Author Topic: Carb spacer  (Read 242 times)

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Phil C

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Carb spacer
« on: 12 January, 2019, 10:35:18 »
Just looking at the tufnol spacer off my 1965 B40F. It is a bit warped. If I put the edge of a 6" rule across its width, there is a bit of daylight at the sides (near the holes.) Obviously if I turn the spacer over then the daylight is in towards the middle. Checking the size of the gap with feelers, it's only about six thou (looks a lot more than that - before I put feelers to it I guessed ten to fifteen thou.) Does it matter?

When I took it off there was a gasket both sides, but I see Rupert Ratio advises engine side only.

By the way, the spacer is 1/4" thick. Is that the usual thickness?

Phil.

A10 JWO

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Re: Carb spacer
« Reply #1 on: 12 January, 2019, 11:04:23 »
I would have thought that an engine jointing compound would take up the slack. If you need a new one try Hitchcock M/C's, great service.

ducati2242

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Re: Carb spacer
« Reply #2 on: 12 January, 2019, 11:31:22 »
I would just flat it off on a flat surface and a sheet of emery .Its more for reducing heat transfer than spacing . The one on my goldstar is from a bultaco trials bike .
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berniej

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Re: Carb spacer
« Reply #3 on: 12 January, 2019, 11:54:19 »
Yes, just flat it down to reduce the chance of air leaks.

The rubber 'O' ring in the carb flange provides the seal on that side so no gasket required.

However.... if the spacer is warped it's worth checking the flatness of the face on the head and on the carb - any distortion there may be the cause of the distorted spacer.

Carb flanges distort very easily if over-tightened and if that's the case then flattening out the spacer only may introduce a leak!

I doubt the head face is warped but you may need to also remove the 'O' ring and flat the face of the carb flange.
Worth fitting a new 'O' ring too - they should be included in a carb service gasket set.

Cheers,
Bernie
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JulianS

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Re: Carb spacer
« Reply #4 on: 12 January, 2019, 12:08:18 »
If you keep the original spacer you need to flat both sides, the O ring is thin and not really up to sealing a warped spacer.

Personally I would get a new one. Air leaks at that joint lead to poor carburation.

Phil C

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Re: Carb spacer
« Reply #5 on: 12 January, 2019, 17:25:05 »
Looking at new ones on Hitchcocks' website, I see there are various sizes of spacer, including 26mm and 28 mm, which I guess refers to the hole diameter. My carb is a Concentric 626, which suggests to me I should be getting a 26mm spacer? The spacer I've taken off has a hole of about 28mm. Which is right? And does it make any difference?   Phil.

A10 JWO

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Re: Carb spacer
« Reply #6 on: 12 January, 2019, 17:33:20 »
Ring Hitchcocks on Monday, Alan or one of the others are Amal experts.

Bees

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Re: Carb spacer
« Reply #7 on: 12 January, 2019, 18:08:53 »
I'd replace it if you can get a new one if you can.

Its essential to get an airtight seal and if you've re-used a suspect part then there will always be doubt if the engine doesn't run right when you get it going.

Personally i would also use compound on all joints gives me peace of mind.

Wellseal is my preferred brand.

Phil C

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Re: Carb spacer
« Reply #8 on: 19 January, 2019, 10:59:16 »
Took a few calls to find a spacer 1/4" thick. Eventually got one from Surrey Cycles - great service, arrived by post next day.

DEAN SOUTHALL

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Re: Carb spacer
« Reply #9 on: 19 January, 2019, 17:25:11 »
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