefully they will help.

Looking forward to see some updates!

Yeah 6 for sure would be best, but bump starting the bike as a street bike would be a pain. Don't stall in traffic uphill!

The one way around it would be to fit the deeper basket on the normal secondary gear and then have a spacer made up for the clutch cover. The other option is thinner plates as some racing clutch firms have done in the past for moto X bikes. EBC make or used to make a EP kit for the CR80, so wonder how many other bikes they did this for? Where there is a will there is a way!!

Bidalot already has derbi and am6 transmission sets. I ment that when you have it you have to buy 2 sets of new discs to rebuilt the clutch... But as it will be needed I will contact Bidalot and maybe they will sale one set of new 6 discs for the rebuilt.

Here I did unboxing of the set.
https://youtu.be/xbv5wvgM4Fk