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1Back to top Go down   Vacum Caps, Surging and Rough Idle Empty Vacum Caps, Surging and Rough Idle Sun Apr 23, 2017 8:02 am

shintaro

shintaro
active member
active member
Hi, I have a '85 R100rs. Lately there has been an issue with the idle being lumpy and faltering particularly when cold. I noticed there was a vacuum cap missing just behind the back of the fairing. Putting my finger over it smoothed out the idle. This seems to work better when the engine is warm. So i got some caps from Auto-One and went for a ride (120km) bike went well, as i got close to home it started to surge and  feel like it was missing. When i got off the bike the cap was missing and the idle was "lumpy". Putting my finger over it smooths it out again. Today I ride the bike after putting another cap on. As I accelerate I feel something hit the inside of my knee, the bike starts to surge again. I pull over and the vacuum cap was again missing, Im pretty sure thats what hit my knee. What would cause the vacuum cap to be blown off.?  The others remain in place. Thanks.

    

Laitch

Laitch
Life time member
Life time member
shintaro wrote: What would cause the vacuum cap to be blown off.? 
A fit that is too loose would contribute to that.


__________________________________________________
1995 K75 90,000 miles
    

3Back to top Go down   Vacum Caps, Surging and Rough Idle Empty Re: Vacum Caps, Surging and Rough Idle Sun Apr 23, 2017 12:26 pm

BobT

BobT
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Using the wrong sort of glue?

    

4Back to top Go down   Vacum Caps, Surging and Rough Idle Empty Re: Vacum Caps, Surging and Rough Idle Sun Apr 23, 2017 12:54 pm

brickrider2

brickrider2
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"Using the wrong sort of glue?"
Vacum Caps, Surging and Rough Idle 44271

    

BobT

BobT
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Here in France we would tend not to use those little black plastic things that fit over the holes, but after 2,000 years of wine production we would probably develop some very small wine corks that fit nice and tight inside the tubes. Vacum Caps, Surging and Rough Idle 8157

    

blaKey

avatar
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I have seen caps made from different materials...some are a vinyl type material and others are rubber-like. The rubber type material would hold on better than the vinyl type.

The fit should be fairly tight...but this is something that you now already know!


__________________________________________________
Neil
K100RS 1986 RED!

Dress for the ride and the potential slide.
    

Inge K.

Inge K.
VIP
VIP
brickrider2 wrote:"Using the wrong sort of glue?"
Vacum Caps, Surging and Rough Idle 44271


Only vacuum glue can be used.


__________________________________________________
Inge K.
K100RS -86. (first owner), K1100LTSE -94.
    

Rick G

Rick G
admin
admin
Inge K. wrote:
brickrider2 wrote:"Using the wrong sort of glue?"
Vacum Caps, Surging and Rough Idle 44271


Only vacuum glue can be used.
I suppose that any sucker will know where to get some.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

shintaro

shintaro
active member
active member
Yes, I tried both Rubber and a Plastic type one also. 4mm size as mentioned in a thread here. My thought was to put a drop of silicone on  and leave overnight to make it stay. I thought maybe there was something else at play here as Ive had the bike for nearly 2 yrs and this has not happened before. Thanks.

    

10Back to top Go down   Vacum Caps, Surging and Rough Idle Empty Re: Vacum Caps, Surging and Rough Idle Mon Apr 24, 2017 10:27 am

Rick G

Rick G
admin
admin
About the only thing that would make them come off is a backfire but you would hear that. I would say that they probably were a marginal fit in the first place. maybe silicone as suggested or rubber caps which will grip better as against plastic which would tend to slip off.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

11Back to top Go down   Vacum Caps, Surging and Rough Idle Empty Re: Vacum Caps, Surging and Rough Idle Mon Apr 24, 2017 1:19 pm

Dai

Dai
Life time member
Life time member
Once they start to rot, then they'll come off really easily. Fall off, in fact. I made a set from 3mm id silicon tube with the ends blocked off.






Okay, if you really want to know, I used 8mm long no.10 stainless steel self-tappers to block the ends off. Go on - you can laugh now Vacum Caps, Surging and Rough Idle 167893


__________________________________________________
1983 K100 naked upgraded to K100LT spec after spending time as an RS and an RT
1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

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