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Thread: Idle trouble/ knocking on a AA 500

  1. #1
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    Idle trouble/ knocking on a AA 500

    Sun came out for a change. Took my scot up to 80mph on free way. But when I come to a stop lite at 60-70 mph it wants to die. Sometimes it does. Is this one of the scots that has the in tank hose trouble.
    Also I get this knock,knock ,knock noise sometime when I come to a stop. Sounds like maybe the transmission belt area down shifting? It has a new belt and everything looked good.
    Thanks for any help
    The old man.
    Last edited by twocams; 01-31-2019 at 11:48 PM.

  2. #2
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    That was the scoot that was rushed into production when Piaggio took over and had the plastic drive gear on the oil pump destroyed/dissolved by a too rich gas mixture, dripping fuel injectors and gas overflow getting into the crankcase. Added to that was too cold a thermostat (bike would not warm up fast enough to evaporate the gasoline from the oil on short trips) coupled with airflow from the radiator going around the fuel tank causing excess pressure in the tank which increased the tendency for the fuel injector to drip gasoline down the intake as the bike cooled down after a longer ride.

    If all the service bulletins which have been mostly forgotten over the past decade are not fulfilled chances are that the engines will self destruct from gasoline diluting the motor oil so if its knocking pay close attention to it especially if there is any hint of a gasoline smell coming from the crankcase when you check the oil or the oil light flickers on occasion. Once the main bearings and crankshaft are compromised its usually considered game over for the 500cc Atlantic. The most problematic were the ones made up through 2003 and early 2004.

    This is a real shame though because the overall package makes for a very nice bike. It was the tainted reputation over the oil dilution related 500cc engine failures that killed them in the US.

  3. #3
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    Whoa, Im talking maybe a roller (s) when down shifting or what ever they do making noise. Not total engine destruction. Where can I find the service bulletins. Things that should have or could have been done forms. Thanks for the help tho and Ill keep an I open. I did take the Calif. hoses/stuff off.

  4. #4
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    What did the rollers look like when you changed them along with the variator guides during the belt service? How was the grease on the needle bearing inside the back of the clutch that idles on the transmission input shaft? If that was not cleaned and fresh grease packed in you can also get binding of the clutch on the shaft causing noise and stalling when idling during a stop. There can also be some clutch plate rattling too. Those will all be more or a rattle than a thumping knock or hammering.

    Piaggio buried all that info that formerly was out available for the public on the Service Aprilia site. Now you have to call a dealer or better Aprilia's main support number to talk to one of their service techs in NY. With the way dealers come and go that service Aprilia bikes its hard sometimes to find one with a tec that was there when the Atlantic 500 first came out in the US and was still there when this issue was finally resolved two years later.

    I spoke with the service engineers at Aprilia's main office along with a local Aprilia Service Manager who was involved with sorting out the problems with the 500cc Atlantics from the day they were introduced in the US to find out the details on this before I purchased one that was not running (I did not purchase it). This was supposedly all sorted out by the time the last new ones were sent to the US but there is no hard data to tell you which ones they were.

    I do keep getting tempted when I see them up for sale but knowing that there could be a ticking time bomb inside with that plastic oil pump drive gear makes me take pause because even if they eventually got the gas in the engine oil sorted out on the Atlantic 500 you purchase there is still the possibility that the plastic gear was compromised and going to suddenly fail. On that series of engine the drive gear is not externally accessible making it so you have to do a complete engine tear down so you can split the case halves open to service it and upgrade it from the AP8560032 oil pump to the new 876225 oil pump which I would probable do for my peace of mind before I used the bike very much. The $80 for the pump is small compared to the work involved changing it but not as bad as having sudden engine failure on the highway.

  5. #5
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    Thanks for the info Rocky. But the mileage is only 2900 miles now. By the time I changed the rear socks, coolant, rebuilt the front forks I didnt feel like messing with the rollers and other stuff. But if the new part # is better than the old oil pump. I could see myself taking the engine down now. My scoot has a build date of 03/2004. What do you think? Just do it? Thanks for the help. I know some times I just get lazy. But that's what us retirees do......

  6. #6
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    The 2900 miles for a 15 year old bike is the scary part. 15 year old belts, tires, hoses, composite laminated rollers, etc are all failure points.

    If its rattling and not actually knocking then you may get away with inspecting the rollers and variator guides which being plastic could be failing and replacing them regardless of how they look. Take care to have everything clean and properly aligned when assembling but do not use a solvent cleaner as the sliding inner half of the variator slides on a permanently lubricated bushing that will already have lost a bit of its lubrication while sitting for 15 years and once you wash out whats left with solvent there is no good way to get more lubricant to soak back in. When you changed the belt you already had 90% of the work done so to me its a false economy to have skipped the variator service. You may find that the polished steel center that the sliding sheave rides on may be gummed up or have some corrosion on it so you would want to polish that up with a rag to insure that its clean and smooth so it will allow the variator to move freely and not hang up in the closed/high speed position as this will cause rollers to flip and rattle too when you decelerate.

    You did not mention the brake fluid flush however that is another critical item.

    Putting an oil pressure gauge on it may not be a bad idea especially if you find the rollers/servicing the variator solves the problem and it was just them rattling. If the oil light starts flickering definitely stop riding it and change the pump. On the build date a call to Aprila's main NY office to see if they have any clear info on whether the issue was resolved by that date would probably be best. When they run the VIN they may be able to tell you if they have any records indicating service bulletins on that bike had been fulfilled and if any are still outstanding.

    Personally if Aprillia's NY office can't put it in the clear and there is anything questionable about the oil pump I would having it gnawing at me to replace the pump however that is an awful lot of work. Its really a hard call to tell you, "yes do what I would want to do" without seeing, touching and hearing the bike myself considering the cost and effort involved in tearing down a 500 to that level.

  7. #7
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    I did do the brake fluid change also & tires. I think one reason I didn't look at the rollers and such is because I didn't have any handy. But will soon cause im ordering some other parts for it. I was going to change the belt flapper pully but the new one had a bad spot where the belt would hit. And A1 sent me another one. So Im going back into that belt area soon. That whole side cover panel on the bike has to come off to get the (2) Variator covers off. But can be done in less than an hr. now.
    Last edited by twocams; 02-02-2019 at 08:33 PM.

  8. #8
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    Rocky,
    Do you know what the 876225 oil pump is made of? or what has been upgraded. I got ahold of AF1 racing,they didn't have a pump. But said pictures looked just like the original plastic ones.

  9. #9
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    TwoCams - Sorry I really did not pursue it any further after I got the SportCity 250 since I have found it the perfect bike for my needs. I tried the BV500, Scarabeos 500's (both versions) and Atlantic 500 and found them offering too little extra in performance to make the jump in weight and costs.

    The difference I recall is a better formulation on the gear and possibly a more efficient design that does not put as much stress on the gear. The originals would pretty much loose all their teeth when they failed.

    There have been some members here who have pretty well documented what happened when the oil pumps on their Atlantic 500's failed. One may have gone the route of finding a machine shop that was able to machine the crankcase to accept press in main bearing sleeves to restore their Atlantic 500 after oil pump gear failure.

    Its been about 10 years since I looked into all this for myself. I have over 30,000 miles on the Sport City now even though I have not been riding as much since getting my Turbo Diesel Powered 124 Spider.

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