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Post by RWS74 on Mar 29, 2017 16:43:11 GMT
2014 PX 125 150 cylinder 45/160 IJ AC150 BE5 102 MJ Sip 2 Hello folks, My Scoot has been running perfectly for a month or so since nailing jetting and performance running around 70mpg then when riding home last night I had a few sudden incidents of loss of power when riding on A40 at 30-40mph, I released and reapplied throttle and it powered through. This morning I cleaned air filter which was a bit dirty but not excessive, I also cleaned all jets & plug which as you can see was rich. I cleaned HT lead too. Then when I rode to work it again on 30mph suburban roads & through central London I again lost power and it wouldn't rev... I pulled over and took the side off & re started it, it ran at low revs and when I revved up it would not increase much. I sprayed carb cleaner all over aircover/and engine to see if I had any leaks & it cleaned up nicely then after a few minutes it suddenly revved at normal speed. I continued riding but it again lost power a couple of times and I had to pull over, wait then rev until normal revs resumed and got to work.... What do you think folks? CDI going even though new a few months back? Fuel tank half full & Mix oil well above indicator lens.      |
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Post by sime66 on Mar 29, 2017 18:42:08 GMT
That’s a bit of a bugger.
Your plugs have always looked dodgy to me, but they haven’t worried others, so don’t know about that, but how do you get such good mpg in town and with it so rich!?
· Have you looked/check the cable-->autolube-->slide arm linkage and slide on the carb are doing what you think they’re doing when you twist the throttle?
· Your mix screw is in place and adjusted correctly?
· It is definitely loss of revs not loss of transmission? – It’s not your clutch worn and slipping with all the town riding?
· Intermittent stator fault? Have you tested it, have you had a look under the flywheel at wiring/timing-mark/woodruff key condition?
· Fuel hose, banjo, and filter top all tight and not leaking? - I just had a fuel leak at carb, which was obvious eventually, but at first seemed like a problem reaching more than about 4500rpm.
I’m clutching at straws really, but maybe a few things to think about or check.
I won’t query your jetting because I know you’ve been spending time getting that right, anyway intermittent faults suggest not jetting, and your jets are clear too.
Maybe you can film it next time?
Hope you get better help than I can give, and get it sorted.
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Post by shipscat on Mar 29, 2017 18:56:53 GMT
what plug are you using ? try changing your plug
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Post by RWS74 on Mar 29, 2017 22:42:35 GMT
That’s a bit of a bugger. Your plugs have always looked dodgy to me, but they haven’t worried others, so don’t know about that, but how do you get such good mpg in town and with it so rich!? · Have you looked/check the cable-->autolube-->slide arm linkage and slide on the carb are doing what you think they’re doing when you twist the throttle? · Your mix screw is in place and adjusted correctly? · It is definitely loss of revs not loss of transmission? – It’s not your clutch worn and slipping with all the town riding? · Intermittent stator fault? Have you tested it, have you had a look under the flywheel at wiring/timing-mark/woodruff key condition? · Fuel hose, banjo, and filter top all tight and not leaking? - I just had a fuel leak at carb, which was obvious eventually, but at first seemed like a problem reaching more than about 4500rpm. I’m clutching at straws really, but maybe a few things to think about or check. I won’t query your jetting because I know you’ve been spending time getting that right, anyway intermittent faults suggest not jetting, and your jets are clear too. Maybe you can film it next time? Hope you get better help than I can give, and get it sorted. Ta Sime66, no leaks from fuel anywhere, I'm going to start with removing Carb and giving it a deep clean and inspect float bowl & fit new gaskets.... |
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Post by RWS74 on Mar 30, 2017 0:43:26 GMT
Ta for all your input folks. I swapped my plug for a spare, this is the one I had in that I cleaned with a wire brush after the previous pics this morning. I also only turned the fuel cap a 1/4 turn in case it was a vacuum issue and the initial 15 minutes ride home at 00:00 through London to the A40 was perfect, however after a couple of miles the same sudden bogging and loss of power came on which resolved when I released the throttle and revved hard. Glad I got home safe & will use tube tomorrow & strip, clean and renew gaskets on carb over weekend.  |
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Post by pxguru on Mar 30, 2017 8:58:55 GMT
I was wondering how it was going, I asked a while ago on the other thread. That is not the plug of a healthy scooter. What might be happening is occasional plug fouling from that black soot. If you dont have leaks and not doing too many mpg, then not so terrible. How is the overall performance when wide open? If the plug looks that choked then the insides of the exhaust are going to look much the same. If you can't make over 55 mph on the speedo then the exhaust might be a bit blocked. Silly question but you dont keep anything under the seat blocking the air intake? had to ask  Remind me what Air Corrector and atomiser you have in there. If the carb isn't leaking, stripping it down won't help any. |
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Post by mijapxman on Mar 30, 2017 14:45:07 GMT
Pxguru, isn't it amazing the amount of people who get caught out with blocking the air intake hole, under the seat, so not a silly question!😀 worth asking.😉😉
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Post by RWS74 on Mar 30, 2017 17:55:32 GMT
True, nothing under seat and plenty of gap for air even when I'm sitting on it too...
