Hi Scootfiends ',;~}~

Hi folks - middle aged owner of a 2004 Piaggio Skipper ST 125 here, trying with very little money to get it back on the road after 2 years standing, and having a tough time of it so far lol!

Not used to working on scooters at all (like peeling a bloody onion without ever getting to the centre... ) so really hoping I can bug some help from anyone here esp. who's familiar with this model and/or the leader type 4T engines - the summer is wasting (and today - 'washing'!) away, along with my travel plans whilst I struggle to diagnose and repair the sickly old girl.

I do have some general experience with engines, as well as electrical/electronic stuff so hoping I'll be of some help to someone else as well.

Good to be here!

Be well all,

ReverendSkipper/Shaun

 

Hi,

Welcome!

I'm an old(ish) owner of a 2007 Peugeot TKR 2 that is getting a rebuild at the moment, with a bit of retro restyling thrown into the mix. My original experience with anything resembling a scooter was with Lambrettas and Vespas and you had to be a gynaecologist to do anything on the engine! I tended to stick to bikes rather than scooters and did some racing on 50cc bikes in Moped Mayhem back in the late '70s / early '80s on a modded Yamaha FS1E.

I prefer 2-strokes although I have stripped and rebuilt 4 stroke bikes too. Tell us what the symptoms are and we'll try to get your baby back on the road where it belongs.

 

Was a 2 stroke fan too when I was younger, and if I was racing a small bike or cart I'd likely go 2T, but for the road I can't afford the extra fuel or limited reliability when pushed of running a 2T!


OK symptoms - off road for 2 years, replaced battery and it was a bitch to start. When it did it wouldn't idle and ran rough as hell at lower revs but would rev out and pull cleanly higher up.

Carb went to bike garage and got a manual clean - it started and ran mostly fine, apart from it spluttered/stuttered and bogged at lower end i.e. when trying to pull out of a junction, almost dying altogether on occasions, and this got worse the hotter the engine got.

Fiddled with more stuff then got the carb ultrasonically cleaned - went through the bath 2 times and I was told loads of sh*t came out, but it made no difference - to me it feels like it's over-rich at lower end.

It started getting worse and eventually wouldn't start.

I checked the auto choke which seemed fine, but I replaced anyway - no difference, plug check showed sooty plug, cleaned plug and it started again.

I discovered the boot on the accelerator pump was loose, and figured maybe it was pulling excess fuel and air through that carb circuit, re-seated it and it seemed much better, but then died on me and refused to start about 3/4 mile from home.

Pushed it home again, checked the carb wasn't flooding (it didn't seem to be), cleaned the plug and again it started fine, but 'bogged' and stuttered at the lower end still, then again died altogether and wouldn't start.

Idle mixture screw has been tried anywhere from 1/2 turn to 3 or more turns out during my tests and it doesn't cure it at any point.

New coil arrived today 'just in case' but it's been drenching it down all day so far so not had a chance to fit it, clean plug and try again, yet...

Scoot is booked in for valve lash check/adjustment next week because at first I suspected that, but now just want to get it done anyway as it's done 10K+ miles and before I got it I haven't a clue if the oil was changed regularly, the oil filter ever, or generally how the engine had been treated.

Before I left it stood for 2 years apart from a dodgy start motor it had been totally reliable, would pull up hills at 4 or 50 mph and topped out easily at indicated 63mph, plug colour seemed to always be right too.

I wondered if the piston/rings were shot and it was burning oil (sooty plug), but it seems a bit too sudden to me, but my mechanic is gonna do a leak-down test for me anyway...

And that's where we're at here so far, so any ideas please feel free to help! - I'd planned to be off to the lake district on it this or next month but that's not looking too good right now, heheheh...

Cheers again Merlin!

Shaun.

 

As a seafaring priest I thought ReverendSkipper apropriate lol!

Cheers Mark appreciate the welcome ',;~}~

 

Sputtering and bogging down from low throttle settings sounds like the carb needle needs a bit of tweaking. Take the carb top off and remove the throttle slide from the cable. Carefully remove any W-clip or plastic clip that holds the carb needle in place and take the needle out.

The needle will have some circlip grooves in it and you need to note the position that the circlip is in before you make any adjustment. Putting the circlip on a higher groove will slightly lean out the low throttle mixture and a lower groove will make the mixture more rich.

