big derbi kit. Little Carb. Littlier intake.

I gots a flat reed 87 derbi variant. Currently has a 15 sha, dremeled out stock intake to somewhat match the carb and some wild jormans pipe from dos cycles.

Should I break in a 70cc metrakit with the SHA? Any idea what jetting I should start with? I want to keep things simple right now, I am burnt out and get confused easily. (edited)

Re: big derbi kit. Little Carb. Littlier intake.

SHA will do the job on reed kits just fine. not as rippy but enjoy the fuel miles

Re: big derbi kit. Little Carb. Littlier intake.

Probably Fred /

15 sha fine but make sure you run a head temperature gauge to watch for seize temps

Re: big derbi kit. Little Carb. Littlier intake.

that's good. I figure I will get new kit up and running and switch to a PHBG eventually. Any idea on jetting?

Re: big derbi kit. Little Carb. Littlier intake.

classic carl jepsen /

dont add one of those triple stack dork wings. Those greatly reduce gas mileage and performance....

Re: big derbi kit. Little Carb. Littlier intake.

i hit mid 60's with the metrakit, sha 16.16 stock intake and big muff. literally nothing special done, just tuned well. stayed sub 410* for miles and miles too.

-yes gps's :)

Re: big derbi kit. Little Carb. Littlier intake.

man I believe it. I hit 40 with just this leaky 15 and a pipe. Haven't touched the variator yet. These derbs are magical.

Re: big derbi kit. Little Carb. Littlier intake.

I just started messing with my variant sport.

untuned 15 sha and literally nothing else. 38mph and torquey too. Debating on just leaving it as is. Derbi magik is real.

Re: big derbi kit. Little Carb. Littlier intake.

you all dremel out your stock intake? Thats what I did, bits it looks pretty janky and restrictive still.

1977 has a 15 sha intake for sale, but I don't feel like waiting 3 months

Re: big derbi kit. Little Carb. Littlier intake.

Nope I didn't open up the stock intake. I have a couple other FR intakes (metrakit i think?), i'm gonna see if one fits a sha.

And are you talking about the rubber intake? I dunno if i've ever seen one of those on a bike.

Dremeling it out should really be fine though.

Re: big derbi kit. Little Carb. Littlier intake.

Got an MLM h90 bolted to my stock PP with 16 inch wheels and no tuning. 12mm SHA. 36mph on the radar message sign. Got a 14mm phva to try next.

Re: big derbi kit. Little Carb. Littlier intake.

There's a variator restrictor you guys should really remove. It's an easy 5-10 mph

Re: big derbi kit. Little Carb. Littlier intake.

Timo runs a 12 on his and still does a solid 50....

Re: big derbi kit. Little Carb. Littlier intake.

so your sayin im gonna blast?

Re: big derbi kit. Little Carb. Littlier intake.

Dirty30 Dillon /

Daniel '' Wrote:

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> There's a variator restrictor you guys should

> really remove. It's an easy 5-10 mph

Elaborate

Re: big derbi kit. Little Carb. Littlier intake.

Re: big derbi kit. Little Carb. Littlier intake.

pleasssseee. this search engine makes me wanna kill myself

Re: big derbi kit. Little Carb. Littlier intake.

Dirty30 Dillon /

◕ ‿ ◕ Wrote:

-------------------------------------------------------

> https://www.mopedarmy.com/forums/read.php?7,2118298

> ,page=1

>

> I should probably start a derbi Wiki

Thanks for the link, I've perused that thread more times than I care to say. Just curious what Daniel's 5-10mph restrictor is. If it's in the rear variator, I'm all ears.

Re: big derbi kit. Little Carb. Littlier intake.

Dirty30 Dillon Wrote:

-------------------------------------------------------

> ◕ ‿ ◕ Wrote:

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

> -----

> >

> https://www.mopedarmy.com/forums/read.php?7,2118298

>

> > ,page=1

> >

> > I should probably start a derbi Wiki

>

> Thanks for the link, I've perused that thread more

> times than I care to say. Just curious what

> Daniel's 5-10mph restrictor is. If it's in the

> rear variator, I'm all ears.

Isn't it like a washer/shim guy in the front var that keeps the cheeks from closing all the way?

