70 MPH on a 250 scoot?

[prodigit]

Aug 22, 2012 10:20:03 GMT -5 ericrockstar said:

They rate cars horsepower at ridiculous high rpm. My accord has like 140hp at 5,000 rpm. I never rev it past 3,000. Maybe that's why they last forever?

It's because at that RPM is the motor's peak performance.
Engines are like CPU's. The higher the voltage, the greater the performance, the shorter the end of life cycle.
There's just, when you overvolt too much, the life cycle will decrease drastically.

Usually running motors below 3kRPM for single cylinder 4stroke, and under 2k RPM for dual cylinder 4 stroke, is giving a significantly longer life than running them at 2k higher. It goes in a curve. Usually between 3,5 and 4k RPM the curve goes down more significantly (life expectancy over RPM)

That's why many diesel engines last so long, because they usually idle close to 500RPM, and usually have their greatest torque below 2,5K RPM!

[ronlee]

To be sure RPM has a lot to do with engine longevity, but there is lot more to it then that.
The longer the stroke the slower an engine must run. Just for comparison think if an engine has a 6 in. stroke, the piston will travel 12 in. per revolution while a 2 in. stroke engine will only travel 4 in. per revolution. It has to do with the surface speed of pistons, rod bearings etc. There is a limit to piston surface speed. It is fun to figure it out and see how close it is on piston engines.
Diesel engines last longer then gasoline mainly because they usually run slower and are built so much stronger, also the diesel fuel supplies some lubrication to the cylinder and piston.

[karpata]

My Grand Vista tops out at 73, verified. I cruise on the highway at 68, and it's pleasant. Don't know what the big deal is.

[lceel]

I have a 2011 Jonway YY250T. I bought it this year - I have just over 2000 miles on it and most of those miles are Interstate highway miles accumulated 48 miles at a time. I've had my scoot up to 80 - but that was drafting behind a big car. Normally, out in the open, by myself and level, I can get it up to 70 and hold it - with the engine running at 6 grand. 7 grand is where the "RED" starts - but the only time the engine should EVER get to 7 grand or over is if and when the belt breaks. Mileage drops with Interstate travel - 68 or 69 MPG running flat out. The same trip on surface roads gets me up to 75 MPG with traffic and stoplights.

[prodigit]

my 260 got 75mpg driving normally and an occasional 'middle finger retard' pass by, on open throttle.

Last measurement was when I broke in the motor, at 80mph, it was running at 45MPG.

My 260 probably can get upto 80MPG driving carefully.

You can extend mpg's somewhat, by when driving slower, and when doing so, by also choosing thicker motor oil.
I've noticed, that instead of using 10W30 as motor oil, 10W40, or 15w40 might be better for long life, but it also performs more smoothly when driving slow. It does reduces performance a bit (a few MPH less fast, and a tad less torque), but I believe the benefits outweigh the cons!

15W40 is good for my EFI bike. Also, my 2012 EFI works best with MID grade fuel, not premium. Tried both, and the lower the gasoline, the lower the performance too.

10W30 gives good performance, but I hear or feel the motor sounds less fluent (sounds sharper, feels harder).

My recommendation, once you get used to your bike, and somewhat given up on open throttle acceleration, then change your motor oil to thicker oil!

[prodigit]

Just done some more testing, thicker motor oil and regular gasoline gets me a constant speed of at least 75MPH on my 260 with EFI. It actually goes to 80, but then drops to 77MPH. I still got to GPS my max speeds, to see how accurate they are, but at 35MPH the speedometer is right on the dot!

(I write rather out of boredom right now, but hey, it might benefit someone out there)...

Putting in premium gasoline gets top speed up by 2MPH (82MPH); wind still, flat (horizontal) roads. I probably am able to go 85MPH for short moments, when driving behind a trailer (reducing wind drag), but won't rate my bike like this, as it would not be a fair rating.
Thinner oil (SAE 10W30) gives better top speeds, but MPG and engine life suffer from it, so I decided to go with thicker oil.
Right now I'm using 10W40, and in the future perhaps 15W40.

I've also noticed that my 260 will slow down uphill bridges to 70MPH.
Usually at that speed, by the time the bike is going 70, you're already over the hill or bridge.
But for large hills, and especially with 2 people, or heavy weight people, even a 260 might slow to 68MPH!

So my original opinion still stands, on flat and even lands, city driving; or for highway driving (short distances upto 60MPH); and for most people (below 240LBS), a 150CC is more than enough!

A 250cc is great for 2 people, and a 300+cc is great for the larger distances!

