Stator Overhaul

[sime66]

I’m still having aggro with cutting out, and I think I’ve narrowed it down to my stator. When it runs, it runs well, but sometimes it won’t start, or starts and revs and splutters, and is likely to cut out at any time. It’s an intermittent problem that’s proving difficult to nail down and fix.

It was good for a while after replacing the carb, so I don’t think it’s that.
It’s fresh fuel, it's getting through, and I've checked the jets and filter.
I tried another CDI, which made no difference, so don’t think it’s that.
I’ve replaced all the HT.

I did some stator readings on the weekend after it was running OK
(Wires at CDI, disconnected):
Red – White 114 Ohms
Green – White 310 Ohms
White – Ground 1.2 Ohms

Kicking over with plug disconnected:
Green – White 45 Va/c

I think that suggests that my pick-up is OK, but my LT coil is not, or that it is grounding where it shouldn’t, or isn’t grounding where it should. The 30-year-old wiring between stator and CDI is definitely suspect. I’m getting low resistance off LT coil circuit, but decent voltage – not sure what that means.

I’m going to get the stator off and have a thorough inspection myself, but I was thinking about sending it to Beedspeed to have it rewired, and to have the components checked and replaced where necessary. I do not want to rewire/solder the stator myself.

· Given those readings, and the jobs previously done to discount other possibilities, does having the stator overhauled sound like a good next step?

· Where is my engine supposed to be grounded to my frame, so I can check that?

I’d appreciate any suggestions; bit frustrated with tracking down cause of this problem.

[bryno]

feeling your pain..

Sorry I cant help on the specifics, I'm not hot on electrics but had a similar ongoing issue on my 85 P20.

It never cut out, just stuttered intermittantly; did new fuel tap, filler cap, fuel pipe, carb, CDI, plug, cap & lead, stator pick up

In the end I just stuck another stator on it and problem solved.

Personally I'd just stick another stator in it rather than sending yours off to Beedspeed, can't be much to buy 2nd hand?

[henri]

a new piaggio stator arent too expensive ,or a indian lml one fits an are cheaper .your readings suggest the lt coil is on the way out,the laquer on the windings is probably failing allowing it to short out internally.if your up for a small soldering job you could just replace the lt coil an keep your stator.the stator earth (black wire) goes to the junction box an then too the regulator behind left side panel an battery .it grounds to the frame on 1 of the reg box fixing screws by a ring terminal .giving it a good clean up might help ya stator ,but if its old an the wiring's lookin dodgy its only a matter of time til it dies.a second hand stator might not last or have problems ,i'd put on a new one ,if ya go lml stator i'd buy it from a shop in this country as ya cant be sure of the quality straight from india ,an while ya checking earth's dont forget the cdi 1 .cheers h

[sbwnik]

Coil's definitely knackered from that.

Avoid any stators that come in a box marked 'Swiss', experience says that around 50% are iffy, and they don't have a timing mark on them.

[sime66]

Cheers all, been chewing it over.
Not getting 2nd hand, Cheapo, or rewiring it myself.
It’s a toss-up between good quality new, and rewired/overhauled/tested.
Probably new because an overhaul won’t be so cheap with a new LT coil.
Going to get this stator off as first job, maybe the state of it will make choice more obvious.
Main concern with new is I haven’t done timing before – I’m thinking it will be less straight forward with a new one, rather than refitting the same one.
I'll read it up today, but thinking ahead do I need any special kit to do timing?

[bryno]

Do you not know anyone with a used stator you can try?

To fit and time to perfection you will need flywheel tool, timing dial, TDC guage and a strobe gun..

or you can just set to the pre stamped marks on the stator and casings, which is what most people do ;-)

[sime66]

I’m miles from anyone else with a scooter. I’ve been paying garage rates and a recovery charge to a Club-mate for jobs too tricky for me up to now, but I keep getting it back with a different problem each time, so I’m going it alone now. Enough said; don’t want to criticise other people; don’t want to whinge either - just getting on with it as best I can.

