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Post by jerseyboy on Jun 17, 2013 21:04:17 GMT -5
I noticed my Gy6 150 scoot really screams everywhere I go,,30 MPH its taching 5 grand,,40 almost 6K,and 50 over 7K,,with the little GY6 motor spinning like this all the time I cant see it lasting very long,,maybe they are designed to spin fast but man,,I would like to lower my RPM a bit if at all possible,any ideas would be appreciated,,sliders,gears,ect...my motor feels like it has plenty of power if the R's where to be dropped down a little to keep my power.
Thanks Tom
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Post by hank on Jun 17, 2013 21:14:00 GMT -5
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Post by jerseyboy on Jun 17, 2013 21:18:27 GMT -5
[replyingto=hank]hank[/replyingto]Yes Hank,,
Thanks,,i guess I will have to get a scale and see what the rollers weigh,,then go up one size heavier.Will try that first.
Tom
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Post by geh3333 on Jun 17, 2013 21:56:44 GMT -5
Going up on roller weight is your best bet if you would want to cruise at lower rpms. I understand not wanting to push your scoot to much, especially if your main engine components are stock. Also if your riding on roads that dont call for higher speed limits. The main reason i did some mods was because even though the sp limit on the main rd i ride on is 45 mph most run between 50 & 60 mph and i was sick of cars riding my as_ . Hopefully u womt loose your top end by going up a gram. Im guessing your stock weights are between 13 and 15 grams.
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Post by Paladin on Jun 17, 2013 22:51:02 GMT -5
I noticed my Gy6 150 scoot really screams everywhere I go,,30 MPH its taching 5 grand,,40 almost 6K,and 50 over 7K.... I don't got no tach, but my Vespa sounds like a angry bumblebee. The specifications cite peak 11.7 hp @ 8,000 rpm and peak 8.7 ft.lbs @ 6,250 rpm. I would expect the engine to be running at top efficiency at between 6-8K rpm. |
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Post by geh3333 on Jun 17, 2013 23:02:31 GMT -5
This is true usually between 7000 and 7500 rpms. But these chinese 150s are a couple to a few hp short of the vespa when stock. And they are usually being pushed to hit those rpms. And its understandable not wanting to "cruise" at wot.
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Post by geh3333 on Jun 17, 2013 23:05:42 GMT -5
Only prob is if wanting to cruise around 52 or higher mph he may have no choice.
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Post by prodigit on Jun 18, 2013 0:09:02 GMT -5
Well, 52MPH can be done at 6k RPM. But if you want to lower it to 3k rpm, you'll probably only go 40-45MPH tops. Engine won't have much power reserve left to accelerate.
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Post by jerseyboy on Jun 18, 2013 8:38:57 GMT -5
Thanks for the ideas guys,,
The motors are cheap enough to repair/replace I may just run it and see how she holds up,,I just cant imagine any little 4 stroke lasting too long running as hard as these little guys do.
Tom
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Post by skuttadawg on Jun 18, 2013 11:29:22 GMT -5
Get Dr Pulley sliders and a larger variator will help . There is also the option of replacing the gears too
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Post by urbanmadness on Jun 18, 2013 11:51:07 GMT -5
I bought a 115mm variator with 12gram rollers and it helped my cruise rpm and I actually gained bottom end with it.
My scoot cruises comfortably at 50 and has been GPS'd at 57 on flat ground with my 310lb butt on it. The rest of the scoot is bone stock.
I don't have a tach... but, now it just feels right.
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Post by joaoeu on Jun 18, 2013 13:19:22 GMT -5
The motors are cheap enough to repair/replace I may just run it and see how she holds up. True, but so are the roller weights. You can get them for $10/set (6 rollers), or $20 for a collection of 6x half-sets (3 rollers per half-set) to try out different combinations. China Cheap-skoots 150cc may last 67 miles, or it may last 26k miles. It all depends on the maintenance and luck of the draw on how proper the engine was assembled. |
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Post by geh3333 on Jun 18, 2013 13:52:38 GMT -5
[replyingto=prodigit]prodigit[/replyingto]I think it may be tough to hit near his top speed between 50 & 55 esp at 6000 rpms if his roller weights end up being 14 grams . If you ho to heavy youll end up loosing top end. And of course you will loose some takeoff speed and power.
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Post by scootnwinn on Jun 18, 2013 14:34:06 GMT -5
I just cant imagine any little 4 stroke lasting too long running as hard as these little guys do. Tom Just wonder why you think that. Lots of single cylinder engines rev higher than that. The CBR250 redlines at 10,500. I think your scooter redlines somewhere around 8000. 8-10k is pretty normal and it should run quite happily all day long 1000 or so under its redline... Not sure why an engine wouldn't run fine when it's in its normal operating range... |
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Post by prodigit on Jun 18, 2013 17:45:37 GMT -5
CBR's and especially Ninja's are what's called 'short stroke' engines.
Their cylinders don't move up and down as much, allowing higher torque values at higher RPM's,
With long stroke engines (which are your stock engines), torque curve is hill curved instead of an up-slope, and the gas mileage is much better (more optimized), as with short stroke engines much more of the released energy goes to the exhaust.
Anyway, in many cases you can get over 10-12k miles out of a 50cc engine, and 15-20k miles out of a chinese 150.
I'm also sure that even before you reach that number, you will find that the scoot has paid itself back multiple times.
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