A couple of 4G questions

[John.reader]

As my 1937 4G is nearing completion, if I could just ask a couple of questions that I am not sure about,

I believe that the horn on this bike should be mounted in front of the engine plates and directly behind the front mudguard. As you can see from the picture, I have reversed the horn mounting bracket which has enabled me to get the position of the horn as far back as possible so that its hard against the front engine plates, but even so the dome nut on the front of the horn is barely 7/8 inch away from the back of the front guard. Obviously I will cut off the protruding bit of the horn bracket. Is this correct? My main concern is that under heavy braking, or encountering a large bump in the road, is there enough flex in the frame, head races and fork blades to allow the mudguard to move back enough to touch the horn, which if it did would probably lock the steering. Or am I worrying unnecessarily.

The other question concerns the oil feed to the rocker box. I have read quite a bit on these pages about over oiling of the rocker box, and I wonder if I might have the opposite problem. When the engine is running with the rocker box top removed, I only get about one drip every fifteen seconds or so from each of the four springs between the pairs rockers. Is this enough to oil the cam followers? The oil pressure is 40 PSI idling and 50 PSI when revving and the oil is Silkolene Hardwick 50. The oil feed stud in the crankcase is from Drags, the oil pipe feeding the rockers is the thin one, the union from the pipe into the rocker box is the original one cleaned out and the two nuts on the ends of the rocker shafts are replacements from Acme Stainless. The shafts have been thoroughly cleaned and all the holes are clear. Hopefully the flow will improve when the oil is properly hot but I cannot do this at the moment as I am still waiting for the return of the petrol tank from the painter. Again, am I worrying unnecessarily

As usual, any advice would be much appreciated, and thank you.

[john.whiting]

I know a person who had a horn mounted down in front of the engine had the horn come adrift and jam
between mudguard and frame ,causing a bad crash.......I put them somewhere else ,even if its not original.

[paul.jameson]

Correct mounting of the horn is as shown in the photo. On my bike this gives about 28mm between horn nut and mudguard which is just under 1 1/8", so about 1/4" more than you have.There are various things you can adjust to get a little more room, such as using the slot in the holes of the centre bracket of the mudguard to lower the mudguard as far as you can.

In cool conditions, with the thick oil you are using, I wouldn't expect too much to come out. I would tip a good volume down each set of pushrods before starting the engine, then go for a run of say 10 miles, then look to see how much is coming out. If you have rebuilt the engine, I would strongly recommend removing the oil you have and replacing it with a running-in oil such as that supplied by Morris Oils. Modern oils are too slippery to enable proper running in of a new Ariel engine.

[John.reader]

Thank you John and Paul for your replies. I'm in a bit of a dilemma here as my heart agrees with John and wants to put the horn in the later position on the N/S rear mudguard bolt, as there it is protected from all the crap coming off the front wheel, and frankly I think it looks better and no clearance problems, however my head says that for originality it should be behind the front mudguard. Paul, I have already got the mudguard as low as it will go on the mounting slots and the front stand lug is behind the mudguard mounting bracket as in your photo, but if I put the horn mounting bracket the right way round as in your photo, then I have virtually no clearance at all between the horn dome nut and the mudguard. Its only by reversing the bracket as in my photo, so that the horn is pressed hard up against the engine plates that I can get even the limited clearance that I have now. I'll have to give it a bit more thought. Paul, I was going to change the engine oil anyway after initially running up the engine so I will follow your advice and change to Morris running in oil for the first 500 miles or so. Thank you both again for your replies.

[paul.jameson]

Looking at the bracket which goes onto the engine plate bolt, is yours the same way up as mine? The instinctive way to fit it is with the base of its flat U shape upwards. In fact, it should be downwards, as per my photo.

[John.reader]

Hi again Paul, and thank you for your reply. Yes my bracket is fitted the right way up, with the flat part at the bottom, and the side arms pointing upwards. I think that part of my problem with the clearance is that my front mudguard is a Draganfly fibre glass replacement, which Drags say is made of 6mm thick fibreglass. Maybe this is where my missing 1/4 inch clearance has gone, and also I'm relying on Drags having put the bottom fixing to the front stand in the right place. I'll have to give it all a bit more thought and see what else I can do to it. Many thanks again for your help.

[paul.jameson]

One option is to have the horn in the correct place if the bike is on show - at an AOMCC rally for example - but otherwise have it in the wrong place. You have, of course, got the correct horn?

[John.reader]

Hi Paul, yes I think that's the answer, I'll leave the bracket in front of the engine plates in position, there is plenty of clearance for the bracket on its own, and for riding I'll put the horn on the mudguard retaining bolt behind the seat. I have horn mounting brackets to fit the horn in either position. The horn that I have came with the bike, and as far as I can see its an original Lucas Altette. It needed a bit of fiddling to get it going and I have replaced the rim and dome nuts, but it looks like any other Lucas horn as far as I can see. Thanks again for your help.

[Roger Gwynn]

The extra thickness on the GRP mudguards is of course on the inside!

[paul.jameson]

This one continues to baffle me. Can we have a few more photos please, showing more of the mounting details? The horn should fit easily and I can't understand why the bracket has to go on backwards. It simply would not fit that way on either my RH500 or my 4G.