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Post by rbates31964 on Mar 25, 2010 23:19:27 GMT -5
Have been checking out the posts on here for a few weeks now and there is a ton of useful information on here. I am new to the scooter scene and was wondering if anyone had any suggestions as to what went wrong. I bought a Peace Sports 50cc scooter off from craigslist. It was a 2008 sport 50 model with about 1200 miles on it. The guy said it had sat for a while and would not start. He had someone check it out and they told him that it needed a petcock (maybe) and a good fuel system flush. Seemed simple enough. So, I got it home and drained the gas out of the tank (smelled like old turpentine) and removed and cleaned the carb. Put the carb back on and filled with fresh gas. Started right up. It didn't run very well, but it ran (alot of spittin' and sputtering). Adjusted the carb a bit and got it to run better. Got to looking online for a new carb and came across this upgrade kit. Included new carb with 85 main jet, k&n style air filter, unrestricted cdi box, and high output coil. I also bought an iridium spark plug. I put all these things on and man did it run. I weigh about 240 and it had no problem burying the speedometer which tops out at 55mph and would take any hill around here (SC) at 30-35. I was impressed. Turned it over to my son to ride back and forth to college (about 13 miles one way) and was feeling good. Well, it was fine for a few days and then he started having problems with it stalling on him intermittently, pull over wait 30 secs. or so and start right back up. It might do this once or twice each way, sometimes none, or maybe 5 or six. The weather was back when 1 day was winter next day spring, so I just adjusted the carb to where it would run the fastest from point A to point B. Long story short, about 200 miles into the upgrade, it died on him and would not start. Tore it down and discovered that the piston had a hole in the top and was cracked half way across top and down side past 2nd ring. So, as I asked at the beginning, any ideas as to what went wrong? I have since bought a new 2009 (same scooter) and do not want a repeat. I'm thinking now maybe it was too lean, but my dad thinks maybe the iridium plug and coil were to blame. Any ideas ?
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Post by gmoney on Mar 26, 2010 10:44:48 GMT -5
If you were running the 50cc wide open for 13 miles that and having it run a little lean is probably the reason you burned a hole in the top of the piston. Changing to a new unregulated CDI was probably the downfall. On your new one I would not use the unrestricted CDI on it since the rev limiter keeps the engine below the point at which it will do damage. 50's aren't designed to run above 40-45, going faster than that will shorten the life of the motor, especially a 4-stroke engine. Go easy on the new one, keep your speed reasonable, change oil often and don't over-rev the engine.
Gary
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Post by rbates31964 on Mar 26, 2010 15:23:35 GMT -5
I have read that the Peace Sports come stock with an unrestricted cdi, as well as none of the other common factory restrictions. So, would I be able to use the HO coil and iridium plug with the stock cdi? For anyone who's interested, I also found out (in the course of repairing the blown piston) that these scooters are not 49cc. They have a 44-45mm piston which is the equivalent of a 60cc. This may explain why these are faster than most other stock scoots. What if I put a small amount of mixing oil in with the gas. Would that protect against running lean?
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Post by gmoney on Mar 26, 2010 15:53:04 GMT -5
A lean engine runs hot, when we're talking lean we are talking about fuel to air ratio. A richer mixture, i.e., more fuel to air ratio will run cooler which lets the oil do it's job of lubricating. The hotter the oil, above 300 degrees, the less it lubricates. At about 325 degrees oil no longer does a good job of lubricating. When you run lean on fuel to air mixture combustion temperatures skyrocket, which in turn makes the engine run HOT. This contributes to damaging the piston, as in burning a hole through it! Running a higher oil mix to a 2 stroke or even adding oil to the gas on a 4 stroke won't help a lean condition. All it will do is make it smoke, or smoke even more on a 2-stroke.
Gary
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Post by rbates31964 on Mar 26, 2010 19:28:50 GMT -5
Ok, oil idea shot down. Makes sense once it's explained. What about the coil and iridium plug, should I use these? Not planning on doing any upgrades untill after break-in period. I'm going with the hard break-in approach. Drove it like I stole it for the first 32 miles (over 2 days) then changed the oil. Man was it black. And i pulled the plug (torch). It was a nice brown, so far so good. Son has driven it to school a few days and no problems yet. Now has 132 miles on it. Had to add about 4-6 ounces of oil. I guess that's normal for a new engine. Since the fuel/air mixture screw is plugged off on the stock carb there isn't much of anything else I can do but keep a check on the oil. I plan on changing it again at 300 miles. At about what miles do you think it would be ok to put on the upgraded carb?
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Post by shalomdawg on Mar 26, 2010 21:43:48 GMT -5
howdy and welcome to the forum. i can't help on the mechanical problem but i can advise a bit on the break in . it may be too late for that. if you are in a town environment then how you described breaking it in is probably ok . one thing i wouldn't do is run it wide open for more than several blocks. getting off the throttle then back on for 30 seconds, then off it for a nother 30 seconds and doing that repeatedly will usually break it in as rapidly as can be done. do that at varied speeds. it should be broken in pretty well by now. you can prolong the life of the belt by not accelerating full torque but letting it gear up gradually then using full throttle to hold speed.
lotsa miles and smiles to ya
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Post by gmoney on Mar 27, 2010 8:17:25 GMT -5
Using your new coil and Iridium plug is fine, the Iridium plug has a little better tip so it will last longer and give a slightly better spark. As far as upgrading the carb, I wouldn't unless you have a very slow, below 40 MPH, or weak on hills scoot. I change oil every 500 miles on my scoot. Reason is there's no real oil filter, the oil quantity is less than a quart, and the high temperatures our little GY-6 engines have can quickly wear out the oil.
Gary
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