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51Back to top Go down    Re: Vibration Problem - K75RT on Sat Dec 09, 2017 6:57 am

Andrew2


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I see what you mean now. So the prongs on mine are too long causing the muffler sit at the wrong angle like what they are talking about in this thread.
https://www.motobrick.com/index.php?topic=8521.0

They're saying to grind 5mm off the the longer prongs. Do you know how long the prongs are for the shorter version?. Just to be sure that I'm not cutting down the already short version .

Cheers
Andrew

    

52Back to top Go down    Re: Vibration Problem - K75RT on Sat Dec 09, 2017 7:36 am

Inge K.

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I don't have the correct length at hand.

To find out what you have, the five last decimals of the part number
is stamped into the part.

W/o Z-brackets (long) : 1 454 981.
With Z-brackets (short) : 1 454 982.


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53Back to top Go down    Re: Vibration Problem - K75RT on Sat Dec 09, 2017 11:11 am

charlie99

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looks like the with z bracket types are about 2-3 mm higher than the rubber insulator
which would give clearance for that insulator

wouldn't be hard to pull it off ... now its loosened ...and inspect ?


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54Back to top Go down    Re: Vibration Problem - K75RT on Sat Dec 09, 2017 3:39 pm

MartinW

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When I got mine only one type was available. Just tried Motor Works and it doesn't seem to be listed. I then tried Motobins and the site would not come up, showed up as a502 Bad Gateway. When the rubber separated on mine there were no symptoms aside for the fact that if you grabbed the muffler you could wobble it around.
Regards Martin.

    

55Back to top Go down    Re: Vibration Problem - K75RT on Sat Dec 09, 2017 5:37 pm

Andrew2

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@Inge K. wrote:I don't have the correct length at hand.

To find out what you have, the five last decimals of the part number
is stamped into the part.

W/o Z-brackets (long) : 1 454 981.
With Z-brackets (short) : 1 454 982.

I was trying to look at the numbers last night but couldn't quite make them out. I'll test it today then pull it all apart and see what the numbers are.


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56Back to top Go down    Re: Vibration Problem - K75RT on Sat Dec 09, 2017 5:38 pm

Andrew2

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@charlie99 wrote:looks like the with z bracket types are about 2-3 mm higher than the rubber insulator
which would give clearance for that insulator

wouldn't be hard to pull it off ... now its loosened ...and inspect ?

Thanks Charlie. I'll go to a mates place and see if I can compare to one of his them rip into it.


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57Back to top Go down    Re: Vibration Problem - K75RT on Sat Dec 09, 2017 5:41 pm

Andrew2

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@MartinW wrote:When I got mine only one type was available. Just tried Motor Works and it doesn't seem to be listed. I then tried Motobins and the site would not come up, showed up as a502 Bad Gateway. When the rubber separated on mine there were no symptoms aside for the fact that if you grabbed the muffler you could wobble it around.
Regards Martin.

Hi Martin,
I had the same result when I tried to get onto the Motobins site last night. Musn't have paid their bill Very Happy. I'm wondering if the rubber may have gone hard being 30 years old and not having a lot of use. How hard is the rubber. It feels like rock to me when I prod it with a screw driver?.


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58Back to top Go down    Re: Vibration Problem - K75RT on Sat Dec 09, 2017 6:51 pm

Andrew2

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@MartinW wrote:When I got mine only one type was available. Just tried Motor Works and it doesn't seem to be listed. I then tried Motobins and the site would not come up, showed up as a502 Bad Gateway. When the rubber separated on mine there were no symptoms aside for the fact that if you grabbed the muffler you could wobble it around.
Regards Martin.
Hey Martin, what is the part actually called. I'm trying to find it and some rubber fork boots on Beemer Boneyard and be buggered if I can find either.


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59Back to top Go down    Re: Vibration Problem - K75RT on Sat Dec 09, 2017 7:11 pm

MartinW

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they are called Exhaust silencer mount bracket and Motorworks have a second hand one for sale for the price of one kidney or 16 UK pounds plus freight. When mine split and separated as a temporary solution I drilled and tapped a 6mm hole right through it and added a 6mm nyloc nut. I also bogged it in place with silicone sealer I did not experience any problems with this set up. However on reflection if I hadn't managed to find a new one, I could have probably made it a bit more flexible by drilling a bigger hole in the centre metal bracket and filling with silicone and then allowing it to dry.
Regards Martin.

    

60Back to top Go down    Re: Vibration Problem - K75RT on Sat Dec 09, 2017 7:58 pm

MartinW

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Andrew if you get stuck, could possibly be a temporary or even a permanent fix.
Regards Martin.

    

61Back to top Go down    Re: Vibration Problem - K75RT on Sun Dec 10, 2017 1:52 am

Andrew2

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So I got a spare off a mate and he promptly deleted the numbers on his wire wheel . So here's a photo of his on the left and mine on the right. Identical. His came off a bike with the Z racks too.


