KymcoForum.com
Scooters - Big Bore => Xciting 500 => Topic started by: ggraven on August 28, 2019, 04:12:14 PM
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I have tried many test as far as spark' have it, fuel to injector' have it, fuel pump works fine, Has anyone had or heard of this problem, from looking around on the internet this could be a blown head gasket, valve touched the piston. Whats the best way to diagnose this issue, could it be a timing issue. I only have 300.00 bucks in it, I would hate to get rid for what little I have in it.
One last thought could it the starter is not engaging to spin the piston rod? The scooter has backfired on me before!!
500 RI Fuel injected and 11,000 miles
Is it worn out??
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How are you concluding it has no compression?
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I got a compression tester from a local auto store and used the 10mm adapter and screwed ii in the spark plug hole.
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That is the absolute BEST way! So, what reading are you getting?
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Are you sure the valve clearance gaps are correct ?
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I had zero reading on the compression tester.
I have not checked the valve clearance.
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Zero? Yes, first like scooterfan suggested, check valve clearances. Then check compression again to see if there is a change.
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Why is this a $300 scooter?
What did the previous owner tell you?
He was doing 'what', when 'what', happened?
We need more history of this $300 scooter.
Stig
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Thank you I will do that and see what happens.
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$300 scooter
I bought it from a guy about 60 mies away from me. He had been trying to get it running and was not able to. He bought it from a guy near him and he tried to get it running. I am not sure what he paid for it, so in all I do not know much about it. I figured for 250.00, I could always sell it parts and get my money back, but I am determined to get to the bottom of this scooter and get it running. They are selling for 2500. to 3500 depending on condition. Hopefully the valve clearance will get me on the road.
Thanks
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You're probably going to have to take off the head and cylinder to figure out what's going on.
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Should I not try checking the valve clearance and have a shop do a diagnostics test on it?
They charge 85.00 for that.
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Should I not try checking the valve clearance and have a shop do a diagnostics test on it?
They charge 85.00 for that.
Yes, the correct valve clearance settings might solve the problem.
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I adjusted the intake side valves, there was no gap i adjusted to the.004 now do i adjust the exhaust at the TDC or do i rotate 180 to the tic of exhaust valve? The exhaust side is very tight no gap even when i loosen the adjusting nut.
I would appreciate some input before I go any further.
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All valves, intake and exhaust adjusted at the same time, at top dead center on the compression stroke. Usually there is an indication on the cam gear when it is in the proper position. That will be generally be two holes that will be parallel with the valve cover surface. You can confirm the cam is in position by observing the rockers are fully tilted away from the valve stems.
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Okay, I got it to TDC and the intake needed a little adjusting, I could not get the feeler gauge and now I can. The exhaust side however was either way out or did not do something wrong. I had to loosen the screw a long ways, like 1/8" to 3/16"out to where I could a feeler gauge in between the valve stem and the rocker screw. If i have this correct, I cannot see how those could be that tight. Unless some one had the cover off and tried to adjust them. I have no history with this scooter to get any info on what could have been done to it. I going to stop for a little while to see I can get any insight from you guys. Thanks for helping me so far.
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I adjusted the intake side valves, there was no gap i adjusted to the.004 now do i adjust the exhaust at the TDC or do i rotate 180 to the tic of exhaust valve? The exhaust side is very tight no gap even when i loosen the adjusting nut.
I would appreciate some input before I go any further.
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I adjusted the intake side valves, there was no gap i adjusted to the.004 now do i adjust the exhaust at the TDC or do i rotate 180 to the tic of exhaust valve? The exhaust side is very tight no gap even when i loosen the adjusting nut.
I would appreciate some input before I go any further.
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You DO NOT need to rotate IF you had it in the right place to start! When in the right rotation position BOTH intake and exhaust gaps should be .004" that means BOTH rocker arms should be "rockable" like a teeter-totter. Having to back screws out an eighth to three sixteenths of an inch means you are at the wrong rotational place.
