Derbi Start V (Fiiiiiiiive)

So I got a cheap ol Derbi Variant revolution. Being a guy who can't ever leave things alone, I of course want to modify it?

So school me on these start v engines, do they share anything with older starts? Any Threads or websites that can help me learn more about these?

What manufacturers make dope stuff for these I hear Metrakit.. Looking for a crank I am coming up short? Does anyone make hop up cranks?

Weak points?


Re: Derbi Start V (Fiiiiiiiive)

todd amundson /

We get the Start stuff from Spain

Pabloass is really good

Re: Derbi Start V (Fiiiiiiiive) has a few parts for start v right now, barikit sells one I guess. Is the crank bad on it? I would say if it is has never been touched by anyone seeking performance, rip those starter clutches out and slap one of those mk black baffles on it.

Re: Derbi Start V (Fiiiiiiiive)

+1 on the starter clutches. Dude in our shop has a start v on the bench now that the starter clutches exploded. The PO of this particular bike thought it would be a good idea to take off the nut and weld the variator to the input shaft, so we’re trying to figure out what to do next.

Spanish YouTube is your friend, mopedcorral, dos, pablo ass and mil anuncios if you have whatsapp and decent spanish/portugese skills. Start V produces a decent amount of power as is. The one at our spot has a MK blue baffle and stock everything else. Pulled pretty hard until the starter clutch thing.

Re: Derbi Start V (Fiiiiiiiive)

Put some real handle bars on it first!

I second the starter shoes, lose them

Go up and tooth or 2 in front (mb5 front sprocket is the same and works)

Flat reed cylinders and intakes work on them

And scooter clutches go in the rear. I have a stage6 for a minarilli horizontal in mine works great! You can use the matching clutch bell but it needs to be machines down a little for it to fit

Re: Derbi Start V (Fiiiiiiiive)

The stock cylinder has pretty decent porting compared to a moped, but the exhaust port could be opened up. The carb is a SHA clone but kinda small, 14/12 i think. It wouldn't take much to make it a quick bike.

Re: Derbi Start V (Fiiiiiiiive)

The stock crank is great, there is no need to replace it unless you are trying to stroke it, then you can stuff a jog crank in there if you do a little machining.

Stage 6 rear clutch, polini variator, and a pipe, and the thing will rip. There is a lot to be gained with porting, (or just get a 70 metra and do wheelies everywhere you go).

Re: Derbi Start V (Fiiiiiiiive)

I want that 12mm Piiiiiiinnnnnn

I have found Barakit cranks makes what I need.

Re: Derbi Start V (Fiiiiiiiive)

Blake Totally a real doctor /

Start 5 should already be a 12 pin. Start 3 engines come with 10 pins and sometimes people swap to a 12 pin crank.

Re: Derbi Start V (Fiiiiiiiive)

I picked up a start V and I plan to run it with the stock cylinder. I did not get a carb with it. What would be a good carb to run with a stock set up?

Re: Derbi Start V (Fiiiiiiiive)

Phva is a good one for the size constraints. I personally use the polini carbs on everything. If you gut the wiring and hack the frame a bit you can Even for a tm24.

Re: Derbi Start V (Fiiiiiiiive)

Well I haven't started working on this yet but I have a set of EBR forks which will get new handlebars and controls.

I have NSR1 wheels coming from japan... although they have been stuck someplace for a month now.

I have a Barikit Racing crank and will be getting a Stage6 R/T70 kit here shortly.

The clutch splines are the same as minarelli? I have a Piaggio Stage6 Clutch here...

Re: Derbi Start V (Fiiiiiiiive)

Splines are the same but I think you have to use the corresponding bell, stock clutch bell is smaller? Don’t quote me as I’ve never played with the transmission on a start v, only ever seen others tune their scooters.

Re: Derbi Start V (Fiiiiiiiive)

Well those EBR's will work... Just not without making new trees with the NSR1 wheels. they are too narrow.

So I grabbed a set of already lowered YZ85 forks I had.. They will need a new Steerer made up but that ain't no thing. Even these are too narrow but if I flip the legs left to right and modify the spacers it should work. I may have to machine down the Rotor surface to move some stuff around too...

Rear Swingarm will need some work too. Well.. alot of work.

Re: Derbi Start V (Fiiiiiiiive)

Check out Barry Torno’s derbi revo, I think his handle on insta is barrytorno. I haven’t seen it posted in a while, but that shit is untouchable. He and the Motomatic boys built a ridiculously fast bike for an amazingly athletic rider. He is definitely the fastest moped racer in the states.

Re: Derbi Start V (Fiiiiiiiive)

That thing is pretty rad, diggin the spoked wheels.

This guy has sorta done what I have done, looks like he used a steel NSR1 swingarm and forks on his. Mine will be a little different. I have a YZ85 Aluminum swingarm I am going to hack up to make work. Or possibly some other Aluminum swingarm.

Also had a kinda inventive way to make a reed block that allows bigger reed/intake and still allows the bushing spacer block. At least on paper anyway. (edited)

Re: Derbi Start V (Fiiiiiiiive)

YZ85 Swingarm. RT95cc....

Or I also have an RT70cc

So the RT70 would suit the Start 3 crank really well.. But the Start 5 crank is 2mm short of what is needed for it to be proper.. so I don't know which direction i am going in yet.

Re: Derbi Start V (Fiiiiiiiive)

I'm going to spitball some stuff here now,

So for front variators there are 2 options, the polini and the malossi.

