Honda-SOHC

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.

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.

Let me check and see what my spare 550 clutch setups look like Nigel, casting marks can look like cracks, I tend to remove all casting marks when I'm polishing casings etc and you'd be surprised how many there are and how like cracks they can look.

Part number is the same as off a 550F, so that's ok. Did it have a large thrust washer behind the basket and a top hat spacer fitted down the centre of the basket?

Check the neutral selector mechanism inside the sprocket cover, remove (carefully) and clean but first remove the electrical wire and hold it against the casing, does the light come on? does the switch have all it's copper strip as per the pic in Roos thread http://www.sohc.co.uk/index.php/topic,26979.540.html post 39. These tend to break off/corrode and if that happens the light can get iffy about coming on, also check the drum on the end of the selector drum, it has a small copper strip embedded into it that get covered in crap and again cause issues.

If you look inside the opening you can see the outlet that the nipple uses, a thin screwdriver or piece of metal can be used to poke it out from underneath. It's tight but doable, did this just the other day.

How much are they charging for polishing that, it's not an easy casing to do, lots of recesses and I'd be surprised if you don't get it back with some dull areas.

A really good polisher should be able to do it all and get it consistent, areas like the small part forward of the gear lever hole look to be contaminated with oil/dirt/grease and it's those that cause a lot of problems. If you look at it the surface looks blemished, like it has a small rash, that's the contaminants sitting just below the surface.

That place in Stoke, can't remember the name, had some genuine ones for sale a few weeks ago.

The bottom one looks to have a slight bend in it, Philpotts will correct that as well FOC

There is also Dynasurf in Sandbach, who are slightly cheaper but won't do the top nuts for free.

To save money Honda didn't chrome the stanchion under the fork ears, it wasn't seen so why bother, hence why they all look like that, some are a LOT worse.

Put a fork back into the yokes, clamp it up and then remove the 6mm allen key hidden under where the bottom end cap goes, do it BEFORE undoing the top nut, get it loose then undo the top nut. Repeat for other fork. You sometimes need a air hammer or impact gun to get the bottom allen key to shift, I suspect yours won't be that hard as they look to have been apart before.

Cutters arrived today.

Results were not good. I got 6 different sizes, all around the size of the choke shaft and the opening the felt washers sits in.

A little explanation first. Most people make these washers by first of all cutting out either the large or the smaller openings, both have there plus and minus points. My tool has 3 positions for the cutters, the smaller ones thread onto the central boss, which is shaped like a hammer. These go up to 10mm, after 12mm you use the middle boss, these go up to 20mm, after that they can get pretty big and those use the outer and biggest boss. So in theory you can pair 2 or even 3 cutters together, which makes them ideal to make washers. The problem is the choke mechanism washers are small, the central shaft is 6.8mm wide and the opening is just under 9mm. Cutters in sets don't come in half sizes, fill mmm only. So the closest you can get is 6mm and 10mm but as explained these use the same threaded boss so you can't do that, so, you're back to the first method. Tried 6mm and 10mm before deciding they don't work, 10mm is slightly too big to go in the opening and 6mm is too small for the shaft, yoiu can force them in there but the shaft is threaded and when you go to push it through the threads catch the felt and just rip it too bits.

So new cutters are required. I bought 6.5mm, 7.5mm(just in case), a special 6.9mm one(you never know), a 9mm, a 9.5mm and a very special 10mm one that been made to use the middle boss instead of the central threaded boss.

So I tried 6.9 x 9.5 first, had to cut them by hand and frankly it's as good as impossible, most tear as the wall is only 1.35mm wide and that's if you get the cutters 100% central, most go off centre and that's that ruined. So you need to increase the wall size, so 6.5 x 9.5, nope, still virtually impossible. You need 7 of these for each bank of carbs, making one involves numerous failures. I could make a set if you're willing to pay £20 for 7 as I'd ruin 90% of them making them. I tried 6.9 x 9 and 6.5 x 9 and still not much better.

I'd already tried the special 10mm cutter which allows double cuts so makes perfect washers virtually everytime, however I didn't like how they fitted, so went back to the first method again.

So can I make them?

Yes and No.

Yes, I can so long as I use 10mm x 6.9mm, the inner hole is big enough not to foul the threads as they pass through, so you can actually thread the felt washer onto the shaft on one side, pass it through the carb body and then fit the other side, I tried that and it's possible, a thin screwdriver and you can actually get the washer to sit inside the opening, a little thin oil on it and it would also lubricate the shaft as it moves as well as sealing it from outside dust and air ingress.

As per pic.



Bryan you want to be the test dummy? if you say they are ok I'll do some more, if you say no then I'll not do them.