Derbi DRD [81,4cc] | Testing.. 7.5.

[J11]

Hello!

I have started this project already on the end of summer, but now decided to make a project thread for you.

The project bike is Derbi DRD Limited Edition '05.
When I bought it, it had green Porn Series sticker set and most of the plastics were in bad condition.

First I was thinking about re-building it with a small budget and earn a few hundred euros with it.. but it all failed, when I started tuning the engine "a lil' bit more.."

#1 setup | 13 333km (by previous owner)

• Airsal D. 48mm cylinder kit
• Dell'orto PHBG 21mm "Racing" carburetor
• Stock intake manifold (modified)
• Stock reedcage
• Modified airbox w/ original air filter
• Stock clutch w/ Italkit clutch springs
• Original ignition (Ducati)
• Doppler WR7 exhaust system
• 14/53 gearing

Top speed: ~110km/h (gps)
0-100km/h: 14,2s
Fuel consumation: 5-8l/100km




#2 setup | 13 380km / 1.2h (on hour meter)

• Airsal D. 48mm cylinder kit | ported: 196° exhaust port, ø28mm exhaust channel and cylinder head lowered 0.75mm (squishclearance 0,65mm).
• Crankcases ported
• Mikuni TMX 27 carburetor w/ powerjet | #25 pilot jet, #175 main jet and #80 power jet.
• TwinAir air filter
• Honda CR80/85 intake manifold
• V Force 3 reedcage by Moto Tassinari (Honda CR80/85)
• Stock clutch w/ Italkit clutch springs
• Original ignition (Ducati)
• Metrakit Pro Race exhaust system
• 12/46 gearing

Top speed: 124,9km/h (gps)
0-100km/h: 8,3-8,9s
Fuel consumation: 8-15l/100km




#3 setup | 13 720km / 6.6h (on hour meter)

• Airsal D. 48mm cylinder kit
-196,5° exhaust port (734,5mm2) and 130° transfer ports
-transfer channels re-done (lots of epoxy & porting)
-ø32mm exhaust channel
-cylinder head modified for higher compression (9,36:1 corrected / 15,2:1 uncorrected)
• VHM 47,90mm forged piston | single ring | TM 85MX
-Stage6 ø13x17x15mm needle bearing
-18g lighter than Airsal piston and quality a lot better
• Crankcases ported even more..
-Takashi TB-6204 P63 crankshaft bearings | NAK teflon coated seals (other seals are by SKF)
-Nachi Quest 6203/C3 bearings (transmission/clutch)
-Koyo needle bearings (transmission)
• ARP C. 45mm crankshaft w/ YZ80 '86-92 connecting rod (by ProX):
-72,4cc to 81,4cc
-conrod length 94mm instead of stock 90mm
-big end bearing is 18x24x14mm (stock 16x22x12.6mm)
• Koso PWK 32mm w/ powerjet carburetor
• Fuel pump by Biltema (0,10bar | max power output 120l/h)
• E-85 / Methanol w/ Klotz Super Techniplate (3,5%)
• V Force 3 reedcage by Moto Tassinari (Honda CR80/85)
-Original reeds replaced with Barikit 0.35mm carbon fibre reeds
-Modified for 32mm carburetor
• Malossi 32/40mm intake manifold (Piaggio LC) + 9,5mm aluminium adapter plate (going to change it to a better one)
• Pipercross air filter
• Newfren Competition 9 plate clutch
• Original ignition (timing adjusted slightly) | going to change to a PVL inner rotor kit + Ignitech's programmable CDI unit
• Metrakit Pro Race exhaust chamber w/ carbon fibre Metrakit oval shaped silencer <3
• 13/46 or 14/53 gearing
• Some gauges.. RPM meter & water temp, exhaust temp and hour meter

Top speed: ?
0-100km/h: ?
Fuel consumation: A lot.







"Never enough power" - sadly, it's true.
Currently I own this Derbi and a Suzuki TS125R '97.

The TSR is being built with a beast engine (YZ250 '90-95, 6-speed) and RM125/250 '03 plastics etc.




Something about me..

I'm a 16-years old kid and live in Finland. Currently I'm studying car mechanics (#1 year).
Building fast mopeds is what I love to do.

Been doing porting for my own cylinders/crankcases for about a year now ('14 ->) and now started doing porting work for customers also. The bisnes isn't really good at all.. I do it only because I like doing it.

"Nothing is better, than winning on a moped 1/8 mile race an imperious & rich kid riding a KTM EXC 125."


--

Edit. 23.1.2015 | Going to make a YouTube channel.. got to borrow my mate's GoPro!

[tracing]

Nice to see some English people (or atleast people who aren't from the Netherlands)
Where are you exactly from?

You have some nice plans already, maybe post a pic how its looking right now? I'm curious.

Anyway good luck, hope to hear good results and see some pictures/videos.

[derbi-ftw]

Indeed, set-up looks a boss. You should definitely make try to get it on Youtube OR Derbi-Forum.