[atlphotog]

I had an 86 Elite CH250 and I tucked in one day on a good flat straight and hit 74mph,...never cruised at that, but did cruise in the upper 60's all the time and touched 70 on a daily basis. I loved that scooter so much that I am planning to trick my Baja sc50 out so severely that I can get someone to trade me an old CH250, nothing fancy bone stock is fine by me.

[rockynv]

My Aprilia 250 will cruise at 80 all day long here in the Florida heat. I regularly cruise from Tampa to Orlando or St Augustine and have no problems keeping up. A Puig Sport Fairing makes it easier on me and gives me about 5 more highway mpg too.

Most I have had it to according to my GPS was 95 or so but I backed it down. I had stopped paying attention to the speedo and got caught off guard after all how fast can a 250cc scooter go.

[prodigit]

your aprilia does it have a single cylinder or dual?
I suppose they only make 4stroke 250cc's...

[jwalz1]

Aug 24, 2012 8:20:18 GMT -5 karpata said:

My Grand Vista tops out at 73, verified. I cruise on the highway at 68, and it's pleasant. Don't know what the big deal is.

Your Grand Vista may also have a stronger engine than some clone bikes do.

[rockynv]

Sept 5, 2012 12:10:50 GMT -5 prodigit said:

your aprilia does it have a single cylinder or dual?
I suppose they only make 4stroke 250cc's...

Single cylinder high compression fuel injected with 4 valve head. Pumps out around 25 or so hp. Has 15 inch tires with a 463.6 lb rider/passenger/cargo capacity yet only weighs in at 326.7 lbs.

A lot of bike for $2,999.

[prodigit]

I'm jealous!
I paid $2600, for my BMS. Also fuel injected; but only registered at 14+HP.
I have a 257cc motor (registered at 260cc).
Seemingly the HP's almost need to double to get 10MPH increase in speed!

If you have 4 valves, does that mean you have a DOHC?
They're known to give more torque/HP on the higher bandwidths. That could explain why...
My Dodge Neon has DOHC, and from 3k RPM I really feel it starts to pull away from the traffic (all the way to 5k RPM), however fuel mileage is way shorter using these valves.
usually staying below 3k RPM on the neon gives best gas mileage...

[rockynv]

Prodgit - The bike continues to amaze and please me. I will be looking at my first real maintenance item shortly as it will be belt and roller time within the next few thousand miles. I am almost at 11,000 miles now and will be doing my second regularly scheduled oil change and belt/roller service at 12,000/13,000 miles along with a check to see if a valve adjustment is needed. Single overhead cam to keep complexity down so it still gets up to 80 mpg.

It has been over a year of get on and ride with zero down time. Full day tours at highway speeds sometimes with groups of 1+ liter touring bikes.

[prodigit]

I had 80mpg on mine too. I probably could get upto 85mpg if I would accelerate less aggressive from a red light, but I guess I kind of grew up from the phase of always starting full throttle from a red light. That was giving me ~65mpg.
If I can I'd start slower, just to save some gas, and to have the motor live longer.

I always imagine that my bike has a main and a pilot fuel injector jet (which it does; the pilot is the small injector, the main is the big injector), and when I accelerate in fully open throttle, both injectors will be injecting the fuel; So I imagine acceleration goes in 3 main stages.
Those 3 stages are kind of audible to me in the exhaust.

Pilot jet is very soft, main jet is loud (especially now that my exhaust has a small side hole, I can hear a more sharp sound when in medium acceleration, around 4-6kHz), and in the third stage (I imagine when both jets are working together), I get more of a 800Hz-1kHz sound boost out of the exhaust pipe.
I hear how the exhaust sounds, and try to drive accordingly.
When I accelerate slowly (in my mind, driving only on the pilot jet), I accelerate almost like a 50cc, and would get 85MPG, possibly even topping out at 90MPG.
I can do that only 'till a good 40MPH, after 40MPH the bike needs more throttle power.
I can not do that everywhere, as most cars would get annoyed driving behind me like this.
The second stage I now use for normal acceleration, and doing so, I get a nice 75-80MPG.
The third stage, or last stage only happens at the last ~10% of the throttle, where I get a good 45-50MPG; however I rarely drive with a constant open throttle.

[rockynv]

The Aprilia has the Minarelli system with one fuel injector which learns the bike and compensates pretty well. At 80+ mph I drop to between 60 to 65 mpg however if I stay below 80 (by GPS reading) I will get between 65 and 70. Below 65 mph I will get between 70 and 80 mpg.

