Date: 28-03-24  Time: 22:09 pm

Author Topic: Top end loss of power  (Read 6816 times)

maniaka

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Top end loss of power
« on: 29 November 2013, 11:27:51 am »
Hello fello Foccers


I'm very lucky to have the privilege of knowing someone who own an old run way strip, so I often get the pleasure of experiencing all 95hp of the fazer


However the past few weeks the bike has struggled to get over 110 / 115. It seems to run out of steam (when I know it could easily hit 135)


The bike runs absolutly fine up to around 95 - 100, with no bogs, or hints of troubles. I havn't noticed any specific lack of power but there could well be without realising it. I ride the bike very mild manored 95% of the time and just like doing some fast runs on the airfield/track when I can.


It doesn't suddenly bog down or cut out, there doesn't seem to be a lack of revs .. i.e ... its not like it doesn;t go over 8000rm or something, they still appear to rise.


Could anyone suggest any points to look at ? So far i've only had the time to check the plugs and spins the wheels to make sure theres no binding or bearing troubles.


the bike: 2003 FZS 600, 26,500 miles on it (its still due the 24000 mile valve clearance check :/ )
Its had new air filter very recently, sprocket and chain appear fine, probably around 1/2 - 3/4 of its life span (still stock). Tyres are corrcet pressures etc. I wonder could it be clutch slippage ?


and in case you foccers hadn't seen enough fazers, heres the bike in question


Meet Baron ... yes ... the red Baron ;)




[/size]And for you all to laugh at heres me being a complete moron six months ago when I put the new down pipes on ... [size=78%]





.. yeah there the wrong way round ...


Cheers guys - see you at the NEC !!

andybesy

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Re: Top end loss of power
« Reply #1 on: 29 November 2013, 11:37:30 am »
Maybe time for a carb balance? Was the air filter changed recently for another standard or a K&N?

Is the idle at all lumpy?

Andy

darrsi

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Re: Top end loss of power
« Reply #2 on: 29 November 2013, 11:38:01 am »
Was it okay before you changed the air filter?
 
What make of air filter did you use?
More people are born because of alcohol than will ever die from it.

darrsi

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Re: Top end loss of power
« Reply #3 on: 29 November 2013, 11:40:41 am »
Maybe time for a carb balance? Was the air filter changed recently for another standard or a K&N?

Is the idle at all lumpy?

Andy

At high end speeds i doubt a unbalanced carbs would be too noticeable, but if it was the cause then at low speeds it would run like an absolute pig!
More people are born because of alcohol than will ever die from it.

bigbluebear

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Re: Top end loss of power
« Reply #4 on: 29 November 2013, 12:25:59 pm »
Another thing to check is the your throttle grip and make sure its still glued in place. This happened to me and the bike wouldn't go above 7k rpm as the grip was slipping back....took it off glued it back and sorted

maniaka

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Re: Top end loss of power
« Reply #5 on: 29 November 2013, 12:50:06 pm »
Maybe time for a carb balance? Was the air filter changed recently for another standard or a K&N?

Is the idle at all lumpy?

Andy

The idle isn't perfect ... I wouldnt say its bad, it doesn't cough and misfire, but it isn't exactly what I would call a perfect inline 4 sound... hard to describe, just a bit ... used and rough. No hesitation or coughing when slowly/quickly bringing up the revs though and no flat spots on power ... except ...at the top. I changed the plugs when i first bought the bike so there 10,000 old, though looked nicely tanned when I looked at them. One point to mention is when on choke in the mornings the bike recently smelled a bit more ... oily from the exhaust ... or my spidey senses are developing

The new air filter was a genuine straight from the Yamaha dealership. It ran fine before and after. The carbs have never been balanced since I've owned it which was at 16000 miles, before that it had full service history.

Poor Baron :(

maniaka

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Re: Top end loss of power
« Reply #6 on: 29 November 2013, 12:50:57 pm »
Another thing to check is the your throttle grip and make sure its still glued in place. This happened to me and the bike wouldn't go above 7k rpm as the grip was slipping back....took it off glued it back and sorted


oooo simple yet effective ... like Tia Chi, I'll be sure to check that on the ride home from work

Fazerider

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Re: Top end loss of power
« Reply #7 on: 29 November 2013, 03:03:26 pm »
Clutch slippage is quite obvious as it results in a rise in engine revs without any increase in speed, it's most likely at peak torque i.e. 8500 rpm with the throttle fully open. Doesn't sound as if that will be your problem if the only thing you notice is a speed limiter effect.
If the air intake is clear and the fuel supply isn't restricted (kinked fuel or tank breather hoses) then maybe it's the sparks... a TPS check might be worthwhile.

