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Post by prodigit on May 10, 2013 23:20:02 GMT -5
This is what happened to a friends scooter who rode around for two months with no muffler . The end on the exhaust valve burned off and ate up the piston and cylinder There could be another reason for it than muffler. If you're running it with a too small exhaust pipe it could happen, It's a big thing on motorcycles; a lot of them ride without any muffling, just straight pipes. They're very noisy, but give you best MPG's and performance. The principle between motorcycle and scooter is the same. When they ride without any pipe, their exhaust valves burn too. Their exhaust valves could even burn with a broken exhaust gasket. |
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Post by prodigit on May 10, 2013 21:06:25 GMT -5
Since I have nothing else to do but to speculate, until the bike arrives, I thought of writing down some stuff that I'm thinking about.
Brand/type scooter
-----------------------HP value posted on the web
--------------------------------Top speed declared on website
-------------------------------------------------Real top speed
------------------------------------------------------------MPG on website
----------------------------------------------------------------------------Real MPG
---------------------------------------------------------------------------------------Weight
TaoTao ATM50-----3.6HP--30-35MPH----48MPH---100MPG-----99MPG----225LBS
TaoTao EVO150-----8HP-----55+MPH----63MPH-----80MPG-----70MPG----300LBS
BMS TBX 260 EFI---14HP-----85MPH-----80MPH-----65MPG-----80MPG----380LBS
MC-05-127---------7.5HP------60MPH-----55MPH-----70MPG-----85MPG----231LBS
MC-05-127(34T)---7.5HP--------MPH-----60MPH--------MPG-----100MPG---230LBS
This bike 125cc, 7.25HP; the HP value is double that of the ATM50, and half that of the BMS260, and about the same value as the EVO150; which leads me to believe that top speed will be in between the two, 60 to 65MPH.
Taken into consideration that the body of this bike is lighter (about the same as the ATM50, but ~80-180LBS lighter than the other 2 bikes) and probably more aerodynamic than both other bikes, but more human bodyparts of the rider are more outside of the frame, cleaving more through the wind than with the scooters, causing less good aerodynamics.
So looking at these numbers, I hope to get 60MPH out of the bike, and should be able to get 80MPG out of it (not 70).
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Post by prodigit on May 10, 2013 20:28:44 GMT -5
That redline will be 11k RPM. The CDI usually limits the engine ~10k RPM. And while riding normally, you'd never surpass 7 to 7,5k RPM. That I get ~10500 RPM @ 60MPH, is a mathematical calculation deducted from riding 40MPH @7k RPM. Engine RPM is linear to speed when the CVT is maxed out. The ATM50 does not have a tach, so the values I tell you are approximate. Working with other scoots, I can tell in what RPM range an engine is running, and am usually within 500RPM correct on it. My evo does have one though. When I rev both to where the engine sounds about the same frequency, I know they're about in the same RPM range and the EVO shows how much that is (EVO goes to ~10.2-10.5 RPM without load). BTW, if you really want to know, you can get an instrument tuner app on your smart phone, and hold it close to the engine. Whatever frequency your phone tells you, usually is 1/2 or 1/4th the real RPM for 4 strokes; or on a 2 stroke they're actually showing correct values. If the instrument tuner app is only showing notes, like eg: C-6, you can convert that using following tables: www.phy.mtu.edu/~suits/notefreqs.htmlAnd use your logic to do the rest (eg: if the outcome is 450Hz, 900, or 1800Hz at idle, you know you're running at 900rpm idle, unless you set it to idle high at 1800RPM; etc...). |
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Post by prodigit on May 10, 2013 20:24:24 GMT -5
Your exhaust valves will not suffer a thing for as long as you have at least an exhaust pipe of 2ft out of the engine.
Running without muffler would give you the best speed increase, as the back pressure will be nearest to zero as it can. however, your, and the people around you's ears will ring.
Any engine, even a 50cc engine, running without some sort of sound damping will damage the ears.
And in many places it's illegal to run without muffler (or some way to reduce the noise).
My suggestion, find a large diameter performance exhaust made out of aluminum. Those won't rust or corrode easily, and damp the sound better than smaller ones; while at the same time allowing better airflow.