At red lights here in Tampa Bay Florida you need to pull out in front of traffic or they will try and pass you cutting it short in the process. Once they see that they you are not going to slow them down then the cagers settle down for the most part. It is a means of self preservation as most cage drivers don't seem to be able to tell the difference between a 90+ mph Maxi Scooter and a 49cc 30 mph one.

[masternav]

My daily 20 minute commute route is on the freeway. My ride is a 2002 Honda Reflex ABS. Stock weights. Synthetic oil. Standard maintenance. WOT I top-end 85mph indicated, 78mph avg by GPS (15 run check under different wind/weather conditions). I easily run with the morning/afternoon commuter traffic and have a little extra to pass with. The Reflex is slippery in the airstream, being well-faired. Sorry if my experience differs from the statements by the resident experts, but I got no dog in this fight, just experience and a decent testing methodology that is accurate. Your mileage/experience may vary.

[relfexerturbo]

i dusted a mid 90's low rider harley the other day off a light on my 2004 relfex all stock kevlar belt k&n air filter 13,000 miles no problem 80 mph all day long i just need a taller windshield as if i am not ducking low i am stuck at high 70's i blow in an out of traffic like i am on a cbr 600rr.. i have owned over 10,000 motorcycles scooters atvs harleys you name it and you can all say what you want the honda reflex will run art highway speeds all day 75-80+ and it runs perfect just think if i hopped it up a bit .. turbo is next ..

[rockynv]

I know the local Ninja riders association probably has a dart board with a picture of my Aprilia on it. I have dusted many a Ninja 250 and sub liter bikes in traffic and the do get really upset about that at times. I am not out to race them but just trying to get to work in a timely fashion.

A well balanced scooter with a decent drive and fuel system is a very capable machine for highway and in town use. I had one guy chase me down and ask "but why a scooter?" that is all he wanted to know.

A Sport Fairing style wind screen does help a lot. Maintains aerodynamics and alleviates the beating you take at 80/90+ mph. Big is not always the answer as you will get more benefit from a well designed mid sized screen than a poorly desiged large one. If it looks like a barn door than most likely it will act like a barn door running flat against the wind.

Your choice of helmet also can have a large impact at speeds over 55 mph. I had a half helmet with a small visor and that helmet would catch so much wind that the neck strain above 55 was unreal while with my full faced modular helmet it is not noticable even at 80+ mph unless you are looking momentarily to the side for a blind spot check during a lane change.

[fieroboom]

After reading this entire thread, I just had to drop in my 2 cents' worth...

If engine displacement decided your top speed, then all bikes of same displacement would have the same top speed. We all know this is not true. For instance, my stock gy6 150cc Super Hornet cruises at 55-60 (GPS speed) on flat ground. However, it's only running 8.8:1 compression ratio, so without adding any displacement, if increase compression to say 12:1, and get a good tune & timing set on it, then tweak the CVT weights, I am 100% confident that my 150cc would cruise at 70-75mph.

Look at a CBR 250 (older gens)... It's rated at somewhere around 35-40hp, with a top speed of 110-120mph. You don't think it comfortably cruises at 70mph? Is there something magically different about it's 249ccs versus 250ccs in a scoot? No, there is not. 1cc is 1cc, however, tuning is everything.

So to the OP, yes, 70mph on a 250cc scoot is absolutely doable. 70mph is also absolutely doable on a 150cc scoot, assuming the correct mods (those not including a displacement increase) and correct tuning of the fuel delivery and drivetrain.

[yoster]

Sept 12, 2012 15:09:57 GMT -5 fieroboom said:

After reading this entire thread, I just had to drop in my 2 cents' worth...

If engine displacement decided your top speed, then all bikes of same displacement would have the same top speed. We all know this is not true. For instance, my stock gy6 150cc Super Hornet cruises at 55-60 (GPS speed) on flat ground. However, it's only running 8.8:1 compression ratio, so without adding any displacement, if increase compression to say 12:1, and get a good tune & timing set on it, then tweak the CVT weights, I am 100% confident that my 150cc would cruise at 70-75mph.

Look at a CBR 250 (older gens)... It's rated at somewhere around 35-40hp, with a top speed of 110-120mph. You don't think it comfortably cruises at 70mph? Is there something magically different about it's 249ccs versus 250ccs in a scoot? No, there is not. 1cc is 1cc, however, tuning is everything.

So to the OP, yes, 70mph on a 250cc scoot is absolutely doable. 70mph is also absolutely doable on a 150cc scoot, assuming the correct mods (those not including a displacement increase) and correct tuning of the fuel delivery and drivetrain.

