Hi Everyone New Here! -- Can't Find TDC -- TURNS OVER / NO START

[Stig / Major Tom]

WAIT!!

We're advising too much info....some of which is incorrect.

He needs ONLY to rotate the engine forward again until: #1 his timing marks line up again, #2 the two lines on the sprocket line up, #3 the big sprocket hole is like my photos AND #4 THERE IS MOVEMENT IN THE ROCKER ARMS! Period!


Do not Loosen and remove the Crankshaft- and crankshaft Sprocket-combination completely, and turn the crankshaft 180 degrees !! Do not loosen anything. Just rotate the engine.

Rotate the engine as many times as you need to - until your marks & 3 holes are correct AND you have that rocker arm movement. Keep rotating until you have all 3. Do not remove or loosen anything......you're almost there! If you'd had that 3rd hole up there - you're rocker arms would have had movement!

Stig

[CROSSBOLT]

What Stig said! What Stig said!

[polishpipes10]

100 % correct. That’s the exact reason why I advised him to turn the crankshaft only 180 degrees, and NOT 360 degrees.  (Should he turn the Crank Shaft 360 degrees while the “T” and “V” marks line up, the Crank Shaft would end up at the very same, INCORRECT position)

@polishpipes10

I almost forgot - while you are lining up everything correctly, I think it would make sense to hook the scooter’s battery to a battery charger in the meanwhile. Due to all the engine cranking while you were trying to start the engine, the battery Voltage might be too low to start the engine at this stage. The reason being - if your scooter has a DC CDI and the Power supply to the CDI is less than about 9.5 Volt at this stage, the engine could easily not start, simply because the power supply to the CDI would be too low to create a spark at the spark plug, and to start the engine.

OK, I have aligned the two lines with the case and the big hole is up, and the T is lined up with the V on the crankcase..............I have also been charging my battery daily. Because of this dilemma  it drains the battery after about 6 times of trying to crank the engine.

Now the results.................................Nothing changed, it's still turning and turning and NOTHING. I tried starting it again and again until the battery could no longer do anything.

As to what you were saying about the crankshaft and turning it 180 degrees or 360 degrees. That has  me a little confused.

Another thing and the reason why I am so confused about most of this is because I have read opposing instructions before I found you guys. For example, another persons video said , ALWAYS turn the flywheel COUNTERCLOCK WISE? You said CLOCKWISE?

So are you telling me that if I have the 2 smaller punch out holes aligned with the case, AND have the big punch out hole pointing up AND if the T on the flywheel lines up with the V on the case, that this still could be wrong if I turned the camshaft too far or too little even though everything lines up?

[scooterfan]

OK, I have aligned the two lines with the case and the big hole is up, and the T is lined up with the V on the crankcase..............I have also been charging my battery daily. Because of this dilemma  it drains the battery after about 6 times of trying to crank the engine.

Now the results.................................Nothing changed, it's still turning and turning and NOTHING. I tried starting it again and again until the battery could no longer do anything.

As to what you were saying about the crankshaft and turning it 180 degrees or 360 degrees. That has  me a little confused.

Another thing and the reason why I am so confused about most of this is because I have read opposing instructions before I found you guys. For example, another persons video said , ALWAYS turn the flywheel COUNTERCLOCK WISE? You said CLOCKWISE?

So are you telling me that if I have the 2 smaller punch out holes aligned with the case, AND have the big punch out hole pointing up AND if the T on the flywheel lines up with the V on the case, that this still could be wrong if I turned the camshaft too far or too little even though everything lines up?

Sorry about this late reply ! It’s now 3 AM at this side of the pond and I actually went to sleep since my previous post. Maybe my guardian Angle became aware of Stig and Crossbolts comments, and decided to worn me that they don’t understand correctly !

Firstly, the Crankshaft ALWAYS need to crank clockwise. Remember, when the engine starts, it turns clockwise anyway ! Also remember - when the crankshaft turns clockwise, the Camshaft will turn anti-clockwise on any given engine. Maybe your other advisors just got confused !

I suggest at this stage you just leave the crankshaft as is, remove the spark plug, ground the spark plug to the engine - and see if you have spark at the plug when you swing the engine.

If you don’t have spark, it might have something to do with that loose magnet inside the engine. I suggest you contact a mechanic - that magnet could be part of the pick-up at the Crankshaft !

Good luck, I’m going back to sleep now !

[Stig / Major Tom]

Which way to turn? My Piaggio turns counterclockwise because the nut to turn is on the left CVT side of the scooter. If you're using a turning point on the exhaust side of the scooter - turn clockwise.


You have things lined up nicely now - but you did not mention if you found movement in the rocker arms.
If not, do not proceed - keep rotating until you do.

OK,  all lined up & correct small up/down movement in the rocker arms - yes?

"How to find TDC?" ….we have just answered your original question.

NOW of course you must check the valve gap using the correct thickness feeler blade. When the valve gap is correct, you should try starting the engine. Obviously if you just find TDC and do not check the valve gap - you have skipped the reason for finding TDC.

