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Post by bwader on May 23, 2013 18:15:35 GMT -5
I don't understand why people think running an engine wot is bad for it as long as its not over revving or getting to hot it should run all day wot look at lawn mowers they run wide open all the time so do generators. Yeah I don't understand either. I use heavier sliders because I like lower rpms and gas mileage for higher speeds. I can understand if the engine had been running lean it would put a hole in the piston from running too hot. I check my spark plug its tan its not white and its not black. , I'll take a picture to prove it! My woman thinks I'm crazy I work on my scooter for hours on my days off. She thinks its a waste of time and I accomplish NOTHING! And I know and you guys know and I'm sure will agree that the more you know about these scooters and try to keep them maintained the better the outcome. Course it threw a rod anyway. She asked me "what's so funny" one day reading this forum or the motorized bikes forum and I told her I was laughing because scooter and motorized bikes people (me being both) are so excited sometimes that they will just sit on their bike assembled in their living room and just go "Vrroooom Vrrrooom!" with throttle motions and everything.  She doesn't ride so she wouldn't understand. Might as well fantasize the experience inside that rainy day or late at night. |
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Post by mrpalmetto on May 24, 2013 7:43:38 GMT -5
So then when is over revving? Bwader said he saw 7800rpm's with 10 gram sliders. I've seen 6800 maybe 7000 on my bike. I can see Bwader is a pretty smart guy. Did he just have bad luck? Jeffery makes a good point about his lawn mower and generator comments, but obviously there is a peak RPM for each engine. Mowers and generators are built to stay below the breaking RPM point for each machine i would guess.
We seem to be pushing these puppy's to their limits. We are changing design specs, sorta entering new territory with each new add on mod. there has to be a limit. So i would like to know what everyone thinks is an acceptable maximum RPM for these engines? Did Bwader find it the hard way or are there others of you pushing 8000 or even higher, AND keeping it there for an extended period of time.
I would really like to know every ones thoughts on this. Keep in mind Bwader said his fail came at a much lower R P M.
Rockny makes a very good point. Lot's of smart guys on this forum.
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Post by justbuggin2 on May 24, 2013 8:37:36 GMT -5
with the quality of the metals these bikes are made of i like to keep the rpms below 7000 if you want to rev higher then you will need to build your motor for it with better parts like crank connecting rod piston and cylinder and the list goes on
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Post by mrpalmetto on May 24, 2013 14:01:02 GMT -5
If i change the gearing, that seems to be something alot of scooter people, will that raise or lower the rpms?
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Post by scootzy on May 24, 2013 16:34:39 GMT -5
8000r's is the max on all 49.5cc. Not good for long periods.
If you're racing or draging the strip, beafed-up of course, 12-15000r's are achievable.
Good point on mowers and generators, but, they do have rpm limiters, like the scooters that are made before 2010, so they can be ran at WOT. Limited. I do know that chainsaws are the same as well, limited to 6500r's
So, 6400r's for the max TQ and 7500r's for the max HP. I would think anything after 7600r's is a waste of gas and money for new parts.
Me, on the other, I cruise great up to 45 (bike speed) slacks to 52. that would be the power curve.
This is beside the subject, has anyone tried to match up the rpm's with kph on the bike. variator closed and clutch open which is top gear. after 35 (bike speed) the rpm's seem to corospond with the kph. I know it's just the config I have. has anyone experienced that?
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Post by bwader on May 24, 2013 16:54:42 GMT -5
I had 6,000 rpms max with 15/37 gears only went 3 miles when this happened.
FOT too so I had figured I just needed to use lighter sliders.
I think we all would like to know
What is the SAFE rpms, and how was I supposed to know my engine was going to throw a piston rod. Some chattering?
Gee whiz if I ever get another engine for my scooter, and if I happen to hear a little chatter or some sound inside the engine I will go home immediately and take the engine apart. Once cool anyway
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Post by scootzy on May 24, 2013 17:55:15 GMT -5
[replyingto=bwader]bwader[/replyingto]the only thing I can think of is you were running too lean, normal cause of engine ceasing.
I personaly, would check inside the motor and see if anthing is missing, like cir clips or dowls that may have sliped. But, I still think you were running lean
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Post by bwader on May 24, 2013 18:29:57 GMT -5
I guess maybe I was running too lean. Sometime when I'm up to it, I'll take the case apart and look inside.
Also I wasn't able to pull apart the cylinder from the case from that rod preventing it. At least I can take it apart without worrying about messing it up like a good engine. I can just hammer and dent and scratch and go to town.
When and if I do I'll be sure to post and picture about it.
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Post by scootnwinn on May 24, 2013 21:34:30 GMT -5
I didn't think it seized I thought it threw a rod...
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Post by rockynv on May 25, 2013 9:10:36 GMT -5
Your lawn mower does not run wide open and is restricted by law so that the blade tips do not exceed the maximum velocity allowed. It ends up being somewhere around 2,500 to 3,000 rpm with the longer blades spinning the slowest. The velocity of a lawnmower blade tip can be greater than a 357 magnum hand gun.
Generators don't run wide open either and are governed to around 1,800 to 3,600 rpm (depending on how the fields are wound) to produce the correct 60 cycles of altenating current. Personally I prefer the 1,800 rpm quiet generators which will last much longer than the 3,600 rpm units.
Running a bike at double, triple or quadruple the rpm of a lawnmower/generator will many times result in reduced reliability and premature engine failure.
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Post by larry001964 on May 25, 2013 9:12:56 GMT -5
DX
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Post by bwader on May 25, 2013 15:41:39 GMT -5
I didn't think it seized I thought it threw a rod... Yeah the rod could have broke and kept reciprocating until it went out the way it did. I was thinking maybe a part jammed it somehow, and the piston rod couldn't handle the stress, so it broke under the load and went through the engine case. That remains to be found out when I take apart the engine case for S.A.Giggles. Plus I like to know what happened and to prevent it and to know if anything else was damaged. I'm going to use everything I can salvage and use. If not then - recycling plant down the road. |
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Post by scootnwinn on May 25, 2013 15:49:51 GMT -5
Poorly manufactured metal happened. 7000 rpm for a motorcycle is not really that much. Most manufacturers set their redlines quite conservatively. Running wide open doesn't affect most bikes I've owned...
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Post by bwader on May 25, 2013 15:56:30 GMT -5
I think it might help you have a Vespa!  Funny part was I was trying to sell my scooter last fall for $700 lowest I'd go was $650. I had a guy who had $600 (along with many low ball offers  ) I turned it down. Looking back, man that wouldn't be a bad deal.....for me anyway. |
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Post by chihuahuas on May 25, 2013 16:40:38 GMT -5
No they don,t
Generators/lawnmowers have a set speed, The throttle works on a load basis. A governor controls it.
A genset running at full capacity will expire way before end of service life.
Gensets here are set to 3600/1800 prms depending on poles.
3000/1500 rpms in UK Europe.
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