Ronnies rough runner!

[ronnie66]

Hi
I'm new and have recently aquired a Vespa fitted with a LML 125(150?) engine.
I am just learning about these engines as I've been away from the scene for best part of 30 years!
The engine ran well up until a few weeks ago, then overnight it drained itself of fuel via the exhaust!
Approximately half a gallon!, I noticed when taking it off the stand it ran out of the exhaust.
I took the plug out and turned it over a good few times to dry it out a bit before stripping down the carb cleaning jets and checking float etc.
It took a while to get started after that and now it starts on choke but once warmed up pulls sluggishly and back coughs on full throttle.
It has a blue box (electronic ignition??) instead of a coil/condenser and a little oil leaks around the exhaust manifold if this may indicate anything.
I would appreciate any help, advice or tips.
Cheers
Ronnie

[henri]

first guess , all that fuel going down the pipe has moved the carbon sludge/burnt 2 stroke an partially blocked the exhaust ,
2nd guess , you havent re-assembled the carb quite right an main jet might be blocked , or even missing , H

[pxguru]

I read it like the float needle is worn out. That will fill the exhaust with petrol

[henri]

yep,i read it as he'd overhauled the carb ,but as pxguru saw you dont say you'd replaced the needle valve ,just cleaned , if needles worn engines goin to be permanetly flooding , H

[ronnie66]

Jun 12, 2015 19:01:32 GMT henri said:

yep,i read it as he'd overhauled the carb ,but as pxguru saw you dont say you'd replaced the needle valve ,just cleaned , if needles worn engines goin to be permanetly flooding , H

Hi Henri & PXGuru
Thanks for the advice, I really appreciate your shared knowledge.
I have ordered an overhaul kit to rebuild the Jetex J20/20LN carb and I've taken the exhaust off and have it soaking in chemicals.
There wasn't much carbon in the exhaust port area but what I did notice looking in at the piston, it was heavily scored on the piston skirt and the lower of the two rings looked as though it was stuck in flush with the piston wall.
Could this have something to do with the original problem?

[ronnie66]

Henri/PXGuru
Please can you catch my updated finds above and comment if you have any knowledge to share
Thanks
Ronnie

[henri]

a jetex carb ,ive only ever seen 1 of them ,guy on here "fredperrybruce" , not on his scoot tho ,he switched to a dellorto/spaco straight away , they dont have a good rep , mostly as there stock on lambrettas gp's an can be crap out the box new ,
if the scoots been bad seized an ring is stuck in piston it could give dropped compression so might contribute to rough running , but as scoot was running good til it flooded dont think thats the case , overhaul the carb an i'm reckoning scoot will be good again , its rare i pull a head off an dont see evidence of past soft seizures .if ya fingernail gets caught rubbing it ,that needs smoothing out ,otherwise leave alone , H

[ronnie66]

Thanks again Henri
I will take your advice and get a replacement carb instead of overhauling the Jetex.
In your experience which carb would be the ideal replacement for the current J-20/20LN ?

[henri]

a spaco 20/20 with genuine dellorto jets in it , failing that spaco jets ,but do try n find dell 1's , H

[sime66]

Might be worth a punt if you're quick:

www.ebay.co.uk/itm/VESPA-PX-DELLORTO-20MM-CARB-WITH-2-SPARE-JETS-READY-TO-GO-/261918931510?pt=LH_DefaultDomain_3&hash=item3cfb95ba36

[ronnie66]

Thanks for the link,
I was Watching that item, along with all the Indian ads!!
Just Bid n bought it, so hopefully it's a good one!
I will get the exhaust cleaned out today n fit the dellorto when it lands, fingers crossed the rings are ok.
Once again great advice and thanks for all your help and support ALL of you!
I have also been looking into dating my Vespa as it is a Vietnamese import from around 2006 and is registered as a Douglas Vespa 1969 year of manufacture.
It was given a 'H' year plate but looking into the history of Vespa models it looks more mid 50's style.
Could it be retro styling? Or just a bit of a 'mongrel!'
It is a Faro Basso style low light with no speedo and 'cycle' style handlebars. Frame number is on rear near side behind fixed side panel (no stars just the number 50H5169) original engine was swapped by previous owner to a modern LML unit!
Is there any way of checking the date of manufacture or does it sound about right?
Again any knowledge greatly appreciated.

[sime66]

Good, glad you got it. I’d have gone for that if I was looking for a 20. Now you must have a NEW, RED tipped float needle:

www.ebay.co.uk/itm/Genuine-Dellorto-4-5mm-Float-Needle-for-Vespa-SI-and-PHBL-PHBH-Carburettors-/291476630651?pt=LH_DefaultDomain_3&hash=item43dd5c6c7b

And, if you’re feeling flush, and want to give it a good overhaul, so you know it’s a good’un before installing, I’d be stripping it cleaning all the jets and replacing all the gaskets and washers:

www.ebay.co.uk/itm/Genuine-Dellorto-SI-Carburettor-Gasket-Set-Vespa-PX-T5-/291481499504?pt=LH_DefaultDomain_3&hash=item43dda6b770

Maybe a float too, but you can check that when you get it; they ain’t cheap, so wouldn’t unless it needs it.

