Honda-SOHC

I agree regarding general noisy/ lumpy tickover (if that is your issue, rather than a clutch problem) and add that this is true if, to varying degrees:
-Cylinder compressions are matched
-No differences in cam wear across the 4x2 set of valves
-Valve adjustments are spot on
-Cam and primary chains are adjusted / in spec
-Ignition is equal across all 4 (plugs, leads, caps)
-Points and timing are spot on
-Advance mechanism isn't worn
-Is the tacho actually accurate
Probably things I've missed.

Too many variables for my old engine to idle at low indicated RPMs. I set it up to pull nicely through the gears at varying throttles, with good plug colours, then set the idle where it is comfortable and smooth, which was about  1200 -1250rpm.

Mine had lost its cover on the fuse box. All my electrical woes went away (slight exaggeration) after I cleaned each fuse holder.

Personally, I wouldn't silicone it, as that would be a bit of a job for the next filter change. Here's
one for £33.:-
 https://www.ebay.co.uk/itm/365195286710

Also, try the part no. In the David Silver search tool on their website?

Failing that, I'd be thinking door draught excluder, those little rubbery strips that stick to the door frame. Might find one the right dimension.

I'm assuming Martin that you have ordered one from Vietnam, although this source has been discussed before I am not aware of any feedback from a member who has actually bought one.

I hope it meets or exceeds your expectations, it will be interesting to read how it turns out, best of luck.

The mudguard and rear light assembly arrived this morning. I started on the swap at 2pm and finished at 8.30! ...There were problems.

First the good:
-The mudguard looks identical to the original, even made up the same way, with the pieces welded together as per stock. It even has an identical metal protector the rear light wires run through.
- The correct holes have their captive nuts.
- The guides are in the right place for the indicator wires.
- The hole spacings were difficult to measure, but are the same as my original, so it accepts the black UK version light assembly and number plate bracket.
- The chrome plate is fine, minor imperfections, but not anywhere visible and not significant.
- All the threads to the captive nuts are the same as stock.

The bad:
- The holes for the rear light wiring were in the right place, but they were smaller, so the 2 grommets would not fit.
- The whole mudguard was about 1/4" too wide for the gap between rear frame rails (between the indicator stalks) and the profile side to side is a fraction shallower. It's like the whole thing didn't quite get bent round enough. Looking at it side on, it looks right. It just doesn't quite have a deep enough curve looking at it from back to front view. I think that is why it was not fitting between the frame.

I retired for a cup of tea and a think.

I decided to give it a go. I was able to force the sides together sufficiently to slide it between the frame rails. It took ages to line the indicator bolts up and catch the thread in the captive nuts, but I got there. Even with these loose, there was no way the two bolts would go through the top frame cross member and catch the captive nuts in the top front of the mudguard. The standard bolts were at least 1/4" too short.

Another cup of tea.

I matched the thread to some longer bolts (screws) and was able to get them both started. I've tightened all four mounting bolts now. The top two are tight, but there is a 1/4" gap between the top of the mudguard and the top hat washers of the plastic front fender.

So that's how I've left it. I'm hoping the mudguard may steadily relax into the right profile under the tension of the fixing bolts, so that I can tighten the top screws further, over time. I would like to get to the point I can use the original bolts in there, but I'll give it more time before I try to swap them. Of course, I am running the risk that I'm introducing too much stress into the mudguard or its chrome plate. I'll not force it any more, just check to see if it can easily be tightened further, after a week or so. If not, I'll make a short spacer, to go on the two top bolts between the rear and front mudguard, so everything is vibration free.

Conclusion: The new mudguard looks very nice on the bike. It is definitely not a simple switch, as there are quality issues with the profile of the mudguard. Time will tell if worst case, that causes a terminal fail, or  best case, it relaxes and conforms to the right shape. For now, it looks right. The old mudguard I removed is pretty nasty, beyond repair.

Sorry this was a bit waffly. 👍

So that's what I've done. Of everything that bolts to the mudguard, the UK tail light looks to be the only difference in the parts book. I've ordered a US repro, with the tail light included. Hopefully it fits without further drilling. May need some work on the light's wiring, I'm hoping not, but shouldn't be too difficult.

Delivery is quite a date range, early June to early July. I will feed back on quality and fit, once it arrives.

Thanks for your advice. 👍

It might be governed by the chain run as well as the swingarm, especiallyif you retain the chain guard.

My Norton Commando came to me with the wrong tyres 3.60 width, instead of the spec 4.10. When I put the wider 4.10 on it, I was surprised just how much slower the handling became. These CB750s aren't the most nimble in the first place, so worth considering if you can get the right profile in a wider tyre, to avoid trashing the handling.

Yes, think you're right Ted, as the indicator stalks are on the grabrail bolt and that's the same part no. for all markets.

The rear light / plate holder on mine at least, are black items, whereas the US are chrome. But don't know about hole spacings. Wonder how different the holes are and whether it can work?

Bet they were able to dig it out of there though.