JL Stub repair /

So its my shift on Saturday, Id had a night out with beers and food with my old mates Rob Miller and Stuart Wilson who stayed over and was pottering around in the shop with the new model D they had collected the day before. Simon Collins had come from Spain to collect Darrells old bike which he'd bought and I'd finally finished all the work which needed doing. People were coming and going all morning and then I got a phone call, 'Mark it's Phil can you have a look to see if we've got a new JL exhaust stub, mines fallen in half and it's only done only 300 miles! Well I looked and looked, we used to have loads, I had piles in the dyno room from exhausts we had fitted and tested, could I find one? No I couldn't, must had sold them all. So I asked if it could be repaired and the answer was yes. So I said 'if you come in and cover the shop and phone I'll weld it up'. When he turned up Slacker told me he was only going over his bike getting ready for a rally and noticed his exhaust was bouncing around. The tube had broken and come loose from the flange.

When I looked at the flange it was so warped it would have been pointless welding it. So me, been me looked and thought if I used one of my Dev-Tour flanges with a bit of this and a bit of that I could re-weld the tube to the flat MB flange. Upstairs we have loads of left over parts from manufacturing pipes I had a few buckets with flanges and tubes.

As luck would have it the JL tube fits straights into our flat flange. But JL do the mounting and sealing different to ours. I've read all the time about wiring up JL stubs to stop the nuts coming loose, I've never known it with ours. And we hear all the time about gaskets blowing and drawing air in and exhausts blowing.

No wonder when I measured the JL flat plate it's only 5.5mm! I looked at flange warping years and years ago and ours are 8mm and leaking flanges are not a problem, it's simple common sense you would think with such a known problem. When I put Phils flange on a flat surface it was miles out and people complain about our gaskets blowing! It's not the gaskets it always a warped flange! But it's not something we have problems with our flanges. The new MBgm Clubman has a slightly thinner flange at 7.5mm which is nowhere near the JL and all the others at 5.5 – 6mm no wonder lots have problems, you only have to tighten the nuts and the flange warps! Some use copper gaskets to stop fibre gaskets blowing and guess what these will leak if you are using a warped flange. Some say flatten off the flange to make it seal and guess what it gets thinner so it will distort as soon as its tighten up!

And then there's the age old problem of getting to the nuts on a JL flange, again not a problem with our MB Dev-Tour stubs! Back to Phil stub, because of the JL flange idea I had to chamfer our plate then I thought umm, more problems! I remember fitting 4 Taffspeed pipes in the early 90's these were the first of the JL flanges and I modified them to get a spanner to the nuts! With ours you can get to the nuts with a socket, much better....... So here it is, ½ an hour in the workshop whilst Phil covered the shop with his son Charlie. Did it work? Of course it did, he was well pleased, new gasket and it tighten up a treat and he's back on the road for the rally. He thinks we should make them to sell......... like I've got nothing else to do!