Here’s good for checking frame numbers (what prefix have you got?):

www.scooterhelp.com/serial/ves.serial.numbers.html

Might not be quite so straightforward if you have something of ‘mixed heritage’ though. – and.... let’s have a look at it then?!

[ronnie66]

Thanks again sime
Your second link is the same as the first but it's fine I hunted down a gasket ad on eBay for the dellorto.
How the hell do you upload pix onto here?
Is it because I'm using my mobile?
I tried the other day when I first found this Excellent site to introduce my Vespa etc but I couldn't work it out.
Not the best with modern technology!!
Thanks
Ronnie

[sime66]

^I’ve updated the gasket link to keep things tidy^, and because Wasp are good. (I was in a bit of a hurry before).

I mainly use photobucket on here for photos, there is a mobile app, but my phone won’t install it. Using it from a PC is easy though; I did a guide a while back:

vespa.proboards.com/thread/4282/quick-guide-posting-photos-photobucket

I’m also changing over to Flkr now too; more storage space and better size images. Both of them are easy enough to use after a bit of trial and error – we even got Henri posting splendid pics with style now.  

[henri]

thats a bit of a odd chassis number ,its in right place for a italian 1 ,but has a more douglas type pre-fix ,but douglas fitted there chassis numbers on a ali rivetted plate on engine side ,
most likely its a indonesian scooter built out there , when piaggio introduced the vbb line the old tooling for "faro-basso" an vnb types was shipped lock stock n 2 smokin barrels to indonesia , an the earlier type scoots where built up into nearly the 70's .the douglas bit on v5c is coz dvla never removed the name from box to tick when douglas stop being sole importer for piaggio in mid 70's , H

[henri]

oh , an i had my eye on that carb too, but as i dont actually need it an was just being greedy for a bargain let it go, i'm happy you got it . H

[sime66]

Jun 14, 2015 16:19:31 GMT henri said:

oh , an i had my eye on that carb too, but as i dont actually need it an was just being greedy for a bargain let it go, i'm happy you got it . H

me too - worth it just for spares, but it's good to share, eh.

[ronnie66]

Hi guys
Thank you both for letting me have the Dellorto carb on EBay very kind !!
I've ordered the gaskets and new float jet too from your Wasp link sime66 (thanks again).
Exhaust is gleaming on the inside! And ready to refit.
I didn't get too much carbon out of it though.
Waiting for the postman now!

Thanks
Ronnie66

[ronnie66]

Hi Again
An update on my progress (or lack of!) regarding my 'Roughrunning!'

I removed the exhaust and chemically cleaned it,(not much carbon in it.)
I got a Dellorto carb to replace the Jetex 20/20 currently fitted.
I stripped , checked , cleaned the Dellorto carb out and replaced the red tipped float needle with a new item (even though it looked ok) and fitted new gaskets and seals etc. the only gasket joint unchanged was the base of the carb to the chamber openining , this had a lot of loose blue sealant which I cleaned up and then refitted (without sealant just existing used gasket?? Possible air leak issue?)

The bike will not start now at all!
There is petrol in the carb float etc, on removal the spark plug was 'wet'

On turning over out of the head, there was a spark at the plug too.
I tried bumping it off in second gear, it threatened to fire a couple of times before back spluttering /coughing(!) with slight backfiring but nothing else!:-(
Any thoughts Vespa Gurus?[
]Could the timing be the obvious next suspect?

Many thanks in advance
Ronnie

[sime66]

It’s often quiet on here over the weekend, so in reply to your PM, I’ll have a go at giving you some new lines of enquiry, but I ain’t no guru:

The first thing you said was that you'd filled your exhaust with fuel, so I reckon it's best to be sure you've sorted your carb out before moving on from it. Reusing your old carb gasket was not a good plan; I’d definitely redo that properly, with a new one – I make my own because the bought ones are a sh↑te match. Air leaks could be your problem now; either here or ………..

……at you flywheel, so after doing the carb properly, it’s probably time to have the flywheel off, check the woodruff key, and that the timing hasn’t slipped, then on to the flywheel-side seal – check/replace that.

Those should have your fuel and airleaks sorted (you can check the head as well, but not necessarily next step), after that it’s probably time to see just what sort of a spark you have, which will be going through the electric from stator to spark plug, checking as you go – but ^^^ there’s ideas enough there ^^^ to get you started finding and fixing the problem, and we can go into the electrics more if we get that far without finding the problem before then.

