Downtown 300i front end wobble

[Going Downtown]

I have a new downtown with only 400 miles on it and experienced a front end wobble that scared the hell out of me.  Has anyone ever experienced that or can tell me why? The tire pressure was fine, front end wasnt hit or any damage to it, like I said new scoot.  Both times it happened I was going into a turn.  Anyone know what it could be?  Thanks

[windwheeler]

A VERY bad out of balance tire can cause that, or an out-of round/out of shape tire. 
Balancing has gone to the wayside with Kymco, I got a low miles GrandVista and it had NO balance on the front tire, and was horribly out of balance. 
e.g: A tire that has a a heavier and inconsistent tire weight for example right side compared to the left side (would be a tire manufacturing defect) can be perfectly balanced, but this causes a severe wobble.

Other: A (loose) steering head bearing with too much play or a manufacturing defect will cause the same. 

No matter what, I would bring that scooter back (I assume you bought from a dealer) and tell them "TOTALLY UNACCEPTABLE" and THEY need to figure it out ASAP, or you want your money back..!  "This is UNSAFE and a danger to yourself and others"; any judge will be on your side.  Be firm with them, they need to get that immediately fixed!

PS: See that you can set a "benchmark" for speed and wobble on a road that you can easily get to,and then compare "before and after" rerpairs

[Going Downtown]

Wouldn't it do it more consistantly if it was a problem with the bike? Could it be I was fighting the counter steering? New rider here.

[sklnzl]

You could try firming the rear shocks,ie put on higher number ,i have read that this also firms up the front suspension

[BettinANDlosing]

Was it with one or no hands?

[windwheeler]

I have a new downtown with only 400 miles on it and experienced a front end wobble that scared the hell out of me.  Has anyone ever experienced that or can tell me why? The tire pressure was fine, front end wasnt hit or any damage to it, like I said new scoot.  Both times it happened I was going into a turn.  Anyone know what it could be?  Thanks

To make sure we have no misunderstanding, you are saying you had a "handle bar shake" when you talk about the front end wobble?  Right?

[Going Downtown]

Yes the handle bars shake.   Both hands are on the handle bars.

[windwheeler]

Yes the handle bars shake.   Both hands are on the handle bars.

If your tire pressure is 35-38psi then you should have ZERO shake, no matter what.  There is nothing YOU can do wrong.  There is something seriously out of whack on the front of your D/T!  Go to your dealer and "complain with DEMAND!"  They better fix that!  Don't wait.  It could end up for you known in motorcycle riding as a "tank slapper".  Look it up...  not pretty!

[ktienation]

Dunno if in the US its also called the same, but here in europe we call this shimmy As to the topic. If it happens when u have hands on the handlebar and u really can feel it its really strange and should not be disregarded. For example, when u put your hands off, this tends to happen at certain speeds - it depends on the tires you have. For example, on my oem kenda tires i used to observe shimmy between 40-60 kmh when i let the handle go and it was increasing the longer i had my hands away. After I changed the tires to dunlops, i observe no shimmy anymore.

[windwheeler]

That is correct what ktienation said or observed. 

Balancing a motorcycle tire is a difficult task when the left of the tire is e.g heavier at one spot than the right. That's "torque values"  that cause the wobble.

You can balance a WHEEL (=tire + rim) perfectly as a "static balance", but still have a strong wobble on the handlebar at a hands-off speed due to the "dynamic forces" of an uneven weight left to right  of the  tire or wheel.  ONLY a properly set up electronic balancer at a motorcycle shop can correct this, but 90% the personnel does not understand the whole thing technicality and does not do a proper "dynamic balance".   

The replacement of the tire and using a more true brand (as our friend above here did) is then usually the solution they default to...
 
(PS: it is not the only solution, as I explained... but most shops don't have either the equipment, or the "brains" to balance a motorcycle wheel 100% properly.  And sometimes, with too much weight off [left to right], it is practically not possible to correct as this are narrow rims when compared to a car rim.)

[mrbios]

I have a new downtown with only 400 miles on it and experienced a front end wobble that scared the hell out of me.  ...

Not good.  My 2005 GV250 will wobble IF I take my hands off the handle bars but it has never done what you describe.  Check for loose bolts . 