But MAYBE anything that will fit a CPI/Keyway 16mm crank will ALSO work.

Looking at the star nut for the front drive face they also have a 15mm spline with a 16mm od.

So that means also a Stage6 Sport Pro kit will work, and further if you took the ramp plate from the sport pro possibly make an R/T Variator also work, Unfortunately though the drive face from that is splined directly and wont work.

This also means a bunch of front plates may fit as well.

There are also a bunch of 16mm DDR/Apex 4 wheeler kits that are non splined so they can also be mounted but would require a splined drive face to operate

ALSO Polini stuff may also work for the EVO cranks, as I think these are special 16mm

Re: Derbi Start V (Fiiiiiiiive)

Swingarm work continues

Tacked it together, still need to make the bolt plates. Also my cutout on the side for rear pulley clearance needs more cut, stock pulley hits and I want to try and run an oversize pulley.

This swingarm is so much lighter than the stock derbi one.

Re: Derbi Start V (Fiiiiiiiive)

Well, ya win some ya loose some.

So the front variators are a bust. They use the larger rollers, which means that by the time you get the variator on the crank you have no splines left.

However, they do physically fit, which means the 16mm CPI front faces can for sure work.

I ended up using a Honda Ruckus variator with the boss and ramp plate machined out to 16mm as these use very small rollers which will allow everything to be sandwiched real small and still give over range to the front.

The front plate is a malossi I will bore out to 16mm, the factory key along with a 16mm malossi key both fit just fine. It is slightly larger than stock.

The rear ! oh boy.. After seeing Barry @ Motomatics setup(La Furia Rossa) I was inspired.. I could see that the kickstart cover would not fit though, which for me on a street ripper is not my cup of tea.

So I bought a S6 R/T rear pulley because, well it was the cheapest option to fuck up!

So pretty much ANY rear pulley will work, but the minarelli ones are spaced the closest to a derbi in regards to the front bearing and rear. You need to pull the rear bearing out and bore the pocket out 1mm to accept the derbi sized rear bearing (HK2018RS)

I think If I turn down the od, use a stock width belt slightly longer this will all fit under a stock kickstart cover, Ohhhhh yeaaaaaaaa. Also to get over range you can't run wide belts as it will eat up your variator spacing..

On to the cranks.

I love me a long rod. No really, long rods are the best. If you keep your rod stroke ratio up in the magic 2.0+ range you make a very rev happy engine. Plus you can play with port timing as well as the longer the rod the more TDC and BDC dwell and mid section piston speed increases

What bummed me out was that it looks like the big pin on both the start3 and start5 are 16pin. I have some 18 pin cranks here and longer rods but no 16 pin stuff. So off to the pro-x site I found a Honda MBX50 rod fits, is 91mm long and will give me that long rod I so desire. Hahah, Rod.

And the last piece of the puzzle, I have both a Stage6 R/T 95cc or a 70cc

Both need to be messed with as the 95 wants a 44mm stroke and the 70 wants a 40mm.. My start5 is a 42mm.. I am leaning towards the 70 as its easier to machine the head up, make the baseplate thicker and center the ports then move the ports around a bit to suit.

Also this 95cc you can't get anymore.. But I did toy with the idea of making a stroker 2mm crank pin and going that route as well.

Wheels I am going to have to run spoked. I have some 2.5" aluminum 17's on the way. After I pulled the NS1 wheels apart I found a big hollow in behind where I was hoping to bore back the bearing pocket and move the sprocket in. I think I will instead try and graft them to the MB5 I just picked up.

That brings me to today.

Re: Derbi Start V (Fiiiiiiiive)

Keep it coming! Really enjoying and learning some stuff!

Re: Derbi Start V (Fiiiiiiiive)

Brandon Weiss (Detective brandon to you) /

Wow, this is good stuff. Keep it coming

Re: Derbi Start V (Fiiiiiiiive)

Russell Huddy /

What crank are you running that has a 42mm stroke? Start V should be 39.6

Re: Derbi Start V (Fiiiiiiiive)

I wont argue with you because I don't know for certain as I have not measured it, but aren't the start3 40 and the start5 42?

I am certain I have found this on the internets, but the internets has lead me astray before.

If it is indeed 40, that makes everything EEEEEYYY ok.

Re: Derbi Start V (Fiiiiiiiive)

Sounds like you may be right.. Well that makes my life a tad bit easier.

Re: Derbi Start V (Fiiiiiiiive)

Russell Huddy /

Start 3 is 37.9 with a 10mm wristpin (edited)

Re: Derbi Start V (Fiiiiiiiive)

I got a cylinder from Spain which the seller said was a 65 cc cast iron metrakit for a Derbi start v.

I installed this on my Start V motor and the piston is 15 mm from the top of the cylinder deck.


This came with the cylinder.


Is this the wrong cylinder? Any way to overcome this?

Re: Derbi Start V (Fiiiiiiiive)

Blake Totally a real doctor /

65006 should be a pyramid reed cylinder.

Re: Derbi Start V (Fiiiiiiiive)

EH 📣FCC of the QCB /

> Blake MD No PM Plz Wrote:

> -------------------------------------------------------

> 65006 should be a pyramid reed cylinder.

Ya with the longest stroke of all durpies

Re: Derbi Start V (Fiiiiiiiive)

What is the ideal gearing for a start 5? I have a 13 tooth front sprocket and two rear brake plate and tire.

One rear wheel has a welded on 33 tooth and the other wheel has a 38 tooth.

I saw buttcheek said to go up two on the front sprocket.

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