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Post by scut on Mar 31, 2012 15:01:10 GMT -6
Have spent some more time today double and triple checking for good electrical contacts and any possible vacum leaks.
I am as sure as I can be that all the above is good.
Still the same issue with difficult starting. Sometimes from cold or hot she will start repeatedly on the first kick. Other times there is nothing using the kick start. I have established a pattern with the electric start which seems to work reliably. This is a 3 or 4 second attempt to start with no throttle. Pause for 5 seconds or so. Repeat. Then on the third go she will splutter and I can catch that with the throttle to keep her running.
There has then been the odd occasion where she is ticking over reasonably well then will stop suddenly. More like the ignition has been turned off suddenly rather than a spluttering stall.
I do still suspect the ignition. I wonder if there is an intermittent fault which needs the above start pause start pause procedure to overcome and build up some charge or energy in the cdi/coil.
I'd love to know if the stator voltage drop with increasing revs is not normal. I have spotted a cheap used cdi/coil on Ebay so have ordered that to see if it makes any difference. Also ordered an iridium spark plug to see if that helps the ignition any.
Will keep you updated.
If any of the new info above Sparks any new ideas or thoughts please let me know.
Thanks
Scut
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Post by scut on Mar 30, 2012 0:42:10 GMT -6
Righto, I have spent some time looking for data on what the stator output should be. I registered on the Scooterhulp site but all I can find for the AY 50 was a parts catalogue with the owners manual and a wiring diagram so unfortunately no information there on what the stator output should be. I then followed the links in a previous thread about the SGX 50 R/R which lead me to the Ducati electrical parts catalogue. From there I could see that a number of other scooters use a very similar Ducati stator (i.e. same number of poles and 1 phase with only one output wire), R/R & CDI/Coil arrangement - one being the AY 50 and one being the Piaggio Zip 50 4T. I then found the following guide on a UK website which describes how to test the Zip 50 4T stator output. .pedparts.co.uk/blog/piaggio-moped-ignition-fault-finding-4-stroke" rel="nofollow" target="_blank"> .pedparts.co.uk/blog/piaggio-moped-ignition-fault-finding-4-stroke Basically it says there should be a good 8-9 VAC when cranking the engine over. I measure this and with a good kick I am seeing approx 10VAC from the stator (both with the CDI unplugged and plugged in), didn't try it with ignition on come to think of it. Also, in my generic Haynes manual it has a data sheet on the Zip which states 25 to 30 VAC from the stator at 2000rpm. When I previously checked this I was seeing approx 25VAC at a fast idle which sound about right. This dropped to approx 20VAC when revving the engine which I am really not sure about - is this correct? I really thought this should increase as the engine revved? This is one of the reasons I am suspicious of a fault in the ignition system. I have double and triple checked for wiring/earth faults but can't find anything. On the above link it also talks about testing for a strong spark by making the spark jump a larger gap. I improvised a set up with 2 screws in a piece of wood set 10mm apart, one connected to the engine earth and one to the spark plug cap. At first I couldn't get a spark, now I am not sure if this highlights an intermittent fault with my ignition or if I had a bad connection in my improvised test set up. Tried again however and was getting a good strong blue spark jumping across the gap between the two screws which indicates that at least sometime my ignition is working OK. Having said that - sometimes the scooter will start! I have tried varying the mixture screw but this doesn't seem to make any difference (3 turns out is as per the manual). The needle clip is in the middle position, have thought about raising that a notch to lean things out but my understanding is that this wouldn't have any affect on starting which is mostly about the pilot and the choke circuits. I am starting to run out of ideas? My suspicions are still around the ignition and am thinking about purchasing a replacement CDI/Coil. Does this sound like a reasonable next step or is there something I am missing? Thank you for your time as always! |
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Post by scut on Mar 28, 2012 12:27:24 GMT -6
Well the manual I have is a generic Haynes scooter manual which includes 1 sheet which has values/measurements specific to this scooter. I also have the Dutch wiring diagram which I found on this forum which has been very useful but I would love to find a full manual for this specific scooter!
The manual I have doesn’t actually state what is a normal voltage for the stator output. All it states is the resistance to earth which I have checked (engine hot and cold) and which seems to be OK at approx 0.9 ohms. However, when I was previously fault finding for the R/R problem I can’t recall exactly how many AC volts I was seeing at idle, maybe 20V AC or so, but I am 99% sure that the stator was outputting up to 90V AC at high revs. I have since changed the R/R to fix the blowing headlights problem and have run the scooter properly on the road for maybe 15 miles. Now I am reading approx 25V at idle which drops to about 20V AC at higher revs.
