Bandit losing power

Hi All,
 This is my first time here and I'm having problems with my 2010 1250 Bandit. 
 I recently purchased this bike knowing that it had some issues.
 Firstly it had a faulty fuel injector which was replaced, the others were cleaned and tested ok.
 The previous owner had replaced the fuel pump and "t bag" filter and cleaned the small filter under the fuel pressure regulator and the bike now runs fine until it gets hot and then it breaks down under load at 3500-4000 rpm. The bike will run perfectly at 3000 for lotsa of klms but won't rev past 3500.
The bike has a new set of plugs, and the air filter has been cleaned. I have been told that it could be coils? 
Has anyone got any ideas what could cause this problem

If not the fuel filter , and if it turns out not to be coils ,sometimes a K&N style filter and a different exhaust combined without any modifications  can cause problems .

Thanks Paul,
 The bike has had a slip on pipe and a KN filter for about 30,000 k but this problem only seems to have arisen in the last few klms (according to the previous owner). But he has told me that it had not been ridden for at least 8 months!

Velo,
Somewhere in the posts is helpful post on this subject in regards to losing power out on a run and having to get home at low speed also posts of changing fuel pumps at great costs multiple times. So I came across the said post at a time I was having trouble and tried it. It has something to do with taking the pump out after taking the tank off turning the tank upside down then inspecting the pump and somewhere in the process you will find with a magnifying glass (yes its that small) a small gauze filter screen about the size of the old one cent piece and what you need to do is get a small diameter piece of harness wire bare one end about 2 centimeter and bend it slightly and spread the wires to make a crude looking brush (now I am not talking fencing wire here but the likes of speaker wire etc etc) and brush the screen numerous times and spray it out with carby cleaner and give it a few goes then a good wash in gasoline and put it back together and try it out. There maybe other reasons for your problem, however whoever wrote the first post had heaps of replies thanking him for their fix after they had taken their bike to numerous dealers spent lots of $$$$$$$$'s on new pumps and workshop fees etc only to do this fix and ride away problem solved as was indeed my problem was without the cost.
You may have to look for the post and I believe that I saw it appear in here about 4-5 years ago.
Worth a try before lashing out with to many $$$$$$$$'s only to have the same problem appear soon after.
PS the screen is small and in my case when I did finally se it DIDN'T LOOKED BLOCKED AT ALL.
Since then especially I run a small amount of Carby Injector cleaner through with every 2nd full tank again especially when I am going on a long run.
Hope you get it solved. Just re read your post and it's past the Tea Bag filter and as I said you are looking for in my case (2007 pulling a chair) a small 1 cent in size gauze filter that (mine was a cream white colour) DIDN'T look dirty at all and the small wire brush back an forward motion and carby cleaner did the trick. I live in the bush not always greatest of fuel and have a few different vehs to drive so fuel may get a little gunky and block a small filter like that (that's why the carby injector cleaner regular). Also I thing the original post follow ups said that even the dealers know nothing of that mnall filter
Cheers syd

Hi velo,
So, it's happy to spin past those rpm, under load at 1/2-2/3 throttle, when cold ?

Thanks Sydnorton,
 I had found that filter and have cleaned it and I have cleaned the tank and replaced the other filter but am still having the problem when the motor gets hot. 
Thanks for you suggestions. 
Cheers Velo

Hi GSX1100G,
Yes No problems until after about 6-7 klms or the the engine gets up to temp.
Cheers Velo

Velo,
Sorry to hear that your problem still exists (but do remember that this has work on lots of other Bandit 1250's)
Hope you find out what the problem is and do a post when you have it sorted.
Yes mine has been happy ever since I did it. In fact it pulled 197kph (speed healer and GPS verified) so has no power problems at all now.
Cheers syd

Have you pulled the pump to check that it's new etc as stated.

Hi Gsx,
 No I haven't done anymore with the Bandit as I've been busy with other stuff, hopefully back to it in the next week or so. I'll pull the pump etc out and just check it again if looks ok I'll put a fuel pressure gauge on it and go for a ride to check that the pressure stays up. I'll keep you posted.
 Cheers

While it's out, strip it right down, clean it out & check everything. The nylon body is where the mesh screen is. I put pics of mine in that section. It should be a go back together firmly. Pressure test is a good idea as if a poor quality pump was bought & put on body, it may not be good enough.

That small screen mesh needs to be looked at again no matter what pump or how old it is you definitely need a small multi strand wire bared back and bent at bout 45 degrees and used like a toothbrush to clean that small filter that you have to look hard for (even Suzuki Dealer Mechanics don't look for it or don't know about it) and spray well with carby cleaner before reassembly. If you find the original post about it in here you will read how, how many guys have suffered multi dealers changing (and charging heaps) for new pumps and the bike still having the same fault no power or having to finish long rides home at very low speeds, only to read that post go look again and fix the problem.
However it still can be something else wrong with it entirely, just don't throw in the towel without giving it another try.
Cheers syd

Thanks Sydnorton,
 I will check all of the pump and filters, I had found the small filter under the fuel pressure reg and cleaned it BUT I'll do it again to make sure, it has a new "t bag " filter on it so that should be ok my next check will be fuel pressure I am going to plumb in a gauge so that I can see it when riding the bike and make sure that's all up to spec.
I'll let you know how I go and thanks for your input. 
Regards Velo

Velo,
Sounds like you are at least following a method that sounds productive.
Fingers crossed for you and if you find what it is I would like as others would, to know
Cheers syd

I'm leaning towards the coil, but in the meantime suggest taking one spark plug lead off at a time and see if the engine runs different. 
I am thinking it should run different with one lead removed, so if it doesn't maybe it's a lead that is breaking down when it gets hot? 

I'm not a mechanic so . . . 

Again, while you're in there, change coil/ leads, shit, might as well do the plugs even if PO says they were done. It's got to be heat related, plugs & coils get toasty.

Hi All,
 I have now been back to the Bandit and have found the problem  it was the Fuel Pump. the previous owner had fitted a fuel pump (a cheap one off Ebay) and it must have been overheating. I found that when the bike lost power if I stopped and switched the motor off  for a few minutes then set off again it'd go fine again for a few miles then lose power again, I thought that as the pump is in the petrol it could be all that could cool off a bit as a coil could not do it in that short time.
 Any way I bought a new Quantum pump kit it also came with a new fuel pressure regulator. I installed both pump and regulator etc. I test road the bike and it is perfect, I have just got back from a 2nd 80km ride and the bike is still going great.
So thanks to everyone for there help and I hope that by explaining what I found might help someone else.
Thanks again this is a great forum.
Cheers Velo

A frustrating 3 months for you, but in the end, a grerat result. Hopefully the ACT gives you enough sunshime to finally get to know your Bandit!

Excellent result.
Definitely a case of " Bargain Regret" by the PO, but, Id say you got a bargain.