Valve Clearance Adjustents - 125 Agility (2009 model)

[scooterfan]

I bought my 2009 125 Agility with just more than 8400 km on the clock during te previous week. In very good condition, it still looks brand new.

Since I started riding the scoot I noticed that when cold, the engine started instantly. But after the engine got hot, the engine needed quite a number of swings to get started.
I also noticed that when the engine was still cold, the scoot picked up speed easily. But when the engine got hot, it became a mission to pick up speed after 80 km/h.
I immediately realized that the valve clearance gaps were probably to small.

Maybe I should mention - before I retired at work, part of my job was to train other people how to do valve clearance settings on all sorts of air cooled engines. I never had any experience on Kymco engines - but the principle on how to adjust valve clearances on all engines remains the same.
So I realized adjusting valve clearances on the 125 should be dead easy - I just had to find the correct gap specs to do the clearances.

Finding the correct gap specs on the 125 engines became more difficult than doing the gap settings itself. The numbers were all over the place. The suggested numbers varied between 0.04mm,  0.1mm. ,  and 0.12mm.
I would never even try wasting time on the “0.04” and “0.1” mm. To my mind settings  like that would be looking for trouble on engines like these.

So I decided to set the gap at 0.12 mm.

Doing the adjustments was dead easy. After the valve cover was removed and the engine being turned to Top Dead Centre, I immediately realized that my initial thoughts were correct. The valve clearances on both valve rockers were too small. At Top Dead Centre both rockers are suppose to be slightly “loose” - and I was suppose to feel at least some play on both rockers by hand. No luck - there was NO play on the exhaust valve rocker, and only a slight play on the inlet valve rocker.

In short - the valve clearances have been set at 0.12mm. I guess that’s the “correct” spec. Since the setting was done at 0.12mm, the “warm start problem” disappeared completely.  In fact, when hot the engine now starts in a split second when I hit the button - just like when the engine get started when cold.
Since the 0.12mm setting the “accelleration problem” between 80 to 100km/h has disappeared as well. Due to speed limit restrictions in our area I have’nt try to go faster than 100km/h yet.

For the time being I am quite happy with the 0.12 setting. I do not know whether the valve clearances on my 125 have ever been re-adjusted before. To my experience with several (even reliable) well known brands of small engines, it often makes sense to dubbel check on valve clearances - even when the engines are new. These things are getting manufactured in enormous numbers each year, and incorrect settings are not uncommon.

Just in case anyone need some advice on how to do valve clearance adjustments:

1. The engine needs to be COLD before adjustments get done.
2. Get rid of all dust in the valve cover area. Use an air compressor if possible.
3. Remove the rubber hoses at the top and bottom of the valve cover.
4.Remove the spark plug. (Not really needed, but it makes it easier to swing the engine in correct
   position.     
5. Remove valve Cover. (Four main bolts + two nuts which holds the breather pype)
6. Remove the engine cooling fan cover (Not needed if you have the correct socket for the nut at the center of the cooling fins -to swing the engine)

Important
Valve  adjustments need to be done when the piston is at TDC (top dead center) position. To get the piston in TDC position :
1. Have a close look at the camshaft Sprocket. The sprocket has four holes between the teeth and center bolt. Two of these holes are smaller than the other two holes.
When the piston is in TDC position, the two SMALLER holes will be in line with the upper level of the cylinder head.
So
2. Swing the engine by hand (by turning the cooling fins) untill  the two smaller holes at the camshaft sprocket get in line with the upper level of the cylinder head.

IMPORTANT

3. Now have a close look at the two camshaft lobes (which lift the rockers).
   - If the piston is TDC position, both camshaft lobes are  faceing the opposite side of the
     rockers (at an angle, towards the rear tyre), the piston will be in TDC position and
     clearances can be adjusted.
   - If both camshaft lobes are faceing the rockers (at an angle towards to front tyre) the engine is
     NOT in TDC position.
      This means the camshaft needs to be turned 180 degrees - untill the two SMALLER holes
     at the cam sprocket are in line with the upper level of the cylinder head again.
     (Turning the engine 360 degrees by hand at the cooling fin pully, means the camshaft
      will turn 180 degrees).
     Have a close look at the camshaft lobes again. The lobes will be facing towards the rear tyre (at
     an angle), and the piston will be in TDC position.
     The clearances can now be adjusted by:
4. Unlocking the 10mm locknuts at the rockers, using a fueller gage, and adjusting the adjustment
    screws at the center of the locknuts. The locknuts obviously need to be locked when the
    settings are done. Just hold the center screw with pliers while the locknut gets locked, otherwise
     the center screw will move and the gap will be to small.