On this scooter the CDI/Coil is a single item. You are correct that it is fed from the R/R rather than direct from the stator but, as far as I can tell, all the R/R does is connect it’s own stator input directly to it’s output to the CDI/Coil i.e. the resistance between the R/R stator input and the R/R CDI/Coil output is zero.
I have checked the wiring between the stator to the R/R to the CDI/coil and all looks fine.
As the stator resistance matches the manual I wonder if the problem could be the CDI/coil. Wish the manual actually stated what the stator output should be then I could be sure!!
Would be great if I had a known good scooter to swap parts with but I don’t so at some point I will just have to jump one way or another and order a replacement part!
Thank you for your advice again, it really is appreciated, I am determined to get this little scooter running properly again!!
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Post by scut on Mar 28, 2012 11:37:05 GMT -6
Thank you for the quick reply.
Have checked main earth and ignition switched earth. Both look good and measure good on the multimeter.
Checked spark plug cap. Measured slightly under on resistance compared to the manual but not by much. Also looked good. cut an inch off the ht lead and reconnected to cap.
No change still difficult to start. Did start eventually but does not seem to be any reliable pattern or routine.
While running I checked the supply from the stator which was approx 25v AC at a fast idle but actually dropped a little when I revved the engine. Does this sound normal? pretty sure this was getting up to about 90v AC previously when I was fault finding the regulator problem.
Do you think the Cdi/coil could be faulty causing the poor start and dragging the stator voltage down?
The stator resistance and pick up resistance is exactly as per the manual.
The spark does look pretty white /blue to my untrained eye by the way.
Sure is proving a difficult little bike to get running properly!
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Post by scut on Mar 28, 2012 5:38:00 GMT -6
Hi, have posted previously here recently about my SGX 50 (Honda Sky) and received some good advice on an electrical problem. I now have another problem so I am back for more help please!
Background is that I purchased as a non runner a few months ago. Eventually identified problem as crank seals which I changed then she fired up on second kick. Then had to change the regulator/rectifier as was blowing the headlights. All seemed fine. Took the bike on it's first real run on the road a for a few miles to the MOT test centre.
Passed MOT but garage said they had a lot of trouble starting her up. This seemed strange as she had been started from cold many times, always first or second kick. Indeed she wouldn't start on kick when I picked her up but did eventually on the electric starter.
When she's running and warmed up she seems to run and idle fine. I can turn her off then, within a few minutes , she'll kick first time. Any longer and gets increasingly difficult to start with kick or electric starter
From cold is very difficult to start, sometimes she will show signs of life and others there is nothing at all. On the odd occasion she does start she is fine when warmed up.
Have checked the electric choke, resistance is as per the Haynes manual and needle extends by approx 4 to 5 mm when hooked up to a battery.
I get what seems to be a decent spark if remove plug and lay it against cylinder.
Compression tester shows approx 125 to 130 psi (after about 5 kicks) which I think is good?
Plug is getting wet with fuel.
Have removed carb & stripped but all looks pristine. Air/Fuel screw is set to 3 turns out in accordance with the manual.
Air filter looks like new.
Reeds look fine and look like they are seating properly.
Removed exhaust to check for any blockages, nothing obvious i.e. I can blow through the exhaust with little resistance.
I previously fitted a new plug when originally fixing the crank seals so have tried swapping back between the new & old plugs but with no noticeable affect.
Have even pulled the rotor etc back off to check the crank seals are still Ok and that the rotor had not slipped or broken the woodruff key. There was a tiny amount of oil on the left hand crank seal but this could have been from when I fitted them. Both seals are in place and look in good condition.
Possibly thinking a weak spark under compression (although it looks fine externally) or it is somehow flooding but as I said the choke seems to work OK.
Not sure where to go next, any suggestions would be great as I'm now at a loss !!!
Thank You
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Post by scut on Mar 10, 2012 13:12:18 GMT -6
Maybe I didn't explain very well what I was thinking of trying.
The R/R has 3 outputs.
One to the CDI which seems ok, that is engine starts and seems to run fine.
One to the battery and the electrics which run of that circuit i.e. indicators, horn etc. This output on the R/R seems fine as the voltage is approx 14 to 14.5 volts.
