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Hello guys!
I am nearing the finish of my 1970 TR6R bobber project.

i am at the stage of mounting the AMAL carb, which was removed from this engine and rebuilt. When fitting, it, I found the carb would only fit part way on to the mounting studs.

It has been some time since I removed it, but the only thing i can think of is that there was a fibre spacer on there.

The first two photos show the gap with the manifold mounted to the engine.

The next wo shots show the fitment of the carb with a spare manifold I had sitting around.

I wanted to use only an 'o' ring to mount the carb and not gaskets. Any ideas or suggestions?

I also added a photo of how the bike looks now.

Thanks again for your help and suggestions.
regards
John[Linked Image][Linked Image]

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parts book show paper gasket , nominal thickness
and a # 4918 , insulating washer @ 1/8 " thick
( youre missing the insulating block )

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Thank you Quinten. I plan on using the later method of using a "fat" o-ring in place of the original set up, however the gap still looks too large for tightening the carb and compressing the o-ring.
Regards
John

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the "later method" is standard for 1970 .
the 1970 tr6 parts book
shows the fatter o-ring ... and the phenolic spacer
( spacer on manifold page , o-ring on carburetor page )
... and rubber spacers and cupped washers on the stud mounts

... if the studs bottom out on the carburetor ? The phenolic spacer on the flange must be retained .

1971 shows the same parts numbers for studs and manifold , but no phenolic spacer .
I wonder if they changed the manifold thickness stud lenght but not the part number ?
.

Last edited by quinten; 09/26/21 3:13 pm.
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Take the studs out and run a 5/16 BSF die down them a bit further and cut them off a bit.
Use a thick o-ring.
OR just get a couple of 5/16 BSF allen bolts and drill the heads, cut them to size and wire them.
OR run a 5/16 bsc die down the larger studs and cut that end off a bit.

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I guess you don't want to use the spare manifold that the carb fits on for some reason.
I had a chromed carb with a similar issue. Could it be the chrome?
I think what I did was filed the studs a tiny bit.


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It looks like the studs in the manifold you want to use are a much larger diameter where they are not threaded than where they are threaded whereas the spare manifold has the same diameter where it's not threaded as where it is threaded. Not to mention that the spare has many more threads than the ones on the manifold of choice. Could it be that the holes in the carb are not quite large enough for the extra thickness of the studs beyond the shorter than usual threads on the manifold of choice? Reducing the diameter of the extra thick studs and adding 5 or 6 more threads might be all that's needed if slightly enlarging the holes in the carb isn't on? And cutting off the ends of the studs you don't need. I think I would just fit the insulating spacer if you have one that fits those extra diameter studs. Works for me.

Cheers, Wilf

Last edited by Wilfred; 10/06/21 8:12 am.

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