Getting the stator off seems pretty straightforward, I know to use the marks, and for now I’ll just have to hope they’re close enough when putting it back. As mine is originally a 150cc I’ll use the ‘1T’ mark. I don’t know how accurate the ‘A’ or ‘1T’ marks will be, or if the kit makes a difference. I’m going to take the old one off tomorrow morning, and I’ll mark it with a punch so I can put it back exactly if I do reuse it.

I’ve watched the Sausage and the Scooterwest DVDs on flywheel/stator removal, and read Haynes, and it’s all clear to me and I have the tools for that. Putting it back, fingers crossed, the marks will do the job. If not, I’ll tackle that later. The timing is the only bit I’m unsure of; I don’t have those other tools, Haynes says it’s crucial, The DVDs say to mark it; I won’t know ‘til I have a go.

The stator has to come off whatever happens, so that’s the plan.

[henri]

for a standard ive never had a problem using the 'it' or 'a' marks ,even when going cheap an using lml genuine stators, never had 1 marked swiss so dont know but have heard enuff horror storys about bad quality stators to always go italian when ive got the cash.as youve kitted an uprated ya px the standard marks should be ok to get it started an ridden to a scoot shop who will have the tools to do the job.or a dial gauge are cheap on flea bay an a piston stop can be made from a old plug ,break off an out the ceramic insulator ,drill through an fit a long m6 bolt an nut through,with the dial gauge on the flywheel taper tight with the nut bend a piece of wire secured to any screw hole to be a pointer,put the piston stop in an gently rotate the crank til the piston touches,note the number an turn crank other way til it stops again,note this number ,take out the stop an turn crank til its exactly halfway between the numbers ,thats top dead centre ,whip of the dial gauge an put on rotor without moving crank an tipex or file a mark ,do it again an this time set it for the timing you want an do another mark .beg borrow steal a strobe gun,preferably one that needs a battery to work,the impulse type arent very bright an your sorted hopefully . if ya near brighton i could lend ya one ,cheers henri                                                                                                                                         sorry was in a rush ,for dial gauge above read 'degree disc' .

[sime66]

Right, the stator is off and inspected, pics below show wiring in very poor state from corrosion and rubbing. Pains me to discard a good quality one and take a punt in the unknown of sourcing a decent replacement, but with the cost of rewiring and a new LT coil, that is the decision.

I have studied timing in case I need to do it thoroughly when installing the new stator. Here’s what I think I know; if I get anything wrong, please say.

· I have a 150cc engine, which should use the IT mark as a guide.
· The stator I removed was spot on the IT mark.
· The IT mark is 18deg BTDC.
· I have a DR177 kit, and from several sources I reckon I should be aiming for 19deg BTDC for that.
· (The A is 23deg BTDC, so I am roughly aiming at quarter of the distance from IT towards A)
· New fuel etc, means that it’s wise to err towards greater degrees to safeguard against overheating/seizing.

With Henri’s description, some improvised or cheap tools, and some reading and videos I reckon I can find TDC and 19deg fairly confidently, so if I need to, I can get the stator set to that accurately.

If I need to strobe, I’ll have to borrow some kit, and hopefully someone who is confident in using it to show me how. (Thanks for offer Henri, but I’m in Cornwall).

Now to the pics:



















I very much doubt that any replacement stator will be built to give me 30 years service like this one has, but the cost of rewiring and replacing coils makes it unviable, which is a shame. I might do it as well later, when I’ve got a bit more cash. The cable wall is disintegrating anyway, but also rubbing away in several places. Disturbing it all made it worse, but a complete short can’t have been far off.

I also took a look at the CDI, which I had been told was checked, and in truth was working, at least some of the time, but clearly not in good order. I noticed that the casing was bulged, which made a clear route for water to get in, and when I turned it upside down it did actually drip for a while. Needless to say this is scrapped and a replacement is on its way.





So I’m waiting for the bits, I’ll clean everything up while I’m waiting, and I’ll update when I put it all back together.

[sbwnik]

Green wire being worn will cause random cut out, but the CDI is a bigger concern there.

