Loosing power ???

[Fazer99]

Hi all,


On my way home from work on Thursday my red beast started playing up, it's getting to about 60mph at about 6/7k and the engine is straining as I'm pulling the throttle and the noise from the exhaust is like that noise when you let go of a balloon. I thought it might be crap or a bit of water in the fuel so I've flushed it through with fuel cleaner and also given the carbs a good blasting with carb cleaning spray, the air filter is clean and there is no pinching to the fuel pipes, I also checked the spark plugs and they look fine but I'm still getting the problem, as I'm no mechanic I'm at the end of any ideas that I think it might be so any help or advice is very much appreciated and needed ??


I was thinking that maybe there is something stuck in the exhaust but then surly if there was wouldn't that noise and straining happen from the start rather than just at higher speeds?


Also something I just noticed today as I was working on it that the rev counter when trying to simulate the issue while on the paddock stand would go a bit crazy just after the straining starts happening so could it be an electrical fault or could that just be due to the engine struggling causing the counter to not be able to read properly and just confusing the system?

[darrsi]

Maybe a blocked or kinked breather pipe under the tank?
If it happens again open the fuel cap and see if it gasps for air, or just check the pipes are routed correctly and not folded at all.

[darrsi]

Sorry, just seen you've checked that.

[darrsi]

Is your TPS okay, do a check on that as that makes the rev counter go loopy if it's knackered, and the general running of the bike will feel ropey.

[Fazer99]

Where would I find that and how do I check it

[Fazer99]

Just checking through my Haynes manual and the TPS was what I thought it was and where I thought was    now just trying to work out how to check it

[darrsi]

The TPS outer case unplugs, it's a bit fiddly, i normally gently use a flat key to unhook it.


With key in ignition switch it on (don't start engine).
Unplug the TPS
The rev counter needle should go to 3000rpm.
Then plug it back in and the needle, if positioned correctly should land on the 5000rpm mark.
If it goes to 0rpm or 10,000rpm it needs adjusting back to 5000rpm.
If it goes to 3000rpm it's totally knackered.
To adjust it the 2 screws need slackening with a security torx allen key, then rotate the TPS unit until it lands on the 5000rpm spot.


Be aware, these units can slowly break down rather than just stop working so can misbehave for a while until you realize it needs replacing.

[Fazer99]

Cheers buddy, I was struggling to understand what my Haynes manual was going on about  :lol  it doesn't help as they mix 2 different bikes into each chapter.

[darrsi]

You need a torx allen key size T25, but the tamper proof type with the hole in the middle of it, to go over the pin in the centre of the screws.

[Fazer99]

I've got a few T25 Torx Allen bits but not security ones so I might try drilling a little hole in one of them so it will fit.


Looks like my Sunday is going to be another day in the garage ?

[darrsi]

Whole process only actually takes minutes to do.
I've had 3 TPS' fail on me, but the 2nd & 3rd were used ones, so years old.
4th one was brand new, think it cost around £70.
So if you think you need to replace it buy new, as a used one will be at least 14 years old and about to peg out as well.


Usual signs, other than the RPM needle are rough/erratic running, most noticeable at under 3000rpm, the bike becomes jerky and not smooth at all.

[Fazer99]

Where did you get the new TPS from? as I tried searching on wemoto where I get most of my parts from but no results there.

[darrsi]

Ebay - "throttle position sensor FZS600"

[Fazer99]

Cheers buddy I didn't think about evilbay  :evil  everywhere that was showing results using google were asking for near the £200 mark so I started to crap myself worrying that this could be a chuffing expensive repair.

[His Dudeness]

If I was you I'd start by trying to figure out if it's a problem with one cylinder or all of them. I'd run the bike in the rev range where it's losing power and then throw some water on the headers and check to see if one of them dries slower than the others. If one does dry slower it'd point to that cylinder having the problem and you could try swapping parts from that weaker cylinder onto a good cylinder. Do it one part at a time. Plug caps and coils are common culprits. If you throw water on the headers and they all dry at the same rate then you know it's a problem with a part that effects all cylinders so fuel supply, tank, fuel filter, pump, carbs, air filter, tps, maybe reg/rec. What did the plugs look like when you took them out?

[Fazer99]

All 4 cylinders are firing as I did test them just as you stated, plugs looked good slight burnt residue as to be exspected and the plugs and leads were only just changed a few months ago. I had been checking through the mechanical side of things to the best of my mechanical knowledge as I know less about electronics than I do about mechanics  :lol  fuel lines are flowing fine as I connected up some clear piping that I had and you can see the petrol getting sucked through with no gaps. From what darrsi has said and from what I've read in general online it does sound like a faulty TPS is a strong culprit, but don't worry I will be testing before I buy a new one as I'm not spending money on something I don't need ?

[maxzer1500]

[quote author=Fazer99 link=topic=22665.msg261506#msg261506 date=1495918970]
I've got a few T25 Torx Allen bits but not security ones so I might try drilling a little hole in one of them so it will fit.


Looks like my Sunday is going to be another day in the garage ?
[/quote
    You can simply use a punch or similar to snap off the central pin and use the Torx bit as is.]

[Fazer99]

[quote author=Fazer99 link=topic=22665.msg261506#msg261506 date=1495918970]
I've got a few T25 Torx Allen bits but not security ones so I might try drilling a little hole in one of them so it will fit.


Looks like my Sunday is going to be another day in the garage ?

You can simply use a punch or similar to snap off the central pin and use the Torx bit as is.
[/quote]


didn't think of that as I thought they were designed to be strong enough to not be tampered with in that way.

[unfazed]

You would by the security torx bit for for about a fiver  :rolleyes

[darrsi]

[quote author=maxzer1500 link=topic=22665.msg261530#msg261530 date=1495958324]
[quote author=Fazer99 link=topic=22665.msg261506#msg261506 date=1495918970]
I've got a few T25 Torx Allen bits but not security ones so I might try drilling a little hole in one of them so it will fit.


Looks like my Sunday is going to be another day in the garage ?

You can simply use a punch or similar to snap off the central pin and use the Torx bit as is.
[/quote]


didn't think of that as I thought they were designed to be strong enough to not be tampered with in that way.
[/quote]


I wouldn't go down that route if truth be told, that might not end too well.


Word of warning as well, if the needle hits 10,000rpm, DON'T TURN THE IGNITION OFF.
The needle will be be leaning to the right and gravity will simply make it drop clockwise.
Then you"ll have to take the clocks apart to move it back round to zero.
Just start the engine and it will move back itself to the correct side.