Air leaks

[5v3d3b0]

I'm pretty sure that I have air leaking in somewhere, but I don't know where to look.
Basically the bike dies if I rev it unless I have the choke on. Everytime I pull away I have to have the choke on, so my plug gets fouled very quickly and I have to clean it every day or two.
I've tightened the carb and filter like a maniac, reed block is also good. Where else could air be getting in, and how can I check/solve it?
Getting a little desperate cause I want to sell the bike ASAP

[Hutchysrs50]

what bike is this on? if its the 2005 tzr.. i have a 2004 tzr 50 and have just posted a similar problem... anyway...

you could spray some WD40 around the manifold to check

but i have had the same problem with my yamaha pw80.. i just needed to change the carb settings and it runs fine now..

[5v3d3b0]

It's an Rs 125.
Do you mean changing the mixture?

[Hutchysrs50]

Yeh, i had a little fiddle on with the air mix and idle screw

been running fine every since...

[5v3d3b0]

I'm not really good at that cause I've never done it. Any magic tips?

[Hutchysrs50]

just see if you can keep the bike running

if you can keep it running use a flat head screwdriver to turn the carb screws about 1/4 of a turn at once and see if it gets any better, if your unsure which screws do what, look for a digram on the internet.

[Hutchysrs50]

just see if you can keep the bike running

if you can keep it running use a flat head screwdriver to turn the carb screws about 1/4 of a turn at once and see if it gets any better, if your unsure which screws do what, look for a digram on the internet.

[5v3d3b0]

The carb is a dellorto 28 PHBH
Which way is rich/lean? And which should I start with?

[Hutchysrs50]

just try the air mixture screw first, and i dont know, sorry.

and i dont know which one could be messing up your bike, try both ways

[cagiva gezzer]

Idle circuit is too lean.

https://i67.photobucket.com/albums/h294/supercitybity/Cagiva/DSC04295.jpg

Screw at bottom right near oil feed on the PHBH28. Turn it out half a turn and give it a go. If it feels worse, turn it back to how it was and screw it in a half turn (whole turn from where you were).

The RS carb might be slightly different to the cagiva one. . .
____________________
"because one stroke isnt enough and four strokes waste two"

[Hutchysrs50]

yeh just keep trying that, you can go more than half a turn but not at once, you can go half a turn in let it idle for abit, and then another half turn in...

you cant go wrong aslong as you remember how many turns you have done so you can put it back to how it was.

[5v3d3b0]

Doesn't really seem to solve the problem which ever way I go...
Was slightly better half a turn out, but still choked when giving it gas when stationary. When I did more turning out it got worse, and turning in was even worse

[stirlinggaz]

hi,
doesnt sound like an air leak.
sounds more like your carb isnt set up properly.
done any modifications to it recently? exhaust/pv, air filter?
changed the main jet?
read kickstarts guide to the dellorto carb on here, it will give you an idea of how it all works.(excellent introduction to carbs, many thanks Keith)
then take the carb off, give it a good clean & set it up properly, idle adjusted,correct size of main jet,needle at correct height, mixture screw at stock settings- 2 & 1/2 turns out iirc)
& doing a couple of plug chops till you get it running as good as you can.
cheers,
GAZ
ps - let us know what exhaust,airfilter & other mods you have & what size of main jet is in there now.

[5v3d3b0]

Everything on the bike is original except the cylinder is mitaka but still 125cc.
I just had an engine rebuild and i'm about 150 miles into the running in process

[5v3d3b0]

Bump