Have you got the stock transmission or a Metrakit transmission?

[J11]

Thanks for replies!

I'm from Finland. Here "high-end" mopeds aren't very popular.. atleast not many of them make project topics about them.
Most of them won't last more than 500km's, so my goal is to build this thing last atleast 1 500km's without blowing up. Of course I'll take care of the maintaince. This thing is going to need (and needs with it's current setup too) a lot of maintaince, but I'm fine with that.

I'll try to take some pics tomorrow of the bike. Currently the plastics are in bad shape and won't do anything for them, because the winter is coming, which means a lot of broken plastics, since I haven't even bought good tires for my wheels!
Also I need to change the front wheel's bearings, because their completely messed up.. there's nothing left from them. Weird, because I thought their supposed to last more than 2.2 hours.. Their made by Nachi Quest, "made in Japan."

Currently I have the stock transmission. It has been driven only 13 500km's, so it's in very good condition.
I have been thinking about getting a new transmission with close-ratio gear ratios, but their very expensive.. maybe if I'll find 1 used for less than 100-120 euros. Do they have better bearings.. ? That would make it way more worth the money.

-John

[tracing]

Nice, Finland seems like a nice country, Sweden to all those Ikea forests to go enduro for a bit.

Do you know how fast this current setup goes?

I don't think they have good bearings but u can buy good bearings urself for it. Like SKF C4 or other good brands that make bearings.
Just pull out the old bearings in the cases and heat the case with a torch or something to make the case expand a little, when u spit on it it needs to be hot enough to evaporate your spit then just place the bearing, if it doesn't slide in by itself find a tube that is as big as the outer ring of the bearing and just try it with a hammer, just give it little taps on the outer ring, not to hard but not to soft either. And repeat with all the other bearings and u will have a fresh case to put ur new transmission in.

Hope this helps u out!

[J11]

It goes about 100km/h (gps) with 12/48 gearing and enduro wheels.. the clutch is slipping on 5th and 6th gears, so it revs to 15 000rpm, but the speed goes very slowly up, because of the slipping clutch.

I have got 124,9km/h (gps) with 12/46 gearing and supermoto wheels (not the CPI SM wheels, I used to have the original Limited Edition wheels a few months ago).

The transmission has needle bearings. I need to ask from Scootfast, what kind of needle bearings the Bidalot (or Metrakit) transmission has..
but I have done engine re-build a few times, so I know what I'm doing. I asked from the seller at the local bearing shop, and he told me that 6204 C3 bearings can handle up to 20,000rpm's. C4 bearings are used only because of the higher heat in a highly modified engine. 2-stroke engine's crankcase doesn't heat up that much, it would need C4 bearings.. so I'll get 6204 C3/Tn9 bearings. Tn9 means polymer cage, which doesn't cause serious damage to other parts in crankcase (crankshaft, conrod), because it shatters in small peaces, when the bearing gets broken.

I didn't get any pictures of the bike, because I cannot drive it yet.. I need to replace the front wheel's bearings and the axle.
But here are some a bit older pics;
Supermoto

http://www.motot.net/galleria/kuvat/kay ... 171954.jpg
Enduro

http://www.motot.net/galleria/kuvat/kay ... 152409.jpg

I'm going to probably buy a Brembo 4-piston caliper (from Cagiva Mito) and a 16mm master cylinder (also Brembo).. the bike doesn't stop quick enough from +100km/h speed, which makes it a bit dangerous.
Rear brake caliper is from Aprilia RS125 '97 (4-piston caliper) with new SBS brake pads.
But if I'll find a better caliper (like from YZF-R6/1 or GSXR600/750/1000) for a good price, I'll get 1 for sure.
I'm going to get a Braking 320mm wavy disc for the CPI SM front wheel, if I can make it fit with small modifications (like just drilling new holes).

[tracing]

The picture's aint working. :p
U could do C3 in the case itself, but for the crank i would go with C4 to be sure.

But damn, that's a fast bike.

[J11]

I added links to the pics.

But yea, it's quite fast. It has enough power to do a wheelie at +80km/h without problems.. just need to use clutch and pull a bit with arms.

I ordered a Metrakit MRD clutch.. I hope it holds the power. If it slips, I'll get clutch springs from KTM EXC 525 Racing (the springs are 1,5-2x stiffer than Italkit's clutch springs, meant for Derbi engine).

[James]

Fixed your pic's

[MHR]

I like it more with the SM wheels! But its an damn nice bike

[rené]

wow nice bike! but one thing, airsal 70cc is not a very powerfull cylinder, you better can take the Malossi mhr 80cc team cylinder.

[J11]

Airsal 70cc is able to produce up to 14-15hp from crankshaft in stock condition, depending of other parts, like carburetor, intake manifold, reedcage, exhaust.. etc.