Are these the short or long ones because I'm not sure as the numbers on mine read like this.




Cheers
Andrew


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62Back to top Go down    Re: Vibration Problem - K75RT on Sun Dec 10, 2017 1:54 am

Andrew2

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@MartinW wrote:Andrew if you get stuck, could possibly be a temporary or even a permanent fix.
Regards Martin.

Good stuff Martin. I've tested mine again and rubber seems ok. I might need to grind some metal off mine yet but just need to know if it is the long or short one before I get stuck into it.


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63Back to top Go down    Re: Vibration Problem - K75RT on Sun Dec 10, 2017 11:00 am

Inge K.

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@Andrew2 wrote: Are these the short or long ones because I'm not sure as the numbers on mine read like this.


Looks like someone being in a hurry when the tooling was set up,
last decimal in first row should have been 1 or 2 and not 4.

Anyway I've been out on the bike and made some measurements,
the length of the distance piece is 15 mm....this is only the tube
the steel plate is not included....this holder is to be used together
with the Z-bracket.


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64Back to top Go down    Re: Vibration Problem - K75RT on Sun Dec 10, 2017 3:51 pm

Andrew2

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@Inge K. wrote:
@Andrew2 wrote: Are these the short or long ones because I'm not sure as the numbers on mine read like this.


Looks like someone being in a hurry when the tooling was set up,
last decimal in first row should have been 1 or 2 and not 4.

Anyway I've been out on the bike and made some measurements,
the length of the distance piece is 15 mm....this is only the tube
the steel plate is not included....this holder is to be used together
with the Z-bracket.

Haha. Maybe it was a Friday afternoon. Thanks for that measurement I'll check it when i get home from work and get back to you


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65Back to top Go down    Re: Vibration Problem - K75RT on Sun Dec 10, 2017 8:15 pm

robmack

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If it was Moto Guzzi, that could have happened on any day after lunchtime.


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1987 K75 @k75retro.blogspot.ca
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66Back to top Go down    Re: Vibration Problem - K75RT on Sun Dec 10, 2017 8:50 pm

Andrew2

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Very Happyhaha i see you have also had dealings with Guzzi. I doubt they would have put any numbers on at all Very Happy


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67Back to top Go down    Re: Vibration Problem - K75RT on Mon Dec 11, 2017 12:35 am

Andrew2

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15 mm so I guess it is the right one.


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68Back to top Go down    Re: Vibration Problem - K75RT on Mon Dec 11, 2017 1:38 am

Andrew2

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I'm going to re-torque the header bolts and do a throttle body sync. The heat shield rattles a little so I'll check that out although I can't see that being the problem.


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69Back to top Go down    Re: Vibration Problem - K75RT on Mon Dec 11, 2017 3:49 am

Inge K.

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@Andrew2 wrote:15 mm so I guess it is the right one.


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70Back to top Go down    Re: Vibration Problem - K75RT on Mon Dec 11, 2017 4:31 am

MartinW

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My OEM bracket which I have only just replaced recently, measures 15mm. My new one which was probably the last one from Motor Works UK also measures 15mm. Came new with panniers.
Regards Martin.



Last edited by MartinW on Mon Dec 11, 2017 4:32 am; edited 1 time in total (Reason for editing : Addition)

    

71Back to top Go down    Re: Vibration Problem - K75RT on Mon Dec 11, 2017 6:11 am

Andrew2

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@MartinW wrote:My OEM bracket which I have only just replaced recently, measures 15mm. My new one which was probably the last one from Motor Works UK also measures 15mm. Came new with panniers.
Regards Martin.
Bargain Martin.....buy 1 bracket and get new panniers thrown in . Or did it cost you a kidney Very Happy.


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72Back to top Go down    Re: Vibration Problem - K75RT on Mon Dec 11, 2017 6:17 am

MartinW

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Andrew just my sanity.
Regards Martin.

    

73Back to top Go down    Re: Vibration Problem - K75RT on Mon Dec 11, 2017 6:44 am

charlie99

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@Andrew2 wrote:I'm going to re-torque the header bolts and do a throttle body sync. The heat shield rattles a little so I'll check that out although I can't see that being the problem.



the rattling heat shield is pretty common on old stuff ...don't sweat it ...

good luck with the syncing and re-torque ...although the syncing is all about balance at low throttle openings... try and get the silencer in line with the hanger as you tighten up ...don't forget the shim around the exhaust to silencer ...look to see if there is movement - slight rotation that might be advantageous to it all coming in line

perhaps a measure of the ignition cables ..could show up some erratic values causing vibration issues as well

there are many posts about plugs , cables and measurements throughout the forum ...but k 75 hmmm a different beast ...with many similar principles

good luck


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

74Back to top Go down    Re: Vibration Problem - K75RT on Sat Dec 16, 2017 11:20 pm

Andrew2

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I checked all the engine mounts today and the front right was no where near spec. When I undid the crash bars nut the engine bolt came with it. Probably only a bit past hand tight. Even so 30 ft/lbs isn't a lot of torque.
Everywhere I look I'm finding old perished rubber so I'm wondering if the engine mounts rubber might need replacing. Is it an easy job or does the motor need to come out.