I asked a similar question about eighteen months ago, not identical symptoms, but similar areas to look at for cause, and these are the sort of areas to look at; have a read here, so I don’t have to re-read it and type it all out again here………..

vespa.proboards.com/thread/3724/cutting-out-idling-revving-own

It’s just a question of working through the possible causes to eliminate or fix them, starting with the simplest/most likely/easiest or cheapest first………….

Mine ended up being electrics – I changed my stator and CDI and it was splendid after that – but I’d done everything else before then too! I’m not suggesting this will be your problem, and it is still best to work through the possibilities as you are doing now – because it hasn’t fixed it doesn’t mean it’s the wrong thing to do, but to eliminate it as a cause you need to do it properly.

vespa.proboards.com/thread/3831/stator-overhaul


(I see you had a go at posting a photo – you’ve done it directly from your computer, without uploading it to a photo-sharing site, which might work, but I think you’d be better off following the method in the previous link, but I don’t imagine that’s so important right now)

[vespasco]

A quick check you can do with a multimeter is to measure resistance between the red and white wires of the blue cdi...this will test your ignition coil...it should read 110 +/-5 Ohms

If you have use of a timing gun then certainly check your timing

Maybe you dont have these things, so make sure that new carb is not flooding, as if it is it will cause similar symptoms..wet plug and spark.

But personally i would take off the cylinder to have a look at those piston rings you mentioned as lack of compression would make it not run rough/ not at all (and you have fuel and a spark)!

Id love to see this vespa

[ronnie66]

thanks for the response guys. always greatly appreciated.
easiest first step would be the carb base gasket, this aroused my suspicion so will source some quality gasket material and make one up.
i will need to purchase a timing disc and flywheel removal tool as i don't possess one yet before i try the other steps.
i'm guessing "Wasp" will supply them Sime, it has an LML II engine 125/150?cc fitted.
Will a PX puller fit do you know as i notice there are different sorts on the market!
i notice too that the blue cdi unit is bound with electrical tape and is catching my eye as to why. (Previous owner applied!)
A long shot but would the fuel tank tap/filter possibly have a part to play as it completely drained itself of fuel? and may have part blockage etc.
also............a simple query, what are the positions of the fuel tap i.e.: on/off/reserve as i can't tell!
i have a timing gun and multimeter so i will try those roads too if i have no luck before.

thanks

[sbwnik]

I thikn I know that scooter, did it come via the North West?

[ronnie66]

Hi Sbwnik

No, as far as I am aware it has never been in the northwest
(Unless anyone recognises it and can fill the gaps!).
It was imported in 2006 by a lady in Edinburgh but she didn't register it.
The guy who I bought it from in Feb this year lived in Marske (Cleveland) and he owned it for just short of 2 years, using it regularly on the road.
It has a Local reg number so i'm guessing he first applied for British registration around then.
There is a 6 year gap that needs filling if anyone can help.

Ronnie

[ronnie66]

Re: Sticky Ring !..............

Hi again,
I am still awaiting my flywheel puller in the post.
I got bored and decided to look into my suspect piston rings, which looked to me as if the lower ring was stuck in the groove.
I removed the head to find that the low ring was fine and free BUT the top ring was the jammed ring!
Approximately half way round was stuck in the groove, showing signs of blow past on the top ring.
Could this be the source of my original problem?
On comparing the two rings one looks a good quality ring (how I remember rings looking when I last played with bike engines 30 years ago!) the top ring looks 'rough cast on the underside and duller metal than the bottom one
I have worked it free and cleaned all up but will need a head gasket set sourcing (any suggestions on a decent make/supplier so that I don't end up with inferior cheap crap!)
Also are the rings interchangeable as they actually fit better in their opposing groove or do they have to go in as they were?
Any comments or advice, greatly appreciated.

Many thanks
Ronnie

[henri]

theres no difference in rings so they could be swapped , but i'd be tempted to throw a new set on whilst youve got it apart , if you swap em i'm not sure if you'd need to "glazebreak" as there in same bore just slightly different areas ,
if all ya want is headgaskets ive a few , i buy lml genuine gasket sets but dont use the copper gaskets on my vespa , yours for postage as there no good to me , H

[ronnie66]

Thanks Henri
How much for the gasket and how do you usually pay for things on here paypal/ cash in post/other?
Please advise and I'll sort payment.
I need the copper upper head gasket and also I am struggling to find a woodruff key (see below!) and a carb bottom gasket too if you have any of them spare to sell.
I have ordered the head base gasket this morning and am awaiting this through the post.
Re: progress with my Vespa problem...................
I am going to put new rings in but how do I measure them to get the correct size? (Daft question but I've never bought them before!) any tips?.
I read with interest Sime66's blog regarding his stator issues that he kindly forwarded to me from last year and on removing my flywheel found that the woodruff key was completely ground flat ! (Big help Sime?)
I noticed also my stator plate was set at 'A' which I believe is 23 deg BTDC(?) I'm guessing my engine should be 18BTDC, (LML II, 125/150cc?)
could these issues be a major part of my problems?
I haven't taken the stator plate off yet, I will check the wiring between it and the CTU tomorrow to hopefully eliminate it from my enquiries!
Thanks
Ronnie

