K100 hard to start

How to; Why did it do that?; What do I do now!...

K100 hard to start

Postby Wombat » Thu Jun 07, 2012 10:13 pm

Hi guys, I've been riding my first Beemer for about two years now, a 1987 K100RS which has developed a problem I'm hoping someone with more experience has seen before..
She has become REALLY hard to start from cold, so much so that I've run the battery flat a few times trying.
I've changed the plugs, checked the fuel pump is working and all the things I know how to check but can't find anything.
The weird thing is, once she does start - she purrs like a kitten. No spluttering, no misfiring, nothing. She runs beautifully.
I can't understand how an obviously perfectly healthy engine can be so impossible to start!
My prime suspect is the choke, but I have no idea how to check it.
I'm in Albany so its a long ride to a BMW expert.......
Any advice greatfully recieved!!
Wombat
 
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Joined: Thu Jun 07, 2012 9:59 pm
Location: Albany

Re: K100 hard to start

Postby wightman » Sun Jun 10, 2012 11:02 am

Hallo Wombat

It's not really a choke, being fuel injected, more a kind of idle advance. I find that using no throttle helps (but the idle advance on full) Try moving it when the engine is running, and if there's no change in engine sound, then you know your idle advance is not working. Is your plug gap 0.7mm or less? I make mine 0.6mm, especially in winter. Just for a lark, open your petrol cap and seal your mouth around the opeing and blow in (pressurise the fuel in there) I have also learnt (from bitter experience, to not less the fuel level get too low) One of the weak points with these K bikes, is that moisture gets in the tank and fouls the sender unit and other asoociated goodies in the tank...........

Also, its better to turn around and come back after 5 minutes and try again, instead of multiple attempts (I know this is difficult when you're already 10 minutes late for the start of a footy match, but less haste, more speed!)

John :mrgreen:
wightman
 
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Re: K100 hard to start

Postby goldie » Sun Jun 10, 2012 7:34 pm

Hi wombat give me a ring after 6 pm 0417968043 might be able to give you some tips
goldie
 
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Re: K100 hard to start

Postby Wombat » Mon Jun 11, 2012 5:49 pm

Thanks for the help guys, I checked the gaps on the plugs and they seem o.k. Once I got her running I put the idle advance up to full and it definitely kicked in so I guess it is working o.k but to get it started I had to leave the idle advance off completely... I found if I tried to use it she made no attempt at all to start, but when I took it off, she kept trying and eventually sputtered into life.
I haven't tried blowing into the tank yet... My wife already thinks I have an unnatural attachment to this bike - if she sees me doing that she'll be carting me off to the shrink! :shock: . It's funny that you mentioned about running low on fuel though, I remember that when this all started was when I let her get very low on fuel... could be onto something there.

Goldie, I'll try giving you a call tonight if thats o.k.
Thanks again,
Paul.
Wombat
 
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Location: Albany

Re: K100 hard to start

Postby goldie » Mon Jun 11, 2012 6:21 pm

ok
goldie
 
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