I a moment of distraction I decided to investigate why my 1985 GPZ600R didn’t like running when it got hot. I stripped and refurbished most of the bike over the last couple of years. But hadn’t checked the valve clearances. Should be a quick job I thought... Turns out they were about half what they should have been, on all 16 valves. It’s a locknut adjustment rather than shims but its fairly fiddly if you have fingers like sausages, so I got the adjustment finished at 11.45 last night. I’ll put it back together tonight! It was my first bike 19 years ago, never got round to selling. This should mean that I have 2 bikes working out of four in the garage! I’ll get back to the Ducati shortly.
Ok, it’s been a while! The GPZ was still messing about, only running on 2 cylinders. An awful lot of investigation (and £80 in parts that didn’t need changed) later showed that a plug going to the igniter was about 1.5mm out from fully seated. It now goes as an 80s 600 with 70ish bop should! Back to the Ducati. I was looking at ways to mount the seat, making brackets etc. All the while I was thinking I’d really like it to work like a stock seat, being able to get under there quickly is often handy in project bikes! Lightbulb moment, how long is a stock seat? Just the right length. Foam off, hole cut to allow space for the battery under the seat (that I’ve yet to fit). I’ve cut off the grab rail to allow me to use the stock seat latch, built up ply laminate piers to attach the new unit to the old pan at the right height. First gluing them in place on the new unit then adding a layer of (messy) fiberglass for extra strength. Once that’s all set I’ll do the same for the seat pad to transfer my load to the seat pan instead of the new fiberglass seat unit. Then build up the front to match the tank using fiberglass or similar. Chain drill then vibrating multi tool on the grab rail section The wood was to hold the seat in place as the glue set High tech means of compressing the fiberglass as it cures!
Fitting the fairing is coming along, I’ve cut around the radiator and trimmed so it clears the radiator hoses too. More gentle trimming with the dremel to clear the huge 8” headlight. I’m getting to the point where it’ll need to go for paint. I think I’m set on red, I was considering black or grey before I got the seat unit and it’s pushed me back towards the colour the bike started out with! I was connecting up the wiring for the clocks and everything on the front so that I could check the lengths of everything and potentially remove the big plug that can be troublesome. Then I hit a snag, where the hell does the ignition plug into? The only plug I can find that’s the right size has 4 wires instead of the 6 coming from the ignition. Black ones ignition, white goes into the wiring loom under the tank. I’m half tempted to connect the battery and see what happens but a cremates ecu would be annoying. Any ideas?
Turns out fortune favours the bold. Plugged them together, connected battery and electrics are working as they should. No smoke or anything! Once I’ve mounted the coils properly I’ll see about firing it up.
IT LIVES! Fired up after about 2 seconds of cranking. Such a relief after having it apart for about 7 months and having modified the wiring quite a bit!
Had a fairly productive day in the garage. My wife is away with work this week so I’ll get more done while I can! Brakes are now all cleaned, fitted and bled with new braided lines all round. The stuff that came out of the rear suggested that it hasn’t seen new fluid in a while! I had to fit a used front master as the one I had was leaking badly and you can’t just buy seal kits for the Brembo stuff. Thankfully it’s working well. While doing the clutch something wasn’t working properly. It appears I’d lost the internal spacer for the sigma clutch slave cylinder. Made a new one so all is well. While I was fitting the sigma I noticed a drip coming from somewhere else. There was a split in one of the coolant hoses, I gave them a good looking at before refitting and they seemed fine! A new set of silicone hoses is now on the way. I also resprayed the top of the swing arm that I scratched while fitting the rear shock, and connected up the new headlight using super seal connectors. Buying a proper cable crimp tool made this a far nicer task, but they’re still fiddly little buggers to put together! Brake fluid should never be dark brown!
Hmmm think there may have been a litttle water ingress into the big plug! Time for more cutting and soldering. Biggest concern is mixing things up so I’ll number each wire as I take them out of each side of the plug and go slow.
Well the big plug has gone! I’d been putting it off for a while but the horn wasn’t working so I thought I’d better get into it. Most but not all of the wires match on both sides of the plug, I started by stripping one side and numbering them all so I could identify them on the other side. Then I stripped and soldered one at a time from the other side of the plug. I used heatshrink solder connections, you just put the wires in from both ends then use a heat gun to melt the ring of solder in the middle and heat shrink the joint at the same time. Saves loads of hassle if like me you’re crap at soldering! Also fitted the new silicone hoses to replace the leaking ones.
I went super high tech for the coolant tank, a modified water bottle clamped to the headlight support will do just fine for now. My mates brother is a welder/fabricator and he made an extremely nice tray to support the battery and relays that normally live under the seat. So nice I felt a bit bad drilling holes in it! The rear light is led and has built in indicators. It’s pretty decent for £30! One thing I noticed is that the coolant temperature is in Fahrenheit, can this be changed to Celsius?
My ST4 is in Celcius so you must be able to change it - I've only ever changed the clock so not sure how to do it?
Ok, looks like the way to change the temperature is to change the gauge! Think I’ll live with F just now
The time had come to extend the 998 seat, I took a while to think about it because this bit would actually be on show. I used aluminium mesh bonded to the inside of the seat unit to give the fiberglass the shape I wanted, then put strips of resin soaked fiberglass over the top to form it round the tank. Then I compressed it using tape to get rid of voids. Once that had set I put another couple of layers underneath and again put it against the tank to get the shape. I intentionally went further than I needed to ensure the thickness of the finished part. Then trimmed using a dremel. Once it was cut and shaped I put fiber reinforced filler over the top. It’s hard as hell once it’s set. Then sanded it to the final shape It’s getting there! About three night work but it’ll look decent when painted
I’m going to see a painter tomorrow and taking the parts that need painted with me. As I took the tank off I noticed a slight rattle, a rusty kind of sound. So I looked further. There’s a previius repair next to the bottom flange, it’s weeping. And there’s a couple of bubbles on the lower seam that are damp (it’s been in the garage since October). Arse. Looks like time for a new tank! Oh and it hasn’t had a fuel filter in 13 years!
I thought about lining it, but I’ve heard of quite a few liners breaking up and blocking things. Also my background is offshore inspection, so I’m very intolerant of masking corrosion for another day. I don’t want to get it all painted properly then have more problems in a couple of years! Looking like I’ve found a tank, just awaiting photos. £200 delivered isn’t great for the budget but I’d prefer it to be right
Agree with the lining, I was thinking that if you are getting parts painted then you could get the seam and old hole welded. But you may open up a 'colander' of worms in the process.....
That’s pretty much my thought process, I’d probably spend £50-100 getting it welded due to Aberdeen prices. Then you always find more problems once you start digging!