Here's the drill:
1. Remove spark plug.
2. Find a way to rotate engine
3. Rotate until piston is at top dead center (TDC).
4. Determine if piston is TDC on the compression stroke
5. Adjust all four valves to .004" gap.
6. Install and connect spark plug.
7. Gentleman, start your engine.
Hope none of the valves got bent before you got it! Ask more questions if needed. Any question will be answered. The answer may even be correct! Har, har!
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Well I have some good news. I did exactly what you said and I now have compression in the cylinder, pulled the plug to be sure of compression stroke and I have TDC on compression stroke. The manual says to make the the cam shaft marks are facing to the top and the T is correct on the flywheel. The intake and exhaust valves are all set at .004 and now I have a dead battery. I had the seat off of it and the seat lock is on and ran the battery down. I have it charging. If all goes well it should start right up I hope. I did the CLEP diagnostics on it and it gave a 33 which is the fuel injector. So I have a fuel injector in case I need it. I am still puzzled why I had to back the exhaust valves so much to get a clearance. Like I said earlier I do not know what someone else may have done to it, providing no bent valves it should run.
Thanks again for your advice and help.
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My pleasure since it all worked! You said code 33 was fuel injector and that is the same for the DT scooter SO, make sure your fuel pump relay is consistent because it also provides power to the fuel injector! I have a post on that in the Downtown section. The service manual says NOTHING about that relay!
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I still cannot get the engine running, I do compression, I open the throttle body a little bit and a do get a little thumping sound from the exhaust pipe. I have spark, but it will not fire any other suggestions. I am missing something?
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I still cannot get the engine running, I do compression, I open the throttle body a little bit and a do get a little thumping sound from the exhaust pipe. I have spark, but it will not fire any other suggestions. I am missing something?
Maybe you should remove the fuel injector, keep it connected to the fuel line, swing the engine by using the starter button - and see if a fine fuel spray is coming from the injector when the engine is swinging. I have no experience with scooters like yours - but that’s what I would do.
You could also just unscrew the spark plug to see if it looks “whet†after the engine was swinging a couple of times. If the spark plug looks “dryâ€, you obviously have a fuel supply problem, or maybe a clogged injector.
This scooter hasn't been used for quite some time, and I wouldn't be surprised if you are having a fuel problem.
The previous owner probably fiddled with valve clearances before, and just didn't manage to get the settings right. I wouldn't be too worried about it. The recommended clearance gap is very small, and even an expert can make a mistake with such small clearance gaps.
Good luck, I think you probably bought one of the biggest bargains in a lifetime.
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You found some gap on the intake valve - but NO gap on the exhaust valve, yes.?
Maybe you did not do the valve adjustment correctly.....
How could it be wrong?- if you were not on the proper TDC and you then gave the exhaust valve a 'gap' by loosening the screw/nut assembly - you have now closed the exhaust valve....when the engine may not have been at the proper TDC.
You must be absolutely certain that you were on the proper stroke and at TDC of it!
You are apparently the 3rd owner who could not make this scooter run.
I think for $85 you should let the dealer take a look at your scooter. Right now it is a $300 lawn ornament.
Even IF everything is adjusted properly ....these 500's are notorious for being hard, or impossible, to start sometimes!
Stig
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Don't forget that code 33 you mentioned. Scooterfan said inspect the spark plug for "wet" or "dry." Wet means the injector is squirting and dry means it is not. That "thumping" you hear while cranking is normal for cranking and no firing!
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I forget to mention - the spark plug might be whet but if the injector is partly blocked, or the pressure before the injector is too low , a small stream of fuel will be squirted into the combustion chamber. This could lead to a “flooding†problem.
Therefore it would be better to remove the injector, swing the engine, and then make sure that a fine fuel “mist†is coming from the injector.
You seem to be willing to learn and quite capable of getting your own scooter going in future. Just go for it. The feeling of keeping yourself mobile, or getting something right yourself with a little help is worth far more than $85.00.
