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Post by micka80 on Nov 14, 2014 1:37:29 GMT -5
Just a quick question - what rpms are normal for a 2 stroke 50cc completely stock, what is the average rpms of the scoots best power?
Is 11000 rpm too high for a stock engine? Is 8500rpm a good figure to see when accelerating up to speed?
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Post by TruseiC on Nov 14, 2014 6:48:19 GMT -5
I don't think that 11k rpms would do any good for a stock crank.
8500rpm is okay imo.
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Post by 90GTVert on Nov 14, 2014 8:13:58 GMT -5
10,000-10,500RPM is usually said to be the max revs if you expect reliability from a Minarelli with a stock crank.
11,000RPM is likely too much if you expect reliability and power out of a stock 2T. If you have a tuned pipe you may make power up there, but with a stock exhaust you are likely a 2,500-3,500 RPM above peak output. 8,500RPM you could do all day and not worry with most of the scooter 2Ts.
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Post by themajekalbum on Nov 14, 2014 9:05:47 GMT -5
I've tuned my cvt to keep my kymco around 9,200rpm. For my set up that's where the power is. The power starts at 7,300rpm and drops off quickly after 9,500rpm. The peak power rpm for you may be different. Sounds like you got some pretty light rollers in there now (needed for this next test). The lighter the rollers the better, you want to try to have the cvt shift as late as possible. You want to find a decent up hill(easier to gauge power on a hill, flat will work thou). Do some runs up the hill and take notes of where the power starts, seems to be strongest, and where it drops off. Once you find where your peak power is, tune your cvt to hit that rpm at higher speeds.
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aland13uk
Scoot Member
totaly new to this and im from the uk
Posts: 21 
Location: north east
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Post by aland13uk on Nov 14, 2014 11:30:02 GMT -5
hi my scooter is a tgb r50x 50cc it has been modified ( I bought it already modified) so I don't know what was changed, My max revs are 9000 and I get a top speed of 40mph= 64.374 then it hits a restrictor of some sort
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Post by Sitticuss on Nov 14, 2014 12:23:39 GMT -5
Mine cruises along at 8800
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Post by jhobe6678 on Nov 14, 2014 12:57:38 GMT -5
Mine is maxed out at 8200 right now. That's with a tuned pipe no less. I have work to do though, I'm pissed that Sitticuss is going faster than me.  |
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Post by Sitticuss on Nov 14, 2014 13:34:03 GMT -5
Mine is maxed out at 8200 right now. That's with a tuned pipe no less. I have work to do though, I'm pissed that Sitticuss is going faster than me. I'm jealous of your swanky exhaust. (I'm so not saying pipe in that sentence) |
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Post by jhobe6678 on Nov 14, 2014 13:55:20 GMT -5
Mine is maxed out at 8200 right now. That's with a tuned pipe no less. I have work to do though, I'm pissed that Sitticuss is going faster than me. I'm jealous of your swanky exhaust. (I'm so not saying pipe in that sentence) I know you're jealous of the pipe too.  |
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Post by micka80 on Nov 14, 2014 16:11:59 GMT -5
I've tuned my cvt to keep my kymco around 9,200rpm. For my set up that's where the power is. The power starts at 7,300rpm and drops off quickly after 9,500rpm. The peak power rpm for you may be different. Sounds like you got some pretty light rollers in there now (needed for this next test). The lighter the rollers the better, you want to try to have the cvt shift as late as possible. You want to find a decent up hill(easier to gauge power on a hill, flat will work thou). Do some runs up the hill and take notes of where the power starts, seems to be strongest, and where it drops off. Once you find where your peak power is, tune your cvt to hit that rpm at higher speeds. I am getting a larger tyre first, its on its way - currently 120/90/10, changing to 130/90/10. Currently use 7gram weights and was told they are heavy? I sit on around 8500-9000 up to 55kph then it climbs to over 10000 on the flat, but going down a slight hill sees her go over 11000 - it feels like i am flogging the crap out of it when revs go over 9500. It seems i am as heavy as i can go with rollers and do not know if an even larger tyre will fit. |
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Post by 90GTVert on Nov 14, 2014 17:24:37 GMT -5
Is the belt in good shape and nearly as wide as it's spec? What contra spring is in there? Any idea what your final drive gear ratio is? 130/90/10 should make only a minor difference. It's sounding like you'd need a gear change unless the tune is wrong or belt is worn.
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Post by micka80 on Nov 14, 2014 17:50:53 GMT -5
Everything is in good shape and stock. The scoot went in for a service not long ago and the rear pulley was changed and the rear tyre swapped to a smaller one. The belt is a bando 747-16-28 and currently the width is 15.5mm and sits 4mm proud of the rear pulley.
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Post by tsimi on Nov 14, 2014 18:45:56 GMT -5
Mine runs at 9000-9200 at max speed and normal driving around 6500-7000.
Anything over 9500 is probably too high for a "stock" 2T. Most horsepower is generated around 7000 to 8500rpm.
Do you have a shim inside your Variator? Or is there only the Boss? If there is a shim/spacer try to remove it.
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Post by 90GTVert on Nov 14, 2014 20:49:37 GMT -5
You could put a mark on the clutch bell and one on the rear tire and see how many revolutions it takes of the bell to spin the tire one time. That will give you an idea of the gear ratio.
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Post by themajekalbum on Nov 14, 2014 20:50:58 GMT -5
I'm with 90GTVert on this, sounds like you need a up-gear kit or maybe a over range variator kit(no idea whats available for your scoot). Check your ratio(mark the clutch bell and count the number of spins to get the wheel to rotate once). 55kph(34.9mph) sounds a bit low to me for 8500-9000rpm. I cruse that speed at 8000rpm with my current set up. Granted we got different sized wheels(12" on mine), cvt set ups (small over range combo on mine) and gear ratios most likely, mine is 12.5:1 (most say 11:1 is optimal). My average flat ground top speed is 46mph(74kph) with rpms at 9200-9400 rpm. Only time I've seen 10,000rpm on the current set up was drafting a moving truck on a long downhill stretch, hit 64mph(103kph)@10,250rpm(my all time scoot record).
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