Use the "Axle Test".  - put scoot on center stand and loosen and remove the front axle - be careful not to loose the spacers.  Use a digital camera to record how all the pieces go together.  IF the axle is difficult to remove / reinstall then the fork tubes are out of alignment.  On many scooters there is not easy to adjust or shim them but at least you know where the problem is.  My front tire - Avon viper strike is scalloped "cupped" do to mileage ~ 7,700 miles and my scoot still doesn't do what you described.   

[Stig / Major Tom]

Not good.  My 2005 GV250 will wobble IF I take my hands off the handle bars but it has never done what you describe.  Check for loose bolts . 

Use the "Axle Test".  - put scoot on center stand and loosen and remove the front axle - be careful not to loose the spacers.  Use a digital camera to record how all the pieces go together.  IF the axle is difficult to remove / reinstall then the fork tubes are out of alignment.  On many scooters there is not easy to adjust or shim them but at least you know where the problem is.  My front tire - Avon viper strike is scalloped "cupped" do to mileage ~ 7,700 miles and my scoot still doesn't do what you described.   

(I have a scalloped 8000 mile rear Michelin City Grip - was told it is due to underinflation (nope, always check them ) and/or too much weight (HEY!!)
Still plenty of good deep tread grooves - works fine in the dry & the wet.
Stig)

[mrbios]

(I have a scalloped 8000 mile rear Michelin City Grip - was told it is due to underinflation (nope, always check them ) and/or too much weight (HEY!!)
Still plenty of good deep tread grooves - works fine in the dry & the wet.
Stig)

Good Stuff Stig,
Totally agree about the under inflation.  I check my tires regularly.  Regarding weight - I don't believe that either because I only weigh 170 lbs and on my factory tires I had a girl that I was seeing on the back many times - and she wasn't exactly small. 

The original factory tires Brand? Scalloped only very slightly in the rear.  The Avon Viper Stryke much more so especially in the front and at lower mileage.  Glad you recommend Michelin because that is what I ordered from the motorcycle SuperStore.  Because my scooter lacks the power and handling of a performance motorcycle I feel like the tires have only a limited effect.  I'm mainly interested in miles and general durability / low maintenance.  I think the Avon is fine for most people because many people relegate their scoot to a novelty or toy and will never put many miles on it.  For me I use it like a car as much as possible. 

Michelin Pilot Power Pure SC Rear Tire
Color- Black, Size- 140/70-12
SKU#401636   Shipped   $49.99   1   
50
   $49.99

Michelin City Grip Front Tire
Color- Black, Size- 120/70-12
SKU#256814   Shipped   $48.99   1   
49
   $48.99

[Stig / Major Tom]

Good Stuff Stig,
Totally agree about the under inflation.  I check my tires regularly.  Regarding weight - I don't believe that either because I only weigh 170 lbs and on my factory tires I had a girl that I was seeing on the back many times - and she wasn't exactly small. 

The original factory tires Brand? Scalloped only very slightly in the rear.  The Avon Viper Stryke much more so especially in the front and at lower mileage.  Glad you recommend Michelin because that is what I ordered from the motorcycle SuperStore.  Because my scooter lacks the power and handling of a performance motorcycle I feel like the tires have only a limited effect.  I'm mainly interested in miles and general durability / low maintenance.  I think the Avon is fine for most people because many people relegate their scoot to a novelty or toy and will never put many miles on it.  For me I use it like a car as much as possible. 

Michelin Pilot Power Pure SC Rear Tire
Color- Black, Size- 140/70-12
SKU#401636   Shipped   $49.99   1   
50
   $49.99

Michelin City Grip Front Tire
Color- Black, Size- 120/70-12
SKU#256814   Shipped   $48.99   1   
49
   $48.99

Yep, any time I can get a pair of Michelins for around $100 I'm on it like white on rice.
I've read a couple of articles by motorcycle guys who say that that scalloping is not unusual.....to just keep riding as long as there is good groove depth.
I had the stock Kendas taken off at 400 miles -- 8000 on the City Grips so far on my daily commuter.
Stig

[mrbios]

Yep, any time I can get a pair of Michelins for around $100 I'm on it like white on rice.....
Stig

Motorcycle SuperStore has good prices and super fast free shipping.