Derbi Pyramid Reed Kits?

I know that the cylinder pattern from puchs/tomos are close enough to fit pyramid reed engines, but what to do with the existing intake if i were to purchase a puch kit? weld it shut? please let me know with any tips. thank you.

Re: Derbi Pyramid Reed Kits?

bad ass scooooooter kitttt

Re: Derbi Pyramid Reed Kits?

campeona del mundo /

make a plate that bolts on to block it off. If you have access to a cnc you could make a dummy reed block to help increase case volume.

Re: Derbi Pyramid Reed Kits?

you mean decrease case volume?

Re: Derbi Pyramid Reed Kits?

campeona del mundo /

ooops yup gotta keep tha case volume down!

Re: Derbi Pyramid Reed Kits?

Nope. Here is all I'll say in this thread, and the last time I'll look at it.

Derbi mopeds came with three engine sets.

1 - Piston port , same stroke as Puch. With modifications you can out a puch cylinder on a derbi piston port bike. Super easy swap back and forth. If you are somewhat clever.

2 Pyramid Reed Derbi. Same stroke as piston port but with case inducted reeds. Not easy to swap things around, because you have case induction. So technically you could run puch kit if you stuffed up the case.

3 Flat reed. Basically the last edition of derbi. Much like a bunch of scooters. Very similar stroke to hobbits and minarelli horizontal scooter kits. Lot's of blasty options but not puch kits. These have DISsimilar bore and stoke to the previous two DERBI motors.

End of story.

Re: Derbi Pyramid Reed Kits?

campeona del mundo /

dual carbs

Re: Derbi Pyramid Reed Kits?

just put a flat reed kit on the pyramid reed case...

you get the longer stroke of the pyramid reed, and the bigger bore of the flat reed.

you need to bore the case some to let the skirt in. and make a baseplate about 3/8" thick to get the piston height right. the cylinder studs are good as is.

Re: Derbi Pyramid Reed Kits?

WHOAH there partner. Put yours together first before offering advice :)

Re: Derbi Pyramid Reed Kits?

campeona del mundo /

or you could get a flatreed con rod pressed into the stock pp/pr crank no?

Re: Derbi Pyramid Reed Kits?

it's "together", though not done...

it's the same kind of advice as putting a puch kit or scooter kit on. same amount of work and knowledge is required.

so yeah, if you don't know what you are doing, don't do it.

Re: Derbi Pyramid Reed Kits?

why bother with the different con rod? so you don't need the spacer?

id think a spacer is a better way to deal with deck height. the other con rod might still not be perfect and still require a spacer.

also the spacer lets you transition the ports between the case and kit with more meat to work with.

Re: Derbi Pyramid Reed Kits?

campeona del mundo /

well, seeing that i don't have access to the tooling to make a 9.5mm thick spacer, pressing a flatreed rod seems a bit easier.

yeah the stroke might not be perfect, but it would at least be within a couple mm of the proper stroke at which point I could handle making a thin base spacer.

if ya got the means to make a huge spacer go for it.

Re: Derbi Pyramid Reed Kits?

tooling? a vice and a drill and a dremel would get you a spacer easy. pressing on a conrod and truing it seems way harder. you still probably need a spacer with any kit that isn't specifically designed for your engine.

also changing out the rod wont give you a different stroke. the stroke is set with the crank. so unless you can get the cheeks off the flat reed crank and onto the pyramid reed crank, you will still have the same stroke.

the pyramid reed crank stroke is only larger by a few mm anyways. and the longer stroke will lengthen duration and might help things.

Re: Derbi Pyramid Reed Kits?

campeona del mundo /

hmmm seems like i don't know what im talkin about then!

always wanted to try a flatreed metra on a pyramid reed but i'll just stick to me pyr mk65

Re: Derbi Pyramid Reed Kits?

King Drunky JCams /

bad ass scooooooter kitttt

Re: Derbi Pyramid Reed Kits?

🇮🇹💦 Of the Loin /

yeah id think it work fine, its only a 3mm difference, it might help things out even

Re: Derbi Pyramid Reed Kits?

