a55 uni filter

what size is the main jet?

Re: a55 uni filter

there is no jet in a filter

Re: a55 uni filter

it comes with one.

i am not a _complete_ retard!

Re: a55 uni filter

it comes with a main jet a secondary jet and a infuser but i dont know the size cant remember, i need to know also to upjet mine. i think it was a 68 or 58 written on the jet but it was hard to see. i hope you find the size for sure so i can get the next size up from it too. i have the uni a55 carb kit too but it was loud so i hoged out the stock airbox and it worked fine and was quiet too....starves for gas at about 42 i think that means its time to upjet

Re: a55 uni filter

i am not affraid of a little noise, as long as i get the preformance. what size carb does a a55 have?

Re: a55 uni filter


the Dellorto PHVA carb on new A55's is a 14 or a 14.5mm somthing like that, but dont worry you can squeeze plenty of juice outa them.

i got the a55 upgrade kit from 1977*

it came with a bigger infuzer, idle jet, and size 58 main jet.

i ran way too loud, and way to lean.


i made a high flow silencer

check it out here break>

and i had to upjet, prolly because of my technigas exhaust.

right now im runnin a 66 with the needle all the way up. and its OK.

more jets are on the way, cuz im throwing my kit back on.

so. if you dont have a pipe, and want the kit, id pick up jets in the 60ish range along with it.

and make a silencer, they sound way better that way the uni is seriously 5X louder than stock and sucks to ride kinda (:.


Re: a55 uni filter

if your on a 2001 tomos, the kit i think your talking about isent for you.


Re: a55 uni filter

what does raising or moving the needle position do?

Re: a55 uni filter

you have a A55 engine with the PHVA carb?

raising or lowing the needle settings fine tunes the gas mixture out of the atomizer inside the carb. that infuzer tube that the jet screws into, and the needle stabs on the other end.

the deeper the need= less fuel= more lean the mix

the further out= most fuel out of that jet= richer the mix

really it affects top end mostly. getting the exact mixture makes the ride very responsive and fast.

Re: a55 uni filter

interesting...i have the a55 streetmate 05 model. with a bored out airbox, snorkel removed and a 58 jet from the unipod carb kit. it runs 38 to 42 but seems to starve for fuel at 41+ i have to let up on the gas slightly to make it go to 42 and 43. im thinking of getting a 60 jet to try and fix the problem, i also stall on takeoff like a stumble or hesitation when starting off. i hope the jet will fix it... any ideas oh i have a performance exaust. the one that looks like factory but is straighter under the engine........

Re: a55 uni filter

sounds like you are jetted high not low

Re: a55 uni filter


I have an '08 Streetmate R with a biturbo, and pretty much the 1977 mopeds A55 carb speed kit. My bike does 45 on the flats....51 downhill Imeasured with GPS). In your case I think that you are running the Tomos performance package from Steve's Moped. The exhaust looks stock, but doesn't have the bend at the end of the header part of the exhaust (under the engine). I think a 58 main jet sounds about right (i belive the performance package came with the 58 jet). When it stalls off the line, it most likely means your idle mixture is too rich. From the sounds of it, you should lean out your idle mixture screw. I have a buddy that has your setup and his idle mixture screw is about 2.5 turns out. Let me know how this goes.

Re: a55 uni filter

raise your needle and see how that affects the top end.

here in the biz we call that a flat spot.

did you get a bigger infuzer or idle jet?

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