bob tatt
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| posted on 19/4/10 at 07:32 PM |
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strange vibration at speed help.....
i have a very strange vibration when going over 90 but nothing below that speed no whining or noise at all. It is definetly on the rear end some where
, so far i have checked and retightened all the bolts on the drive shaft
checked for play in wheel bearings and in the cv joints.
None of this made any difference so tonight i pulled the diff, checked the out put shafts no excess play how ever it is throwing a tiny amonut of oil
from where the drive shafts bolt on to the out put shafts.
Removed the rear diff cover no shards only some very small filings like every other diff ive ever worked on.
I then removed the output shafts to check the seals all seems ok there.
anyone come across this before or any ideas of anything else i can check i have a spare diff so im going to give this a go. I d just like to get it
sorted so any help greatfully received.
many thanks rob
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bigrich
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| posted on 19/4/10 at 07:39 PM |
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does the vibration build from 90 and get worse or does it clear, if it keeps bulding i would guess at the propshaft being out of align or balance. if
it clears try wheel balance.
had a similar problem on my old car vibration used to build from 100 upwards and used to force you to shut off.
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roadrunner
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| posted on 19/4/10 at 07:42 PM |
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Is that 90km/h
Have the wheels been balanced or a weight fallen off.
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bob tatt
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| posted on 19/4/10 at 07:54 PM |
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the vibration seems to stay constant all the way upto when i lift then the vibration gets a lot better then vanishes. its really foxing me i was
expecting to remove the diff and find some play somewhere going to give the spare diff a go and see what happens. Ill run it with the road wheels on
as it only seems to happen on track but i tend to keep the speed down on the road anyway so probably never noticed it.
any more suggestions for me to check.
cheere rob
and no its not 90 in silly euro money.
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speedyxjs
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| posted on 19/4/10 at 07:59 PM |
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Thats sounds suspiscously like the prop if it gets better when you lift off. If it were the wheel, lifting off wouldnt make a difference.
Have you looked at the prop to see if a weight has come off?
How long can i resist the temptation to drop a V8 in?
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bob tatt
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| posted on 19/4/10 at 08:07 PM |
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not checked the prop yet i thought all the props weights were welded on anyway. if the weight has come off will i need to get it re balanced and if so
where near leeds does that.
rob
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vyperstrype
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| posted on 19/4/10 at 08:10 PM |
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vibration
Are the universal joints lined up correctly on the driveshafts?
Sometimes if the Driveshafts have been dismantled and not aligned, they can vibrate at speed. i.e., the splines on the C.V. Joints must be assembled
so both U.J's line up and run together.
Hope this helps.
Where there's a will, there's a death!!
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bob tatt
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| posted on 19/4/10 at 08:17 PM |
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never had the drive shafts apart and i removed this lot from a car so its not them, could the center bearing be worn and sending the vibration
backwards as the bike engine is so ridgid in the frame.
rob
mind you saying that so is the diff
[Edited on 19/4/10 by bob tatt]
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vyperstrype
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| posted on 19/4/10 at 08:33 PM |
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I suppose anything like centre bearings or UJ's are worth a check. Have you checked the prop' by twisting it one way with one hand on the
front, and the other hand on the rear, twisting the other way. Then see if there is any movement in the joints, or any clicking noises coming from the
prop.
cheers Eric.
Where there's a will, there's a death!!
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blakep82
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| posted on 19/4/10 at 08:44 PM |
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quote:
Originally posted by speedyxjs
Thats sounds suspiscously like the prop if it gets better when you lift off. If it were the wheel, lifting off wouldnt make a difference.
Have you looked at the prop to see if a weight has come off?
erm, how exactly? the relationship between wheels and prop speed is always the same, if the wheels are turning, the prop is turning. lifting off
won't make a difference to one and not the other really
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dlatch
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| posted on 19/4/10 at 10:12 PM |
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out of balance prop feels different to a wheel out of balance too.
prop gives the vibration symptom where as a wheel feels more like a wobble
from whats been described i would be suspecting the prop. definatley check that next
[Edited on 19/4/10 by dlatch]
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bob tatt
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| posted on 20/4/10 at 06:04 AM |
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it looks like the props coming off this evening then, found a place in leeds that does kits and race cars even has a pic of a mnr on there web site
dont know if they do theres as well.
i hope it is the out of balance prop and not the diff its a 3.14
thanks so far will keep people upto date as and when i find anything might make it easier for someone else in the future.
rob
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speedyxjs
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| posted on 20/4/10 at 07:14 AM |
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quote:
Originally posted by blakep82
quote:
Originally posted by speedyxjs
Thats sounds suspiscously like the prop if it gets better when you lift off. If it were the wheel, lifting off wouldnt make a difference.
Have you looked at the prop to see if a weight has come off?
erm, how exactly? the relationship between wheels and prop speed is always the same, if the wheels are turning, the prop is turning. lifting off
won't make a difference to one and not the other really
As the prop is transferring torque, while the engine is under load, the vibration would be worse that when you lift off and the torque is removed from
the prop.
A wheel is rotating at a constant speed and has a much reduced torque due to the differential.
How long can i resist the temptation to drop a V8 in?
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