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Old 05-10-2017, 12:55 PM   #1
rhysmort
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Default Decel wobble around 50MPH

Hi all,

take away the obvious, neck bearings, top nut etc, is there anything that would cause this? I have a OEM springer, 21 spool. It's absolutely fine but coming off the throttle over 50 I get a mild wobble, it's not horrid like throw you off tampin speed wobble.. but if I can stop it I'd obviously like to.

Avon speedmaster 2 on the front, 21 PSI, spool hub, oem springer etc.

Thanks!
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Old 05-10-2017, 01:21 PM   #2
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Default Re: Decel wobble around 50MPH

21psi is too low....should be somewhere between 32psi-35psi,... & get it balanced, it works wonders
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Old 05-10-2017, 01:40 PM   #3
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Default Re: Decel wobble around 50MPH

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Originally Posted by magnum45pete View Post
21psi is too low....should be somewhere between 32psi-35psi,... & get it balanced, it works wonders
I wondered if it needed a balance Pete.

No problem I'll give it a try. Being a jockey shift wobbles at high speed aren't my favourite!

Rhys
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Old 05-10-2017, 04:04 PM   #4
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Default Re: Decel wobble around 50MPH

What Pete says rhys...and take a look at the rear wheel as well. Many wobbles are caused from the rear as well especially the old let off the gas and get a bit of shake type wobble. The drive chain loads the wheel and bearings one way and then when you let off the throttle any play in the rear causes it to shake and shutter. Wheels should really be balanced and check your rims for run out too. As for the neck bearings...did you check 'em? - Dave
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Old 05-10-2017, 05:01 PM   #5
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Default Re: Decel wobble around 50MPH

Check tire pressure on the rear too. Too little can make the front woggle.
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Old 05-10-2017, 05:19 PM   #6
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Default Re: Decel wobble around 50MPH

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Originally Posted by DoggyDaddy View Post
What Pete says rhys...and take a look at the rear wheel as well. Many wobbles are caused from the rear as well especially the old let off the gas and get a bit of shake type wobble. The drive chain loads the wheel and bearings one way and then when you let off the throttle any play in the rear causes it to shake and shutter. Wheels should really be balanced and check your rims for run out too. As for the neck bearings...did you check 'em? - Dave
I've just had my rear respoked by the local top guy so I know that's out of the question. I've put air in my front tyre, running as cross ply rear and have about 18 lbs in it! maybe need to put that up more!
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Old 05-10-2017, 08:07 PM   #7
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Default Re: Decel wobble around 50MPH

But you don't want to go to high on tyre pressure as being a hard tail you'll feel every little rock on the road.
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Old 05-10-2017, 11:32 PM   #8
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Default Re: Decel wobble around 50MPH

Good grief. Eighteen pounds seems terribly, waddlingly low. I'd try 25, 26 at least.
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Old 05-11-2017, 03:19 AM   #9
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Default Re: Decel wobble around 50MPH

I ran a hardtail triumph chops 16x5 rear tire at 10 psi for years with no handling problems above what you would expect for a 10" over tele front end !
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Old 05-11-2017, 06:55 AM   #10
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Default Re: Decel wobble around 50MPH

14 on my rear 16x5 avon sm mkII
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Old 05-11-2017, 10:12 AM   #11
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Default Re: Decel wobble around 50MPH

I'm thinking the Pan manual say's 16 for single 150# rider and add 2 for each additional 50. I'll look again too be sure.
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Old 05-11-2017, 10:19 AM   #12
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Default Re: Decel wobble around 50MPH

Rhys is talking about his FRONT tyre, a skinny 21 with only 21psi in it,
far too low, needs to be 32psi-35psi.........only time I had 21psi in a front tyre was when it had a Puncture,.....
the rear can be anywhere from 12psi up, depending on what tyre is fitted

............................& CHECK YOUR TYRE PRESSURES WEEKLY, LESS YOU WANT TO KILL SOMEONE OR BE KILLED YASELF !!......................TAKS LESS THAN 30 SECONDS TO DO
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Old 05-11-2017, 10:19 AM   #13
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Default Re: Decel wobble around 50MPH

I run 23psi front and 26psi rear.

both avon MKII tyres, 16 rear, 21 front.. seems alright.
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Old 05-11-2017, 11:14 AM   #14
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Default Re: Decel wobble around 50MPH

I've put some air in the front, I have 18 in my rear it's a 5.5" cross ply Firestone.

Once I get a dry day I'll try again. It may be the front wheel needs a balance. Checked last night there's a definite heavy spot.

thanks all!
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Old 05-11-2017, 07:38 PM   #15
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Default Re: Decel wobble around 50MPH

rhys - The decel wobble....has your bike done this since you got it or is it something new? When it does this does it feel like the front is shakin' or what? You mentioned it being an issue while one hand is on your shifter....you feel the bars shakin' back n' forth with your other hand? - Dave.
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Old 05-12-2017, 10:03 AM   #16
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Default Re: Decel wobble around 50MPH

Quote:
Originally Posted by DoggyDaddy View Post
rhys - The decel wobble....has your bike done this since you got it or is it something new? When it does this does it feel like the front is shakin' or what? You mentioned it being an issue while one hand is on your shifter....you feel the bars shakin' back n' forth with your other hand? - Dave.
Dave,

It doesn't occur to I'd say over 50 mph.. I can't remember if it's always been there to be honest, but other than the actual front wheel I've changed everything else! It's like a slight tamping through the bars, a small wobble, it's not like a speed wobble where it tamps out of control.. and it's only on decel. Happens with both hands on the bars.. I think it could be balancing.
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Old 05-12-2017, 11:03 AM   #17
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Default Re: Decel wobble around 50MPH

Forgive me if this is unhelpful -- I know you said you'd been through everything -- but on a BMW that'd be a pretty sure sign that the races were adjusted too loose. It don't take much.
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Old 05-12-2017, 11:04 AM   #18
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Default Re: Decel wobble around 50MPH

I was wondering anout bearings meeself.
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Old 05-12-2017, 11:49 AM   #19
rhysmort
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Default Re: Decel wobble around 50MPH

Quote:
Originally Posted by JAWS View Post
I was wondering anout bearings meeself.
I've put 30 PSI in my front and it's a lot less. Brandt it has new bearings, being a spool they're old style not timkin.

maybe worth putting the castle nut up another 1/4 turn..
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Old 05-12-2017, 05:52 PM   #20
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Default Re: Decel wobble around 50MPH

Or an eighth. Like I said, it don't take much adjustment to achieve strong (good or bad) results.
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