 IMPORTANT

After the locknuts at the rockers have been tightened, dubbel check the clearance gap with the fueler gage again. The rockers must only have a slight “bite” on the fueler gage. Just a slight bite, it mus’nt be too tight. If the feuler gage does’nt slide into the gap fairly easy, it means the gap is too small.

It is important to know that when the locknuts at the rockers get locked during  settings, the gaps tend to get smaller - even when the fueler gage is still in place, and the center screw gets held by pliers, a screwdriver, spanner, etc.  Therefore the gap MUST be dubbel checked again.
In reality - during the initial settings the rockers should only have a slight bite on the feuler gage, then the adjusting screw at the center should be loosened VERY slightly before the lock nut gets locked. Otherwise the gaps WILL be too small. This is applicable on all engines, not Kymco only.

Just remember to put the cooling fan cover, as well as the spark plug back in place (if removed).

Unless these 125cc four stroke engines have been changed since 2009, I can’t think of any reason why valve clearance adjustments on later models should be done any different as described above.

[Stig / Major Tom]

Aren't the valve, idle speed, timing, plug gap, etc. specs on a label under the seat?
Specs are there on all four of my scooters (Kymco, Piaggio, Suzuki, Honda)
I, too, believe in an overnight cool down before doing the valves - but many shops (Burgman, for instance) say a few hours after a run is all that's needed. "Hot, no", warm OK. Done it that way for years with no issues they say.
Always did my VW's after over night.

Stig

[scooterfan]

Aren't the valve, idle speed, timing, plug gap, etc. specs on a label under the seat?
Specs are there on all four of my scooters (Kymco, Piaggio, Suzuki, Honda)


Stig

I’ve just had a look under the seat - there is no lable or indication about any specs.

Hopefully more Agility owners will have a look under their seats and forward specs if they find anything.

[CROSSBOLT]

Your write-up is excellent! Hey, Kymco! Gotta a guy here to write your manuals so English-speaking people can understand!

Have you an owners manual? I think all the placards/stickers are in there.

[Stig / Major Tom]

Have you found the 'birthday' label?
Sometimes found on the frame...has the month and year it came off the line..
load limits listed, sometimes engine info as well there.
Maybe the underseat stickers came after 09, or have been peeled off.
Shows vent/smog tube routings, etc.
Agree with xbolts, usually each label is shown in the owner's manual.

The engine info (valve lash specs) sticker under the seat of my 2018 Piaggio Liberty differed from the latest official Piaggio service manual specs. So I phoned USA Piaggio HQ in NYC and spoke with their technical rep. He phoned back to say, "the underseat label specs were to be followed with this engine".
Stig

[scooterfan]

Your write-up is excellent! Hey, Kymco! Gotta a guy here to write your manuals so English-speaking people can understand!

Have you an owners manual? I think all the placards/stickers are in there.

Thanks ! My first language is not English, so I’m glad if the wright up is understandable. I had to make several changes to make it look better.

The wright up can be used on all different size Kymco engines - even if the camshaft sprocket on other size engines do not have holes which line up with the upper level of the cylinder head when the piston is at TDC.
The prinsipal regarding valve clearance adjustments on all engines on our planet remains the same - the piston needs to]be in TDC position, and the two camshaft lobes must be faceing the opposite side of the rockers when valve clearances get adjusted.
If the camshaft does’nt have holes which will line up with the upper level of the cylinder head when the piston is in TDC position, the sprocket WILL have a mark which lines up with another mark elsewhere.

To find out where the marks are, one can just do the following :
1. Remove the spark plug (it’s easier to turn the engine a couple of times by hand at the cooling fin pully)
2. While turning the engine a couple of times at the cooling fin by hand, just have a close look at the two cam lobes on the camshaft.
    - When the two lobes are faceing the OPPOSITE side of the rocker, just look for a mark somewhere on the sprocket - as well for a mark somewhere on the cylinder head, or bracket which holds the rocker.
The two marks WILL line up when the piston is at TDC position.   

In short - if you just follow the comments (above), you WILL be able to do proper valve clearance adjustments on any given engine with an “overhead cam”.