Yet another horn mounting question

When I bought my '71 Roadster it had a Triumph rear mudguard and was missing the horn and bracket. After obtaining replacements from a friend's stash of Commando bits, I discovered that the front of the guard is hitting the mounting bolt for the horn, thus not letting the 2 bolts that secure the horn bracket to the battery tray reach the mounting holes in the guard.
I was wondering if the horn is supposed to angle forward to give clearance? It's vertical at the moment ie perpendicular to the battery tray.


http://rs1078.pbsrc.com/albums/w488/kom ... pg~320x480

http://rs1078.pbsrc.com/albums/w488/kom ... pg~320x480

Yeah, that bracket off the battery tray is supposed to be angled towards the front, so the triangular bracket is about at the same angle as the side frame tube you see in the background. At least mine is.



Dave
69S

That makes sense, thanks Dave. Guess that means the 2 bolts will be angled down too. Pity about all the new paint.. Hopefully I can bend the tab without removing the tray

Graeme

I would not attempt to bend the double steel plate "brace" against the single sheet metal tray. Go ahead and tug a bit to make your own call. A bit of quality fettering time with a vise and big adjustable jaws or hammer is how I've fine tuned the horn hang. Been awhile since my worship time down there but may have to shorten the two long bolts if tire too close. The better the horn is made to clear the worse it gets to route oil hoses to live well. Oh yeah do test the horn before covering over as the mount tension can mess with it bleeppings. Its not a bad idea to silicon or shrink wrap secure the horn terminal connections on as road blasts can loosen so takes ya down and around and in again.

So THATS what those holes in the battery tray are for. :roll: yet another mystery reveled. At least I knew better than re-attaching the rear mud guard here- as the PO had it.

LOL Roadrash that's exactly how I felt many times after what I call a British Iron Blank Staring State. I don't remember if the brace had a bend or not but I didn't have to bend the Combats, just drilled the snot out of one. Hope the high lasts till the next hang up.

You're missing two spacers that need to be between the horn bracket and the battery tray mounting point. They need to be in place on the two bracket bolts. The factory ones are about 1/4 inch in thickness, round and unthreaded. Alternatively, an additional nut could be used in place of the missing spacers.

The spacers will move the horn forward the required amount, and also shorten up the distance of the bolts protruding through the fender towards the tire. If you're not using factory bolts, make sure the ones you're using only protrude as far out as necessary towards the tire.

By reversing the direction of the two bolts, too, and using additional nuts as spacers instead of unthreaded spacers, you would gain the advantage of having the fender cinched independently of the nuts holding the horn on. Might be a disadvantage, though, due to difficulties fitting wrenches.

Use good spacers to protect the tire side of the fender at the mounting point. Over the years I've seen plenty of fenders splitting at those mounting points, which I assume is from nuts being tightened without the proper spacers to distribute the force to the fender.



I'm too lazy to check the diagrams for you, but I believe if you check the drawings in any reputable manual, you'll see there were spacers included from the factory.



Final piece of advice is to make a pattern mudguard of rubber and mount it hanging downwards on the tire side of the fender. There's a type of rubber material that's commonly used by workshops to line countertops, and it works well. Last time I did this I made the pattern from a front wheel interstate mud flap. It should hang down far to have the bottom at or below the lowest point of the swingarm cross-member. The purpose is to keep all the road dirt off, and slinging rocks from striking, the swingarm.






Hobot, I'm kind of surprised at you, I thought you knew these things inside and out.



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Graeme,
I had fun mounting the horn on my 850 rebuild. I made and used spacers to give clearance on the mudguard. Some people joke that on a Commando total rebuild, you start with the horn and work outwards from there!
Make sure the UNC bolt in the horn is tight, mine came loose and they are almost impossible to get at after the bike is assembled. I would add loctite to the anti vibration washer, just for good measure?
Cheers Richard

P.S. make sure the horn works, they do tend to get moisture inside and corrode. The non standard mudflap sounds like good idea if you ride in the wet.

Ugh Robert-Norton, I changed Peel bat tray and removed her heavy horn so modified mounts and spacers along your suggestions but with rubber hose and rubber washer on mount points that deadened the clang you don't notice until its gone. Its been over 6 yr since I had to get into stock Trixie Combat restore horn and too lazy to look in manual, so I needed your refreshment on the horn and spacers too. Trixie is test for me to stick to factory issue only but on Peel I mounted two light "effective" horns in the crooks of the Z plates, ala Kenny Dreer style.

Ms Peel was day and night lived on about a year so had 3 mud flaps, behind front fender, and on each side of rear guard plus a alloy splash plate on down tubes. I use a section of stif-fish leather from old saddle bags, it really helped keep under side and rear cleaner for road grim. I let this flap stick down between swing arm and tire for best coverage though tire kind of rubbed on it some didn't eat it up. On Peel i also extended the front of chain guard with a stiff plastic tube cut length wise and spread, it reached over to the primary cast lip and held in position there with a small spring tension. In the wet on Gravel it sure helped keep the gritty grime chain sling down where it belongs chewing on the links and teeth.

I don't know which is more effective the bee under a bonnet or screaming under closed helmet.