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Post by RWS74 on Mar 30, 2017 17:56:24 GMT
Performance has been brilliant for last month at all revs 1/4-WOT.
AC150
BE5
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Post by pxguru on Mar 30, 2017 19:29:50 GMT
In that case all the issues are around the pilot to main transition then.
Depending on what jets you have to hand try a 48/160 pilot and then BE3 atomiser, either way around and one by one (confirming the MJ chop each change) but I think you will need both.
And if the plug is still a bit dark a 160 air corrector instead of the 150.
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Post by RWS74 on Mar 30, 2017 22:52:16 GMT
In that case all the issues are around the pilot to main transition then. Depending on what jets you have to hand try a 48/160 pilot and then BE3 atomiser, either way around and one by one (confirming the MJ chop each change) but I think you will need both. And if the plug is still a bit dark a 160 air corrector instead of the 150. Fair enough will try, but what I don't understand is how come it has been in its current set up of over 4 weeks and done about 500 miles seamlessly without missing a beat while maintaining 70mpg? |
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Post by pxguru on Mar 31, 2017 8:17:29 GMT
It is possible that the soot is building up in there. Once running hotter it might burn off (isn't modern fuel just great?). See how it goes with the new jets.
btw, what brand of 2 stroke oil do you use? And not doing any extra pre-mix in the tank?
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Post by RWS74 on Mar 31, 2017 21:54:21 GMT
It is possible that the soot is building up in there. Once running hotter it might burn off (isn't modern fuel just great?). See how it goes with the new jets. btw, what brand of 2 stroke oil do you use? And not doing any extra pre-mix in the tank? I use Castrol Synthetic and no pre mix. |
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Post by RWS74 on Apr 1, 2017 19:41:58 GMT
Now here's the strangest thing.....
I took a short ride of 1 1/2 suburban miles at 20-30mph this am and same problem occurred in minutes, I then decided to ride to Agius for advice... on way I refueled at usual Stn and decided to use the posh Unleaded instead... the pump I normally use at 05:00 was out of order? empty? ?dirty?
But as soon as I pulled out the Vespa behaved & performed immaculately again? I rode 40mph on A40 then 55-60mph on a national later and back through 20-30's without missing a beat?
My guess is unlucky with fuel last week, maybe water or sedament even though tank was clear on inspection etc.
I've yet to check plug and will be de-coking cylinder in a couple of days but thus far I'm happy.
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Post by pxguru on Apr 2, 2017 7:22:28 GMT
Petrol pump, might have got contaminated with diesel? If it is water the carb will need cleaning out. It does sound like you've found the main issue though.
Unlikely that the 1/4 throttle plug chop will be digestive colour though, I am sure it will still need the bigger BE3 atomiser.
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Post by RWS74 on Apr 2, 2017 21:01:10 GMT
So.....Atomiser....Lower number richer or leaner mate?
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Post by pxguru on Apr 3, 2017 7:10:03 GMT
Compared to your BE5 a BE3 is leaner at lower rpm and richer at higher rpm. Exactly what you need for that sooty plug!
This is a usual issue with engines which are more powerful. The higher revs need disproportionately more fuel while the bottom end doesn't.
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Post by RWS74 on Apr 4, 2017 12:54:11 GMT
Ta Mate, interestingly I've started using Premium Unleaded in my last two fill ups.... it feels like my Scooter is riding better and smoother than ever..of course this could be a placebo effect after last weeks intermittent loss of power.
However for an increase of just £1:20 a tank I think it's worth it....
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Post by pxguru on Apr 5, 2017 6:26:12 GMT
It's got to be fairly close now but once jetted right, it will have the same feeling on 95 petrol |
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