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Post by urbanmadness on May 27, 2014 18:07:56 GMT -5
Welcome
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Post by urbanmadness on May 27, 2014 18:06:33 GMT -5
yes, if it spins the rear pully fast enough to engage the clutch but chances are the belt will move up the variator a little before that happens. (am I right?)
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Post by urbanmadness on May 27, 2014 16:40:30 GMT -5
Welcome
Ouch.... I'm not sure how I'd fix that one....
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Post by urbanmadness on May 27, 2014 16:33:53 GMT -5
Assuming this to be true, also that the belt reaches its outermost travel at 40 mph as he stated, and that the belt does not slip as he stated, implies that the lower rpm would occur on acceleration which is the opposite of his findings. The reason I ask such questions is because in my first job, an experienced guy before me did a project without people asking him hard questions. The result was that the company invested more than a million dollars in production equipment only to find out that the prototype was the only unit that behaved the way it was required to behave. The company had to write it all off as a huge loss and the guy was terminated. Scared the daylights out of us new hires. I think one source of confussion on this thread is we are talking three different class bikes with different set ups. Alley rides a trike (150cc I think), OCG rides a 250, and I ride a 500cc. My bike is good for over 95MPH stock so it has a much larger Variator, so much more surface to play with. The 250 that started this discussion also has a bigger variator then alley's bike. 250cc bikes are good for anywhere from 65mph to 75 mph stock depending on set up and the 150cc class bike that's usually good for 50-60. Alley will have the same thing happen at lower speeds. Two different RPM's at the same speed. It's just a different "gear".... But once you get to top of the variator, they don't loose rpm when you let off the gas. It's only when you are not at the top of the travel of the variator. That happens at 40mph on Alley's bike... I Don't know where it happens on my bike (don't want the ticket) and probaly around 60 on OCG's bike. Have you ridden a CVT bike? |
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Post by urbanmadness on May 27, 2014 15:46:55 GMT -5
I didn't know Ford was using a CVT. I know Nissian does, and so does Mini.
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Post by urbanmadness on May 27, 2014 15:30:43 GMT -5
Thanks for the welcome oldchopperg. Urbanmadne The problem is that Alleyoop eliminated that from the equation when he said, but we were talking about two difference engine rpm's at 50 mph. And that is possible. I've seen it. I can cruise at about 500 rpm less then acclerating on my big bike. (the only one I have that has a tach) Alley was talking under acceleration only, I believe. What we are talking about is accleration, coast, then accleration. The gear ratio is going to be different depending on conditions, load and a given RPM and I notice it more on the larger bikes. Afterall CVT stands for Continously Variable Transmission. When coasting or cruising, the rear pully pushes the belt thru the variator, which keeps the belt up in the variator, lowering engine RPM, then when you goose it, it the engine pulls it tight, pulling it into a lower ratio until it throws the wights back out. <----- this may a more to the point answer to what you were asking. CVT's are pretty dynamic... |
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Post by urbanmadness on May 27, 2014 13:22:53 GMT -5
Just about any of the sponcers up top will have what you need, but I have had really good luck with Scrappydawg but, all of the sponcers are really good. what size engine? 150cc?
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Post by urbanmadness on May 27, 2014 11:58:28 GMT -5
sounds like a nasty mess...
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Post by urbanmadness on May 27, 2014 11:55:59 GMT -5
He is telling you to look where the exhaust meets the engine. There should be two nuts there. If one backs out, sometimes the exhaust ring (gasket) falls out and it doesn't seal.
You shouldn't ride the scooter until this is fixed as it can cause additional damage.
The scooter getting loud is an exhaust leak, the popping sound is from the same cause. These engines need some back pressure (exhuast system restriction) to run correctly.
The fix is very simple, just losen the other exhaust flange bolts (you will probably find one or both missing), get a couple exhuast nuts (don't use nylocs) a couple of lock washers, and a new gasket, and you will be on the road for 10 or 15 bucks.
A simple trick to keep the gasket in place when putting it back together is to stick the new gasket in the head with a small dab of RTV sealent. Just a little on one little place of the gasket is all you need. Oh, and make sure the old gasket is out of the head as well. Use a awl, or small screwdrive and pry it out without nicking the head.
A tip for people who are learning to work on scooters is to use only 1/4 drive socket sets instead of the 3/8 sets. The reason being is you are way less likely to break a bolt or stud with the 1/4" drive sets from over tightening things.