I have ported the cylinder and I'm going to do some more porting for it when I have opened the engine. My current setup should be able to produce atleast 17hp from crankshaft, because the bike is faster than a full power Husqvarna SMS 125 2-stroke bike!
Of course my bike doesn't have as good top speed, but it accelerates faster.

The Airsal 70cc cylinder has a lot of potential. That's why I am using it. Not all mopeds have forged pistons (Wössner)?
I'll order the piston set, needle bearing and piston pins next week. The clutch should arrive in 4-5 days.

I'm going to install the supermoto wheels today and get some better pics of it.

Also I might get some better plastics.. currently waiting for pictures. I have been thinking about ordering from Tapesnake a custom sticker set.. something simple, unique and cool.

-John

[Mclaren]

It looks great with the supermotard wheels, how are the roads in your area?
Any issues with cops?

[J11]

Thank you! It has got a lot of positive attention from my friends. And I love the look of golden wheels.. gold + black = simply great combination.

The roads are quite bad actually in some places atleast in my town. But there are some awesome roads, that I like to ride at high speed (over 100km/h). I have a Cagiva Mito 125cc also and it's a great bike for +80km/h speedlimits.. thought I ride it at 140-150km/h speed. Belive it or not, but the Mito feels a lot less powerful when compared to my DRD.. the powerband is a lot calmer on Mito.

I haven't been pulled over by cops.. I have escaped 2 times, when I have been speeding and cops have seen that. 2 weeks ago on Saturday I escaped from cops with this DRD and my speed was all the time over 90km/h and the rear tire had zero grip.. but it's easy to get away from cops in my town because they cannot drive as fast as a bike.

97% of mopeds in my town are full power and 70% of them have higher top speed than 70km/h. 10% has mopeds that can reach higher top speed than 95km/h. And 2% more than 110km/h.

And sorry, I didn't get any pics, because some of my tools are missing because I just moved to another house.
Also I need to get the rear sprocket (46H) modified, so it'll fit to the CPI SM50 rear wheel.

[tracing]

Damn, that's a nice bike, I like both looks.

I want mine to be exact like that, only the brake calipers both red.

Or Chrome frame, chrome weels, black motor, chrome exaust and the plastics a mix of light green/dark green with red accents on them.

Like this one ;

[J11]

Yep, just wait till I get some new pics.

I'm going to try out 13/46 gearing next week.. can't get the 46H rear sprocket modified tomorrow, so it moves to Monday.

In theory it should be able to reach 130km/h top speed if it revs to 14,500rpm (I have a rpm meter, so I know how fast I'm going).
Shouldn't be a problem with a better clutch that doesn't slip. The clutch should arrive on Monday or Tuesday.

[rené]

Airsal 70cc is able to produce up to 14-15hp from crankshaft in stock condition, depending of other parts, like carburetor, intake manifold, reedcage, exhaust.. etc.

I have ported the cylinder and I'm going to do some more porting for it when I have opened the engine. My current setup should be able to produce atleast 17hp from crankshaft, because the bike is faster than a full power Husqvarna SMS 125 2-stroke bike!
Of course my bike doesn't have as good top speed, but it accelerates faster.

The Airsal 70cc cylinder has a lot of potential. That's why I am using it. Not all mopeds have forged pistons (Wössner)?
I'll order the piston set, needle bearing and piston pins next week. The clutch should arrive in 4-5 days.

I'm going to install the supermoto wheels today and get some better pics of it.

Also I might get some better plastics.. currently waiting for pictures. I have been thinking about ordering from Tapesnake a custom sticker set.. something simple, unique and cool.

-John

you are right about the potential of airsal 70cc, but with the mhr 80cc team you will get unprepared around 20hp.

[J11]

Yea, but I like to port the cylinder by myself. Also it's kind of a sleeper with the Airsal 70cc cylinder.. nobody can belive it has that much power. I have build the engine to have an "angry nature." And that's how it works.. the powerband is very violent and causes the front end to lift up when accelerating on first and second gears (I have almost flipped it over on first gear, when there was enough grip and the cluch held).

Today is tested the bike with a rpm meter.. highest rpm was 15,200rpm when riding. On 5th gear it reached 14,900rpm before I changed gear and on the 6th gear it revved up to 15,100rpm because of slipping clutch.. top speed was 105km/h@gps this time.

[J11]

Alright.. so finally an update.
The stock conrod's big end bearing got damaged.. it lasted 6.6 hours. Didn't last long..

So I have ordered parts from Scootfast and Maxiscoot.. I've updated the #1 post, so there's the final setup.

I'm expecting to get about 25bhp from crankshaft with E85 fuel.

The engine should be re-built next saturday (week 47) with new parts. After I have jetted it and abjusted the ignition correctly, I'm getting it dyno'ed.

Going to post some pics of the cylinder and crankcases tomorrow when I finish the porting.

[derbi-ftw]

To bad the stock conrod's bearing failed xd.

Can't wait for the pics of of engine, cylinder and crackshaft, keep going.