[sime66]

From a quick read you seem to have half-done several jobs; carb, rings, stator/flywheel/woodruff/timing – that’s OK, they will probably all benefit from attention, but in doing it this way you’re likely to fix it without knowing what the problem was. I can see that she might be suffering from multiple ailments though.
I’d have gone a more methodical route, eliminating one job at a time, but no matter. (For example, how are you going to check your timing without knowing if your carb is right, and without rings?)
H is advising and sorting out head and rings, I have no doubt he’ll find a carb gasket too – it’s the sort of sh↑te that tends to accumulate; I’ve got one kicking around on my desk somewhere actually – it isn’t even worth a stamp because it’s so far from being the actual shape you need, by the time you’ve cut it to fit you might as well have made one.
Anyway, that’s the carb question sorted for now too.
Timing: I have my 150/177 set to 19°, that ain’t gospel – it’s just what I ended up with after asking on here. In any case the markings on the stator are a guide and you still need to set and strobe your timing to be exact – though using the stator markings (when you’ve replaced the woodruff key) will probably eliminate it as a cause of your problem. In any case, if you really have a flattened woodruff key there is no guarantee you have any sensible timing set at all. These little odds and sods are easily obtainable from a local scooter shop if you’re lucky enough to be near one; or Ebay, Beedspeed etc, though it pains me to recommend Beedspeed at the moment.
Electrical measurements of stator are simple to do; there’s several threads on it on this and other forums, or somebody might write them out again here, but I haven’t got time to find them right now because I normally just have a quick read with my coffee before going out early.
Try to do one job at a time; finish the carb, change the rings, replace your woodruff key, measure your electrics, set and check your timing – then stop and try it out before moving on to any other jobs; that’s what I’d be doing anyway. I’d find it easier to keep track of your progress, and more inclined to chip-in too. Also some photos when you’re asking and describing stuff – the rings, the woodruff etc; a photo might well show the clever chaps something that you’ve missed or not described well - even the physical appearance of your stator coils and wiring might do it. – As you’ve found yourself already, photos also help others coming along later with the same questions, we’re building up a knowledge base with decent records of stuff tackled.

(I cannot currently find the carb gasket that was on my desk yesterday; it’s either been tidied away or got buried under even more chaos, I’ll have a better look later if H hasn’t sorted you out. – search for my thread “inaccurate carb gaskets” or I did a carb strip thread “2nd hand dellorto”? that may cover gaskets)

I’ll dig out some links and some numbers for your stator tests (we’ve got some numbers for CDI too) later if someone doesn’t beat me to it............................



...........................Right, here’s some numbers; ignore that it says PK.

‘Black Box’ means CDI (your ‘CTU’) – those ones aren’t so important really; newly discovered and tentatively tested, though they may prove useful.
The other two; ‘pick up’ and ‘charging coil’ are the main ones to check, and your earths. – There’s the state of the two coils to check, and any poor earths or shorting due to old/bad wiring; we’re checking resistance – Ohms on your multimeter. You could have checked you AC coils too, but your top-end is in bits, so you can't kick it over - hence one job at a time - 



I refound that quite quickly using the search facility on the forum; it’s worth mastering that too, to find stuff, where I also quickly found these:

vespa.proboards.com/thread/3257/inaccurate-carb-gaskets

vespa.proboards.com/thread/3235/2nd-hand-si24-24e

I also found the carb base gasket; it had been tidied into my currently dormant engine-build box; if you can’t make your own (^read the links first^), or H can’t slip one in with the other stuff, I’ll post it later if you PM your address; I really wouldn’t use it myself, though, but it’s up to you.

[henri]

www.ebay.co.uk/itm/391144111076?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT . thats a carb gasket set for lml engines ,including the reed valve ones . it is for auto lube carbs tho ,an i think your running pre-mix .will still fit an work so long as the oil hole for auto lubes blocked already ,if not a non auto lube base carb gasket should be used to block the hole ,
i'm away from brighton til sunday , paypal me 2.78 as a gift for postage to "[e-mail]" an i'll send what copper gaskets ive got monday ,include a address as a note with paypal ok, there no good to me an not worth enuff to weigh in as scrap . H

[henri]

oh an for tech info on timings n suchlike the "lml owners club" has a good guide on there forum ,theres not many differences to vespa engines anyway but its good to be sure . H