Got the carbs back from their ultrasonic bath, cant say I'm too impressed, they don't look much different from before. I'll just clean and polish them by hand. There are a couple of chrome parts that need attention before being refitted. First the side stand pivot bolt, and second the two wheel spindles, both of which are corroded in places. Rather than have them re-chromed, I decided to make replacements, so I've ordered a length of 17mm stainless Hex bar to make a new pivot bolt. While my initial idea of making new spindles from Grade 5 Titanium wasn't such a good one, as Ti has issues with fatigue, I was told Ti spindles are banned from racing for that reason. Instead I've ordered 600mm x 25mm diameter 303 (marine grade)stainless bar, which will be enough to make two spindles. Luckily the thickest part of each spindle is exactly 25mm. Apart from that, I gave the stainless splash guard a polish and fitted it to the frame, though its covered in my oily fingerprints in the photo, so doesn't look its best. For the next few weeks there wont be any progress in the big changes I'll be making, just lots of small fiddly jobs..
Also made a start on sorting out the engine breather hoses. There are three different sized hoses needed, only had one to hand that was left over from my Harley drag bike project.. cotton over braided Nitrile hose. This was used to make a couple of short hoses which vent to the heads via the frame, along with stainless clamps. The Guzzi is unusual in using the frame as part of the breather system, pretty good idea really.
Got a couple of small jobs done yesterday when I went round to see my mate Jeff and use his miller.. First, we milled the top yoke bar mounts down as far as we dare, as the speedo bracket that now uses the bar mounts sat a bit high, it looks better now it sits as close to the yoke as possible. Then we made four alloy 'top hats' for the Tarozzi rear set mounting bolts. The problem here was that the rear sets have 12mm holes (a bit OTT) while the equivalent mounting holes in the frame were a more sensible 10mm. Using 10mm bolts through a 12mm hole worked ok I guess, but I didn't like the idea, so we made top hats to take the rear set holes to 10mm... much better.
After that, I went to my local machine shop to use their blasting cabinet on the carbs, having first spend a lot of time carefully sealing the carb bodies to protect the internals from any blasting medium. It worked ok for one carb, but the other somehow got a small amount of medium inside (its very fine, almost like talc powder). Oh well, I'd already ordered new gasket kits for the carbs just in case, so when they arrive, I'll dismantle the carbs completely and use new gaskets throughout, they're nearly thirty years old, so new gaskets aren't a bad idea anyway.
I'll be away for the next couple of weeks, so wont be any progress till I get back home. Before that, I've been finishing off a couple of small jobs, and making note of even more changes to be done next. First I fitted the rearsets, which went on with no problems using the new top hat spacers we made. Though its clear that the stainless brake rod I made back in the mists of time is 10mm too long and a bit heavy. So I've ordered a couple of male rose joints and dug out a piece of alloy bar which will need machining to fit the rose joints, and slim it down a mm or two. Then I fitted the carbs, just to see how they looked, as they'll need to come off again when I rebuild them with new gaskets.
For something completely different, I recycled an old Brembo from a 916 which I rebuilt, by donating it to my mates new drag bike project... its now fitted to a pair of much modified 80's Gpz forks... waste not want not !
Made the new shorter gear link rod today, in alloy rather than stainless as its lighter. Started off by drilling a suitable hole through the middle of the alloy rod, then tapped an M6 thread into both ends, before machining the centre section to narrow it a bit.. The 25mm stainless bar has been machined to duplicate the original chromed steel wheel spindles, the threads will be cut on a capstan lathe when I take them to a local machine shop, which is why the thread end is longer than needed for the time being. At the fatter end, I've made the spindles 10mm longer because they'll be getting a hex end machined to take a socket in place of the original slot which I didn't like. It'll also provide a useful mount on the LHS for a paddock stand. The stainless hex bar has been shaped to make a replacement side stand pivot, again it needs its thread cutting, which will be done at the same time as the new spindles are done, hopefully this week.
The cast iron floating Brembo discs were looking very tired and rusty, being cast iron they're always going to rust, but nevertheless they could be cleaned up. The floating rotors are held to the centres by steel bobbins which are in turn held in place by a sprung washer (called Belleville washers) and a circlip. The front discs came apart easily, while the rear was badly corroded and put up more of a fight. A couple of the sprung washers were rusted through and fell apart, so it turned out to be one of my better ideas to rebuild the discs. The tops of the rear discs bobbins were badly scored too, they needed to be skimmed in the lathe, which worked ok, a pity the rotors wouldn't fit in the lathe too as they need cleaning up.
