Yeah, I have done it. Sacrilige! But I had to do it. For a number of reasons.
I asked the wise and all knowing forum members for suggestions, and received a load of help from a number of members. I thank you all!
Ultimately, I got chatting with Archmill, and he was able to supply me with a kit to do the work. I liked the look of it, and I liked the price of it. Kits were available from the US at quite high cost, made worse by import taxes and eye watering postsal charges. Was going to cost me £80 foor postage from one well known supplier. On top of the £190 +VAT and import duty. So I took the plunge and orderd a kit from Archmill.
This is what I got in the post, well packed and lost for a week or two by my local post office. But, eventually...it surfaced and landed on the mat., With a thud. It;s quite heavy!!
It's basically 8 steel bungs, 4 threaded stainless M12 rods, 8 nuts and washers and 2 flat plates threaded for dome headed screws along with washers and nuts.
Step 1 is to break out hte hacksaw...and there is no turning back now! Detailed instructions were supplied as to how to do this, and Arch also gave me some additional help with the best locations to cut and the measurements to get best results. Can;t thank him enough for the help he gave me when I got stuck..but more of that later!
He suggested using a jubille clip to get the cuts square, and it does work. Gives a clear guide edge to follow.
I drilled and bolted on the 2 plates to rejoin the gussets before I cut them, so I can located them and use them as a datum for reassembly. I slapped the plates on outside for now. They go inside when it's all done so they don;t show so much.
The instructions made it VERY clear that you need to assemble and bolt up all the parts before welding. It ensures that all the threads are correctly positioned and all lined up the same. If you don;t, you could end up with a plug fractionally off, and it;s not going to bolt up. That would be bad. Very bad. So it was all dry-fitted and positioned exactly where I wanted it before any metal gluing began!
I had picked up a new welder recently, which has a bit more 'guts' than my old one, and this was my first real use aside from a couple of tests. It;s not the prettiest welding...but it glued the metal together, and I was able to confirm I had decent penetration.
Still...a soft pad and some elbow grease makes the welds look better. Honest!
With the welding all done, I dismantled the thing and began to clean up the residue. I'm using a gasless MIG, which is OK, but it leaves a lot of residue behind to clean up. As well as a few bits of weld spatter. No matter, I thought, soon get all that cleaned up.
Then...it hit the fan.
You basically use the paied nuts as a jam-nut to wind out the threaded bar and remove the centre section. 3 came out lovely. One...did not. It just locked up solid. I was able to wind it one way fine....but it would not come back! With much jigger-pokery, I removed the centre section again, but was left with the threaded bar jammed solid into the bung and it was NOT budging. I tried threats, swearing and ultra violence...and no joy. My joy at seeing the bungs all welded and lovely sank like the Titanic.
I broke out the saw, and was able to chop another few mm back and remove the bung. Which..incidentally...allowed me to see my welding had indeed penetrated through and the little piece of tube was firmly attached. and is still...to this very day...one with the bung! As is the threaded bar. I ground flats on it to hold it in the vice and leant on it with a breaker bar, nope. That thins is in there. Most likely, it has picked up some debris from inside the tube, and that rode up the threads to jam them tight. You can only apply so much force through the jam nut, and that was me done.
A despairing e-mail to Arch, and the man came up trumps again. He took pity on my poor soul, and sent me a rep[lacement bung, a spare piece of threaded bar and some replacement nuts for the ones I had butchered horribly.
If I ever meet him..I owe him severl beers! Wouldn't even take postage money. Absolute hero!
Busted out hte welder again, and with the centre section back in place ( after REALLY cleaning out the tubes...which had debris that had to have come from Mr Honda judging from the state of it ) I was back in business! I took a slice of frame off a chopped out piece to replace the lost 5mm, and to line it all up evenly. The bung was plenty long enough and with an extra ring of weld, it was all good.
A bit of clean up, primer and paint, and I have it all done.
I am really pleased with how it all turned out. I have already benefitted from this as it let me trial fit hte head and barrels so I could play with exhaust mounting. A bit of copper grease was put on the threaded bar to help prevent any future corrosion. The bar is stainless, but the bungs are not, so this seemed like a sensible thing to do.
So the project rolls gently on!
Thanks again to all the folk who offered help and advice before I started this daunting task...and thjanks again to Archmill for his massive help. If you are thinking about doing this kind of CB surgery, you could do a lot worse than one of his kits. Just not on a sandcast though
Mines an F2, so not quite so precious!
