Carb stud washers

[Phil C]

May be a stupid question: my Concentric carb is bolted on with split/spring washers. Is that right, or should they be plain washers? Or doesn't it matter?  I'm conscious of the need not to tighten too much in case of distortion.  Phil.

[hoogerbooger]

The Amal site says use nyloc nuts  on Mk1 concentric ( see link) However when I eventually sourced them I found I didn't have enough space to squeeze them in onto the stud on the tickler side.....as the nyloc nuts are deeper. Depends a bit on the thickness of the carb spacer. Originally I'm told they would have been fitted with standard nuts & spring washers..... which is what I now have. See link and comment on tightening spring washers.

http://amalcarb.co.uk/installing-amal-carburetters


( I also have a 1965 B40F.   The carb stud nuts on mine are 5/16 CEI/BSC nyloc nuts....took a while to find some. ended up buying from Nooky's Nuts)

[Dean Southall]

I have always used spring washers. Tighten so the spring has just gone flat so you don't overtighten and warp the flange.

[A10 JWO]

Draganfly don't list a washer at all for carbs but do for most other parts of the bike. Most of the bikes I have had have been fitted with spring washers.

[AdrianS]

Don't think it matters too much If plain or spring washers are used. I've never had one come loose with plain washers. The important point that has already been mentioned is that the nuts are not over tightened so as to cause the carb flange to distort

[ducati2242]

 I bought a box of mixed imperial stainless steel star washers and use them for everything . They are slimmer than spring washers and I find them easier to use .

[Bess]

Hi,
    Plain washer is fine.

Spring washers are normally flat by the time the nut is fully torqued. At this time it is equivalent to a solid flat washer, and its locking ability is nonexistent. They have been found to actually loosen the bolt under vibration even faster than a joint with no washer. In summary, a lock-washer of this type is useless for locking.

Best wishes...

[AdrianS]

Interesting that you say a spring washer will rattle loose quicker than no washer! How does this compare with a star washer? Not just in relation to this thread but in general?

[Bess]

Hi,
      Main thing to consider is the materials you are trying to fix, these types are better on softer materials.

Star washers are used for electrical grounding, sometimes used for spring action but mostly for locking action by biting into the mating surface. Although this washer does provide some locking action, it damages the mating surfaces. These scratches can cause crack formation in highly stressed fasteners, in mating parts, or both, as well as increased corrosion susceptibility. I use the internal serrated type hoping to keep the corrosion at bay.

Spring washer (split lock) loosening issue published here along with other types:

https://www.fastenerandfixing.com/media/31891/ffm-technical-ffm150520.pdf

(Stop loosening of fasteners  https://www.fastenerandfixing.com/ )

Their summary, sums it up 

Best wishes..

[AdrianS]

Thanks. Interesting reading.

[MICKREEVES]

I have always used just plain washers, never a problem.
Thats how they were made.
Mick

[ducati2242]

I have always used just plain washers, never a problem.
Thats how they were made.
Mick

No they didnt come with a flat washer . They came with Came with a star washer .