Kymco 500ri no compression in cylinder

[CROSSBOLT]

You just keep on asking, just don't give up! You have gotten farther than your predecessors! No, the air filter would not be that important at this point. You mentioned the "T" mark and the marks on the cam sprocket lined up properly, right? That gets the cam off the hook for being out of time so that kinda leaves all the switches that can kill the spark by turning the ECU off and the "pulsar coil" on the stator unless something is loose on the coil and plug wires/primary wires.

[ggraven]

I do not have the seat on it and there is a red indicator top right of instrument panel that lit up . Do I need to have the seat in place and that light off. If I put the seat on it does go out?

[CROSSBOLT]

That panel light is activated by the seat latch(es) being open. So just push a small screwdriver shank or allen wrench down in the slot where the seat wireforms go. That will activate the "seat open" switch and turn the light out. That light and the tub light will run a battery flat.

[ggraven]

I have checked the TPS and CDI and I am getting the correct ohm readings, I do have spark with the kick stand up, is there by chance another kill switch besides the kick stand that I am not aware of..? I have checked almost all of the modules and etc on this darn thing now I am at a stand still. If you think of something I am all ears.

[CROSSBOLT]

Try to rig a jumper from battery to ECU power in somehow.

[scooterfan]

What compression reading did you get during the engine compression test ?

[Stig / Major Tom]

I have checked the TPS and CDI and I am getting the correct ohm readings, I do have spark with the kick stand up, is there by chance another kill switch besides the kick stand that I am not aware of..? I have checked almost all of the modules and etc on this darn thing now I am at a stand still. If you think of something I am all ears.

So, the engine IS turning over, "cranking", --- just won't start?
Is that where we're at?
Stig

[Trucker jay]

Do you hear the fuel pump while the gauges do there sweep.

[ggraven]

Yes the engine turning and cranking, but just does not want to start. The fuel pump is coming on and the gauges sweep. I pulled the fuel injector off to the side and bumped the starter and gas sprayed out of it. I have a spark from the plug. I checked the kickstand and the ohm reading is correct. I even tried spraying starting fluid in the cylinder. I opened the throttle all the way and tried and then a 1/4 turn still would not start. I have checked the compression again I will check it again this evening.

[scooterfan]

On most engines engine compression must be at least 90 Psi for an easy start, or to run without problems. This should be applicable on your scooter as well. A lower compression reading than 90 Psi could be causing this problem.

[stuo]

Compression reading should be at least 100 pounds. If you have compression, spark and fuel then it's either timing or flooded. If you pull the plug after trying to start it and it's wet you've flooded it. Leave the plug out to dry, try again later with no throttle or starter fluid. Keep your battery charged so it cranks rapidly.

 

[stuo]

I posted before I had a chance to read Scooterfan's post: I concur: you need at least 90 psi to fire. Also when doing the compression test hold the throttle wide open, spark plug wire should be grounded so as not to damage the coil. All that high voltage wants to go somewhere, let it go to ground.

[ggraven]

I have 140 psi

[Stig / Major Tom]

Well, I  hope I'm wrong - but these 500 Kymco scooters have a known issue with refusing to start.
This has been well documented by owners here, and in past years even by owners on youtube!

Interested parties could read the previous comments related to this issue posted by other 500 owners over the years.
The 500 is Kymco's most problem prone scooter - and it is most often a refusal to start.
Stig

[scooterfan]

Well, I  hope I'm wrong - but these 500 Kymco scooters have a known issue with refusing to start.
This has been well documented by owners here, and in past years even by owners on youtube!

Interested parties could read the previous comments related to this issue posted by other 500 owners over the years.
The 500 is Kymco's most problem prone scooter - and it is most often a refusal to start.
Stig

@ggraven The engine compression is obviously more than perfect and there is no reason to be worried about valve clearances, bent valves, etc.
On a positive note, there is no way in life I would give up on trying to get the engine going. Since Stig's comments I did some reading about comments regarding starting problems on these models and I think some of those comments might be very useful to get the engine running.

Firstly - on any given gasolineuu engine, if you have proper spark at the right time, proper compression at compression stroke, and the correct air / fuel mixture at the right time the engine WILL start.

I think some old comments regarding starting problems might hold the key to get the engine going. Two comments are very interesting:

1. One owner got his engine going by replacing the scooter's stator.
2. One owner did an upgrade on the scooter's EFI system to solve a "cold start" problem.  Apparently the normal power supply to the EFI system was not sufficient, and therefore caused starting problems.

To my mind this simply means there is a good possibility that power supply to the EFI might be suspicious by times.

So right or wrong - I would do a simple modification by installing a "normally open" 4 pin Relay as close as possible to the ECU The idea would be to draw power feed to the EFI directly from the battery - instead of via the existing wiring. The existing power feed wire (+) to the EFI will be used as power supply to the switch part on the relay. (86 is the positive (+), and 85 is the negative (-) on the "switch part" at the relay).

The connections to the relay would be as follows:

1. Connect the existing power supply (+) on the ECU to 86 on the Relay. (This wire probably has "low" power feed)
2. Connect 85 on the Relay to Earth.
( 85 and 86 is the "switch part" of the relay, and doesn't need much power to activate the switch)

3. Connect 30 on the Relay directly to the Battery, with a fuse in between.
4. Connect 87 on the  Relay directly to the ECU.

By doing this modification, chances are 100% that the EFI system WILL get a better power supply than usual.
Before I retired at work we did several similar modifications to several other applications, and it ALWAYS worked.


My 2cents.
Please ignore if you are not interested in trying this.  But who knows - it might just work.