anyone rebuilt a derbi? need pointers

working on reviving another pile. engine was partially apart and had half of the internals taken out before i got it. most of the internals were sprawled in a box, im not sure what im missing, as usual.

cases say "derbi rabasa coaxial"

i found a shop manual online but it seems like the engine internals they have shown are different than the one i have. the pics here show two internal chains, the parts i have only seem like one is used as there are only two sprockets.

DFB9E71F-1195-420F-A2F6-F38C249C96D4.png

unfortunately i didnt realize my engine was different until it was too late....the weird clutched gear exploded on me whilst trying to figure out the puzzle without the proper diagrams.

i lost two tiny spring-loaded ball bearings that went flying around my shop. i have the spring, but does anyone know if i can just toss some balls that fit decently in there?

7166DB16-0ED8-4519-9C9C-3775BC43F132.jpeg

my other questions:

1--anyone know what size/length is the internal chain? the one i have is broken.

2--do i need washers on the outside of the shafts, between them and the inside case halves? what about between the claw collar? here is how i am assuming the internals get assembled, does this look right?? the arrows point to the areas i am wondering if i need washers, circled areas as well. the pedal shaft internal sprocket has washers ziptied in place from previous owner.

8EBEEC21-7D7B-42ED-BE21-4B9B7975893B.jpeg

Re: anyone rebuilt a derbi? need pointers

3-- in the above photo, the right side shaft has a large double needle bearing that fits inside the mini output shaft. that same bearing will fit on the left side shaft, without it the left side gears dont fit on the shaft properly. is it safe to assume there are two of these and im missing the other?

7412DBEF-475B-4221-81BC-7D4013325314.jpeg

4-- last question....what the fuck is this arm mechanism? whats its function and does it attach to anything internally?? (yes i know the bearing is supposed to be open, im leaving shield on for protec until its ready for assembly)

85A19D49-B019-4543-81A8-911AF28811FD.jpeg

sorry i know this is a lot, but i appreciate any pointers!! or if you can link me to the correct engine manual as i could only find the one and its not right. thanks

Re: anyone rebuilt a derbi? need pointers

Downhill Harvey (OFMC) /

This might help,

http://homealonemopeds.blogspot.com/search?updated-max=2014-03-05T12:21:00-08:00&max-results=2&start=8&by-date=false

I know what you mean about it not matching the manual pics, freaked me out.

#4, is the pedal engagement. (edited)

Re: anyone rebuilt a derbi? need pointers

Those ball bearings are a total booby trap

Re: anyone rebuilt a derbi? need pointers

Arm mechanism is #11in the drawing. Do you have the little tabs that sit in the arm?

Re: anyone rebuilt a derbi? need pointers

idk if I remember right but I think the internal chain is some weird/non-standard size. I think this guy is your best bet: https://www.treatland.tv/USED-derbi-piston-port-internal-chain-gear-p/derbi-internal-chain.htm

Also, on the pedal engagement feet, be sure that they’re facing the right way when you get everything back together. My first pp rebuild, the bike would randomly pop outta gear cuz I put them in backwards

Re: anyone rebuilt a derbi? need pointers

Downhill Harvey (OFMC) /

Make sure you sand the pedal shaft smooth, you'll have a hell of a time separating the case, if there is rust on the pedal shaft.

Re: anyone rebuilt a derbi? need pointers

i think the arm mechanism is to engage/disengage the engine from the pedal function. it puts the bike in neutral.

last time i rebuilt a PP was 20 years ago.

i have a Derbi PP manual if you want to buy?

Re: anyone rebuilt a derbi? need pointers

correction.

i have the flat reed repair manual.

bottom end rebuild procedures should be the same.

bearing you will need: one of each, 5 bearings total

6301,6302,6203,6304,6006

seals you will need:

35x 50x 7 need 1

16x 24x 4 2

10x 16x 4 1

17x 30x 7 2

20x 35x 7 1

HK 1612 3

belt is Dayco 7188

don*t buy your bearings off of Ebay.

they are all Chinese.

go to your local bearing house in your city.

Re: anyone rebuilt a derbi? need pointers

sry dude, FR and PP/PR bottom ends are different. good news is I’d argue pp/pr is easier

Re: anyone rebuilt a derbi? need pointers

> iskra chornia Wrote:

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

> sry dude, FR and PP/PR bottom ends are different. good news is I’d argue

> pp/pr is easier

As long as you don’t mix up the shim locations or take the stacks apart, yes.

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account