Hard starting points to a valve setting which has drifted away from ideal.
Once you find TDC and check that the valve gap is correct - you will have eliminated one common cause for hard starting.

What to do after finding TDC....

Stig

[scooterfan]

Which way to turn? My Piaggio turns counterclockwise because the nut to turn is on the left CVT side of the scooter. If you're using a turning point on the exhaust side of the scooter - turn clockwise.


You have things lined up nicely now - but you did not mention if you found movement in the rocker arms.
If not, do not proceed - keep rotating until you do.

OK,  all lined up & correct small up/down movement in the rocker arms - yes?

"How to find TDC?" ….we have just answered your original question.

NOW of course you must check the valve gap using the correct thickness feeler blade. When the valve gap is correct, you should try starting the engine. Obviously if you just find TDC and do not check the valve gap - you have skipped the reason for finding TDC.

Hard starting points to a valve setting which has drifted away from ideal.
Once you find TDC and check that the valve gap is correct - you will have eliminated one common cause for hard starting.

What to do after finding TDC....

Stig

Stig, you can open the CVT box and turn the CVT nut on any scooter out there, but the actual nut to turn the engine is actually located at the opposite side of the scooter engine - the nut at the centre of the FLYWHEEL , where the cooling fins are located (exhaust side of the engine).

Most engines on this planet turns clockwise. Apparently some Honda car engines and boat engines came with anti-clockwise engines, but that's all, I never saw any of those engines before. Apparently the boats with two engines came with one engine running clockwise, and the other engine anti clockwise - the idea behind this was to run the propellers in opposite directions.

 One way to determine engine turning direction, is to judge turning from the OPPOSITE side of the gearbox.  For example - on cars, trucks, etc. , you will see that when the engine is running and you have a look at the rotation direction of the fan belt pulleys - you will see those pulleys are turning CLOCKWISE. This obviously means the engine turns clockwise.

On  scooters you need to judge engine rotation from the opposite side of the gearbox as well. In other words, if you have a close look at engine rotation from the opposite side of the gearbox (at the flywheel / cooling fins - while the engine is running) you will see the engine is turning CLOCKWISE. This obviously means the engine turns clockwise as well.

I had a look at images of your Piaggio scooter - and the gearbox is located at the same side as gearboxes on Kymco scooters. Engine rotation on your Piagio scooter is clockwise as well - just like on Kymco engines !

I must admit - I do not agree about the "feel for rocker movement" to determine TDC in this case, for the following reasons:

1. To remove the cylinder head, the timing chain had to be removed / seperated from the Camshaft, and Camshaft sprocket. (There is no other way to remove the cylinder head).

2. When the timing Chain has been hooked to the Sprocket during re-assembing, the camshaft Lobes were facing the WRONG direction. (IMPORTANT - Polishpipes10 initially clearly indicated that whatever he did, the "T' and the "V" marks, as well as the big hole at the sprocket dit NOT line up correctly.)
So
 At that stage it would NOT make sense to feel for play at the rockers - because the cam lobes were facing the wrong direction.
 
 3.Since Polishpipes re-alighned the camshaft Sprocket by alighning the "T" and "V' marks first, he actually proved that the camshaft lobes were off by 180 degrees, or more or less 180 degrees. (There is no way in life how he could "correct" such an incorrect alighment, just by keeping on turning the engine. Fact is, when the alighnment is out by 180 degrees, there in no way in life how the "T", the "V", and the big hole at the Sprocket will line up correctly).


4. Even since Polishpipes10 corrected the Camshaft's (and camshaft Lobe-) position, we do not know whether the valve clearance settings were correct BEFORE this work has been undertaken. We do not even know whether the Rockers were removed during this period. Therefore my point - I am not sure whether the "feel for play"method would be advisable in this case.
 
 
Please don't get me wrong. I am NOT trying to be the "wiser guy".  All I know, giving advice at Forums is often quite complicated. People who ask questions often do not supply all needed information to get the right advice. To my mind people who ask questions at Forums plays a major role in keeping forums alive, and we need to do whatever we need to do to keep them mobile.

[scooterfan]

...........................….So if he were to turn his crank one more turn from his picture, then his cam ought to look like Stig's except not as shiny! (Nobody's cam is as shiny as Stig's!)

Sorry Crossbolt - it looks like you only got me "halfway"!
 The first part of your comment is 100% correct - but my understanding of what you mean by the quoted part (above) is that you might still be missing something.


Firstly - you need to understand that once the Camshaft timing is off by 180 degrees (or any given degrees), the timing can NEVER be corrected by just turning the crankshaft. For example - should the timing be off by 180 degrees, you can turn the crankshaft a zillion times or more, but correct timing will STILL be off by 180 degrees !


The reason is very simple - if the timing marks are off by (i.e) 180 degrees, the camshaft lobes will always  be facing the wrong direction when the piston's is suppose to be at "compression stroke".
 This means whatever you do, the camshaft lobes will ALWAYS be at the wrong position when the spark plug is suppose to ignite the fuel mixture at the correct moment !
 
