PX125 with SIP 2

[pauliewalnuts]

Hi all,

I'm a newbie on here and realitive novice when it comes to working on my scooter.

Within the past few months I bought a mid 80s non-kitted PX125 (non autolube) with a SIP 2 exhaust which I'm now having starting problems with.

It can sometimes take 15-20 kicks to start - even if it's only been switched off for a short time so I left it into a local scooter mechanic to check, he said both the spark and compression were good and has recommended replacing the SIP with a standard exhaust (it did start after 3 or 4 kicks whenever he disconnected my exhaust) but I would rather keep the SIP if possible - anyone offer any advice? Thanks in advance

[pxguru]

The exhaust has nothing to do with the starting. If everything is good then it is just getting too much fuel. Check all the jets in the carb are 80's 125 spec and that the pilot jet is tight in the carb. If all is still correct then it is just the mixture screw is too far unscrewed. If it is an original 80's carb, it should be set near to 1.5 turns out from fully in.

With the engine running, set a fast tickover, then wind the mixture screw right out more than 4 whole turns. The tickover will drop a little lower now, so speed it up to about 1500 rpm again. Then slowly wind the mixture screw in until the revs really speed up, continue winding until the revs don't go any faster, then back out slightly. Turn down the tickover and check that it revs off from slow tickover without hesitating. Switch of the engine and check how many turns out the mixture screw is now set at. Should be somewhere near 1.5 turns if it isn't you need to come back here again.

[pauliewalnuts]

Thanks for your reply.

The mechanic reckoned my SIP exhaust was choked up and that's what was stopping it from starting. He recommended either replacing it with a standard exhaust or putting the SIP on a bbq for a few hours to burn off the build-up of inside it. As I said I'm a novice, does this sound plausible or bs?

[citydaz]

You may need to decoke your exhaust - ive done this in the past with a small wire brush and caustic soda.
Ive never heard of putting it on a bbq before?

wont the sausages get in the way?

[ironsloth]

I've also heard of people lobbing them on a fire, if anyone has any better ideas, please post them up.

[scooterbooter]

Over night soak in caustic . easy. Putting it on a fire sounds old skool. Or b.s..

[henri]

overnight with caustic soda , the fire methods old-skool brit bike method .you need to be able to scrape away deposits with a bit of wire as pipes heated for it to be effective, not really a option with a box scoot exhaust .H

[pauliewalnuts]

Thanks for all the replies.

Before I take this exhaust off to decoke, what's the thoughts on the following jet set-up for a non-kitted 80s PX125 engine with a SIP 2 exhaust... 42/140 idle, 140 air corrector E3 mixer 94 main jet?

As I said I'm a novice but from what I've read online it doesn't sound right to me and I'm wondering if this might be part of the problem?