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Post by rab on Apr 24, 2014 18:53:10 GMT
a day after getting my new rings fitted my scoot started playing up on a small few mile run out you had to give it some decent throttle from standing start as it had a flat spot on lower revs and would try to die.the same would happen if i let off the throttle while riding it would die in motion .if i left the scoot to cool down it would be fine again so i changed the plug and all has been fine for a few weeks .now its started doing it again the only thing thats changed besides the rings is that i re connected the auto lube and its working and feeding 2 stroke in. the plug is a light brown but seems a bit on the light side like a dry brown that gets a bit lighter as it drys out . could it be that its not feeding in enough 2 stroke for the 166 kit im going to try adding a bit of 2 stroke to the tank in the morning and see how it runs . it did not have the problem before the rings were done and when i was self mixing the 2 . since these 2 things were done the problem has started so at the moment it seems that's were the problem lies
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Post by pxguru on Apr 25, 2014 15:11:43 GMT
Rab, Did you take the carb box off to put the autolube shaft back in? Could be a small air leak
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Post by rab on Apr 25, 2014 19:57:27 GMT
just took the lid off to check it was all connected and working its bugging me as when i turn the engine off for a few mins and re start the scoot its fine. i rode to work this morning without a fault but it did it on the way home then after a mile or 2 started running fine again only other thing i did was take off and clean the air filter and turn up the idle screw quarter of a turn as i twas too low and causing the lights to flicker as its non battery
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Post by kru251 on Apr 25, 2014 21:35:32 GMT
If you re-connected the autolube you did run the first tank of fuel through still as pre-mix I assume? That way the pump gets to bleed/purge itself of air. On my mates 166 kit I fitted to his PX 125 he wanted to retain the autolube, but 'we' still put a capful of oil in as pre-mix just to be sure. So far, so good.
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Post by rab on Apr 25, 2014 22:51:18 GMT
yes i did kru i filled her up pre mixed it and let tank get down to reserve before i let the auto do its job im mixing 1 cap to every full tank of fuel to make sure its ok on the kit. im going to take off the barrel cover in the morning make sure the head bolts are tightened down enough see if i can see any leeks i washed the engine down a week ago and so far haven't seen any sign that there is a leak anywhere to indicate a nakerd seal .pxguru may be on the right lines with carb box as there was what looked like old oil on the rear of the engine and onto the selector box so maybe the carb box seal is on its way out.but that looked like it had been there a long time
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Post by kru251 on Apr 26, 2014 8:53:05 GMT
Another thing you can do. Use two gaskets (with the correct oil hole in the gasket, not the pre-mix style one which lacks the all important hole; yes, my PX200EFL came to me pre-owned and was like that; hole-less!!!) to help in case there is slight distortion on the carb face.
Worth a check for sure.
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Post by henri on Apr 26, 2014 14:01:14 GMT
adding more oil leans up the mixture ,so probably why your plugs a bit light ,now youve got thru 1st tank an auto-lube should be primed/bled the plug should be showing a "true colour" .i sense a chopping session coming your way .
like kru said above about friends malossi,i know a guy running a mallosi/px an he also sticks a extra capful in every time he fills up ,reckons it needs it coz of different tolerances/clearances between piston/barrel.dont know if he's right but about 16months an 4000miles without a problem .H
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Post by rab on Apr 26, 2014 20:33:45 GMT
no the fuel and oil both pass through as the engine demands it no matter what head you have on (within reason of course) the extra cap or 2 is added just as a wise precaution
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Post by rab on Apr 26, 2014 20:38:13 GMT
adding more oil leans up the mixture ,so probably why your plugs a bit light ,now youve got thru 1st tank an auto-lube should be primed/bled the plug should be showing a "true colour" .i sense a chopping session coming your way . like kru said above about friends malossi,i know a guy running a mallosi/px an he also sticks a extra capful in every time he fills up ,reckons it needs it coz of different tolerances/clearances between piston/barrel.dont know if he's right but about 16months an 4000miles without a problem .H a chopping session is probably on the cards sometime tomorrow i did not get time to check for leaks today i was too busy finishing off the spotlight wiring and putting a new stand on but im getting on with it in the morning i have a new plug sat waiting for a chop test if this stupid rain holds off. the plug that its ben running on is a b9 so ive got a b8 for the test b9 is too high i would have thought but saying that its been running off a b9 without fault for 2 months |
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Post by joey on Apr 27, 2014 10:38:04 GMT
I love the old autolube debate, a bit like the even older "which is better, Vespa or Lambretta?" It's Vespa by the way.
So here's my take on the Vespa autolube..............
Unlike modern engines where the autolube was a part of the initial design the one fitted to the good old PX (and it derivatives,) is an afterthought, and a crude one at that, but that's not to say it doesn't work.
Unlike a vacuum pump which would feed oil dependant on crank case pressure (in conjunction with your carb,) a Vespa autolube is mechanical and feeds a set amount of oil (forget for a minute about percentages,) per crankshaft revolution.
