Restricted derbis?

We were poking at this derbi my buddy picked up a while ago and noticed a curious bit.

In the intake, there was this little aluminum ring. It looked like the top hat in a monopoly game, except there was a hole in the top. I think the inner diameter was like 9 or 10mm, so it was obviously a restriction.

I am wondering if this is normal, or if there was a derbi model that is castrated and not fastable, like a PA50 that sucks major balls and is a hassle to make fast.

If there are other restrictions, anyone know what and where they are? Is there like a system of rating, like a sachs with A B C and D or the puch 1 1.5 or 2 hp or the motobecane or peugeot ratings? If so, how do I tell what it is?

It is a 1980 variant sle in case that helps.

Thanks in advance.

Re: Restricted derbis?

The revolutions were restricted, its possible that the earlier ones were too. I don't think there was a rating system, i think they just stuck the stuff on there so they could make the bikes legalish to sell on the American market.

Re: Restricted derbis?

there is a spacer in the variator of some derbis.

Re: Restricted derbis?

My new revolution had a restriction washer in the exhaust at the opening and the intake plug. My Variant had an intake restriction and a spacer on the variator.

Re: Restricted derbis?

Not a derbi, but I had a spacer in the variator of my grande, replaced it with a smaller one

Re: Restricted derbis?

When we are talking variator spacer, are we talking about like on a vespa when you have to grind down that brass bastard in between the cheeks?

If we are just talking about one of those and the ring in the intake, thats cool. I can handle that. The exhaust is no worry, seeing as how I will obviously be getting an expansion chamber asap.

Whats the run down on derbi exhausts?

I was looking at the ninja, but word on the street is they are not so hot. The malossi one that treats sells as the giant muff looks pretty tempting at 100 dollars. I have a Leo Vince on my revolution I might swap over for a little bit until I get a new one.

Re: Restricted derbis?

Yeah that's the one

Re: Restricted derbis?

The intake restrictor was the difference between 1.5 and 2hp bikes. They all had the variator restrictors cause it keeps the bike under 30 per federal moped laws in the 80s.

Re: Restricted derbis?

bore that shit out!



15 mm

this was on my variant america. it had the variator restrictor washer too. i had a 3 weight and just ditched it for a tjt, huge boost just with that.

Re: Restricted derbis?

Yeah, I was planning on boring out the intake to 14 or 15. I have a 14 or 15 sha laying around to toss on there right away.

I am going to have a spare variator from a revolution here, I might see if that might work.

Re: Restricted derbis?

Revo variators won't work on any other derbis

Re: Restricted derbis?


Well I guess I have to find a 6 roller off of a newer model derbi.

Maybe I will try notching out a spare hobbit variator and see what happens.

I am not going to have the loot for a TJT for a little while. Going to go for a pipe first, maybe a kit too.

I have heard mixed reviews on the TJT. I am not convinced its worth the loot.

Re: Restricted derbis?

apparently it makes chins hobbit wheelie to 50mph and max out at 70mph

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