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Arrow 2008 de restricted jetting q

22K views 31 replies 14 participants last post by  pego30 
#1 ·
Hiya everyone finally got round to de restricting the rs

It's a 125 2008 model

Put an arrow pipe on and just put the jets in as per standard aprilia full power settings got a bit of conflicting advise regards jetting and was just wondering what everyone reckomends

Bike is now standard fp part from the arrow pipe

Many thanks for the help and advise

Tom
 
#2 ·
got an email yesterday from a VERY GOOD bike tuner about jetting.

"aprilia rs 125 with 28mm carb + race pipe should run 125main jet"

theres a good starting point for you........ oh and it was bob farnham
 
#4 ·
steele01

slightly off topic here,

but looking at starting to de restrict mine over the next week so please keep thread updated to help myself and others the main jet you used

which will help me determin what yet to use for my jolly moto

anyway my question is to you is .'
did ya drill the hole in the cdi as per the aprilia de restriction manual if so did it display any errors on the dash ie efi warning light or any others, after ya done
 
#11 · (Edited by Moderator)
anyway my question is to you is .'
did ya drill the hole in the cdi as per the aprilia de restriction manual if so did it display any errors on the dash ie efi warning light or any others, after ya done
I've got 2008 RS125 and I derestricted CDI first (drilled the hole).. and I had EFI warning light.. but then I fitted a power valve and there is no EFI warning light anymore


EDIT:

Btw.. derestriction manual from Aprilia for 06+ models says that restricted 11kW bikes have main jet 132.. and full power bikes 185

And now you guys talk about 120 jet.. I'm confused
Mine is 132.. not fully derestricted RS but running lovely.
 
#6 · (Edited by Moderator)
not drilled it yet got the parts today been waiting a month for them lol typical aprilia will let you know how I get on

only reason I was asking before doing plug chops

is that it states on the instructions 185 max jet seemed like quite a big difference (maybe just me)

after all knowledge is power lol (whole point of forums)

Thanks lads

will let you know how I get on regards the drilling sure a full power cdi is 60 quid

Tom
 
#7 ·
quick update drilled the cdi Mate works perfectly small hole that the drill bit fits in perfect
no errors flashing up runs pretty good but a nasty stutter on the lower revs

did a few plug chops and its coming out black sooty so gonna have to change the jets pulls like a steam train though above 7000
 
#8 ·
good glad to hear working ok.

will be doing mine soon jus waiting on blade and blade housing to come
 
#14 ·
the carb in the new shape bikes is not the PHBH it is the VHST 28 CD carb :) so the jetting is totally different to the PHBH got the service aprila instructions if anyone wants them on how to fit the kit on the later bikes

has info on jetting and the pictures are in colour

still messing with mine though as the bikes idle is intermitent probs down to the arrow pipe got to fiddle bout and sort that out As the idle adjustment knob isnt doing squat

but got the plug a lovely tanned colour just cut out a few times yesterday whilst riding so got to do some more tests when I get a replacement tiny spring or the car (the supressor was loose on the top of the plug so probs that

all the best,

Tom
 
#15 ·
Ok here we go not responsible for anythin you do use at your own risk

but here we go :) here is the instructions for the 08 bike should give you a better overview found on another forum





















quick note when messing with the conical rod be really carefull of the tiny spring not to loose it lols they are 1.58 from delorto on the site

Hope this helps you lads just explains the general proccess

Tom
 
#16 ·
im about to put my euro3 rs125 full power,

ive ordered the same race exhaust as mentioned in the above documents, and found on various parts websites the main jet (185), min jet (s45), and conical rod (d53).. powervalve + sparkplug also on their way soon

im having trouble finding the 'throttle valve 50' ref no. 14 part no. 856104

can anyone help me? anyone know where i can buy this?
 
