KymcoForum.com
Scooters - 125 to 300 => Grandvista 250 => Topic started by: Bill G on July 22, 2015, 04:31:51 AM
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I have a 2005 GV 250 that I bought brand new. I know it is not recommended to take one's hands off the handlebars. That is kind of a no-brainer. However, I have noticed for a long time that if I take one hand off the handlebars and then have one other resting very lightly on the handlegrip, the bike starts a very profound shimmy. It is as if there is no caster effect or gyroscopic effect for the font wheel. I am wondering if this is typical of the bike or is there some alignment or wheel balancing that needs to be done?
I took a spin on a friend's standard motorcycle and I noticed a huge difference in stability as compared to my Kymco.
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Do you know how fast you were going? That may have an effect on the stability. It's a new bike, but if the tires are under-inflated that may effect it too. Just curious. Where are you that you can purchase a new GV? In the US the model was/is discontinued.
-Wolf
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Bill,
A shimmy or wobble at various speeds is something I experience on almost every motorcycle or scooter at some time. On an older bike, it can indicate worn steering head bearings or improper tire pressures or worn tires. But in my experience, the wobbles I've encountered are due to hanging weight (trunks) off the rear of the bike or certain fairings which can upset the bike's balance. For example, on my Super 9, a small scooter, I can take my hand off of the bars at almost any speed (top speed 45-48mph) and it will track straight. But if I attach my medium sized Givi trunk without even loading it, the extra rearward weight can cause the scoot can start to wobble if I take my hands off the bars. This is behavior I observed even when the scooter was new. The wobble is not uncontrollable, so my easy solution is to not take my hands off the bars!
Motorcycles have an advantage in that they are much heavier vehicles and inherently more stable, but shimmy and wobble problems more dangerous (higher speeds) and can literally throw you off the bike at speed. Often, if there is no obvious problems detected, the only solution is a steering damper which will counteract the wobble effect.
Wil B.
Broadview, IL
'71 Guzzi Ambassador
'91 Honda Nighthawk
'04 Kymco Super 9
'10 Kymco Yager 200gt
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I have a 2005 GV 250...if I take one hand off the handlebars and then have one other resting very lightly on the handlegrip, the bike starts a very profound shimmy.
My 2005 GV which I bought 4 years ago with 2600 miles has always done the same thing even with the stock windshield and no trunk or top case. I changed the windshield to a taller givi and added a givi trunk. I now have over 17,000 miles and recently I installed my 3rd tire: first was the stock Kenda? second the Avon ViperStryke and I just installed the Michelin City Grip Front Tire but left the old balance weights on without re-balancing for the new tire -- UPDATE -- last night at around 35 mph I got the shake.
My last ride - a 1992 bmw k75 had the same problem but the solution was to correct and incorrect alignment of the fork using the simple "axle test" which works a follows: loosen your axle and remove it. If it does not slide out smoothly and is difficult to re-install then your fork are either bent (unlikely) or misaligned - one is longer than the other, they are not in the same plane or are not parallel. My GV does not seem to have any of these problems yet it still has the problem.
I use a stick throttle and so I often take my hands off the handlebars to adjust my helmet, glasses, etc. Overall, I think the GV has "good" handling characteristics but the short wheel base + 12" wheels vs 16" inch or so found on the people 250, and most motorcycles leaves the scoot at a disadvantage regarding handling, cornering and a rough ride over bumps that can pop you out of the seat.
Hope it helps and long live the GV.
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I have two GV's. One does it and one does not. My People 250 also has the wobble when I take my hands off the wheel. Who knows?
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I have two GV's. One does it and one does not. My People 250 also has the wobble when I take my hands off the wheel. Who knows?
Impressive collection; you like collecting pairs of scooters ;)
Here is a video that explains the issues of fork alignment:
https://www.youtube.com/watch?annotation_id=annotation_518533&feature=iv&src_vid=gRnAhiClzoY&v=tVWHfyG4jB4 (https://www.youtube.com/watch?annotation_id=annotation_518533&feature=iv&src_vid=gRnAhiClzoY&v=tVWHfyG4jB4)
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Most of the Kymco 250's shake if you go no hands. I think it has something to do with not dynamically balancing the tires. I've swapped tires and it totally goes away.
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... I think it has something to do with not dynamically balancing the tires. I've swapped tires and it totally goes away.
My factory tires did it and the next set of tires - Avon ViperStryke which were installed at the dealer.