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Post by urbanmadness on May 27, 2014 11:40:12 GMT -5
Maybe I am the Devil. Haha. I own a motorcycle and a scooter. The motorcycle has a steel chain and steel gears. This phenomena does not happen because the steel chain and gears cannot slip so there is a fixed relationship between the engine rpm and the rotation speed of the rear tire. One difference between the motorcycle and scooter is the transmission. As the referenced article states, the people who design these CVT's say the belt slips more when applying more torque. So under acceleration the belt slips more resulting in a higher rpm for the same 50 mph speed. Backing off the throttle and reapplying to maintain the 50 mph means applying less torque to maintain the same speed resulting in less slip so a lower rpm results in the same 50 mph. This is no different than using a wrench to loosen a nut. When the nut is not loose, you have to apply a lot of torque to loosen it, but once it is loose the amount of torque required to continue turning it is much reduced. On the other hand wrenches like strap wrenches based on a belt can slip under torque. This explanation also explains why this is less likely with smaller engines. Smaller engines have less available torque so they cannot cause as great an increase in slip. It also says that if you increase speed very gradually which applies less torque over a longer period of time the phenomena is less likely to occur. If you have a scientific explanation or a scientific paper to explain the process I am willing to listen. What is being described here is not belt slip. It's the variator changing ratios. To slip a belt on a scooter, would take more horse power then they generate unless there is something wrong with the bike. For example, my 500cc makes about 39BHP with a belt that is not much larger than what is used on a 150 or 250. It is a little thicker but that's about it. Think about it, if the belt slips too much, it is going to burn up or squel (and you'd smell it). They don't unless you have a clutch problem. The "Slippage" being described here is the CVT doing it's thing. Comparing it to a clutch and gears bike is like comparing apples to oranges. A closer comparison would be to a 10speed bike. The rear pully acts like a de-railer that is taking up the slack in the chain, and the varator like the front set of sprokets with the front sproket being completely automatic, depending on RPM. As RPM's increase, the Variator (front pully) closes and the belt ramps up, changing the ratio. Check out a couple Youtube vids on how a variator works and you will see, just how ingenous they really are. You really have to hand it to the engineers that designed these CVT's. They are cheap, relaible and brain dead simple in function. The fact that the design has been around for so many years, on everything from 50cc 2 strokes up to my 500cc Italian bike is a testoment to how well this style of transmission actually works. Is it as efficient as clutch and gears? Yes and no... For this type of bike, in stop and go traffic and in a down town situation, a bike with a properly tuned CVT can pull 75-100 mpg (150, 250 class). My 500cc, for example pulls about 58MPG in city stop and go driving... Get the 500 out on the open road, and it drops to 50MPG. This is because when a CVT bike with a properly tuned variator takes off, it's in the powerband thru acceleration, when crusing you may not be in the powerband (the 500cc runs on the freeway at about 6k rpms). A clutch and gears bike, ridden well, you can cruise at lower RPM's and get the milage numbers out of it on the open road, but you will take a hit when you accelerate as you are moving in and out of the torque curve. In case you are wondering where I got the MPG numbers for the 500cc, the touring computer on the bikes tells me and resetting it every tank gives me a very good idea on what riding style with that bike nets the best MPG numbers. I know, long winded, off topic, but I hope that at least sheds a little light on what you are saying vs what alley is saying. |
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Post by urbanmadness on May 27, 2014 8:03:49 GMT -5
You could always go old school muscle bike.... better riding position and loads of torque.... think Honda Magna or Sabre... with a V65... Nasty bikes..... with Honda dependability and with a price point around 2500 for a clean example in good shape.
Or do what I did.... old school goldwing. Yeah, it's heavy but the 1500 is no worse then my 500cc Scarabeo and in some ways, better. You just have to be a leg lifting Ninja to get on the beast. Very flat and forgiving power delivery, smooth and reliable and very, very comfortable.
The goldwing is never gonna be a great in-town bike, but it is doable, and the stereo will keep your mind off of it.
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Post by urbanmadness on May 26, 2014 14:58:15 GMT -5
On a Mac, Safari, hands down, unless I'm using facebook, then I use firefox.
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Post by urbanmadness on May 26, 2014 14:49:29 GMT -5
Not gonna try it on my bike.... I won't do a top speed run on it, because, not only would I get the speeding ticket, get hauled off to jail and the bike towed, I won't because I'm not interested in becoming a street pizza at over 90mph. So count me out for this one. but then again, it's a fuel injected 500cc..
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Post by urbanmadness on May 26, 2014 9:25:13 GMT -5
The only reason I don't ride a CR is they are notoriously uncomfortable for someone my size and age... Age more then anything.... LOL
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Post by urbanmadness on May 21, 2014 14:54:57 GMT -5
It's one of the reasons we can filter to the front of a traffic lane here in California. Of course that wouldn't of helped your situation.
Scary as all heck too.
I'm glad you are okay, but of course time will tell.
As for the bike, they can be replaced, you can't.
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