So, just to make things easy let's say that your autolube delivers 1ml of 2 stroke per 1000rpm, so at tickover your autolube is delivering between 1.5 and 2ml. At 5000 it's delivering 5ml and so on.
Now that's all well and good if you have fuel injection and your fuel delivery was also a set amount per 1000rpm, you would have a consistent ratio of oil to fuel at any given revs, but as we rely on aspirated carburetion this is not the case as the amount of fuel delivered depends entirely on crankcase pressures.
Next throw into the mix the fact that jets in your carb deliver fuel at different rates depending on rpm yet your autolube is still delivering a set amount so the reality is that at no stage is your autolube and carb working in perfect harmony.
I think that so far I've shown that at no stage is your autolube delivering this magical 2% that everyone goes on about..........
Next up....... you decide to throw on a kit.
Keep in mind that you oil plays no part in the combustion process, it is there purely to lubricate... bearings, crank, cylinder wall etc... with a standard 125 (123.4 cc) you oil has to lubricate 137.3 square centimetres of cylinder wall (I'm only using the area above the piston= swept volume,) chuck a Malossi 166 on and this area increases to 167.6 sq cm, a 22% increase in area, however your autolube is delivering the exact same amount as before.
You also now have a bigger jet (a much bigger jet,) delivering a fair whack more fuel and STILL your autolube delivers a set amount of oil.
There are a few more variables, choice of pipe, porting etc which affect the amount of fuel delivered yet your autolube remains constant, so are you really running a 2% mix?
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Post by rab on Apr 27, 2014 10:58:46 GMT
ty for that joey ive always been under the impression that it delivers 2 stroke at a rate controlled via the throttle ie bigger the fuel demand the bigger the 2 demand hence both deliver more at the same time . so even if im adding an extra cap to the tank its still up in the air what percentage its actually getting so the best and only solution would be to re disconnect the auto lube and get a measuring jug then i know its right.
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Post by joey on Apr 27, 2014 11:24:12 GMT
Rab, the linkage between the carb and the oil metering device does give a limited amount of control over the flow of oil however it is all still RPM related, quarter throttle in 1st gives a different RPM to quarter throttle in 4th......... so same throttle opening but less oil being delivered due to crank speed being less. If you want to be sure of a constant ratio of fuel to oil throughout the entire rev range there's only one way to go.  |
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Post by rab on Apr 27, 2014 11:59:29 GMT
I know m8 I've added another cap of 2 to the tank when it's ready for next fuel up I'll be disconnecting the auto lube. I think I've found my initial problem carbon washers on fuel banjo were leaking fuel into the carb box so I've just replaced them and cleand out the box the filter and everything thing in there had petrol all over it
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Post by henri on Apr 27, 2014 15:09:48 GMT
i see joey's put a lot of thought into auto-lube/pre-mix ,an what he says is right/makes sense .i only use pre-mix myself an have always done so on all 2strokes ive owned ,chainsaws excepted as stil have got a excellent system.its a choice made on gut reaction ,as ive never had a auto-lube fail on me ,tho i have once forgotten to fill the tank on a bike leading to a light heat seize an 2 skid marks ,1 on the road 1 not.ever since ive pre-mixed as i got into the routine an never forget to add it when filling up,an its 1 less thing to go wrong an trash ya engine.years ago tuning/racing rd350lc's/rd400 everybody pre-mixed an removed/blanked off the auto-lube as a matter of course .1 idiot tried to tell me he'd done it to save the tiny power drain the pump caused the engine,but really everbody did it to simplfy/reliable there tuning an ability to adjust oil delivery .KISS (keep it simple s****d) as i was taught . H
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Post by rab on Apr 29, 2014 11:32:20 GMT
Stoped using autolube gone back to pre mix only and problem has gone with it
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Post by kru251 on Apr 29, 2014 15:22:17 GMT
My large two stroke outboard which is making a tonne more horsepower than these scooter engines (but does have total loss water cooling ha ha) uses a metered oil system whereas the smaller 2T outboards I have use the cheaper and more crude petroil system.
Everyone has a choice on these oil supplies etc................... so just use what you're happiest with!!!
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Post by jackthekipper on Apr 29, 2014 17:35:23 GMT
had my P210 malossi for 15 years running on autolube adding a capful extra on a full tank...never had any bother...this was advised to me by mike Webster & Norrie kerr from midland scooter centre from where I bought it....certainly works for my scoot  |
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Post by rab on Apr 29, 2014 19:52:12 GMT
all i know is when i use autolube alone it gives me problems even if i mix 2 caps in the tank i still get a problem just no were near as bad adding 3 caps and using auto lube cured the problem so i might aswell just do what i did before i re attached the auto lube and pre mix the bugger as its obviously not giving anywhere near enough 2 stroke to run the 166 it may be a gasket problem or something else . its an investigation for another time as i don't need it i just liked the idea of not having to stand in the petrol station measuring out oil .fill it add a cap then ride was nice for a few weeks anyway lol
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