The third supplies the lights and the automatic choke. This one is not fine hence blowing the bulbs.
I was thinking of disconnecting the lights/choke circuit from the bad R/R and connecting it into the good output which supplies the battery.
I think it might work but maybe it would be too much load on that R/R output. Hmmmm, not sure!
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Post by scut on Mar 10, 2012 8:48:07 GMT -6
I am now actually contemplating a little re-wire rather than buying a new regulator (the regulator will cost me half what the bike cost!).
Thinking that I could disconnect the yellow lighting circuit feed from the regulator and splice it in to the battery supplied circuits as that part of the regulator output seems fine. I would need to remove the lighting circuit resistor so that it doesn't drain the battery circuit (plus it wouldn't be needed for that circuit).
Do you think this might work?
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Post by scut on Mar 9, 2012 10:57:11 GMT -6
Thank you for the quick reply.
This afternoon I removed the rotor and checked all the wiring but all looks fine. Ran the multimeter across all the resistors (there are 3) and all were as per the label.
Then played around checking continuity between various connectors and all appears as per the Dutch wiring diagram.
I was surprised that, with the regulator disconnected, there is continuity between the white wire which connects the stator to the regulator and the yellow wire which connects the regulator to the lighting circuit. I measured 15 ohms. Looking at the diagram I guess the two circuits can connect via earth and the resistor.
I then thought I'd experiment with the bike running. The output from the regulator to the Cdi seems to be AC and seems to match the stator feed as far as I can tell. if this is the case I do wonder why there isn't a supply straight from the stator to the cdi, maybe I'm missing something?
The regulator output to the battery seems fine, around 14 to 15 volts.
The regulator output to the light circuit was again very high. To rule out a short between the stator output and the feed to the lights I disconnected just the regulator wire which feeds the light circuit. The actual regulator output was high again, although I guess there was no load on it so that may have an affect. There was no voltage on the light circuit though.
Think I am now pretty convinced that the regulator is bad so will bite the bullet and order one.
Has been interesting playing around and I think I have learnt a few things!
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Post by scut on Mar 9, 2012 4:23:57 GMT -6
Hi, I have another Honda Sky SGX 50 electrical query, seems to be a popular issue looking at some of the previous posts in this forum!
Firstly, I would really love to get my hands on a wiring diagram if anybody has one available? Noticed in a previous post that there might be one available in Dutch?
Secondly I would really appreciate some advice on a problem I have. I am having trouble with my sgx 50 blowing the headlight and taillight when the engine is revved.
Background is that I bought the bike as a non runner a few weeks ago. Following various investigation I replaced the crank seals and now she starts and runs great. Whilst I had all the bodywork off I also painted the frame as it was starting to rust quite badly in places.
Last night I put all the bodywork back on and did a quick check to make sure everything was connected back up properly and working. All OK except when I revved the engine the headlight blew, strange I thought but maybe just an old bulb. Switched to high beam which came on fine, revved the engine and that blew as well.
Removed the bulb & confirmed it had blown then did a quick check a multimeter at the headlight bulb socket. DC voltage at the bulb holder goes from approx 6V at tick over to 50V at high revs. Was getting late so didn't have time to do any more investigation.
Strongly suspect the regulator but before I purchase I want to rule out anything else as the 5 pin regulator costs over 60 pounds and it seems a strong co-incidence that was all fine before I pulled things apart to change the crank seals.
By the way I am assuming that the lighting system is supplied from the regulator - this is where a wiring diagram would be especially useful.
Given I had to remove the Rotor & Stator to replace the crank seals I intend to double check I haven't done anything silly when re-assembling. Also going to check the voltage at the battery with the engine running to see what the regulator is supplying to that part of the electrics (I think that the regulator probably has two outputs - one for the battery supplied electrics and one direct for the lights).
One thought I've had is that when I first got the bike running the tail light was not connected up - could this cause any problems, could this have damaged the regulator due to there not being the correct load from the lighting system? Would seem a bad design if it did as bulbs can blow in normal operation and wouldn't want a blown bulb to result in an overloaded regulator. The headlight seemed to work fine at that stage and did not blow. Could a bad earth somewhere be causing this if I have disturbed the wiring somewhere and not realised? Could the lighting circuit resistor be involved?
Am not great with electrics and learning as I go along therefore any advise would be much appreciated & apologies for the long post!!
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