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K100-forum.com » Technical, repair and troubleshooting » Engine and transmission » Lack of power above 3500RPM...

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1Back to top Go down   Lack of power above 3500RPM... Empty Lack of power above 3500RPM... Fri Jul 12, 2024 6:53 pm

HZolio

HZolio
active member
active member
Hi there!


So, i need your help!

The bike is my 1992 K100RS 16V, with 152000km. Starts, idles and rides flawless, but (more noticeable on 5th gear), it doesn't make more than 3500rpm easily... she can rise downhill, but at a cost!

I already adjusted CO and ignition, balanced those ITB, new plugs and "usable" plug wires. ALL fluids changed, refrigeration gremlins sorted, and air filter is new! Also changed the shot steering bearings and serviced the forks, new seals on the front brake pump, flushed all the DOT4 (ABS fully working Very Happy ), all of this is obviously not the culprit but FYI...

On 2 months reading the forum i learned: the tank is mirror clean, the fuel filter (IDK) looks new, as the pump also!

I noticed, when adjusting the CO, the potentiometer was VERY sensitive. It is normal?


Where do i start? New fuel filter? Or...



Any help would be appreciated!


May thanks


__________________________________________________
HZolio




'92 K100RS 16V
'86 R65
'10 R1200GSA

...and too many to list...
    

2Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Fri Jul 12, 2024 7:11 pm

duck

duck
Life time member
Life time member
You can test the fuel filter by taking it out and attempting to blow through it.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

3Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Fri Jul 12, 2024 7:50 pm

Jordan53

Jordan53
Silver member
Silver member
On a bike with carburettor, I found a fuel filter that could not be blown through - but looked pristine.
I now don't use the pesky things on such bikes. The float bowl is an effective sediment trap.
Is it reasonable to leave out the filter with fuel injected engines?


__________________________________________________
1989 K100 RS

VIN: xxx0149621
    

4Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Fri Jul 12, 2024 8:37 pm

Rick G

Rick G
admin
admin
Not at all reasonable to leave the fuel filter out it is very necessary as any particle larger than 4 micron can cause an injector to seize.
I routinely replace the fuel filter each year and have cut a few open to see what has been caught, you would be very supprized what comes out of a fuel pump at a service station.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

5Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Fri Jul 12, 2024 10:25 pm

duck

duck
Life time member
Life time member
They can also clog due to age because the filter fibers can swell, especially if the gas has water in it absorbed by ethanol.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

6Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Sat Jul 13, 2024 9:32 am

Bricklayer

Bricklayer
Silver member
Silver member
I had a similar loss over power as the engine RPM climbed over 3k. It was a bugger to troubleshoot. A fuel line inside the tank had a small crack that only leaked either from higher vibration or vacuum drop causing FPR to increase pressure (or both working together to infuriate me).

I was at wits end until I open the fuel tank lid and viewed inside with a flashlight/torch and worked the throttle.

If one is changing the fuel filter and are unsure of the fuel line hose age, might as well replace those whilst in there.

https://anthonymrugacz.net/
    

7Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Sat Jul 13, 2024 12:52 pm

Two Wheels Better

Two Wheels Better
Moderator
Moderator
HZolio wrote:The bike is my 1992 K100RS 16V

I already adjusted CO

I noticed, when adjusting the CO, the potentiometer was VERY sensitive. It is normal?
I'm curious, do you have an exhaust gas analyser stuffed up the exhaust tailpipe that allows you to "see" the changes you make to the potentiometre when turning it? Yes, they are very sensitive. A screwdriver blade width can make a big difference. Also, it would be the very last thing to do after all other proper tuning and maintenance requirements are met.


__________________________________________________
"A long ride is the answer to a question you will soon forget!" ~ Anonymous
1977 R75/7-100, '93 K11/K12 Big Block, '93 K1100RS, '95 R100 Mystic, '96 K1100RS, 2 x '98 K1200RS, '06 K1200R & '09 K1300GT
    

8Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Sat Jul 13, 2024 3:42 pm

HZolio

HZolio
active member
active member
Two Wheels Better wrote:
HZolio wrote:The bike is my 1992 K100RS 16V

I already adjusted CO

I noticed, when adjusting the CO, the potentiometer was VERY sensitive. It is normal?
I'm curious, do you have an exhaust gas analyser stuffed up the exhaust tailpipe that allows you to "see" the changes you make to the potentiometre when turning it? Yes, they are very sensitive. A screwdriver blade width can make a big difference. Also, it would be the very last thing to do after all other proper tuning and maintenance requirements are met.



Yes, of couse: first with my trusty Bosch on my own garage, but then, as i only noticed few changes, i took the K100 to the work, as i'm the technician on MB Classic Center in Sintra, and "my" gas analyser there is checked by the government at least, one time/year... but, with no great sucess...


__________________________________________________
HZolio




'92 K100RS 16V
'86 R65
'10 R1200GSA

...and too many to list...
    

9Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Sat Jul 13, 2024 3:46 pm

HZolio

HZolio
active member
active member
duck wrote:You can test the fuel filter by taking it out and attempting to blow through it.


Unfortunately i'm near the end of my vacations far away from the K100, but when i take it off, i will notice you!

Thanks!   Cool


__________________________________________________
HZolio




'92 K100RS 16V
'86 R65
'10 R1200GSA

...and too many to list...
    

10Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Sat Jul 13, 2024 3:51 pm

HZolio

HZolio
active member
active member
Jordan53 wrote:On a bike with carburettor, I found a fuel filter that could not be blown through - but looked pristine.
I now don't use the pesky things on such bikes. The float bowl is an effective sediment trap.
Is it reasonable to leave out the filter with fuel injected engines?


