Hello, my first post, and unfortunately it's on a bad note, but I could really use some help!

My superfour is a '93 model, had it less than 2 weeks and it's gone already!

Several days ago I noticed 'flat spots' in the power at varying revs, having had a sh** previous bike I turned round and headed home immediately because of bad experiences breaking down a lot.
It seemed OK for a few days until today, a warm day, when the flat spots came back with vengeance. I was riding normally when they came, but this time they only got worse, more often, and over all the rev range, until, it was no longer a flat 'spot' but rather like the bike had very little power at all - all the time. Sometimes the power would come back for a minute but then soon go. It deteriorated all the way home until eventually I was using almost full throttle and only at 2,000 ~ revs and going very slow.

First thought was compression. Or fuel/air mixture, or clogged something or other?

Any ideas would be very much appreciated.

Sounds like fuel starvation to me.
Turn off the petrol tap.
There is a small rubber pipe that comes from the left hand (as you sit on the bike) cylinder head this connects to the petrol tap ( the tap is opened by vacumm) remove this pipe from the tap remove the main petrol pipe from the rear of the tap.
Connect a pipe to the petrol outlet on the tap and place in a suitable container
Turn on the petrol tap there should be no fuel coming out.
Connect a small bore flexible pipe to the vacumm pipe on the tap and suck you should be able to sense/feel the diaphram opening to allow the fuel through there should be a good steady flow of fuel through this let it run for awhile to see if there is any restriction in the fuel flow.
If the flow is slow there is a fuel filter incorperated in the tap remove it if it is dirty/blocked clean and reassemble and try again to see if the flow is faster if it is go for a ride and hopefully problem cured .
Ps if you mention your location perhaps you have a member nearby willing to try and give a hand these are cracking little machines dont be disheartened. Jack

Thanks for the advice! I'm going to have to straight remove the petrol tap to check for blockages, I can't find any handy little tubes anywhere to test with.
I'm a little worried about fuel gushing out, not being terribly experienced in this. If I undo the big nut holding the tap on to the tank and take the tap off will fuel come out, even if the tap is switched off?
Lol I'll try not to be disheartened! She is a beauty mine, I like her a lot when working. I bought a Honda for reliability though and it's a little annoying this so soon after buying. I'm near Nottingham by the way.

If you remove the whole tap fuel will gush out.
If you look on the bottom of the tap you will see a 10mm nut this holds the filter in position.
Make sure the tap is in the off position (pointing towards 3oclock) undo the nut slowly a couple of turns (the bowl may stick on the oring seal) if it does just tap it gently on the side until it comes free you will probably get some fuel coming out but it will not be much (a bit of rag underneath will catch what petrol comes out and also catch anything else you may drop try and make sure nothing drops into where the starter motor is fitted there is not much room in there and anything you drop may be difficult to find (I know this from experience).
There is not much to the filter just a bit of gauze and a water trap if there is anything in there it will be easily seen just clean it out reassemble and hopefully away you go. Jack

Something else you may care to try is make sure the tank can breath properly, there are 2 rubber hoses that lead from under the tank and emerge on the right hand side (as you sit on the bike) and go down to the bottom of the bike.
There should be three hoses in this position , one is the water expansion hose that enters the plastic expansion tank behind the plastic panel , the second one is an overfill leak off pipe the third one is a smaller breather pipe for the petrol tank this needs to be clear if it is blocked or kinked it could also give you similar symptoms .
Once you have checked the petrol filter and you try a rideout and the symptoms return try opening the petrol cap if you hear an inrush of air that pipe is either kinked or blocked .
Incidently if a blocked breather pipe is the case once you have opened the cap the engine should run normally until sufficient fuel has been used to form a vacumm in the tank and the problem will return. Jack

Just been out on the bike and it's riding normally again after being left overnight. However I feel like I'm just waiting for it to happen again. I feel your last suggestion could be right though can't find these hoses?

qEasiest way to find out is to go for a ride (keep it local) when it starts to happen if you open the fuel cap and you hear the air rush in blocked vent pipe is the cause.
To gain access to the pipes remove the seat and you will see 2 10mm bolts holding the tank down remove these and you should be able to lift the tank from the rear far enough this should allow you to look under the tank to see the 2 pipes the pipes must be routed so as to allow the tank to breathe if the smaller of the 2 pipes is kinked or blocked this could cause your problem.
If you want to remove your tank completely (best done when there is little fuel in) turn your fuel tap off to 3oclock position there are 2 small pipes pushed onto the tap remove these the larger pipe may have a small clip keeping it on, once removed and the bolts taken out the tank is only held on by 2 front rubbers lift the back of the tank (you should now have easier access to the pipes under the tank) at the same time pulling it back towards you it may stick a little on the rubbers but it will come off .
Once the tank is off check/follow the route of the 2 breather pipes from where they came off the tank and follow them down through the frame to where they emerge under the bike towards the rear of the right hand side of the engine.
A simple test is to blow down the pipes to see if there is any restiction especially with the smaller of the two.
You say you went for a ride and the bike went ok suggests that a blockage is your problem
I would clean the filter first (10 minute job) and then check the breather pipes (30 minute job)
When you replace the tank make sure the pipes are routed so that they do not kink when the tank is dropped back into place.
With the tank off its a simple matter of removing the small 10mm nut holding the filter onto the petrol tap and cleaning it, its also an ideal time to remove the tap and check for any obstruction in the fuel inlet pipes (unlikely) just remember to put something soft under the front of the tank to prevent damage to paintwork once the tap is out remember that what fuel is in will rush out if you place the tank flat on the ground. Jack
Ps something else that might be worth checking the small vacumn pipe from no1 cylinder that connects to the petrol tap (opens by vacumn) make sure it is in good overall condition.

I found and checked the hoses which seem to be fine, the bike is working fine and has been for a few days now so hopefully it's fixed itself! Good old Honda engines. One thing i did notice was that a slight ticking noise at low revs suddenly disappeared.
I would like to take the tap off still but the 10mm nut underneath looks fused on, and the metal has become so soft it can't be done with a spanner anymore.
Thanks for your help, I will come back to it if the problem re-emerges!

Problems are unlikely to cure themselves if you want to take the tank off remove as much fuel as possible first , as soon as you crack the large nut that holds the tap in position fuel will leak out if you dont.
I still think you have a blockage somewhere.
If it does not happen again enjoy the bike they are great machines. Jack

It might not be fuel; a loose electrical connection can have very similar syptoms to fuel starvation.

It may be worth checking the battery terminal connections are tight, and all the connectors in the main feed from the battery such as the main fuse holder and fuse are secure. Check the earth straps are tight too.