Replace every phrase "cruises at " with "has a top speed of"


Prodigit - About MPG claims - make sure you're basing this off GPS. The odometers on these scooters can be as much as 20% off. You HAVE to keep these items in mind when thinking about all of this. Your comparison of 15-40 and 10-30 is questionable, especially the comment about engine life. You haven't done any testing there so I'd probably leave those kind of comments out (I can make the argument that a 10-30 synthetic is going to protect better than a 15-40 dino). So if it isn't factual (and you seemed to be doing testing and making factual conclusions,) probably not worth mentioning. Strange though about a MPG drop with 10-30; that kind of flies in the face of reason but oh well.

Bottom line, to the OP, 70mph is not a cruise speed. It's a hard to get to speed. It can do it, yes, but it's not something that's just easy to come by.

If the vehicle cannot easily do a good 20mph+ over the top speed, then it isn't a 'cruise speed.' Cruise speed isn't going down the road at a given speed with nothing left in the tank.

I think we can pretty much close this thread at this point. The horse has been beaten.

[rockynv]

So a 4 valve fuel injected Aprilia 250 at 11 to1 compression that tops out at 95+ mph by gps reading can cruise on a 70+ mph highway. If we put a GPR exhaust on it and bump it to a max of 110 mph then are we cruising at 90 mph? Aprilia is known for its high performance 250cc engines. They helped Rotax and Suzuki with their designs some of which with Aprilias engineering top out at 150+ mph in extreme form.

All bikes are not the same based on only displacement. GY6, Honda, Yamaha, VOG, Master Legend and Rotax engines along with whether they are OEM or copies in addition to the aerodynamics of the bike they are mounted on, fuel delivery system, exhaust, transmission set-up, tire size, ext all impact the top and cruising speeds of a 250cc bike (any bike really).

You can't state one generic rule and scoff at the results of someone on a stock 25+ hp 250 cc when it does not match the results of anothers 16 hp 250cc bike. The higher compression, more powerfull bike with better engineering and aerodynamics will go faster than the others in the pack.

My 250 snaps right up to 70 mph very sprightly while others do not. I took that into consideration when I chose which bike to drop my hard earned cash on. Yes it did cost me about $300 to $400 more than the Honda or Yamaha clones that were available locally but I felt that the extra interstate capabilities justified it. I did not want a bike that would leave me stuck in the far right lane all the time when on the interstate and with the one I chose I spend most of my time in the middle or far left lane unless I am stuck behind a rolling road block doing 5 to 10 mph below the speed limit, then I take what ever hole opens up. Cage drivers just seem to hate being passed on the intestate by a scooter.

[yoster]

The OP is talking about a Chinese 250 Bali. An Aprilia is not quite in the same league here.

[prodigit]

Sept 12, 2012 15:47:07 GMT -5 yoster said:

Sept 12, 2012 15:09:57 GMT -5 fieroboom said:

After reading this entire thread, I just had to drop in my 2 cents' worth...

If engine displacement decided your top speed, then all bikes of same displacement would have the same top speed. We all know this is not true. For instance, my stock gy6 150cc Super Hornet cruises at 55-60 (GPS speed) on flat ground. However, it's only running 8.8:1 compression ratio, so without adding any displacement, if increase compression to say 12:1, and get a good tune & timing set on it, then tweak the CVT weights, I am 100% confident that my 150cc would cruise at 70-75mph.

Look at a CBR 250 (older gens)... It's rated at somewhere around 35-40hp, with a top speed of 110-120mph. You don't think it comfortably cruises at 70mph? Is there something magically different about it's 249ccs versus 250ccs in a scoot? No, there is not. 1cc is 1cc, however, tuning is everything.

So to the OP, yes, 70mph on a 250cc scoot is absolutely doable. 70mph is also absolutely doable on a 150cc scoot, assuming the correct mods (those not including a displacement increase) and correct tuning of the fuel delivery and drivetrain.

Replace every phrase "cruises at " with "has a top speed of"


Prodigit - About MPG claims - make sure you're basing this off GPS. The odometers on these scooters can be as much as 20% off. You HAVE to keep these items in mind when thinking about all of this. Your comparison of 15-40 and 10-30 is questionable, especially the comment about engine life. You haven't done any testing there so I'd probably leave those kind of comments out (I can make the argument that a 10-30 synthetic is going to protect better than a 15-40 dino). So if it isn't factual (and you seemed to be doing testing and making factual conclusions,) probably not worth mentioning. Strange though about a MPG drop with 10-30; that kind of flies in the face of reason but oh well.

Bottom line, to the OP, 70mph is not a cruise speed. It's a hard to get to speed. It can do it, yes, but it's not something that's just easy to come by.