Here are a couple pics of a pyramid reed case and a flat reed kit. In the first one you can see how the case was bored out to let the larger cylinder skirt in. In the second is the spacer, which needs to be matched to the kit and the case. In the third is the kit on and the piston at TDC. Works out pretty nice.

Derbi-1.jpg
Derbi-2.jpg
Derbi-3.jpg

Re: Derbi Pyramid Reed Kits?

not a Baron Asshole /

YOU WILL need more spacer for that to work, but maybe thick base gaskets between will solve that? let us know how goes

thanks

pete

Re: Derbi Pyramid Reed Kits?

It's not done. Thick base gaskets might solve it, and it needs at least 2, one on each side of the spacer. Also I haven't cut the head yet for the larger bore.

You're welcome.

Re: Derbi Pyramid Reed Kits?

then there is the short stroke derbi 37.4mm stroke lik on the urban, and the furax they have 2 times the transfer size as the normal flat reed, they also all were ks

Re: Derbi Pyramid Reed Kits?

like other peeps said, just use puch or pp kits and cap the intake on the cylinder... just dont forget to add the third eye.

case induction trumps pp all day.

Re: Derbi Pyramid Reed Kits?

im in too.

i think the skirt of the piston has to be trimmed, at least 5mm, i only have the airsal one, i bet that crazy purple one would fix some stuff.

Re: Derbi Pyramid Reed Kits?

campeona del mundo /

you talkin about the teflon coated vertex piston? that thing is blasty

Re: Derbi Pyramid Reed Kits?

I used the teflon vertex 47mm piston

On May 24, 2012 5:00 PM, "Steven Sabatinelli" wrote:

what piston did you run?

i need something way taller. i may just trim this airsal one, if i can do it

but cant even get a rotation right now. bleeh

good think about having two motors i guess.

Date: Thu, 24 May 2012 14:32:44 -0700

Subject: Re: stupid fast derbi's

From: jimmy nolan

To: SABAT!

yeah i ran a flatreed motor with a piston port crank

On Thu, May 24, 2012 at 2:31 PM, Steven Sabatinelli wrote:

ok, so im acctually taking a different approach here, i think somewhere in boston theres some flatreed cases, but they may have been lost.

im going to double check the kit, ect but im trying to mount a 40mm stroke cylinder on a 43mm stroke crank.

now im going to have to mock it up first, but the piston crown will travel approx 1.5mm past the exhaust (possibly into the crankcase) and prob, 1.5mm out of the cylinder bore.

soo, if i get a 3mm base gasket, and recess the head i should be clear.

but you ran this with a flat-reed bottom end, thats my now investigating problem....

anything special @ the base? so you only modified the crank, and head?

Date: Thu, 24 May 2012 13:50:57 -0700

Subject: Re: stupid fast derbi's

From: jimmy nolan

To: SABAT!

hey there... so yeah we machined a derbi piston port crank so it would fit in the flatreed cases. i still have the motor actually i was thinking about selling it, maybe..

the piston, not sure where it lines up with a regular flatreed motor? but in any case yeah you would either have to have the head machined down or in depending on the alignment of the wrist pin.

as for rebuilding a derbi heating up the crank bearings on removal is a must and for assembly i made a crank pulling tool. its a common tool for pressed bearing cases. i read what that guy sent you and i WOULD NOT DO WHAT HE DID!!

Re: Derbi Pyramid Reed Kits?

heh, i assume that bottom email was in reference to the email i sent you about crackin the cases. a crank puller would be quite nice.

Re: Derbi Pyramid Reed Kits?

hahaha yep, im thinking about making one, but i'll most likely use heat/mallet

but i was prob gonna re-use the tranny, pedalshaft seals to safe munny, only replace crankseals and the drive sprocket seal.

Re: Derbi Pyramid Reed Kits?

bumpers, lets talk about splitting the case.

any examples of case splitters?

Re: Derbi Pyramid Reed Kits?

🇮🇹💦 Of the Loin /

oven: 250 degrees: 15 minutes

Re: Derbi Pyramid Reed Kits?

and just mallet the.. crank-Shaft> pedal-shaft >Counter-Shaft

in what order and how many times each?

this is gonna be HellRaiser all over again

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