Firstly, here’s a pic of the fuel stub that the Monza cap will be bonded to:
I’ve now reached the stage where I need to get the motor fired-up and get it running properly. So with that in mind I’m working toward getting the exhaust fitted. This will be about as far from standard as it’s possible to be, I guess. The pipe is a Marving 4 into 1, which is actually for a DOHC motor. But I bought it anyway, even knowing this, as it looked like a nice pipe! It’s new, but old stock.
I’ve decided to ditch the standard finned collars, in place of flanges and studs - more in keeping with the off-road/endurance/scrambler theme that I’m now going with. Anyway, after originally intending to have some local machine shop make up some billet flanges, I had a change of plan and decided to take the ‘homemade’ route. I had some 6mm duralumin (dural) plate in my shed, and with a pillar drill, cobalt burr, file and scothbrite – well how hard can it be!
Here’s a few pics of the process.
Chain-drilling the centre hole is tedious, but I had no hole saw man-enough to cut the dural (tough stuff). After a quick tickle with the burr and a wipe with the file and scothbrite, they look like this. I may give them a further ‘finishing’ as they are right up front and need to look good. Note the detailed 'engineering' drawing!
So, here we are all studded and flanged-up, ready to hang the pipes:
Having to cut the header pipes to slide the flanges on would normally be out of the question, with a new manifold. But as I have to ‘modify’ it anyhow in order to get it to fit the slightly different port spacing of the DOHC, it really doesn’t matter. Here’s a couple of pipes temporarily in position:
Next thing is to tighten the downpipes into the head and tackweld the collector/main pipe back together before MIG welding. And generally ‘jiggle’ the fit to get it sitting up close to the underside. The pipe will then take a turn out and up, to bring the ‘Arrow’ race can somewhere around number plate level. Bit like this:
I'll be busy with the MIG, next few days!
Steve
