Skip to content

Ask an Expert loss of power Technical

You are in... Forums > Ask an Expert > Technical > loss of power

Got something to say?

Got something to say?

Go to most recent reply

taksi

Joined:

Oct 11

Posts: 9

taksi says:

loss of power

I have a '58 plate FZ1 Fazer that has developed a peculiar and severe loss of power at low revs. If I'm idling up to a traffic light or junction at idle to 2000 revs and open up there is a severe loss of power till it reaches 2500 revs then  she's off like a rocket. If I slowly open the throttle there is no problem. The bike has a full Akrapovic system so no cat or ex-up. There are no fault codes showing on the dash though it does seem like an air problem to me.

I've checked all the connectors under the seat and the tank including ECU and TPS and have changed the plugs and checked the air vacuum hoses for the Scottoiler take off, also changed the fuel to Shell Vpower, nothing seems to work. I have spoken to two Yam dealers and they say I've done everything they could think of as well!  Any help would be greatly appreciated. Ta, Taksi.

 

Reply to this Topic  
  • Posted 3 years ago (28 January 2012 11:46)

Post a message in Technical

Fields marked with an asterisk * are required

   

Please note. You cannot submit more than 4000 characters as a message.

Upload image(s) from your computer (up to 3 images)

  1.  
  2.  
  3.  

Terms of use

Use of our community areas and forums is subject to important terms of use. By joining our community and using the features you agree to be bound by these terms. See terms of use below. 

Cancel
taksi

Joined:

Oct 11

Posts: 9

taksi says:

loss of power

Cheers guys. BTW I've been a car tech for 30 odd years but I've no bike experience this deep into a problem. Right, here goes.

1. checked oil/coolant levels.On car engines if oil is low it goes into 'limp mode'.

 2 Removed all fairngs and fuel tank. Disconnected every connector I could see including TPS, primary pump, O2 sensor, injectors, spark plugs and ecu. All clean and dry. Cleaned with contact cleaner and reconnected. Not able to check the operation of the tps as I don't have the ohm values or wiring diagram

3. Checked the vacuum pipes to the throttle  bodies and found Scottoiler feed adrift so refitted. Thought I'd found it then. Bugger. Checked airbox rubber seals between upper and lower halves and between airbox and throttle bodies. Air filter ok. Whilst the airbox was off and the air sensor was diconnected  I turned on the ignition and code 22 came on indicating that the lcd dash was reporting faults. 

4. Refilled tank with Shell Vpower fuel. I fill up once a week from the same fuel station. Idle speed is 1200rpm, where its always been before the problem arose.

 5. Although only 2k old, changed the spark plugs for the old ones (10k old) for elimination purposes.

6. Done 12k in 18 mths without a problem. Bike gets washed every weekend after work/rideout and put in the garage. I've left it in there for a month last year because of snow/ice but it ran without problems straight from the off. Not convinced washing has any bearing on this fault.

6. The Akro system (minus cat and ex-up) has been on since new and has not previously caused any problems. No there isn't a power commander fitted.

 

I think that about covers it. Can't think of anything I've missed but my head is up my a*** with this at the moment so I hope not.

 

Many thanks again,

 

Taksi.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reply to this Topic
bbstrikesagain

Joined:

Nov 08

Posts: 878

Lamba sensor?

Does it have one?  If so a severe error should show up on the dash, but if dodgy connections go undetected then get you might get an overly lean engine when running closed loop (light and steady throttle), so when you crack it open there's nothing there for a moment.  Washing and drying can have an effect on more exposed connectors.  Maybe not, but you seem to have checked most everything else...

Reply to this Topic
smidget

Joined:

Nov 07

Posts: 2407

smidget says:

Hi taksi

Run bike up in the dark, and check that there is no tracking from the HT leads.


Also are you sure that the HT lead integrity is good, silicon leads have a tendency to break along the silicone core with continual heating and cooling cycles. (where possible I always use copper core leads)

From reading your first post again I am inclined to think that the TPS may be at fault, KCMC will probably know what the values should be.
Also have you checked the ECU fooling devices as per KCMC's post? 

OK KC buddy over to you.:tongue: 

[This Reply has been modified by the Author]

Reply to this Topic
taksi

Joined:

Oct 11

Posts: 9

taksi says:

loss of power

Eureka - Found the problem! No2 ignition coil breaking down. Bloody thing read ok on the multimeter but I suppose it's not under load then. Bought four from e-bay and all ok. Swapped them one by one to see how many had failed, so now I have 3 spares. But more important I will now recognise the symptons straight away and there is nothing more valuable than a new bit of knowledge.

Thanks for your replies and your interest.

 

Taksi

Reply to this Topic
smidget

Joined:

Nov 07

Posts: 2407

smidget says:

Taksi

Always good to hear back that a fault has been found and what the final cure was, wish more would do so.


Great news, now get out there and ride safe.

Reply to this Topic

Page

Compare Insurance

Save money by comparing quotes. It's quick and easy

Motorcycles for sale

 

It's only £13.99 to advertise your motorcycle on MCN

Sell your Motorcycle

Motorcycle pricing tool

New! Find used bike prices