Fuel Leak at Carb Bowl - SF1

JoePurple73

JoePurple73

Junior member
Location
Gatineau Quebec (Eastern Canada)
'73 SF1 - I have a fuel leak at the joint between the bowl & carb body on the R.H. carb. I managed to seal it with a sealant that was supposedly made for that & it held all of last summer, but it started leaking again today. The original gasket o-ring is still there, but hardened.

Any suggestions as what I can use? Is silicone any good for that?

Thanks

Joe
 
JoePurple73 said:
Didn't know they were still available. I'll contact Wolfgang. Thanks.
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Get a few, Joe. Doesn't hurt to change them every few years, just as a precaution.

Btw, they're nothing that special: standard O-ring, 70 x 1.78, if I remember correctly :unsure:. If not, someone will be along to correct me ...:)
 
Ventodue said:
Get a few, Joe. Doesn't hurt to change them every few years, just as a precaution.

Btw, they're nothing that special: standard O-ring, 70 x 1.78, if I remember correctly :unsure:. If not, someone will be along to correct me ...:)
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74 x 1.8 is what I have.

We'll have to get used to generic parts on our old clonkers, just like a 1912 Humber.

Paul
 
The cord section is more important, just big enough to create the seal without putting strain on the bodies. You can usually stretch or compress the overall length a couple of mm to suit, or even cut a few mm out and rejoin with superglue.
 
JoePurple73 said:
Paul - dumb question: that 74mm, is that inside or outside? (I haven't yet had the time to pull the carb)

Thanks,

Joe
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Normally ...

If there's just one dimension, it's the internal. But that's 'normally' and not 'always' ..

As Andy says, the cross section dimension is the most important. And 1.78mm it is. Sounds bizarre, I know. But that's the consequence of history : 1.78mm = 1/16 inch, see ... ;). And much in hydraulics is still imperial (including brake master cylinders).

And thanks, Paul, for your 74. Guess it's the 'same/same', if it's the external dimension. (S'pose I could/should go and measure one, but I can't be ars.. :giggle:)
 
The O ring you need is a dash 039 which is an imperial size O ring. The link below will take you the size you need.

www.mcmaster.com

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.
www.mcmaster.com www.mcmaster.com
 
Great stuff - Thanks!
I pulled the carb this morning & measured the ring, and it is effectively 74mm x 1.8mm. It isn't hardened, just squashed. Guess it got caught between the body & bowl at some time. Off to my Bearing & Seal store this afternoon.

BTW - seriously thinking about selling it sometime soon - arthritis in both hands made the last ride painful for a full day afterwards. Guess I'm getting too old for this. Can still handle the Bonnie OK - it's a "wuss" compared to the Laverda. Wife says she'll miss it (had it painted purple just for her), but since we're both not getting any younger, I guess it's time to reconsider our pastimes.
 
JoePurple73 said:
Great stuff - Thanks!
I pulled the carb this morning & measured the ring, and it is effectively 74mm x 1.8mm. It isn't hardened, just squashed. Guess it got caught between the body & bowl at some time. Off to my Bearing & Seal store this afternoon.

BTW - seriously thinking about selling it sometime soon - arthritis in both hands made the last ride painful for a full day afterwards. Guess I'm getting too old for this. Can still handle the Bonnie OK - it's a "wuss" compared to the Laverda. Wife says she'll miss it (had it painted purple just for her), but since we're both not getting any younger, I guess it's time to reconsider our pastimes.
Click to expand...
I've put a DAM kit to lift the clutch and the lightest slide springs Dell'Orto offer. My old arthritic hands are coping.
500 miles these last 2 days.
Paul
 
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