If the vehicle cannot easily do a good 20mph+ over the top speed, then it isn't a 'cruise speed.' Cruise speed isn't going down the road at a given speed with nothing left in the tank.

I think we can pretty much close this thread at this point. The horse has been beaten.

Yes, today I was driving past another speedometer, and it turns out my speedometer actually is 10% off. Previous speedometer read 33MPH, while mine read 35MPH, but this time I was driving 65MPH, with 72MPH on my speedometer.
That makes a 10% difference in actual MPG, so instead of 80MPG, actually I have cruised ~10% less than what the speedometer tells me, so I have about 72MPG, probably can top that off at around 75MPG when driving carefully.

Eventhough my bike can drive 75MPH (82 on speedometer), it drives 70MPH (78 on speedo) pretty comfortable; anytime, all day!

Concerning 15W40 and 10W30, I can clearly feel the difference on my bike, on any rev below 2k RPMs.
Especially when idling, the motor vibrates significantly more with lighter oil!

Also when driving, I kind of have the impression with lighter oil the acceleration goes faster, and the top speed increases by about 2-3MPH. But the sound of the exhaust sounds a lot sharper (more painful to the ears).

So yes, I listen to MY bike, and I can notice a difference!
With 10W40 oil the motor runs and sounds more like diesel engine, than RC speedboat!

[prodigit]

What also determines max speed is the shape of the motor. The burgman clones (Touring bikes), and CBR clones (Sports bikes) are created very aerodynamic, which helps with wind turbulence; and increasing of MPH!

If your bike is like a chopper or cruiser, the bike has more wind resistance, and thus top speed would suffer.

[fieroboom]

Sept 12, 2012 15:47:07 GMT -5 yoster said:

Replace every phrase "cruises at " with "has a top speed of"

Since you don't own my bike, I'll just go ahead and tell you, sadly, you are wrong. End of story. Just because your equipment can't perform the same as someone else's (maybe "inferior") equipment is not an arguable point, and attempting to argue it so shows your lack of knowledge on the subject.

Having built Briggs & Stratton 5hp motors that turn 12k and push a go kart to 100mph+, I can tell you that tuning is everything. I understand that you just want to flaunt your opinion, but the answer to the OP's question is, and always has been "yes, a 250cc scoot can definitely reach - and CRUISE AT - 70mph. Easily. It might take some tuning, but even less than a 150cc, which can also CRUISE AT 70mph."

[gregw]

If I had taller gears (and didn't have the weird vibration over 65mph), I'm sure I could cruise at 70mph easy, I can get up to 80mph when needed. As is, I'm spinning 7,100rpm at 65 mph, redline is 7,500. I don't want to rev too high for too long...

[rockynv]

Fiero - Briggs and Straton is the largest producer of performance engines in the world. yet most people only think of lawn mowers and edgers when they hear their name.

When you tear down some of their top end offerings the machining and polishing is to the point of being art.

[fieroboom]

Sept 21, 2012 20:40:33 GMT -5 rockynv said:

Fiero - Briggs and Straton is the largest producer of performance engines in the world. yet most people only think of lawn mowers and edgers when they hear their name.

When you tear down some of their top end offerings the machining and polishing is to the point of being art.

True, and that's one reason I loved building them. However, my point is simply that displacement does not determine cruising speed or even top speed.

[psychedelicode]

Gotta pipe in here...It's been along time since ive ridden a SCOOTER over 63cc... but my old Piaggio BV200 would murder the bay bridge (in san fransisco) at over 80 all day every day and between cars as its legal there. I would drive to Oregon from san francisco without question or stopping for cool down. The entire ride it never lost its time. Now my Piggy died an early death at under 5k miles.....
I can imagine that this is possible with a large motored china scoot. Even if you dont drive like me.

[prodigit]

Sept 21, 2012 18:41:26 GMT -5 gregw said:

If I had taller gears (and didn't have the weird vibration over 65mph), I'm sure I could cruise at 70mph easy, I can get up to 80mph when needed. As is, I'm spinning 7,100rpm at 65 mph, redline is 7,500. I don't want to rev too high for too long...

On my BMS 260, I've noted something funny.
In final gear (usually ~40MPH), the tachometer is more accurate than the speedometer, in telling my speed!

At 60MPH, the speedometer shows 66MPH, the tachometer is running ~6100rpm. Of course, when I release the throttle, the tach goes wrong, but at constant driving, and acceleration the tach displays the speed quite correctly from 4k RPM all the way to 7.5k RPM! (4000RPM =~ 40MPH; 7000RPM =~70MPH)