Terry

Yes if the vacuum hose is off, the flapper is held open all rge time by the spring in the diaphragm chamber. I would make sure the vacuum hose that would normally connect to the flapper is properly sealed as you will otherwise have an uncontrolled vacuum leak and that might cause some surging. I'm not sure what else might cause a surge or noise; there are relays but they are located on the front left of the bike.

I took the easy way out; don't touch the rear calliper or hose connections. When you unbolt the linking hose from the PCV, you will find that the hose can now be rerouted smoothly and end up at the rear master just like it was designed to go there; the end fitting is even at the right angle. There is/was a double banjo bolt on the PCV as well, so I just bolted both hoses on to the new master and called it done. Not a great picture as it was zoomed in a long way, but gives you the idea.

I have heard odd noises when the solenoid that operates the vacuum flapper on the airbox moves. In neutral or clutch-in, the flapper should default open, but if your clutch switch is a little dirty it can oscillate on/off or open/closed; on my 5th gen that presented as more of a crackle or buzz. The solenoid is mounted to the right of the airbox so that may be the source of the noise. Not sure whether that would afect the idle however. For a surging idle I 'd suggest checking the starter valve synchronisation.

I hope his wife likes doing the dusting.

The only thing that sticks clutch plates together is cold oil and viscosity. My bikes never suffer from that, probably because they never sits still long enough. The clutch has an inner and an outer, where the fibre discs engage with the outer, driven from the crankshaft, and the steel discs engage with the inner and drive the gearbox input. When the engine is in neutral, the clutch spins as one unit, but when you drop into 1st gear with the clutch lever pulled, the inner will quickly stop and the outer carries on spinning, which is why there is often a bit of a clonk. I'd suggest letting the engine get up to a good operating temperature as that will give the clutch a chance to be bathed in nice hot oil. At that point I would shut off the engine and put the bike in gear with the clutch pulled, and then try rocking the bike back and forth to free up the sticky plates. If you need to get to it, clutch disassembly is no big deal but you will need a spare gasket and the patience to scrape off the old one without galling the mating surface. You can do it without dropping the oil, on the sidestand. Just don't drop foreign objects into the open sump...I just swing the case to the side and hang it up so I don't need to do anything with the ignition pulser wires. My 6th gen is below but the 5th is basically identical. Remove the 5 bolts and the clutch can be easily pulled apart, but use a torque wrench and go softly when rebuilding it.

You were going to make a motorcycle pallet anyway; just make it so that it bridges the beams with some leeway. According to a local supplier, 3.2m span and 140mm deep beams has a load rating of 2746kg. That's plenty. But can you fit two bikes end-to-end in that bay? My gut feel is that you need more like 2m of shelf length. Maybe three x 2m bays would be best.

What a fun project. From an engineering perspective, the closer you sit the bike to the vertical supports, the lower the bending moment on the cantilever will be. I do occasionally drive a counterbalance fork lift (I have a licence and everything!) and I can tell you that putting 1 tonne loads onto the third level of pallet racking takes some hand-eye coordination and a little nerve. You shouldn't have too many problems with your nifty lift truck as I expect the visibility will be much better. You will need to make sure the floor under your shelves is really smooth as the wheels look quite small.

Webbike Japan lists these for USD79.

Not sure about a lurch but as the fibre discs wear, they become more prone to grabbing and engaging over a shorter lever span. I have replaced the plates in my 09 (with about 86000km) and that made for a lovely smooth clutch engagement. I used a TRK kit from Wemoto in Australia. The comments above are also very relevant, make sure all the other parts are clean and slippy i.e. the lever pivot, the clutch slave piston and the clutch pushrod.

Not really that hard; remove the small hoses/cables while propped up, then remove the rear pivot bolt and flip the tank right over and then undo the fuel banjo. Place lots of padding on the rear rails to protect the paint then keep the tank upside down while stored. I had my half-full tank off for a fortnight while I serviced the valves on my VTEC and never lost any fuel.

I'm thinking that wire is probably the air temperature sensor; the sensor screws into the nose fairing, projecting straight down.

Well both of those are interesting snippets Mohawk. My 5th gen certainly does like to slowly drain the battery when it sits unused, moreso than my other bikes. I had assumed that maybe my battery wasn't the best.

I asked Mr Google and got the following: 100/90-16 front tire and a 130/70-18 rear tire. That gels with my memory as well. If they make them in those sizes, the Bridgestone BT46 tyres are very good, I had a 16"/18" combo on my RC24 recently and they felt great.

I recently serviced the VTEC valves on my 90000km 2009 800. All were low, some very tight. I have noticed since installing the correct buckets that the VTEC transition is much smoother, there used to be almost a SNAP sound as they kicked in but I don't notice that now. May be all in my mind of course. I certainly feel better knowing that maintenance has been attended to.

