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Post by rockynv on Apr 20, 2017 12:02:28 GMT -5
Upping the front tire pressure by 2 to 3 psi will usually mitigate the head shake as will going with a tire that does not have a alternating chevron tread pattern such as the Michelin Pilot Power Pure. Motorcycles using the same tread alternating chevron tread patterns will also have head shake as many race track videos will prove out.
Heavy fisted front braking will cause the chevron tire treads to squirm more and wear on the leading edge of the tread blocks further magnifying the head shake.
Of course that is assuming that the bike is not overloaded and the preload on the rear shocks is set to match the weight being loaded on the scooter.
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Post by w650 on Apr 20, 2017 15:39:28 GMT -5
Upping tire pressure won't overcome the basic problem with scooter handling. Rear weight bias is so severe from the configuration it slants everything about the handling. Review the video where the Kawasaki blows past and away from the BMW C 650 on a twisty road. The best scooter in the Country couldn't keep a 650 twin in sight. Ask yourself how bad it would have been had the bike rider been on a 600cc Crotch Rocket like a CBR or Ninja 600.
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Post by ricardoguitars on Apr 20, 2017 16:37:04 GMT -5
Scooters weren't designed to go fast, there are better means of transportation to achieve that goal, scooters where designed to get around town cheaply, large displacement scooters get out of that scope, they are usually not cheap.
I do try to make my scooter go faster, but that's just a hobby, not a necessity for me.
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Post by pistonguy on Apr 20, 2017 16:48:04 GMT -5
Upping tire pressure won't overcome the basic problem with scooter handling. Rear weight bias is so severe from the configuration it slants everything about the handling. Review the video where the Kawasaki blows past and away from the BMW C 650 on a twisty road. The best scooter in the Country couldn't keep a 650 twin in sight. Ask yourself how bad it would have been had the bike rider been on a 600cc Crotch Rocket like a CBR or Ninja 600. You are 100% correct on the Weight Bias "Bar Slap". of a Scooter. What maybe 70/30 or 80/20, with a passenger even worse. Im getting curious enough to put mine on the scales and see for real the Weight Bias. I used to open up my hand, lean back and the bars Slap between my thumb and Fingers, thats maybe 6-8 inches apart, was just for the fun of it. any of my passengers were freaking out. |
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Post by w650 on Apr 20, 2017 18:03:04 GMT -5
Scooters weren't designed to go fast, there are better means of transportation to achieve that goal, scooters where designed to get around town cheaply, large displacement scooters get out of that scope, they are usually not cheap. I do try to make my scooter go faster, but that's just a hobby, not a necessity for me. You're absolutely right but you would be stunned how many times I've read about people bragging how they beat a motorcycle. They're totally convinced that a scooter is just as fast in all situations as a bike. So not true, as the video I posted showed. Given equal riders a scooter loses in contests of speed. Scooters certainly have their place and are enjoyable, practical and a good utility device. |
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Post by spandi on Apr 20, 2017 19:17:16 GMT -5
Scooters were meant as an economical (not fast) way to get around. For example, as a grocery getter, or for the ease of parking when Cosco is having a big sale and you can't find a space to save your life... ( a space for a CAR that is.)
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Post by w650 on Apr 21, 2017 9:14:09 GMT -5
Scooters were meant as an economical (not fast) way to get around. For example, as a grocery getter, or for the ease of parking when Cosco is having a big sale and you can't find a space to save your life... ( a space for a CAR that is.) Quite true. On the basis of small scooters it all makes sense. Good 50cc scooters can be had for around $1500 and will work. Online sellers saw the folly of selling bigger scooters and are going motorcycle. They just make sense as highway capable, cheap transportation. |
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Post by rockynv on Apr 21, 2017 12:12:27 GMT -5
I have absolutely zero bar slap since changing to a tire that is not prone to causing it and I only got it once the front tire had started to wear unevenly when I was running the Sava Diamond 28s. When I asked the factory mechanics at Aprilia they said after showing me the wear pattern that was causing it along with race video showing how it impacts all two wheeled motobikes that it would be resolved by upping the tire pressure by 2 to 3 psi and they were exactly right. From whats being discussed here it sounds more like folks running rear spring preloads to light or trying to ride double on a scooter with only a 330 lb weight capacity along with under inflating tires for a more cushey ride. I have 30,000 mostly Interstate miles on my Aprilia which was designed by a Sport Bike company as an Interstate bike with a 465 lb capacity.
What real good though is a street bike that does over the maximum legal speed limit in first gear? There is only one road in the USA where it is legal to go over 80 mph and its a relatively short rural streatch of highway out in the middle of nowhere.
BTW: The scooter design came about because an aircraft engineer was tasked with coming up with a design that people could ride without getting oil splashed all over their clothes and could provide affordable daily transportation to folks recovering from the economic hardships that followed WWII through Europe. What they did not like was how dirty a motorcycle rider typically got.
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Post by Jarlaxle on Apr 21, 2017 12:21:22 GMT -5
No bar slap at all on my Burg...front tire is the factory Bridgestone Hoop. Plenty of highway time in my 16,000+ miles, including two trips to North Carolina. Seems to have a sweet spot right around 72-74MPH.
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Post by w650 on Apr 21, 2017 14:00:49 GMT -5
What real good though is a street bike that does over the maximum legal speed limit in first gear? There is only one road in the USA where it is legal to go over 80 mph and its a relatively short rural streatch of highway out in the middle of nowhere.