I would try taking the circlip up one notch and try that - if it gets worse, then try it one notch lower than the original setting. If it improves slightly, try going up another notch (this obviously depends on how many notches the needle has - my Pug has five notches on the carb needle).

Try this and report back how you get on.

 

Hi again Merlin - the needle on this particular carb is fixed/not adjustable and the little support washer it's pressed into is right at the top of the needle so it couldn't be dropped anyway. Coupling this with the fact that the engine/carb etc. has had no modifications since the time it ran perfectly and I can't see it being a mixture adjustment related problem - if there is too rich a mixture getting through then I think it has to be due to some kind of carb fault - something by which extra fuel is escaping or being forced into the venturi?..


Shaun.

 

Update - went to fit the new coil, and the new plug cap only fits threaded spark plugs, and the metal 'bulb' on mine doesn't come off to reveal threads, so I went to swap the plug caps - the one on was marked as a 5K Ohm resistor cap so I decided I'd check it first - it measured open circuit even on highest Ohm setting, and I wondered if I'd found the problem - an open circuit in the high voltage circuit can cause the coil to break down inside giving all sorts of horrid symptoms, and has also been known to damage CDI units (eek!)...

So anyway I took the spark plug to the bench grinder and re-shaped the top to fit the new cap, fitted it all and it fired almost before I hit the start button lol!

However it still ran like crap, bogged down, cut out and refused to start, so no matter the coil and HT lead and cap were not causing my symptoms...

I am hoping the open circuit plug cap has not damaged the CDI because, well, I don't much fancy paying for another immobiliser one, and won't buy an after market non-immobiliser one because my insurance would go up, and I am so broke I make broken things look fixed by comparison...

Looks like I'm gonna have to wait and see what results come from the valve lash check/adjustment before knowing what to look for next... !

Oh well, onwards and uhhh... onwards!


Shaun.

 

Is it a diaphragm carb on your bike? If so, I would maybe suspect a split in the diaphragm.

 

One of the first things I checked bud - it's a Keihin CVK summinkorother - diaphragm looks brand new in fact.

Cheers again,

Shaun.

 

The state of affairs so far - took her into the bike shop a couple days ago for valve lash check and cylinder pressure/leak-down test - cylinder pressure good, valve clearances were measured at 0.1mm inlet and 0.15mm exhaust - exactly what they should be even after 10,000 miles - wasn't expecting that!

So neither of those things is the issue but 60 quid cost (incl. new spark plug), still worth having it checked out.

Mechanic managed to get it started on the bench and is under the impression it's an electrical fault and we are both thinking CDI - the original plug cap was open circuit, and I know an open circuit HT/secondary can damage CDI units due to high voltage and high frequency EMF and RF produced getting to it via the coil wires so that will be the next thing to check...

In better news though I managed to secure the Skipper I got the 'new' clocks from, that has only done around 60-100 miles, for £300! It's only 60 miles away, and since they can't let me have the main frame section (single part with the frame number on) due to the particular write-off category law they received it under, the rest will fit into my FIL's large estate car and we can collect it any time after Friday afternoon. <G!>

It's even the same colour as mine, with fully intact body panels in near perfect nick all-round - any luck this 'donor' should get me back on the road and keep me there for years to come, and looking tidy too.

I forgot to ask if he had the keys with it, but it may well be that this is not an immobiliser model anyway since there was no LED or connections for it on the clock's film circuit board (I drilled the clocks, added the LED and wiring to the plug for the immobiliser light to work on my scoot).

So if it is the CDI etc. either way I should be able to get it running and can always add an immobiliser feature back at a later date if I want to.

Also now I finally get new wheels since mine are corroded and porous under the rubber and lose pressure over the week, then will be able to get my old ones cleaned up with old tyres fitted for quick swap emergencies etc. - I made my Sito plus exhaust into a 2-piece so it's quick to get the back wheel off...

I'll post an update after we get the parts and if there's still a problem to diagnose I'll start a new thread in the appropriate forum.

Cheers folks, and be well.

Shaun.

 

LOL! Well not up to much riding no, heheheheh... ',;~}~

 

I love threads like this, tinkering is te bes way to keep these scoots on the road,

good luck with her!

Sean

 

And if i is there is always duct tape (JK!)

 

It got me home when a suspention uni sheared off, it held the mirror on my 50 on for 10 miles, it has its uses

 

Silence is golden, duct tape is silver (ask the wife).

 

oohhh reallly now