Earlier today I was doing some routine work and decided to remove the oil tank. I discovered that the SS feed/return lines (installed by the PO) were nearly cut through from vibration! Yep, the return line had all the braided SS completely separated and the rubber hose abraded over half way through. And I was planning to ride this bike up to San Miguel in Oct. Basically the lines were right on the verge of rupturing.
What I found interesting is that braided SS lines are always considered the "best" stuff to use. But they had been rubbing against the base that the oil tank bolts to. Looks like a really poor set up that wasn't examined carefully when originally done (Yet ANOTHER issue with the "prominent" britbike seller from whom I purchased the bike).
I added the oil lines to my extensive Old Britts order...
Yes, Im not saying they shouldnt be used or that I would never use them.
But I would only use them with a plastic shield and I would make sure they were the correct lenght and carefully located. None of the comercially available ones I have seen would meet these criteria and I think you would have to make your own.
I have seen a few photos of your bike on the forum and it is very smart. It looks like the sort of bike where if your going to do something you would do it right!
One thing that surprised me is that the bike parts ate up the wire braiding, not the other way around. Makes me wonder if the SS braiding on the particular hose used was actually SS - it feels/looks like it but that would mean the mild steel of the Commando oil tank base plate is harder... seems unlikely.
I ordered the Gates hose available from Old Britts to replace all the existing braided hose.
I experienced the same thing. I just chalked it up to the fine wire diameter of the braid. I've since sleeved the lines with a spiral wrap in sensitive areas. The wrap comes in both a sacrificial plastic or a longer wearing steel wrap. I use the plastic where there is contact with aluminum. I really consider the stainless steel brake line and the ss rocker arm oil line a necessity. As for the feed and return oil lines, I guess I just like them.
Here's a pic of the return line to the tank and the feed line to the engine. The return is the really bad one. Again, seems odd that the wear is all on the line; there is no sign of wear on the oil tank mounting plate where it was rubbing except for rubbing off the paint. The feed line was abraided where it passes through a little locating ring. One of the things that contributes to this is that the return line tube in the tank is angled a bit too far forward so the hose almost has to hit the plate. I'm afraid to try bending the tube though...
A wound steel sleeve? Perhaps that's on a different year. My 1973 factory parts manual shows cloth-braided rubber hose with plastic spiral protectors over the hoses at the oil filter for about 6-8 inches. No other areas have any protective plastic.
My 850 is SN#311xxx, a mark IIA, and while it is possible the steel protectors were later added by the owner it is unlikely. He didn't touch the bike enough. I'll try to shoot a pic and share. Oh, and I did replace both the rubber lines and sleeves with braided steel lines and inspect them periodically - no unusual wear so far.
Well, I can't say what my bike might have had originally since it was all replaced with SS braid. Perhaps, regardless of the parts manual's depiction, they came with whatever the guys at Wolverhampton (or wherever they were assembled) had handy and they installed it in whatever fashion the particular assembly guy felt like at the moment!
I stand corrected! You guys are absolutely right. I looked at the shop manual and the pic looks like spiral plastic so I made that assumption and we all know about ASSumptions. BUT in actually reading the manual description of part 37, it states that it is a "protection spring" which actually sounds like what was described by other folks. But the area around the filter is the only place it is shown which, on my bike, had no wear at all. The wear on my return hose was at the 90 degree bend just below the tank where the number "7" is shown on the diagram.