[bryno]

Personally, I'd just re-wire that stator, coils themselves may be just fine and your problem is more likely with the CDI looking at the state of it

[kru251]

As above! The CDI with water is a definite issue, but I just re-wired a stator on that P125X project which had similar issues to yours. Once redone (took new wiring right back to coils) I then used heatshrink tubing over the wires where they pass through and that not only keeps it all neat and tight as a bunch of wires but provides another anti-chafe covering.
Some pix on my thread re Wiring on P125X on here.

Rewire & new CDI will sort your issues I'm sure!!!
Good luck.

[henri]

that stator has def seen better days,as bryno said it is re-wireable ,but with the resistance figures ya got the lt coil was low ,that could of been a short from the breaks in the insulation tracking to earth through the dirt/oil/grime on outside of wires.if you track the wires back to where there soldered onto the coil an meter the coil itself you might find its ok an just have to replace the wiring ,saving the stator plate .your cdi looks like its been overheating from too much voltage tho,an is def scrap.you said on kickover without plug you were reading 45volts ,was that a peak voltage as it seems high at that slow a crank speed .especially as its resistance value indicates a internal short ,meaning part of the coil is being by-passed.less wires in coil means less leccy when a magnet swings by.if the coil still meters low when tested at the soldered joints its scrap ,an will kill a new cdi if used .ive only ever seen a swollen cdi like that when a scoot was left in a leaky shed without a side panel an water seeped in the join an later froze.inside the components are set in a resin, like reg boxes,there's no way to mend em. a lot of people like to go piaggio/ducatti for cdi's ,but i havent noticed them lasting that much longer than cheaper copys ,at the same price i just get 2 cheaper 1's an swap em at the first hint of trouble,same with reg boxes.taking the spares with me if going far from home. with the kit you've got an modern petrol your right thinking the timing should be better at 19deg instead of 18,but you will need a strobe to set it accurately ,but the standard marks should get you running safely enough to ride to a scoot shop an get them to do it if ya havent got 1.if ya mark the rotor on the outside where ya want it timed it will cut down the time they'll charge for the job .as said above the cdi probably was failing an giving you the problems ,but it looks like ya stator was causing the cdi failure .i'd be tempted to fix the wiring faults an throw on a cheap cdi an see how long it last's,at least you'll be riding now the suns out an rains stopped at last .cheers henri

[sime66]

I'd ordered all new stuff yesterday morning. A new Stator and CDI should be with me today for fitting tomorrow. It will all be quality and new, and I’m doing it myself including the timing.

· I'll set the stator based on the gap between IT and A, so I'm just off IT(18) towards A(23). I’ve got the degree disk and piston stop, and I know how to find TDC and mark the flywheel at 19deg BTDC, and will get it strobed to get it precise afterwards; several possibilities – neighbour, garage, Ebay 2nd hand gun. Not done it before, but I understand what to do myself now.

· I might, in the future rewire the old stator when I have some cash to spare – not important for now. I pictured the reading of 310Ohms meaning a short within the LT coil shortening the coil correspondingly, ie about 3/5ths. I didn't get any better readings just directly over coil, so it will definitely be a new LT coil as well as rewiring, which is why I'm getting a new Stator for now.
· I had also thought about water getting in and freezing, causing the CDI swelling, in any case it’s binned now. It was 2 years old. I am convinced water was the initial cause. Scooter lives under a cover outside. I have seen a rubber boot that goes over whole of CDI, which covers the join between plastic and resin rather than just the 4 terminals, and I might get one. Or Vaseline, or a condom has even been suggested! (condoms and vaseline - down Kru )
· Something of interest that I did notice last night was that the main damage on the stator was due to the LT coil overheating. (see pics at end showing affected area). There is also general wearing on all the wires at several points of potential shorting.
· Whether the CDI failure caused the Stator failure, or vice versa, I do not know; they’re both buggered now anyway.
· The 45Va/c was the max blip multimeter reading on kick, if that makes sense.

Heres the pics; main damage to stator due to heat from LT coil:








Although it’s cost me another £100, I’m glad to have actually found something wrong this time, rather than searching for the cause of this ongoing aggro. Of course it had to be the most expensive bits, which I obviously left to last.