In my other carburated bikes, i also do not recommend one fuelfilter, as i can clean one carb bowl and gigleurs easily, but here... NO!


Thanks!


__________________________________________________
HZolio




'92 K100RS 16V
'86 R65
'10 R1200GSA

...and too many to list...
    

11Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Sat Jul 13, 2024 3:55 pm

HZolio

HZolio
active member
active member
Rick G wrote:Not at all reasonable to leave the fuel filter out it is very necessary as any particle larger than 4 micron can cause an injector to seize.
I routinely replace the fuel filter each year and have cut a few open to see what has been caught, you would be very supprized what comes out of a fuel pump at a service station.



Next task to do!!!


Thanks!!!


__________________________________________________
HZolio




'92 K100RS 16V
'86 R65
'10 R1200GSA

...and too many to list...
    

12Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Mon Jul 15, 2024 11:42 am

Point-Seven-five

Point-Seven-five
Life time member
Life time member
Definitely change the fuel filter.  I had a problem with one.  The worst part was that it was right on the edge of not enough flow so that sometimes the engine worked okay, and sometimes it lost power.

It's a good idea to change the filter every couple years, because even if it doesn't block enough flow to hurt performance, it can make the fuel pump work harder and that can't be good for the fuel pump.


__________________________________________________
Present: 1991 K100RS "Moby Brick Too"
 
Past:
1994 K75RT "Ilsa, She Wolf of the SS"
1988 K100RS SE "Special Ed"
1994 K75S "Cheetos"
1992 K100RS "Moby Brick" R.I.P.
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

13Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Mon Jul 15, 2024 1:58 pm

Arlina

Arlina
Moderator
Moderator
As said before, the fuelfilter.

But besides that, possible that the TPS (not Switch, but Sensor) needs to re-learn his tricks.

I have a file in my cloud on howto, download and have fun Smile

https://mega.nz/file/Guw0GBDC#iy63G00X3NE_ZfwgNYlvUXYmxVcKvXJkk-oxj8Ah9Eg


__________________________________________________
Lack of power above 3500RPM... Eu-log10  K1100RS/LT - R1200RT - R1100RS - Cagiva SST 350 Ala Verde - K75LT project - K75 Schurgers - K75S - K1100RS - K75RT - K75C
    

14Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Tue Jul 16, 2024 3:48 pm

HZolio

HZolio
active member
active member
Hi all,


Yes, you were right! 2003 fuel fiter, almost blocked on the blow test!

Lack of power above 3500RPM... Img_3810




Yesterday i changed it for a new one and today the bike rode perfectly!


Thanks for the tips!


__________________________________________________
HZolio




'92 K100RS 16V
'86 R65
'10 R1200GSA

...and too many to list...
    

15Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Tue Jul 16, 2024 4:45 pm

Two Wheels Better

Two Wheels Better
Moderator
Moderator
We love a definitive fix!  cheers


__________________________________________________
"A long ride is the answer to a question you will soon forget!" ~ Anonymous
1977 R75/7-100, '93 K11/K12 Big Block, '93 K1100RS, '95 R100 Mystic, '96 K1100RS, 2 x '98 K1200RS, '06 K1200R & '09 K1300GT
    

16Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Tue Jul 16, 2024 6:01 pm

HZolio

HZolio
active member
active member
Two Wheels Better wrote:We love a definitive fix!  cheers


Me too!  Cool

Now the fun part: i didn't have the time yet to purchase a new fuel filter, but i need to try this. So at the work (MB) i have laiyng around a bunch of used (new??? Cool) f filters from the SLR McLaren... the maintenance schedule DEMANDS to change them, even if the SLR like in most cases, have runned for 500km... in 2 years! And yes, they are also inside the tank, and you have to remove the tanks from the car (2 of them) to change those filters...  So i keep them for testing purposes and yes, my K100 is using now one of those!!!


McLaren filter made the K100 pass 180km/h today!!!!!!!    Very Happy


__________________________________________________
HZolio




'92 K100RS 16V
'86 R65
'10 R1200GSA

...and too many to list...
    

17Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Tue Jul 16, 2024 7:38 pm

Point-Seven-five

Point-Seven-five
Life time member
Life time member
Good to hear that you found and corrected the problem.

Even better that it was an inexpensive fix.


__________________________________________________
Present: 1991 K100RS "Moby Brick Too"
 
Past:
1994 K75RT "Ilsa, She Wolf of the SS"
1988 K100RS SE "Special Ed"
1994 K75S "Cheetos"
1992 K100RS "Moby Brick" R.I.P.
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

18Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Wed Jul 17, 2024 5:52 am

Dai

Dai
Life time member
Life time member
HZolio wrote:McLaren filter made the K100 pass 180km/h today!!!!!!!    Very Happy
idea2


__________________________________________________
1983 K100 naked upgraded to K100LT spec after spending time as an RS and an RT
1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

19Back to top Go down   Lack of power above 3500RPM... Empty Re: Lack of power above 3500RPM... Wed Jul 17, 2024 12:29 pm

Arlina

Arlina
Moderator
Moderator
Never mind the date on the fuelfilters.
There is a lot of NOS, even when you buy a new one at the dealer these days, big chance it's 20 or more years old.


__________________________________________________
Lack of power above 3500RPM... Eu-log10  K1100RS/LT - R1200RT - R1100RS - Cagiva SST 350 Ala Verde - K75LT project - K75 Schurgers - K75S - K1100RS - K75RT - K75C
    

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