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Author Topic: My Weeble's Wobble  (Read 2890 times)

barenekd

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Re: My Weeble's Wobble
« Reply #30 on: August 22, 2011, 10:35:30 PM »
I don't know if the fender setup is as stiff as the G5. But the G5 has a one hell of a fork brace!
Start from the steering head shaft. If that nut's loose, all kinds of weird things can happen. It lets the triple clamps flex between the two of them and leaves the head bearings loose. Definitely could explain your difficulties. Grab the front fork down low and see if you're getting any back and forth movement in them. That's loose bearings. I thought way back you said you had checked that stuff. Must've been someone else.
Bare
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Ducati Scotty

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Re: My Weeble's Wobble
« Reply #31 on: August 22, 2011, 11:01:37 PM »
No fork brace on the C5 but it'd be worth loosening the front fender struts and re-tightening just the same.

Scott

bittercrick

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Re: My Weeble's Wobble
« Reply #32 on: August 22, 2011, 11:53:19 PM »
Thanks Scotty but i've done all the things you named thats why I say I'm really stumped on this.the only thing that works at all is lying forward on the tank like a monkey breeding a football,  sorry .       bittercrick
bikes Triumph 06 T100 - 01 Triumph Adventurer - RE C-5 chrome -78 Honda GL1000-83 Honda CB1100F

Ducati Scotty

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Re: My Weeble's Wobble
« Reply #33 on: August 23, 2011, 12:05:41 AM »
Two bigger things to try...

1) Get the bike warm.  Loosen all the mounting bolts for the engine until they are just loose.  Then, with it running at dile, tighten them all up.  Go roundy round, a little on each until they are all snugged to spec.  Like Kevin said, this lets the engine "find its center" which is important when it's a stressed member of the frame.

2) You could check to see if you have the Gorilla problem.  Unbolt one side of the rear fender, just two bolts.  You can unbolt either the fender or the whole strut which might be a little easier.  If it springs distinctly out of place you've got pent up stress in the fender causing a frame harmonic at speed.  Gorilla valiantly foudn this problem and solved it by drilling new holes and re-bolting the fender and now he's smooth as silk.  Well, he was always smooth but now the bike is too ;)

If neither of those helps, get to the dealer.  A fresh pair of eyes can't hurt.  My bike is dead solid to 80mph+ so there's no inherent design flaw.  The frame should be more than stable enough for all the engine can give.

Scott

gashousegorilla

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Re: My Weeble's Wobble
« Reply #34 on: August 23, 2011, 01:56:06 AM »
 :D :D :D.....Or 60 grit sand paper more like it. :D :D ;)
 Just to add what Scotty has said about the tail section. Do ensure that the notch on the front of the rear fender is fully seated in the rubber bush that is below and behind the seat. It's not easy to see, Try looking from the under side of the fender. I think I posted a pic of it in your last post.   THIS IS A MUST !  If it is not seated the entire tail ..fender..and both fender stays will wag. It will get worse as speed increases, and more air is rammed under that high set fender. The faster you go, the more the tail wags, then so does the bike.
   I've tested it by removing the entire tail. running the bike to around 80-85 mph, with the higher tire pressures stamped on the plate. The bike was rock solid..... Reinstalled the tail , with the fender seated correctly, still with the higher tire pressures.  It was better, but like yours bittercrick....not like it should be. That's when we dropped the tire pressures, and it worked. Sort of sounds like yours?
 I would also check your swing arm pivot bolt that it is torqued correctly. You may also want to add some washers , to fill that extra side to side play at the shock mounts. Upper and lower. The idea is to get rid of any excess sway or wag in the rear, that will resonate up the frame, and upset the stability. It worked for me. also, Spin your wheels, do the rims look like they are true and round? Any excess hop or run out?  Fork oil  level the same in both Legs?   Mine wasn't.  Could be one thing...could be a few things adding up?  Like is was said earlier. It  should have been test ridden.


An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.

PAndy

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Re: My Weeble's Wobble
« Reply #35 on: August 23, 2011, 09:57:25 PM »
I've been dealing with a 65+ mph wobble as well that is quite frustrating, something always seems wrong with this bike.

So, I tried to loosen the front axle cinch bolt and bounce it a few times, only to find that the bolt breaks before I can re-tighten it enough to actually pinch the front axle.  I've broken 3 bolts already.  All the bolts were non-SS so they should be pretty strong, I'm trying to track down a grade 8 bolt but this seems pretty unnecessary, at least based on how easy it was to pinch the axle with all my other motorcycles.

If it was always loose this would definitely give me stability issues, I'm just amazed that the fork was made stronger than the bolt intended to pinch it.

Anyone have this issue as well?

drbvac

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Re: My Weeble's Wobble
« Reply #36 on: August 24, 2011, 12:16:29 AM »
I am amazed that any of the bolts would break before being torqued to the appropriate amount. Sometimes if pinched and then over tightened the stresses put on the forks actually twist them.