Just to clarify that I am from Kent/S.E. London originally. Believe me when I say there is no such thing as mates with scooters round the corner, or a Scooter shop here in Cornwall, which is still just a bit 3rd world despite its rugged charm! I pretty much have just the forums and mail order to rely on. If it wasn’t for these forums I’d probably have to give it up, so thanks again for everyone’s help.

[kru251]

Next time I visit my mate in Camborne I'll look you up!

[sime66]

It's all good.

I took readings for the stator coils straight out the box, to make sure it was good before I started:
Pick up – 115Ohms
L.T. – 525Ohms

The CDI is a Ducati.
(I will buy a budget spare CDI later, and get the other stator rewired too when I have the cash)

I used the stator marks to set to 19deg BTDC. I’ll strobe it as soon as possible, but it runs sweet as it is.

It started first kick, even after standing for a week, and runs lovely. I checked my lighting, reg/rec and battery charging, and that is all good to. I’ll do some readings next time, just to keep as a record for future troubleshooting.

Not much more to say. I’ve done a quick 50km, I’m pretty confident that the problem is solved, all previous symptoms have gone.

A few pics for the record:















Thanks for all the input everyone, it’s very much appreciated.

(Next jobs – Rear suspension, new exhaust, new brake shoes and cables, rust and Waxoyl underside)

(Kru, Camborne is 100km further down from me, there’s loads of scooters further down in Cornwall; I’m in Launceston, between Dartmoor and Bodmin Moor. Most of the Cornish lot don’t tend to cross to this side of the Moors when there’s an R in the month – I ride all year, they’re just waking up now. Let us know if you come down.)

[henri]

that looks all good ,by eye i'd say youve got it at 19deg ,you say its running sweet an startin first kick so the jobs a gud un,just in time for the sun ,remember if you cross the moors to "stay on the track" an theres still laws about smuggling carrots an turnips an other root veg out of cornwall ,so dont get caught eh .h

[kru251]

Just a word of minor caution. At the W/E I was working on one of these Stators like your new one that was creating an issue. The three very soft rivets that hold the coil pack to the backplate had loosened and allowed some 'floating' to take place. Meant that there was a 'swishing' noise when lights (ie a load) was placed on this unit. The swishing was the coils moving a fraction & just brushing the flywheel!!!!
Re-fastened the rivets with some Super Glue around the base and peened them well over. A lot quicker to type than do but problem solved!!!!!!!

[sime66]

I'll most definitely have a look at that and do some preventative work there, cheers for that.
I was hoping to enjoy a bit of riding in the sun without getting my hands dirty this weekend, but I've already noticed that now I'm sparking and running nicely, the new 24.24 carb needs a bit more attention to set it up properly.
It was very lean when I checked after the ride on Sunday, so first job Saturday morning I'll be giving a bit more attention to some jetting and plug chopping to get it nice.
(I remember before thinking it was running lovely, when it's running lean - then it goes bang!)

[henri]

yep, when lean they can feel lovely right up to the point it all goes bang ,what kru251 said about the rivets has got me thinking,as last time i did the stator on my px150 engine i thought i could hear a swishing sort of noise when started without the side panel ,thought it was fan noise as i'd put on a new st/steel flywheel cover ,now not so sure ,scoots ya got to love em,eh. H

[sime66]

Ain't it true, there's always something.
Wise to lean feeling good though; that got me last year.
I so much want it to be right so I can have a well-deserved worry-free bit of fun in the sun, but just a bit more work is needed.
I don't mind doing these last few jobs in the sun, I've been trying to sort this outside in the rain since Christmas.
As it happens I need to take the cowl off anyway to put a new nut dust cover on.
The old one was quite loose, and when I first rode it last weekend it made alarming noises for a bit, but just until the flywheel spat the chewed cover through the cowl. (Wasn't going to tell you that)
So it's cowl, flywheel and stator off - make sure she's all good, checked and tight,
then do a bit of carb tweaking and chopping, (going back to a 118 and also ordered a 55/160 because I knew the 48/160 I'd inherited with the carb was non-standard)
then I'll do a bit of innocent over-the-border touring.
Happy days.