Re: big derbi kit. Little Carb. Littlier intake.

https://www.mopedarmy.com/forums/read.php?7,1944908,1944959

relevant posts by shaw:

shawdog ( shaw) — Feb 29, 2008 02:09AM

What year variant...couple a different ways to handle this ...is old belt trashed...is rear tensioner functioning right ? Im gueassing its the varitaor with three weights..? You can machine the rear tensioner where the two cheeks come together...there is alittle space there to get some more tension...you pick up a little bottom end with that mod...how are gettin the belt on you got that giant socket...? that rear tension set up needs a special puller...as does clutch.. can be made out of front wheel drive axle nut email me if you want...shaw

shawdog ( shaw) — Feb 29, 2008 02:36PM

If you take the belt off you can see that the rear pulleys do not touch ....there is room there for a noticable gain ...the inside of those pulleys can be machined down with out a loss of strength so they pinch more and then you can machine the front pulley down in where the belt sits at low speed to make it sit lower in the "V" don't machine into the higher part or this will effect top end.. this will make that bike rip out the hole...back too OG prob ..I think you stretched the belt cuz that variator dremel job does not affect belt tension those belts are hard to come by and yes you should always take variator off to change those belts and they cant be gettin oily ...If you could find a 6 roller variator and put that on there with only 3 rollers and then do the machining ...also that stock pyramid cylinder can really fly... get a metra puch 65cc piston and have that thing bored out and a port job...love them derbeeez...oh that belt is rumored to be the same belt as some bakery machine(for reals)...hahaha serious though...If you cant find one I could dig one up as I already promised a lady with a derbi one ..better see how many I got ...good luck (edited)

Re: big derbi kit. Little Carb. Littlier intake.

Lee Hoffguy Wrote:

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> Isn't it like a washer/shim guy in the front var

> that keeps the cheeks from closing all the way?

Yes, restricted models had a plastic? bushing that prevented the front pulley cheeks from closing all the way. Most have been removed by this point.

if you're not doing 45 on your derbi, any setup, something is wrong.

Re: big derbi kit. Little Carb. Littlier intake.

Tommy are you talking about transmission mods or am I missing something? Stock equipment can do 45???! (edited)

Re: big derbi kit. Little Carb. Littlier intake.

Jonathan R Wrote:

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> Tommy are you talking about transmission mods or

> am I missing something? Stock equipment can do

> 45???!

yes, we're talking about transmission mods.

Most Derbi's with a pipe on a stock cylinder will do 45 easy. It's all about porting and tuning your transmission. Starter clutch mods also help you achieve powerbottom status. (edited)

Re: big derbi kit. Little Carb. Littlier intake.

Stock flat reeds usually had two restrictors to get them to do 30.

There is a plug in the intake, and the shim on the variator, just removing those, and taking 3 balls out a new derb would do 42 with no other mods.

Re: big derbi kit. Little Carb. Littlier intake.

Dirty30 Dillon /

Ton of info Tommy, thanks.

I ride my derbi from Brooklyn to Manhattan every day, and I feel like it's got more to give. Running Gila 50/Zen 50/Bing 15. The bike pulls really well through the mid range, but is definitely topping out in the low-mid 40's. Kind of wishing I had just ramped up the displacement originally.

I know I have to pull my variator weights, they're just some spare tjt's I had and they wear out crazy fast.

I've also been considering swapping the Bing out for a 15.15 SHA, but the bing's needle is a big plus. (edited)

Re: big derbi kit. Little Carb. Littlier intake.

are you variating fully? stock gearing? case match that gigantic third transfer? squish? sorry, coming on strong

Re: big derbi kit. Little Carb. Littlier intake.

Sucks Derbi wiki is so incomplete

BUT at the same time like how derbi knowledge is blk magik status

Re: big derbi kit. Little Carb. Littlier intake.

Easy guide:

Go to rally

Find derbi

Lurk in hiding for owner

Approach owner with beer

Learn

Re: big derbi kit. Little Carb. Littlier intake.

A2 Andrew Wrote:

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> Sucks Derbi wiki is so incomplete

> BUT at the same time like how derbi knowledge is

> blk magik status

not for real though. There's not much on them in the forums or wiki because there aren't really any tricks, they're mad simple.

1. metra 47

2. 4 petal and like any carb over 15mm

3. CDI

4. good pipe

5. clutch springs

Re: big derbi kit. Little Carb. Littlier intake.

I mean, aside from the restrictions, there really isn't much secret to the setup. It's on pretty much every Derbi that I know of. Also, it's one of the few that's still in production and widely available for now. There was older faster shit but she gone.

the only black magick is maybe minutia detail tuning, but that's in the same vein as any other Vespa or Moby or Peugeot or Hobbit, in terms of getting the most out of a variator?

I prefer to ride desk chairs to mopeds these days anyways. (edited)

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