PS, to answer the question about what project the Brembo was donated too.. it was for this... about as different from a Ducati as you can get.. homemade frame, yokes, rear wheel, billet block, transmission etc... all made by my mate in his old shed..
It looks a bit crude, but its actually an accurately made frame jig, my mate is a self taught machinest, after 30 years he's getting quite good.. ie.. Home made engine..
As for the Guzzi, not been able to do much this week, things should speed up at bit soon. I'll be hammering my credit card at the Stafford Classic show this weekend, when I'll order the alloy endurance tank from TAB II, and new rims and spoke sets from Central Wheels. I have painted and reassembled the discs, had to do it twice, as the high temperature paint I used the first time turned out to be too delicate, I had WD40 on my fingertips when I handled the painted parts, it lifted the paint better than paint stripper. Started again, this time using satin black hammerite, which seems to endure high temps surprisingly well according to the internet. My masking of the disc edges was rubbish, but that's ok, as they'll be tidied up when the discs are skimmed on the lathe, which needs them to be assembled first. Also, before a couple of parts go off to be chromed, including the exhaust collets, I used them as a template to mark a couple of scrap pieces of 10mm billet plate, and made a start on hacksawing and filing new collets from them. It would be much quicker to ask my mate to shape them on his miller, but sometimes I just want to do it myself and see how it turns out. That said, I may decide not to use them in the final build..
While I eagerly wait for my alloy tank from TABII to arrive, should be delivered in a couple of weeks, there are still lots of small jobs to do.. First replace the old rusty brake pins with my shiny stainless pins, and polish the caliper stainless socket head bolts too..
Next the original headlamp brackets didn't look quite right, so they've been replaced with a pair that look more café racer-ish. Fitting the front forks on the frame, confirmed that the headlamp shell definitely needs to be chromed, which I took to Niphos in Crewe this week. I was told they'd be ready for collection in 4 weeks, and a bit more expensive than I expected. While I was there another customer was collecting his newly chromed parts from a KH500, and I have to say they did look good. Also bought a 50mm thick disc of billet alloy, which will be used to make (a hopefully) cool part for the engine...
The discs have been cleaned up on the lathe, the front two discs look good, but the corrosion on the rear disc is pretty bad in places where the pads don't touch, but we did the best we could. I'll probably end up fitting replacement discs all round from EBC at some point, but at £140 each, that can wait. That done, I machined a few more stainless bolt heads before they went back on the bike, and cut a small bevel on the socket heads, just because they look better that way.. I'd been holding off refitting the swing arm, while I waited until the wheels were rebuilt, as the whole back end would be needed when a new billet mount was made to hold the modern Brembo caliper I recently bought. I changed my mind, so for now I'll be using the original mount and caliper, which meant I could go ahead and refit the swing arm at last.
a big day today, a parcel arrived.... like a kid on Christmas morning, it didn't take long to open it and see its contents My Endurance racing alloy tank had arrived from TABII in Wales.. Fitted the frame no problem, just need to sort out a rubber strap for the rear mount.. very pleased with it.. Shall I paint it, or leave it polished? decisions, decisions... Also have to decide on what style of seat to go for, its a tricky decision as there are half a dozen options I'm considering. One complication is that the seat rails of the Guzzi Tonti frame are very low, so any seat unit will have to sit an inch or more above the seat rails. It wont be easy to get right, without it looking awkward, or resorting to a thick foam seat, which may be comfy, but not look the part ..
After much indecision, finally ordered a new seat from Mead Speed, which arrived today. I knew it would be 20mm or so too narrow to fit over the seat rails of the Guzzi, but I think it will look ok if I mount it to sit on top of the frame. I did make a simple copy in cardboard from the dimensions found on the internet, which I find helpful. It will be an expensive mistake if it doesn't look right, at least its the right colour.. Its a Ducati Imola seat unit, as fitted to bevel SS750 and my own SS900 (the one bike I wish I'd never sold). Complete with handy storage area accessed by a zip in the bump stop.. a good fit for the bike?