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I have a question? I had spark for awhile and after adjusting valves and putting it back together I now have no spark at the plug. Did I maybe loosen something, should I replace the spark plug?
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I have a question? I had spark for awhile and after adjusting valves and putting it back together I now have no spark at the plug. Did I maybe loosen something, should I replace the spark plug?
No.
Pulled the spark plug cable loose from the spark plug boot, maybe?
Tighten it by 'screwing it on' motion, righty tighty.
It's not the plug itself most likely.
You have a $300 500cc scooter.
Why NOT take it to a dealer? Pay an expert to check it for an hour, even two?
But, your call.
Some love to tinker. Some love to ride.
Stig
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I have everything back to working condition, I forgot to put the kickstand back up nothing was working no spark. Now the spark is back and the injector is working fine it sprays gas. I reset the CLEP for the fuel injector and it cleared. I have no error codes and it should start right up , but will not start. I had taken the throttle body off a couple of times and I am going to do a reset the throttle body. I am bound and determined to get it running, I am asking one last time for help. I have made an appointment for the 16th for a local shop that works on them. So if you any other suggestions I am all hears. Thanks to all for input so far. I am sure you guys understand the not wanting to give up when I feel I am so close to have it start.
Thanks again!!!
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one last thing, I noticed today that it has no air filter in the slot where it should be. Would that make any difference?
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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.
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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?
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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.
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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.
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Try to rig a jumper from battery to ECU power in somehow.
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What compression reading did you get during the engine compression test ?
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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
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Do you hear the fuel pump while the gauges do there sweep.
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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.
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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.
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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.
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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.
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I have 140 psi
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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
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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.
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Thanks 2cents for the info.
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Thanks 2cents for the info.
No problem. After some reading I started thinking these models might not be worth more than 2cents anyway.
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No problem. After some reading I started thinking these models might not be worth more than 2cents anyway.
It's a puzzle...some have good experiences with the 500. Others have no luck.
I sure wouldn't buy a non running one! Chances are not good it will be an easy fix.
Stig
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Well I finally took the Kymco 500 to a dealer and it turns out that the cams in it were almost flat and fuel was going into the oil, so they are installing new valves, cam shafts and new piston rings. oil change. Parts are 450.00 and labor 500.00. But I am still ahead on the deal I will have 1200.00 in it all said and done.
Just wanted to give some info for maybe someone else to help. They told me it needs 185 psi of compression to get it started.
Thanks for time gentlemen!
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Get the cams tested for hardness BEFORE installation!! The hardness/heat treatment was
The problem with all cam failures. Don't let them talk you out of it!
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Get the cams tested for hardness BEFORE installation!! The hardness/heat treatment was
The problem with all cam failures. Don't let them talk you out of it!
I'm guessing you think they'll do that for free, right? Most shops don't do this, and would have to send it out.
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Probably you will have to pay for a lab to test them. Either way, you are gonna pay. The only difference is the engine will probably last longer than both of us if the cams are of proper hardness.
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Well I finally took the Kymco 500 to a dealer and it turns out that the cams in it were almost flat and fuel was going into the oil, so they are installing new valves, cam shafts and new piston rings. oil change. Parts are 450.00 and labor 500.00. But I am still ahead on the deal I will have 1200.00 in it all said and done.
Just wanted to give some info for maybe someone else to help. They told me it needs 185 psi of compression to get it started.
Thanks for time gentlemen!
Ask for the old parts back. I'd like to see photos of them.
Gas in the oil can cause low compression by washing out oil in the piston rings. 185 psi compression is the spec but I'd think it could run on less. Compression is checked with the throttle wide open.
I had a 2016 with under 15K miles on it that had a major loss in power, I measured at 140 psi with the throttle closed and turns out with the throttle wide open it measured around 210 psi. The dealer tried several things and ended up putting a muffler on it claiming a broken baffle inside. I haven't had a chance to ride it and see if it's fixed because the owner doesn't have current registration on it.
Curious as to why this post isn't in the Xciting 500 sub forum?