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Post by prodigit on May 10, 2013 20:20:28 GMT -5
Veeery nice!  I'm sure you'll have plenty of fun riding it! |
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Post by prodigit on May 10, 2013 20:09:13 GMT -5
Amazing they can actually build something like that for such a price! I'm still looking where the weakness would be, other than the smaller/weaker frame.  Probably the suspension will be hard as , non adjustable; set for 200-300LBS people; I'm only 160 (170 at best), and I always suffer from hard suspension on new bikes. Lucky over time they wear out a bit, and become softer. The foot pegs from the passenger look to be a bit on the high side (like for a teenager or kid). Can't wait for it to arrive! |
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Post by prodigit on May 10, 2013 17:54:40 GMT -5
The transmission could always be something different from motor cross bikes, as it's something that can be installed separate from the engine. A typical Motorcross bike (or dirt bike, same engine):  One thing I do worry about is at the product spec page they say "Front/rear suspension" and "/' (meaning none). I can clearly see the front suspension, but from the pics, I don't know if I can see the rear suspension. I suppose it uses a monoshock. Anyone can see it from this pic?:  I see a little yellow cylinder, which I presume is the rear shock/suspension; but am not sure. I certainly hope it's not a hard tail with those tires! |
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Post by prodigit on May 10, 2013 17:45:21 GMT -5
you can test to see if the CDI is restricted by putting it on it's center stand and running WOT.
(not recommended for long times).
If it seems all to go pretty nice, the CDI is the restricter. If it seems like the engine is going to explode, or the tire goes so fast the bike is literally jumping on it's center stand, then the CDI is not restricted. An unrestricted 50cc 4 stroke should do 10.5-11k RPM unrestricted
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Post by prodigit on May 10, 2013 15:08:23 GMT -5
yeah, remove washer, or air intake/exhaust restricter, or change CDI.
You can hope to gain ~5-10MPH that way.
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gear ratio?
by: prodigit - May 10, 2013 15:05:46 GMT -5
Post by prodigit on May 10, 2013 15:05:46 GMT -5
Should it be too heavy, you can somewhat compensate with lighter rollers/sliders.
That way you don't have to lose too much take off speed, while top speed would be higher!
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Post by prodigit on May 10, 2013 15:02:39 GMT -5
On some website, they actually say the motor is a copy of a cross bike's.
I've seen lots of cross bikes with 125cc engines in the past, so I can believe what they're saying.
It's either a 100cc engine with a 125BBK, a 125cc engine natively, or a 150cc engine with a 125 BBK (which would be strange, as most of the time they try to get as high cc's as possible).
However if it where a 150cc engine with a 125cc BBK, (or SBK, small bore kit), the engine would last longer, and the fuel efficiency would go up compared to the stock 150cc engine.
Cross bikes are known not to have very good gas mileage; and I don't know if that's because of their low gearing, or their inefficient engine.
I'm sure the engine is adapted to normal city, meaning gears are adapted for higher speeds, instead of fast acceleration, and air filter is not the dust/sand-type.
We'll see. Estimated delivery is next week (may 17). I'll keep you posted!
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Post by prodigit on May 10, 2013 14:57:02 GMT -5
It'd think you're actually pinging (the cdi is detonating too early).
At higher speeds it might actually detonate before the cylinder is at it's top position, in which case that could be the case.
Either that, or the carb bowl gets sucked empty of fuel faster than the line provides the fuel, which is not what I think happens).
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Post by prodigit on May 10, 2013 14:54:57 GMT -5
Try to select roads that are only going downhill, and ride only on days with wind in the back. And pump up your tires, air costs next to nothing. Thadaa! 60MPH! Hi One more thing to add is that you should never push a stock 4t 50 cc engine that hard even for short periods as its not going to last for very long with that type of stress and abuse Take care and ride safely dear friend Yours Hank That would be wise advise. The manual also says not to let the engine rev without load. Going downhill at those speeds is basically the same. However at ~60MPH, the engine is still doing below 10k rpm. Higher than 10k RPM, and the engine rattles itself apart (screws literally come loose due to the vibrations). |
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Post by prodigit on May 10, 2013 0:33:23 GMT -5
wish my stock tao's went 60 would of saved me 600 bucks on each scoot on upgrades  Try to select roads that are only going downhill, and ride only on days with wind in the back. And pump up your tires, air costs next to nothing. Thadaa! 60MPH! Speed off the chart! |
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Post by prodigit on May 9, 2013 19:54:49 GMT -5
I'd suspect it has to do with the fuel system.
If that's ok, then perhaps check your oil.
Usually if your scooter does that with 10W40 oil, try 5W40 or 5W30 oil.
I don't know what oil you have, but if you reduce the first number one step (by 5), your scooter will start up better. (eg: if you have 15W40 in it, which is too heavy for a 50cc, get 10W40)
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