K75 - Misfire 1800 rpm to 2500 rpm

[Deise]

Bike starts first time - idles perfectly. In any gear when between about 1800 to 2500 rpm it. misfires.

Seems to get worse having ridden for some time .

Plugs changed , fuel filter changed. Noticed split in crankcase breather pipe so changed that.

any pointers would be appreciated please .

 

[squibb34]

Whilst not sure of the age/mileage/SH of your bike, I'm thinking Hall Effect Sensor at this stage.

Has this occurred suddenly, out of the blue, after a wet ride, or after a lay-up with stale fuel. Tell us more.

 

[steve hughes]

I suggest you pm Steptoe a message. He has worked on a few of these and maybe able to offer some suggestions

 

[DrFarkoff]

Bike starts first time - idles perfectly. In any gear when between about 1800 to 2500 rpm it. misfires.

Seems to get worse having ridden for some time .

Plugs changed , fuel filter changed. Noticed split in crankcase breather pipe so changed that.

any pointers would be appreciated please .

Age of bike would be handy ??? Misfires?? Why do you "think" it is misfiring ??

Symptoms??? Effects ??

Does it do it whilst gently easing through this range or Can you pull hard through it ??

When is the last time you put Injector cleaner or the like through the tank, or a big dollop or 3 of castor oil (Lubes injectors and smells nice )

I would think to Inspect Coils x 3 Mount points Insulation and connections and the plug leads!! Also What Plugs did you fit ???

What ever you do ??? Do it one change at a time and don;t just load a parts cannon and then think I wonder what fixed it???

Diagnosis and substitution of KNown good into your system

 

[Deise]

Thanks for replies

89 k75s, 32k miles.

Longest time idle over winter was 1 month

Dr Farkoff
At 18800 - 2500 it goes stutter,stutter. Can pull thru at increased revs

Never used injector cleaner

Castor oil not used since parents forced 60+ years ago lol

Plugs fitted Bosch in service pack motorworks

Will pursue as suggested, thanks

 

[theoneandonly]

run some injector cleaner thru' it , do 2 tankful's.
take off the plug cover , put it in the garage , turn the lights off ( do it at night ) and run it . can you see sparkles on the leads/plug caps ?
mist them with water too.
break and make all the electrical connections to the ign system . bit by bit , not all in one go , run it inbetween .
slow and methodically. test and check.

 

[Deise]

run some injector cleaner thru' it , do 2 tankful's.
take off the plug cover , put it in the garage , turn the lights off ( do it at night ) and run it . can you see sparkles on the leads/plug caps ?
mist them with water too.
break and make all the electrical connections to the ign system . bit by bit , not all in one go , run it inbetween .
slow and methodically. test and check.

Thank you

 

[Deise]

Update and Apologies to all who offered assistance on this. For various reasons it has been a slow process.

have tried out all suggestions and am now left with Hall sensor issue.

Have ordered a replacement from Hornig, Germany only because of the charges i would have to pay on Motorworks product since Brexit.

As a matter of interest the BMW dealer quoted 648.17 euro for original part 12111459049

thanks again

 

[DrFarkoff]

Update and Apologies to all who offered assistance on this. For various reasons it has been a slow process.

have tried out all suggestions and am now left with Hall sensor issue.

Have ordered a replacement from Hornig, Germany only because of the charges i would have to pay on Motorworks product since Brexit.

As a matter of interest the BMW dealer quoted 648.17 euro for original part 12111459049

thanks again

What have you actually Tested?? K75 have 3 x hall sensors

Sounds more like coil or coils or Leads or Sparkplugs breaking down under load

Maybe not correctly seared ECU connector ?