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Z650 / GPz engined Restomod
- Bevelhead
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Over the previous few months I'd been slowly buying the parts I'd need for the bike, including forks, swing arm, wheels, brakes and most of the bodywork. Still looking for a tank at a good price, while the side panels and tail section are reproduction parts made in ABS, with improved, stronger mounts.
The goal of the project was to build a bike which still looked like a Z650, but with much better suspension and brakes. While making more power, and being as light as possible, without resorting to the expense carbon wheels and Ti parts. The simplest route to more power was to use the 650's bigger brother the Z750 engine, the most powerful of which is the GPz motor, by chance I knew of someone with such an engine he didn't need..
Not sure yet if I'll go to a 810cc conversion, as the only pistons I can find are from Wiseco, and they are three times the price of a standard set of pistons. Target is at least 80bhp.
Its not easy to find out the weight of individual parts of a standard bike, but again the target is to get as close as possible to 400lbs dry weight.
An additional target was to complete the bike this year, as my projects have a habit of dragging on for years.
The frame arrived on a pallet one cold, wet January morning, and it didn't take long to start work, first by narrowing a ZRX1100 swing arm to fit the frame, and making spacers so the 16mm pivot bolt will work with the 20mm bearing in the swing arm. But first some crash damage to the underside of the swing arm had to be repaired.
I checked the price of a new pivot bolt, since I didn't have one, then decided to make one in stainless steel. Even with having to pay for a bit of welding, it turned out half the price of a new standard pivot bolt. I'll make the engine bolts in stainless too, as its the same process.
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- Bevelhead
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However, when the rear wheel was fitted into the swing arm, it was clear something was very wrong.. it didn't fit!
With the wheel hard against the left side of the arm, it was still miles out from being central in the arm. Very odd, took awhile to work out what was going on, as the ZRX1100 is similar in width as the ZRX1200, which I'd used successfully before.
Eventually found that the rear wheel wasn't in fact from an R6, it was from a later model, an FZ8, though it was sold on Ebay as from an R6. Despite looking identical, they are not, the hub is much wider, even the cush drive is different.
I've since bought a cheap R6 rear wheel, but its silver, not the gold of the original, so now I have a mismatched front and rear wheel. Will probably have them both powder coated. A pity as the front wheel is in perfect condition.
To fit the wider back end, which has a 5.5 x 17 wheel, the pillion mounts on the frame have to be removed, not a problem as they were rotten inside in any case.
FZ8 wheel wont fit the ZRX swing arm..
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- Bevelhead
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The engine last ran 24 years ago, but it turns over ok by hand, and fingers crossed its long sleep hasn't caused too many problems with its internals.
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- Bevelhead
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One problem was that the splines on the gearbox output shaft were badly worn, as if the front sprocket had been run loose. I later found out the the engine came out of a bike which had CMA wheels, and the rear wheel had no cush drive. Since I intend to fit a 5.5 inch rim / 180 rear tyre, it seems that the later ZR7s output shaft is longer so I have bought a good used transmission from a 2002 ZR7s, hopefully it'll fit with no issues.
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- TexasKZ
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What is a V5 log book?
1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough
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- Wookie58
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This is the UK registration document that shows vehicle details (Vin, engine number etc) and ownership
What is a V5 log book?
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- Nessism
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www.kzrider.com/forum/11-projects/610573-saving-a-81-kz750-e
www.kzrider.com/forum/11-projects/602462...0e-resto-mod?start=0
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- Bevelhead
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Meanwhile the clutch basket has been modified to remove the looseness caused by its cush rubbers getting old. This was done by grinding off the rivets holding on the back plate, then inserting steel sleeves around the cush rubbers which take up up any slack and prevent movement of the rubbers. Finally the back plate was welded back into place. New cush rubbers are now available, but at £108 a set, this option is cheaper.
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- Bevelhead
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Finally, made a bracket which goes over the lock stop post beneath the steering head, as it had to be wider to give the correct lockstop with the R6 front end. It was still drying from being painted, so couldn't fit it yet.
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- Nessism
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Maybe you know something I don't, but I thought the GPz engines used rubber engine mounts, and the frame uses different mounting tabs than the early bikes?
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- Bevelhead
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- Bevelhead
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