#17 ·
Aprilia Yorkshire mate also go under the name of ultimate parts Adrian there has been a massive help aver the past Wei and a bit can't recomend them highly enough

If you find our hike model on the site then it's on one of the carb bits. I'd post a link but can't so it on my iPhone
Hope it hleps

Tom
 
#21 ·
looked on both websites, on the aprilia yorkshire the carb for the 2006 model you can buy the whole carb but description is "Carburettor phbh 28 bd" which is old style carb? so im guessing the parts are only for the 2006 facelift model (which was shared alot of parts from the older rs125's, including old style cdi + rave unit)

going to have to give them a ring, how much in total did it cost you to buy the bits to do the carb? i was thinking no more than £30?
 
#23 · (Edited by Moderator)
Aprilias RS125 onwards had 2 types of carburettors fitted PHBH 28 or VSHT 28. On apriliayorkshire.co.uk my carb is not available.. I found mine on apriliagenuineparts.co.uk in CarburettorIIII section
http://www.apriliagenuineparts.co.uk/compo...or-iiii-694.php

So 08 RS125 with PHBH 28 needs a main jet 128 for full power apparently.. but mine which is VHST 28 needs 170 main jet for full power.. I was thinking about getting 34mm carb but my bike has got a few more cables with connectors coming from a main loom ending by the carburettor area: there is some sort of additional electronic sensor fitted to the VHST 28 carburettor I think (running with that unplugged doesn't change anything except the EFI warning light is on).. and there are 2 more electric cables connected to the body of the carburettor - grounded at carbs body only, ending there. Apart from that there is a hose going from carb to another electronic piece of crap.. again unpluging it doesn't make any difference to how the carb works. 34mm VHSB carb doesn't have all those electric connectors.. All the other bits are the same as in VHST 28 so in theory I could be able to run 34mm VHSB carb however with EFI warning light on (pretty annoying for me) unless I take the bike to Aprila and they sort the warning light out later.

For the time being I'll keep my 28mm carb and just rejet it.
 
#27 · (Edited by Moderator)
update on how my derestriction is going (euro3 2007 rs125, vhst28 carb)

powervalve & solenoid fitted and working
cdi drilled + working
racing exhast fitted (no cat)
airbox snorkel both holes cut open
secondary air pipe from exhaust blocked off
correct spark plug fitted (br10eg)

and I changed carb bits as per the aprilia service manual (posted on page 1 of this thread) which was 185max jet, min jet s45, d53 needle, throttle valve 50 and the bike wouldn't rev above 6k.. seemed like an electronic fault stopping it from revving correctly.. tried re-seating all electrical connectors, tried revving with various connectors unplugged - all gave me no joy..

anyway got a mate round whos a bike mechanic and he checked over all the stuff, he was happy it was all done correctly to the aprila manual... he suggested putting the origonal max jet in (132), and the bike now runs properly!

so with the 185max seems to be putting far to much fuel into the carb, the bike can't burn it fast enough and it can't rev high properly..

but with the 132 jet, went on a short test run and bike performed as expected - full power, powervalve opened, it flew keeping up no problems with my mates FP rs125

just going to do more investigating now to jets and carb settings.. i know they are set to run lean from factory because the euro3 exhaust is catted to hell and they need to run lean to cope with the exhaust.. so maybe because my exhaust now is completly open (no cat, race exhaust) and the bike is full power, the same max jet in adequate?

any opinions or suggestions?
 
#29 ·
Hi, first post!

hello lee this is Rob by the way, got some info for you guys.

Just checked out my bros 2009 RS 125 FP Euro 3. found out some interesting stuff, the bike is totally standard apart from the cdi drilling. it runs ok to about 80 mph but does feel limited. the standard carb settings are all over the place.

FULL-POWER JET = 170

CONICAL ROD = D53/1" (clip 2nd from top)

MIN. JET = U36

THROTTLE VALVE = 45

Mixture screw = 3 full turns from full in (i think?)

its like a mixture of 11kw and full power? well going to be testing some stuff in a few days so will let you know. later Rob
 
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