Aprilia sr 125 tuning...

Hi guys... I've got stef's old aprilia sr125, and recently brought another engine with a 172cc malossi kit and 28mm dell'orto carb...



I wondered wether the discolouration on past the rings ment the rings were leaking? The barell looks fine, and the crank appears fine too...





I'm in two minds wether to use the 28mm dell'orto carb... Could i use the 172cc kit with the standard 20.5mm carb...

If i could, what jet do you guys reccomend using with either carbs?

Cheers, Lewis.

 

i'd use the 28mm but u can use the 20.5 aswell as

really not sure on what jet tho..supose it depends on if ur useing the airbox or filter etc

 

Currenty a 125 with kundo pipe, malossi foam filter... Running 100 main jet, standard rollers...

Would you upjet more for the 172 with 20.5 mm carb... Its overfuelling i think atm... I could start with a 105 jet and see from there?

 

jet size

i've just bought 172 kit from psn he gave me 86 main jet thats with standard airbox and exhaust

 

Re: jet size

86... Thats a tad low isn't it? Have you fitted the 172 kit? How does it run?

 

jet

i'm gonna put it on tomorrow night i thought it was a bit low myself but the geezers at psn seem to know what there on about i'll let you know when i get it together

 

midland scooter centre tell everyone a 98jet with an open filter on 20.5 carb lol..to be fair my bike ran sweet with that jet...

 

i ran a 90 jet with my 172 with a filter. i then ran the same jet on the standard airbox

it still didnt make it go any better though :w00t:

 

Na,. this is my first time with a 172cc... It should be a good laugh

So you reckon between 90-100 jet with a filter should be fine imp:

Cheers all

 

known runner 172's with k&n mesh style filters to run 104's, every bike will run different, best bet is to buy a range.

 

i run my bike with a open air filter with a 172 kit and 25mm with a 105mm jet
but my with my new 172 and pm 59 and 25mm carb i will be running a 108mm jet

 

not one engine will have universal carb setups, every engine is different and requires different carb setups due to manufacturing tolerences, rider weight and sea level. so your best off just using what works as a ROUGH guideline and going from there in small increments. if you want a 172 on the bike and running, standard airbox rough guide on 20.5mm would be 86-90
25mm rough guide would be 100-106
28mm rough guide would be 100-108

if i remember rightly an old mate matt had a ported zip172 and was using 112 and over jets in his 28mm Delly

(edit : just asked him and it was actually 140 with open filter on 28mm delly ported engine haha )

 

so what jet sizes should i try in 28mm delly off a rs 125 with open filter on me 172 a/c ,standard pipe ? why is nobody else using these carbs ? you can pick em up for 20 nicka ? gotta be better than spending 150 quid on malossi carb kits

 

well a 28mm is harder to set up and the real benefit its a higher top speed if gearing allows

people just want speed so dont bother with a gear up around town