That is good news that you have found the smoking gun Glystras. I would suggest that you refit a new thermostat as one day, even Greece will get cold, and then your bike will become much slower to warm up when you start it, and may never reach "normal" temperature when running on a highway. That may lead to higher fuel consumption as the engine stays in "must warm up" mode longer. Interestingly (?) my modern 2018 Yamaha MT-10SP has a thermostat that opens at 69C so the bike is quite happy to sit at that level on a chilly ride, but the EFI system is expecting that to be "normal".

Glad to hear that normal service has been resumed. Maybe you had some water in the fuel? There is a strainer (like a stainless steel pot scubber) on the fuel pump inlet and also a proper filter on the pressure side. Water can enter these tanks if the filler overflow drain gets clogged and you park outdoors.

The FI light will come on if the ECM detects any signals that are outside of the norm. For example if the inlet manifold air pressure (MAP) sensor doesn't see a vacuum when the engine is running, the FI light comes on and the ECM goes to "limp" mode. That specific example can happen if the vacuum hose is not connected to the MAP sensor or if the electrical connector comes loose (or more likely gets forgotten by the mechanic). You'd be best to download the manual, clear any old error codes, then ride the bike until the fault occurs. At that point you can use the fault code to identify where the issue is coming from and (hopefully) rectify that.

Do it when your wife is out shopping and the pot will be fine. The action in boiling water is very obvious from closed to open.

A green 3-pin plug might be for the bank angle sensor but the wire colours don't look quite right. Any 12v connector can potentially melt if it gets some corrosion as that increases resistance and that causes heat. If the BAS circuit is interrrupted that will definitely stop the engine as it will interpret that as a tip-over and shut fuel pump and injection down at least. VFR 800 Electrical Schematic After 2005 Standard Type REV 01.pdf

Temperature senders are normally screwed into the back side of the front head but in some models the sensor is connected to the thermostat housing; certainly that is the case with the VT250F which is of a similar vintage, and the NC30 looks the same so probably applies to your NC21. The manual for the NC30 says you can jump the cable for the thermosensor to earth and switch on the ignition and the gauge should jump up to "H", but not to do this test for more than 5 seconds. The thermoswitch on the radiator is there to start/stop the fan only. Over 100C this switch closes and completes the path to earth for the fan motor. You can test the motor function by jumpering the wire to earth (bypassing the switch) and the fan should run with ignition on.

Right there in the owner's manual:

If you look at the troubleshooting guide in the service manual for poor low speed/idle performance, the recommended checks in order are as follows: 1. Spark plugs 2. Ignition timing 3. FI faults 4. Starter valve synchronization 5. Intake pipe leakage There is no mention there of the FPR but you'd assume anything within the fuel system that interferes with normal injection could be an issue e.g. fuel pump, regulator, blocked injectors, vacuum leaks. I'd be suprised if the FPR could have an intermittent fault as it is purely mechanical operated by intake vacuum on a diaphragm, that will either work or it won't. I have read that failing fuel pumps can be a bit intermittent and worse when the tank is low. I'd start with new plugs and see whether that resolves the issue.

Congratulations on your purchase; I am a former VF750F owner and have many fond memories of the bike (but only B&W photos!). Your description of the faults does sound like a bike that has sat for some time, and maybe got parked up by the PO because of the faults. The cooling system doesn't empty itself unless there is a leak somewhere so you should keep your eyes open. At this point I would be thinking that you have pulled some old crud from the fuel tank into the carbs and blocked up the jets. My suggestion would be to remove the carbs (as a set, and don't separate them unless you absolutely need to) and then remove the float bowls. I expect the issue might be obvious at that point but I would then remove the jets and carefully clean them out. The slow speed jets are exceedingly tiny (so very easy to block) and are responsible for idle and slow speed running. Note that the carb float bowls are usually held on by JIS-head screws; if they are hard to turn a Phillips driver will often chew these up, so getting a proper JIS screwdriver might be a sound investment. I would also drain the gas tank fully and see what comes out, and if fitted, look at the fuel filter. Post up some photos of your new bike and whatever you find.

You can test the basic functionality of the thermostat without removing it. Start the engine from cold and keep a hand on a radiator as the bike warms up. If the thermostat is working it stays shut until around 78C to just circulate the coolant in the engine. Above that point it starts to open and the now-hot coolant will flow to the cold radiator and you will quickly feel it become to hot to touch. If on the other hand the radiator slowly heats up from the time the engine is started, the thermostat is stuck open.

The turn signal bulb and the dash bulb are in parallell; the same 12v feeds to both (basically the circuit is 12V+ to flasher to direction switch to bulbs to earth), but they have their own earth path. So it is certainly possible for a faulty dash bulb to be the problem as that won't affect the turn signal bulb (and vice versa). IIRC the bulbs in the dash are accessible once the nose fairing is removed, and they just pull out in a removable socket.