JoeRock

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Re: Top end loss of power
« Reply #8 on: 29 November 2013, 03:46:31 pm »
Clutch slippage is quite obvious as it results in a rise in engine revs without any increase in speed, it's most likely at peak torque i.e. 8500 rpm with the throttle fully open. Doesn't sound as if that will be your problem if the only thing you notice is a speed limiter effect.
If the air intake is clear and the fuel supply isn't restricted (kinked fuel or tank breather hoses) then maybe it's the sparks... a TPS check might be worthwhile.

Which would be around that speed the OP said he tops out at in 6th! Although it would also be doing it in the other gears if that was the case?

Ruby Racing

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Re: Top end loss of power
« Reply #9 on: 29 November 2013, 04:49:05 pm »
I don't know if it will cure your problem, but as you've changed the exhaust and air filter you should really have balanced the carbs afterwards, so worth getting that done asap.
Feel the Fear and do it anyway!

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Fazerider

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Re: Top end loss of power
« Reply #10 on: 29 November 2013, 05:12:44 pm »
Clutch slippage is quite obvious as it results in a rise in engine revs without any increase in speed, it's most likely at peak torque i.e. 8500 rpm with the throttle fully open. Doesn't sound as if that will be your problem if the only thing you notice is a speed limiter effect.
If the air intake is clear and the fuel supply isn't restricted (kinked fuel or tank breather hoses) then maybe it's the sparks... a TPS check might be worthwhile.
Which would be around that speed the OP said he tops out at in 6th! Although it would also be doing it in the other gears if that was the case?
Fair point. Having read his post again he does imply the revs continue to rise. Maybe he's not revving it much in the lower gears.

ChristoT

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Re: Top end loss of power
« Reply #11 on: 29 November 2013, 09:53:52 pm »
And for you all to laugh at heres me being a complete moron six months ago when I put the new down pipes on ... [/size][size=78%][/font]





.. yeah there the wrong way round ...


Cheers guys - see you at the NEC !!


That would be awesome for a 4 into 2 zorst system! I've said for yonks that a Fazer would look cool with twin cans... ;)
The Deef's apprentice

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Re: Top end loss of power
« Reply #12 on: 29 November 2013, 10:31:41 pm »
Hi aka

Its one of those annoying problems that you will have to investigate and tick all the boxes and revisit/back track and check the jobs you have done. Before you go spending money on new parts do the jobs that are only going to cost in cleaning parts. My bike was stuttering and bogging down at top end of revs. It turned out to be one of three problems and it took me an age to sort it (money/time/pissed off with her)

I suspected icing so took the carbs off and cleaned them. Put K&N air filter in and did a rad flush. It now runs a treat but could not tell you what the problem was. This was my last attempt to solve the problem as I had thrown money at her and changed allot of other parts.

I would start with a carb clean its not hard just scary if its the first time.

Daz
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darrsi

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Re: Top end loss of power
« Reply #13 on: 29 November 2013, 11:25:43 pm »
Hot engine carb icing "unlikely" from experience.
Carb heater circuit pipes do get blocked rather easy though.
I still give my bike a good booze up during winter with 99% Isopropyl alcohol, never had it again in 5yrs.
It takes any water/moisture out of the fuel and burns it off.
Plus if the bike is prone to it it'll happen just pottering about.
More people are born because of alcohol than will ever die from it.

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Re: Top end loss of power
« Reply #14 on: 02 December 2013, 04:10:15 pm »
Did it run O.K. with a standard exhaust?

I just wondered if it might be the exhaust system, I've experienced a similar problem when I changed my header pipes.


There is an easy fix oddly enough.


maniaka

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Re: Top end loss of power
« Reply #15 on: 03 December 2013, 02:09:11 pm »
Hello all fellow foccers,

apologies for a latish reply, currently at work so it will be a quick reply.
New pipes have had no effect previously and have been on for over 6 months, the bike revs perfectly fine to top end in all other gears under hard / gradual acceleration. In sixth gear however when reaching the 110 / 115mph region i can feel a vibrating coming from the rear of the bike, which is rather alarming, I wonder if the sprockets need replacing asap. They are not shark toothing or anything to give any immediate signs of damage (and yes the front sprocket is fine with the new 12mm nut)

I'll take some piccy's when I'm home tonight hopefully.

Foc sake

JoeRock

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Re: Top end loss of power
« Reply #16 on: 03 December 2013, 03:02:33 pm »
Hello all fellow foccers,

apologies for a latish reply, currently at work so it will be a quick reply.
New pipes have had no effect previously and have been on for over 6 months, the bike revs perfectly fine to top end in all other gears under hard / gradual acceleration. In sixth gear however when reaching the 110 / 115mph region i can feel a vibrating coming from the rear of the bike, which is rather alarming, I wonder if the sprockets need replacing asap. They are not shark toothing or anything to give any immediate signs of damage (and yes the front sprocket is fine with the new 12mm nut)

I'll take some piccy's when I'm home tonight hopefully.

Foc sake

Check your wheel bearings - if ones collapsed/partially collapsed then it could be causing sufficient drag to give the symtoms you're experiencing?