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75Back to top Go down    Re: Vibration Problem - K75RT on Sun Dec 17, 2017 2:12 am

Andrew2

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Soooo, I backed off all the clamp bolt joining the headers to the mufller and then did the muffler up. I then went back and tightened the header/muffler clamps. Put the footrest hangers back on at 11ft/lb as per the manual ( doesn't seem tight enough though ) and threw the mrs on the back on the centrestand. All vibes in the left footrest have gone but still some vibes in the right foot peg. Anyhow I thought I would loosen the right foot peg and re-torque. Good Lord, I could budge the bolts so out with the long bar. Either they have been over tightened or corroded in from 30 years of not being touched. Torqued to 11ft/lb and now waiting for the back seat tester to jump on and give an opinion. I'll be back.


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76Back to top Go down    Re: Vibration Problem - K75RT on Sun Dec 17, 2017 2:51 am

charlie99

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probably just dissimilar metals galling on those bolts

copper slip ...nickle slip etc offer an interference layer to the corrosion that forms over a long time

good to hear the left side vibration has changed ...and giving you hope for a resolution perhaps next might be the monkey nuts on the alternator ?


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

77Back to top Go down    Re: Vibration Problem - K75RT on Sun Dec 17, 2017 3:06 am

Andrew2

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No difference on the right peg after re-torquing the right foot rest hanger....but when I unbolted the Z rack at the foot rest hanger guess what. The vibration went away. So for some reason the vibration seems to be coming through the pannier rack.Go figure. The rack doesn't sit square where it connects to the hanger so tomorrow I'll loosen all the racks bolts off and try and square it up and maybe find some thin rubber to isolate the vibes a bit. It's been an interesting day .


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78Back to top Go down    Re: Vibration Problem - K75RT on Sun Dec 17, 2017 3:07 am

Andrew2

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@charlie99 wrote:probably just dissimilar metals galling on those bolts

copper slip ...nickle slip etc offer an interference layer to the corrosion that forms over a long time

good to hear the left side vibration has changed ...and giving you hope for a resolution perhaps next might be the monkey nuts on the alternator ?
I might check them as well. It looks like I'll be ordering a fair few rubbery bits over the next few months.


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79Back to top Go down    Re: Vibration Problem - K75RT on Sat Dec 23, 2017 3:20 am

Andrew2

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I thought I would just keep updates coming in case anyone else has the same problem in the future. I took the wife out for a test ride today and she confirmed the left footrest is pretty good now but the right is still vibrating a bit. Better than it was but not as good as the left. Half way through the ride I disconnected the 2 bolts holding the pannier rack to the footrest hanger and the continued on. The right foot peg now matched the left cheers.

The rack unbolted.


In the bolted position.


Seems like the plastic has distorted. So tomorrow I'll be bolting it back up with some rubber o rings between the rack and the hanger and I'll also be adding some thin rubber between the foot rest and the hanger just for the sake of it. I'll also relieve the bolts holding the rack on and see if it might realign itself a bit better. I'm still thinking a lot of it could be rubber parts that have gone hard over the years. Anyway some progress has been made and I'm confident the boss will be happy with it. I'll report back after the next couple of mods.

Cheers
Andrew


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80Back to top Go down    Re: Vibration Problem - K75RT on Sat Dec 23, 2017 4:19 am

charlie99

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good work Andrew

more likely resonance issues causing the right footpeg vibration

sometimes a little extra weight on the resonating part can help solve the issue

perhaps a bolt through the pannier bracket with a sold piece of metal behind ...something like the effect of the bar end weights has on handle bars

keep at it mate


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

81Back to top Go down    Re: Vibration Problem - K75RT on Sat Dec 23, 2017 4:22 am

Andrew2

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Good idea Charlie. It would have to be thin though to clear the swingarm. I'll look into it.

Cheers
Andrew


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82Back to top Go down    Re: Vibration Problem - K75RT on Sat Dec 23, 2017 4:51 am

charlie99

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maybe not near the swing arm ...divide the length of the whole piece ...then pick an odd distance either side of half ..then clamp the weight there or move to the place where the resonance stops or slows down ..whilst connected to the footpeg plate

that's my thought at least ...were trying to counter the resonance not enhance it


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'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

83Back to top Go down    Re: Vibration Problem - K75RT on Sat Dec 23, 2017 6:11 am

Andrew2

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I see what you mean. I'll give it a go and get back to you.


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