Timing adjustment PGO BIG max 50 2007

[legroscalis]

Hi everyone, so I just did a bottom end rebuild on my 2008 PGO BIG max 50 and I realise that I messed up the timing when putting it back together so now it wont start. I know i need to adjust the timing to 17 degrees but I dont know whats the equivalent in mm so that i can adjust it with a Dial Indicator Gauge. Do you guys have any ideas on how to get the measurement I'm looking for?

Thanks

[WD Forte]

get access to the crank and imagine it like a clock face.
Get it to TDC then make a mark to establish a 12 o clock position
at TDC
Then turn it back ( advance) a smidge under 3 minutes.
( 1 minute = 6 degrees of rotation )
A card as an impromptu dial(angle) gauge on the crank can help with this

A clock gauge will only tell you distance not angle
so you'd need to know the stroke to calculate the relation between angle and piston movement.
From my experience farting about with a a 50cc Mobylette I reckon you're only looking at around say 1.5mm using a clock gauge.
If you tell me the stroke I'll tell you the distance.
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[legroscalis]

The stoke is 39.2mm

[WD Forte]

17 degrees will be 0.832mm as near as, but a smidge under 1mm probably wont hurt as it will only be a degree or two if that.
I would probably use 0.83mm as a base and experiment/adjust accordingly.
take your time with the clock gauge when finding TDC
There's only about 0.1mm margin between tdc and 6 degrees either way
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[legroscalis]

Are you sure because a mecanic told my that my timing was the reason why my scooter wasn't starting and after that I checked youtube videos on how to do that and a lot of them were adjusting it to 18mm or even 30mm for one. That why 0.8mm seems like not a lot to me but I could be wrong.

[Robby]

I'm trying to work out how you messed up the timing.

It looks like the scooter in question is a 2 stroke, so the only timing it has is ignition timing. This will be controlled by the alternator rotor, and the CDI. The CDI can't be adjusted, and the rotor should be lined up on the crankshaft with a woodruff key, so it's also fixed.

Did you take the rotor off and put it back on without the woodruff key?

If you are using a dial gauge, it should be graduated in degrees, so no need to convert to mm.

[legroscalis]

The dial gauge I looked up on amazon were all in mm. Could you send me the dial that you found that were in degrees. I dont know if the woodruff key on the new crankshaft could be removed so im pretty sure it's still there but when rebuilding it I could have put everything together while the piston is mid stoke and the Ignition set to TDC. That why I pretty sure that my ignition is so off. If you think thats not my problem for my scooter not starting what could it be? That carb is brand new, gas is coming in, spark plug brand new and it's working, ignition coil brand new and it's working, CDI brand new and it's working. The only remain thing that I could have messed up when rebuilding is the timing.

[WD Forte]

[legroscalis]

So with all that you are saying that I should move it for how much mm?

[WD Forte]

I reckon your 'mechanic' was talking shite.
Just looked up a parts list and its got a typical AC CDI system
so as Robby mentioned, the pulser like on so many small bikes is fixed
and all this degree/mm stuff is barking up the wrong tree.

My suspicion is your source coil and /or pulser or CDI is bad

My advice:
Forget timing
Don't buy gauges buy a meter and test it out

Parts are cheap

https://www.racing-planet.co.uk/pgo-big-max-50-2t-ac-electric-c-3126_7242-1.html?newcPathco=165&sessID=905cf3435984df2067b60ccd90ed6a51
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[legroscalis]

I tried multiple CDI and Ignition coil all the same result. My tought is that when putting everything together I put the timing set when the piston is at his lowest or something like that and correct me if im wrong but a CDI magicaly get the right timing to ignite at 17 degrees BTDC.

[stinkwheel]

[Robby]

Also worth mentioning that this looks like a classic case of fixating on the thing you don't understand. It was very common with teenagers trying to do diagnosis and always blaming the CDI, because it was the inscrutable black box of magic. The problem was never the CDI, it was them fucking something up.

So, fault finding from the top:
Spark, fuel, compression.

You mentioned the spark plug working, so I assume you have a spark. You're assuming this spark is happening at the wrong time. Follow Stinkwheel's advice there to find out if the rotor is in the correct position. If it is, we can assume that spark is not the problem.

Fuel. You mentioned a new carb. Is it the right carb, and does it have the right jets, needle height and other settings? Alternatively, do you still have the old carb and can you try that.
Fuel mix - it's a 2 stroke. I don't know if you're running pre mix or retaining the autolube system, but it needs to have the right amount of 2 stroke oil.

Compression. You've rebuilt the bottom end. I assume you rebuilt the top end too. Worth doing a compression test. If it's your first rebuild, you probably fucked it up somewhere.

For a simple diagnostic test, spray something flammable down the carb throat and try to start it. It should at least cough if things are anywhere near running.

[WD Forte]

That horrible little Moby just had a taper and no key, the cheap bastards.
Fitting the rotor was fun as when you slipped it on the shaft the magnets tried to align with the coils and throw the timing out.
It took me a few goes to get it right.

If the OP is getting a spark then the ignition gubbins are probably fine and its something else like assembly error
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bikers smell of wee

[legroscalis]

I don't remember fitting the woodroffe key. I have put back on the old carb with all the right adjustment and im runing premix with a 32:1 ratio. Compression is good. I tried spraying carb cleaner directly down the carb throat and it did nothing. One time it semi-started but didn't go far.

[stinkwheel]