Monday, 1 March 2021

Technicians Guide To Yamaha Motorcycle Electrical Systems

Technicians Guide To Yamaha Motorcycle Electrical Systems


Click on Ebay UK here to buy a good Multimeter


Need parts for your motorbike try on Ebay UK here 


Basic electrical and circuit information ( excellent watch ) well worth watching even if you are above the basics level.


More advanced electrical circuit operation testing and fault finding 



Sunday, 24 January 2021

How to test spark plug with multimeter to see if is it is good or bad


Click on Ebay UK here to buy a good Multimeter


Need parts for your motorbike try on Ebay UK here 



 Its a very easy but useful test to make sure your spark plug is ok , you may need to clean the electrode to ensure you get a good reading but all you then have to do is set meter to read ohms and measure from the spark plug cap end to the electrode tip , and then from end to body to make sure no leakage to earth.




How to test spark plug with multimeter to see if is it is good or bad

Get set up turn meter to ohms reading on dial and clean the electrode as below 

How to test spark plug with multimeter to see if is it is good or bad

Test between end of spark plug where HT lead cap fits and the tip of electrode the reading is very low only 1.2 ohms 

How to test spark plug with multimeter to see if is it is good or bad

on a dirty part of electrode the reading goes wild and eventually read 188.9 ohms so very bad and to avoid this clean electrode tip 



How to test spark plug with multimeter to see if is it is good or bad


Next test from spark plug cap end to the body to make sure no earth leakage your meter should read OL which is a good reading as it signals no leakage to earth via the body.

How to test spark plug with multimeter to see if is it is good or bad

See video of this process below 


Monday, 28 December 2020

Motorcycle electrics fuel injection components





Motorcycle electrics fuel injection components

On most modern motorbikes carbs are a thing of the past, and in replacement we have the fuel injection systems. The cdi will control both the fuel injection and ignition timing on these systems and uses sensors to time the exact time and duration of the spark and injection pulse.


You have sensors fitted on the bike that measure certain parameters these are and could differ depending on the manufacturer model and system used.


Input side

CTS coolant temperature sensor .

ACT engine air temperature sensor.

BARO read the barometric pressure at or above sea level to aid calculation of injection pulse.

TPS throttle position sensor obviously tell the cdi where your throttle is positioned .

MAP manifold pressure reading to held aid in calculation of the fuel to air mixture needed.

ECM engine management computer where all fuel and timing is controlled

CPS crack shaft position sensor or pick up coil 


Output side

Injectors - inject fuel into the engine via a timed pulse from ECM

IAC - idle air control valve the controls the tick over of the bike 

Ignition Coil - increases the 12v signal from the ECM to 10000 plus volts needed to produce spark

Fuel pump relay - this energises the pump to pressurise the fuel system



Saturday, 26 December 2020

Battery testing and charging system quick test


Click on Ebay UK here to buy a good Multimeter


Need parts for your motorbike try on Ebay UK here 


I usually measure the voltage with my multimeter set to min - max and the turn the key over and test battery under one of the bikes main electrical load conditions when the starter motor is operating.

If the multimeter hits 10v or below on its minimum and 14.00v on its highest it proves the battery is good as the battery is to dropping below 10v under load and its reaching 14v on highest reading so it charging well too.

If you battery drops below 10v is probably time to replace it and it is not reaching 14v its only reaching 12.0v- 12.9v it shows the charging system is not functioning correctly.



see video below of me doing this on a car.