[henri]

bugger the nut cover ,there just there to look pretty really.an nobody will spot its not there as ya fly past ,pockets full of old an new plugs an a plug spanner clenched between ya teeth .til its right im betting its not the only thing being clenched.cant be easy finding a longish flatish straight road to chop plugs where you are .have "fun in the sun" , H

[sime66]

Got a bit of colour in me plug...

[henri]

the 1 on the right aint lookin to bad ,are ya still on the 118 main jet or have ya gone up,an too what .H

[sime66]

The RHS is as it is now with a 118 and the 55/160, which I reckon is OK, especially as it was a cold morning. That was as I left it on Saturday. I might try a 120 though.

One thing niggling me still is the uneven colour on either side of plug now (see below):



When I get a chance on the weekend I’ll check my cylinder head again, but I wonder if uneven colour might show anything else to look for inside the barrel. It’s got a good colour on one side, but the other side is lighter and oilier around the edge. Note that this isn’t a plug chop; just a quick monitor after a 20km journey this morning – I’ll have more time on Saturday.

[henri]

to really tell youve got to chop proper ,kill switch an clutch in together at more than 2/3rds throttle to check main jets,just the tickover when you got back from 20km would alter the colour a little.ive not run a 177dr kit so dont know where the plug is on the head , unless its still the standard,but any plug colours up unevenly as there always with 1 side to the exhaust an the inlets elsewhere ,causin 1 side to heat up slightly quicker an higher ,what grade of plug are you running,i think i'd be tempted like you to go safe an see what a 120 main jet an a proper chop gives you ,an if i remember right a cold morning would lean it out a touch but not sure on that ,apart from that ,how was the 20km blast ,H

[sime66]

I did proper plug chops on Saturday, and it was a cold morning, which is why I reckon the RHS plug colour in the first picture is near to OK, but worth looking at a 120. (I agree cold air makes it a bit leaner – cold air is dense air is more oxygen for same volume).
I posted the image this morning because I keep noticing the plug being darker on one side, which was bugging me, but your explanation ties up with what I was suspecting, though I was wondering if it maybe suggested air leaks/rings/ports clagging up or something else. I was going to mark the plug to work out which side in the barrel/head was giving which colour. The plug is in the standard location on the head. I’m less worried about that now I know it's normal to be uneven.
I’m going to get a 120 and also do some proper chopping at different throttles on Saturday when I have more time to mess about. I understand that to read the main jet it needs to be ¾+ and killing it (ignition and clutch).
I’m currently using a B7HS, with a view to using a B8HS for longer rally-runs later in the year.
I haven’t done any long runs since all the changes over Winter/Spring because I haven’t really trusted it again yet after all the aggro, but I’ll give it a good thrashing once I’m certain I’m not too lean.
The 20km was early pre-rush-hour through town and a few lanes, not really a thrash. As it is now it is running well, very lively. Starts cold easily with very little choke, a little less easily when warm, but I think that’s just me while I’m sorting the new carb and jetting out, which I couldn’t do before because of the CDI and Stator. (GPS top speed today was 90kmh, without really hammering it (GPS 90kmh = 100kmh on speedo – it goes off the speedo, but that wasn’t the purpose of today’s ride)).
I’m just being cautious, trying to get it right so I can enjoy it without wondering if it’s going to break down or go bang!
My first decent ride will be up and over Dartmoor in early April for a little Scooter Jumble Sale in Bovey Tracey; I need it reliable for that because it’s remote and there’s no phone reception in the middle of nowhere - a long walk!
I reckon I’m on track with a bit more tweaking.

