Pan screw

[Davelu88]

Anyone  know the best place to buy the carb bowl pan screws as on the usual sites they seem very expensive.  TIA

[Nurse Julie]

Do you mean the original carb bowl JIS screws Dave? If yes, I do a bowl and top kit.

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[Davelu88]

Cheers Julie , I will order them on your site

[Nurse Julie]

Cheers Julie , I will order them on your site

OK Dave. Thank you.

[Oddjob]

Aren't the bowl screws supposed to have spring washers as well Julie?

I also don't use the original Honda sizes when replacing these, they are too short and leave threads unused, over time these threads corrode until IF you try and use a longer screw it won't allow you to, I always retap the thread and in the case of the upper 8 screws I recommend using a 5 x 20mm screw instead of a 5 x 16mm, those extra 4mm of threads may not sound like much but they pull in better and stop the threads stripping out as there are more threads engaged.

Same with the bowl screws, they are too short, 4 x 12mm IIRC, I would recommend going longer, use a flat washer under the spring washer ( I'd advise these for the upper 8 as well) to stop it digging into the alloy of the bowl, a couple of the bowl screws will hit the body of the carb if you use too long a screw. Best advice would be to use a longer screw, measure and cut the screw when it would just be flat to the body, you don't want threads exposed to air as they corrode and when being removed will start to damage the threads as they pass through. The problem with cutting screws like these is that you can damage the threads as you cut, you don't always get the cut straight either. To avoid that use a flanged nut, thread it onto the screw and position it where you need to cut, use the side of the nut as a guide for the hacksaw, when cut the nut will clean the threads off and straighten them of any burring caused by the hacksaw. A run over with a file is also a good idea to get the surface flat.

Because I tend to cut them to suit and JIS are not normally stainless but BZP plated this means the part cut isn't now BZP, this can cause corrosion and rust, which is why unless I can source JIS stainless I prefer to use just stainless instead. Even the cut is corrosion resistant.

Just my experiences and thoughts, feel free to ignore. However look at how many members complain of stripped threads in carb bodies and you can see how they happen.

[Nurse Julie]

400/4's didn't have spring washers Ken. But, the kits I sell fit the 400/500/550. Having sold 218 kits on the forum, Facebook and other platforms with no complaints, I think they're just fine. More importantly, we fit them to all our own carbs as well, so I know they are fine. Most restorers are more concerned in the JIS dimple than anything else to be honest.

[Oddjob]

Not knocking the kit Julie, just asking why not supply the springs washers for the bowls if Honda fitted them, If not needed for the 400 then the buyer can just omit them. I also understand why you supply the lengths Honda fitted, as I said over time the threads corrode/get muck on and then a longer screw doesn't want to go down these threads and of course you can't know if the buyer has the taps required to clean them up.

As for the JIS thing, I find the actual opening in the screw isn't that different from a normal crosshead, it's shallower is all,  it's the actual screwdriver that makes the biggest difference, the very tip is ground off on a JIS screwdriver, this tip is left on on a Phillips screwdriver and because of this it stops the screwdriver from going into the screw as deep, this means less contact on the sides and that's why they round off JIS screws. JIS screwdrivers fit Phillips screw just fine, but the reverse just isn't true as we have found out.

[Nurse Julie]

Not on about the opening for the screwdriver Ken, it's the little recessed dot by the side that restorers want, it denotes they are original JIS, not Philips and not SS.

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[Oddjob]

I'm aware of the significance of the dot Julie, I'm just pointing out that it's pretty stupid to compromise a rebuild just for the sake of a punch mark.