Okay. Let's try this again. Go back and watch the video of an $8000 Kawasaki 650 Versys smoking a $10,000 BMW 600 on a twisty road and in a drag. As a grocery getter a scooter is a great device. As an interstate vehicle or backroad bullet any scooter will be hindered by both its plastic coating and rearward weight bias. A passing truck will cause great consternation to a scooter in its wake. I recall a story years ago about a 650 Burgman owner stating "Never again" on using one on a highway tour. Even a Honda Rebel is more stable in that environment.
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Post by ricardoguitars on Apr 21, 2017 17:40:44 GMT -5
Scooters smoke any vehicle filtering on busy traffic, and smoke any motorcycle carrying stuff; that's exactly what they were designed to do.
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Post by w650 on Apr 21, 2017 21:02:20 GMT -5
As a scooter owner that may be true for you. Out in the world there are numerous bikes zipping through standing traffic and carrying goods in their luggage.
People who ride either are loyal. They both serve a purpose. I have both.
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Post by oldchopperguy on Apr 21, 2017 21:52:25 GMT -5
Upping the front tire pressure by 2 to 3 psi will usually mitigate the head shake as will going with a tire that does not have a alternating chevron tread pattern such as the Michelin Pilot Power Pure. Motorcycles using the same tread alternating chevron tread patterns will also have head shake as many race track videos will prove out. Heavy fisted front braking will cause the chevron tire treads to squirm more and wear on the leading edge of the tread blocks further magnifying the head shake. Of course that is assuming that the bike is not overloaded and the preload on the rear shocks is set to match the weight being loaded on the scooter.
OK, I do know not ALL techniques will work on ALL bikes, but... That being said, My first scooter, a Chinese Xingyue 150, exhibited terrible wobble ANY time I "tested" it by letting go of the bars at ANY speed above a walk. In fairness, grabbing even one bar would stop it, but that wobble sucks. I upped the front tire pressure from "recommended" 32 psi to 36 psi (max. psi on the crappy low-end factory Kenda tires) and the wobble almost went away! Almost, but not completely: but SO much improved that I was ecstatic considering the super-cheap factory tires. When I got "Minnie Mouse", my current well-used Kymco Grandvista 250 she wore brand-new Kenda cheapie "J" speed rated tires (62-mph). They were AWFUL! My front end wobbled and shimmied at most any speed, ESPECIALLY when decelerating from say, 60 down to 20. At 20 I could hardly hang onto the bars! I was DIS-FREAKIN'-SGUSTED...  I immediately changed out the tires to "P" rated ( -mph) better quality tires (Michelin Power Pure rear, and Shinko front). The brand-mix was due to my wanting whitewalls, and Shinko was the only P-rated whitewall I could find to fit the front, and nobody makes a whitewall to fit the rear... The Michelin had a good sidewall profile for painting a fake... Just me! The mix works fine, and ALL shimmy went away (as long as both tires are fully inflated). It was like a NEW scooter!!!
Even today, if I let the front tire get below 28 psi, I get a teensy bit of wobble when decelerating, but very little. I find my particular scoot handles it's very BEST at all speeds from walking-speed to top-end of 80-  on the flat with no wind with both tires inflated to 36 psi.
That's probably a tad hard for some riders, but "the Mouse" is at her best at 36 psi fore and aft.Since MANY scooters exhibit wobble, I'd bet the farm that often it's due to the common "build practice" of the front fork downtubes ONLY being attached to the BOTTOM triple-tree, and made WORSE with a step-through frame... Cheesh... Can't they at least run the dang fork tubes through BOTH triple-trees like a MOTORCYCLE? That surely would stiffen up the front fork! And reduce wobble tendency... Hooray for the 1950's Cushman Eagle... LOL!
So, to make a long story shorter, Rockynv's advice DID work on my 150, and, going to major-brand J-rated tires, fully inflated did WONDERS for my 250. Regardless of tire pressure, the style of tire MUST make a real difference and if possible, it's good to try different types. However that is probably unrealistic for most casual riders like myself. These ARE scooters... Not crotch-rockets. I'm a "grocery-getter" rider who just loves getting my knuckles in the wind with occasional romps on the interstate, so as long as the old Mouse is fairly safe, I'm happy.When I feel "the need for speed" I now have the luxury of wringing out my "new" 2004 Honda Accord with a Type-R motor and drive-train... Woo-HOO! Does that frisky little hamster go, or WHAT? She's about as quick, and as fast as my beloved "Old Blue" chopper... Durned clever them Japanese!We all know even the best racing motorcycles CAN exhibit fork wobble. Many have little hydraulic dampers from the frame to a fork-leg. Even my old 1957 Hog had a screw-down friction damper on the fork that worked GREAT... I'd LIKE something like that on a scooter!
Ride safe, and save the wobbles for the "Weebles"... LOL!Leo ("we scooter-jockeys wobble, but we don't fall down...") HOPEFULLY... in Texas |
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Post by pistonguy on Apr 22, 2017 9:03:29 GMT -5
If one has Not Experienced Bar Slap on a Scooter I'de would venture to guess one has Never Taken there Hands off the Bars and Sat up or Better Lean Back. its the weight bias.
I have Michelins on my Scoot and love them.
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Post by w650 on Apr 22, 2017 11:04:38 GMT -5
Scooters smoke any vehicle filtering on busy traffic, and smoke any motorcycle carrying stuff; that's exactly what they were designed to do. You mean carrying stuff like this?  |
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-mph) better quality tires (Michelin Power Pure rear, and Shinko front). The brand-mix was due to my wanting whitewalls, and Shinko was the only P-rated whitewall I could find to fit the front, and nobody makes a whitewall to fit the rear... The Michelin had a good sidewall profile for painting a fake... Just me!
on the flat with no wind with both tires inflated to 36 psi.