[henri]

thats why i asked about plug position ,so you could mark it or if ya pull the head ,put plug back in an note which side the colur is ,if your still suspecting rings/seals/ports it will give you a idea where to look ,a seal would probably affect all sides at once as it would mess the whole mix before it came up the ports ,an sticky/rusted rings would very quickly colour the whole plug .uneven colour can mean you havent run it long enough to get to temp as plug colour should be even really .thats why the advice is to set rich an work down ,then you can run it long enough without any expensive bangs to get a "true" colour .you saying it starts easy with little choke an is hard when warm makes me think you might be a little rich on your pilot/slow running jet ,but should be able to adjust by the mixture screw.as ya say 1 more sunny days tweaking an you should be gud for bovey tracey ,i'd stick with the b7hs/b8hs plan were you are coz of the distances,on my shopping/offy run/local hack i have gone down to a b6hs as most runs are 2-3 miles or less,but got sick of changing plugs before going on longer runs an stick with a b7hs now.but for a rally/motorway run a b8hs will handle the temp better ,have to admit tho as i dont run kitted/tuned scoots anymore i avoid motorways or long runs (over 30 miles), i cheat an take my motorbike ,not brave enough for the faster traffic up my back all the time .i gave up tuning 2/4 stroke bike/scoot engines as i'm not naturally gifted enough to tune by eye/ear,an being half deaf from what i have done doesnt help,came to the conclusion the only worry free way is on a proper dyno with a exhaust gas anyliser,an thats too rich for my blood ,with my px150 engine ive gone for optimised standard ,matched inlets/casings ,drilled air filter ,right squish gap (.8-1mm),an same timing (19deg)as you ,havent got gps but as its in a sprint/rally frame/headset can get the speedo needle to swing near to 90kmh,tho reckon i'm prob jus touching 60mph.downhill/following wind an a full baked bean/cabbage supper giving "jet assist", hard to say as its a tiny speedo i'm shortsighted an dont like looking away from the road long enough to focus on it, an remember if it all goes t**s up on way to bovey an ya walking ,"stay on the track" ive heard horrible rumours about wat roams "THE MOORS",(dat-dat-DAHHH)an i dont mean the locals an there sheep (girlfriends).good to know youve made progress anyway ,not long now an ya can really enjoy some runs ,an start dreaming/saving for ya next upgrade (expansion/reed-valve/porting/nitrous/jet-pack),beware tho as the mechanic's sign in mad max 1 says "speeds just a matter of money,how fast do you want to go" ,tuning's a addiction, 1 of the expensive ones too,an there aint no betty ford clinic for 2strokers ,cheers henri

[sime66]

Saturday:
BIGGER JET --> GIVE IT LOADS --> PROPER PLUG CHOPS --> TWEAKS --> CHOPS --> TWEAKS --> HAPPY DAYS 

As middle age creeps up, I’m also becoming increasingly deaf and blind, but it my case it doesn’t help that I don’t really know what I’m doing either.
I have no plans to do more tuning upgrades – keeping it reliable without any more hired-help is my goal.
My PX150 was already kitted when I bought it 2 years ago, but it didn’t really keep up with the others (primarily Lammys & 200s) until I got the exhaust (Sito+) sorted. I had new piston and rings in the old barrel last year. Now with the 24/24 it’s basically set up almost the same carb and jetting as a 200. Most of my riding is solo now anyway. I’ll get a SIP Road 2 later in the year if it’s still the best option if and when I need it (the Sito+ is 2yrs, & 10,000km old); jetting will probably need more attention then.

On a good straight road, accelerating hard, I’m going through 2nd quickly, and staying in 3rd to about 80kmh on my speedo, then reaching 100kmh pretty easily, and if I really feel the urge, maybe downhill wind-assisted, I can quite slowly get it from there to approaching 120kmh (on my speedo). I know for certain though, that 100kmh on my speedo is only 90kmh on GPS, which is 56mph. I haven’t done a GPS for needle-off-the-speedo, and I'm less inclined to go there after seizing it last year. Anyway, it’s plenty fast enough for me on little wheels and drum brakes, (low to mid-sixties I’d guess). Also, it's not really top speed, so much as climbing and acceleration that are important.

I expect to do exhaust, tyres, brakes and shocks during this year, but hope that’s the extent of my expense for a bit.
 
If you’re referring to a certain film, I’d happily push my scooter over Dartmoor in exchange for a long shower with Jenny Agutter – bless her!! (That scene had a lasting effect on my 15-year-old mind )

[henri]

would be worth a bite or 2 wouldnt it ,H