 The only way to get the time settings correctly - is to use the marks on the Flywheel and engine Casing as a "starting point", and then to make sure the timing marks on the camshaft Sprocket line up correctly AFTER THE CHAIN HAS BEEN HOOKED TO THE SPROCKET.

[Stig / Major Tom]

Remove fan cover 3 screws on this Piaggio, Turn this nut counter-clock-wise to TDC.
Whole lot harder on the flip side.

Stig

[scooterfan]

Hi polishpipes10,

Did you see a spark at the spark plug during a test ?

[polishpipes10]

Hi polishpipes10,

Did you see a spark at the spark plug during a test ?

Good morning, Yes I did see a spark after test! But still no luck.

I have another question, I where can i find a cylinder head that is the size of the one pictured on the LEFT? That is the one I need and i cannot find it anywhere for the life of me, everywhere only seems to have the "shorter" one on the right? I think the previous owner may have installed a big bore kit, but not sure how to tell. Any tricks as to how to tell if the engine has been upgraded with a Big Bore Kit?

[scooterfan]

I assume the cylinder head has been removed from the engine at this stage ? If not, and the "incorrect" cylinder head is still mounted on the engine at this stage, I would do a compression test on the engine fist, just to confirm whether the engine do have  compression or not.
If you do find proper compression, you should be able to start the engine. I would only be concerned about the cylinder head once a compression test indeed confirms that the cylinder head can not be used.

Just two questions:
Have you been able to start the engine when you bought this scooter ?
If not - are you sure the carburetor jets are not clogged up, and you are not having a fuel supply problem at this stage ?

[scooterfan]

@ polishpipes10

Just another thought - I just had another look at your previous comments, as well as the attached photo, and I think you might have another major problem :

You mentioned that the "taller" cylinder head is the correct cylinder head, and to my understanding the "shorter" cylinder head (at the right on the photo) is shorter in height.

To my mind this can quite easily cause a major problem - because if you install the "shorter" cylinder head, the original timing chain will be too long, and should not be used when the shorter cylinder head gets installed.
The reason being - when the shorter cylinder head gets installed, the chain will be too long for this application, and the tensioner guide / slider would easily become far less effective.  In fact, when the original chain get used on the shorter cylinder head - I think the sprockets will constantly jump some teeth at the chain.

Therefore - unless you are able to find a timing chain with the correct length, you should rather not use the "shorter" cylinder head.

Another thought:
I just had a look at images of timing chain guides and slides on Kymco scooter. (see picture below).

I am not sure whether the chain guides on these scooters have magnets, but if you have a look at the photo (below) you will see that the chain guide come with some sort of attachment.
 I am not sure whether that attachment could hold a magnet ?
I was just thinking - while the original timing chain would be too long, and would probably be slapping like hell when you tried to start the engine - maybe that attachment came loose, and maybe that attachment was holding the magnet you discovered when you opened the engine ?

[mhaseebalam]

I have question regarding this. Im afraid of messing up the TDC as the mark on the flywheel is not enough if I understand it correctly. The T mark can be aligned but you can still not be TDC on the compression stroke. How can I track this or be sure im at true TDC. in other words does the crank shaft rotate evenly because just in his case he had aligned the T mark but not at the TDC when you look at the camshaft. without the camshaft does it matter if the T is in the same position or if i rotate 360 degrees line the T mark again it wont make a difference?

[Stig / Major Tom]

I have question regarding this. Im afraid of messing up the TDC as the mark on the flywheel is not enough if I understand it correctly. The T mark can be aligned but you can still not be TDC on the compression stroke. How can I track this or be sure im at true TDC. in other words does the crank shaft rotate evenly because just in his case he had aligned the T mark but not at the TDC when you look at the camshaft. without the camshaft does it matter if the T is in the same position or if i rotate 360 degrees line the T mark again it wont make a difference?

It IS easy to get flustered here.
Try this:
if T is in correct position
and
sprocket looks like the photo
and
there is slight (tiny!)  up>down play on both of the rocker arms
you are at TDC - unless someone has been there before you to mess things up!

Let us know if you do NOT feel that small movement at the rocker arm ends.

Stig

[maxhitz]

Good morning, here are the pics of what I see if I align the T onto the V on the casing. Looks Like it's correct to me, or am I wrong?

One thing I did notice however is that the rocker heads have zero play. They will not move at all?

Another question I have is, is putting the exhaust pipe back on a necessity when trying to see if it will start? Cause I have NOT been doing that because it is such a pain my a**! I just assumed that if it did start without exhaust pipe it would just be hella loud. Is that causing any trouble by not putting it back on before trying to start?

Also I attached the piece of magnet that I found. I'm pretty sure it did not fall out of the case. It looks to me as if it might be one of the magnets from the inside of the flywheel perhaps. Would that make it not start if one of those fell off?

Thanks again for taking time out to help me with this annoying and time consuming problem. I greatly appreciate your knowledge and expertise.

any update, V to the T mark or?