High speed wobbles are usually due to the fender problem - and/or tire pressures and as a last resort the engine mounts themselves as stated before.

And - these are not really high speed ( 70mph to 150 mph road rockets) bikes. My ride on mower shakes really badly at 40mph
Dr B

P. Schraub

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Re: My Weeble's Wobble
« Reply #37 on: August 24, 2011, 12:56:09 AM »
Hey Guys,
      Just a thought, did you have your wheels balanced ?

PAndy

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Re: My Weeble's Wobble
« Reply #38 on: August 24, 2011, 02:21:38 AM »
I loosened the pinch and bounced it a few times, then I tightened until it started to snug, then tightened 1/2 and eventually 1/4 turn at a time, at no point did it actually pinch the front axle, even as I tightened 1/4 turn until the bolt broke. 3 times

Arizoni

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Re: My Weeble's Wobble
« Reply #39 on: August 24, 2011, 04:57:55 AM »
Some thoughts on breaking the bolt:

The pinch bolt on my G5 has a 6mm thread.

My recommended torque for a bolt this size is 8 Ft/Lbs of torque if the threads are dry.  (This amount of torque will break a SAE Grade 2 bolt and should be used with either a SAE grade 5 or 8 (or its metric equivalent) (ref SAE J429)

The minor diameter of this bolt is .200".  When this is combined with a Grade 5 bolt (85KSI Yield) it should be capable of creating a load of 2670 pounds before it yields.  It should be capable of withstanding a force of 3770 pound before breaking.

A torque of 8 Ft/Lbs applied to a 6mm bolt with dry threads create a clamping force of  2000 pounds leaving a surplus of 670 pounds before it yields.

I can't help but think that a 2000 pound load should be enough to tighten the pinch enough to tighten on the axle.  If it is not, then try a Grade 8 bolt and nut (or its metric equivalent).

 
Jim
2011 G5 Deluxe
1999 Miata 10th Anniversary

PAndy

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Re: My Weeble's Wobble
« Reply #40 on: August 24, 2011, 07:11:43 AM »
I'm just going to the dealer, it's still under warranty and there's no reason that I shouldn't be able to pinch the axle before these bolts break.  I don't want to throw a grade 8 in and end up breaking the mount itself.

bittercrick

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Re: My Weeble's Wobble
« Reply #41 on: August 24, 2011, 11:12:54 AM »
Good thinking Pandy.We shouldn't have to work this hard to make a brand new bike rideable.However it's not the dealers fault either other than it's his responsability as having sold the thing.I know why some dealers drop the RE line after a year or two they get tired of fighting problems that should never have left the factory. My 2c    bittercrick
bikes Triumph 06 T100 - 01 Triumph Adventurer - RE C-5 chrome -78 Honda GL1000-83 Honda CB1100F

gashousegorilla

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Re: My Weeble's Wobble
« Reply #42 on: August 24, 2011, 01:31:57 PM »
 I would think ,if you snapped three bolts trying to pinch down on the axle. Something is not machined correctly. Maybe the axle is undersized where it slides through the lower leg?  Is the hole in the lower leg over bored? Not enough space in the slot?
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.

barenekd

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Re: My Weeble's Wobble
« Reply #43 on: August 24, 2011, 04:19:16 PM »
Quote
o, I tried to loosen the front axle cinch bolt and bounce it a few times, only to find that the bolt breaks before I can re-tighten it enough to actually pinch the front axle.  I've broken 3 bolts already.  

Try Allen headed cap screws. they are generally stronger than hardware store bolts.
While you are doing the tightening, have you checked to see if the gap in the fork leg that the bolt squeezes together is closing? If it is, then no bolt is going to squeeze the metal tighter.
But if you're tightening down that much, either your axle is too small, or the hole is too big.
Some minor machining error at the factory, it would strike me. Is your bike still under warranty? Have the dealer figure out which one is wrong and get a newbie. Or if you can get the specs from RE, and have the mikes to measure it with, do it yourself. As an interim, see if you can find some 1 or 2 thou shim material to wrap the axle with.
Bare

« Last Edit: August 24, 2011, 04:24:52 PM by barenekd »
2013 Moto Guzzi V7 Racer
2011 Black Classic G5 (RIP)
I refuse to tiptoe through life only to arrive safely at death
http://www.controllineplans.com

PAndy

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Re: My Weeble's Wobble
« Reply #44 on: August 24, 2011, 07:47:20 PM »
@gashouse;  My thought's exactly, there is no reason I should be able to snap a bolt while at the same time being able to push the axle in and out with my bare hands.  Something down there is the wrong size, and since it's under warranty it's not my problem.  Just glad I can't ride for a few weeks anyway while it's getting taken care of.

@Bare; If I didn't have warranty I would have already torn out some old .001 shims and wrapped them in there, figure if I get all these issues fixed correctly in the beginning, by the time the warranty runs out I'll hopefully have a decent motorcycle.