Could some kind soul suggest on the balance of probabilities where to check next? MY 1989 LT starts on the button when warm, but I have to feather the throttle when cold(white smoke) and give her lots of revs before she will idle ok - I suspect it's effecting my mpg as the red light comes on at 150 UK miles (241km).Bikes on 32k miles, sounds turbine great.

Main jobs done (by my mechanic who is ex BMW) over the past 2 years.

Recon injectors fitted, new exterior fuel lines, tank clean & filler cap(crudded up), Major service inc valve check, plugs, filters fuel. New battery & uprated earth kit. New ramspeed ht cables(these make a big difference, only £50). New crankcase breather hose(was cracked).New temp sensor near radiator. New oil/water pump fix kit (was very worn), new tps switch (old one failed)..
I also cleaned all undertank contacts including the ignition unit and treated - EXCEPT the relay box & computer. (The computer connections look tight and well greased - but I didntnt open it.

I've also had the clutch & suspension upreated,exhaust gaskets renewed, handlebar rubbers, front brearings... so spent loads of £££, - just need to address the starting issue!!

From reading posts - my suspicions are

• Poor contacts inside computer/relays (my seat is worn and holding water!)
  
• Blocked fuel regulator (I had problem with dirty filler cap/fuel filter and may be a blockage??)
  
• In tank fuel lines worn
  
• Worn throttle body rubbers (my mechanic says they are ok as all is balancing fime when injectors replace)
  
• Any other worn rubbers?
  
• Hall sensors or their contacts
  
• All of above!! (my mechanic is very good - but not an owner)
  

If anyone else has had similar problems - advice would be gratefully recieved before we set off to Portugal later this year and I spend more money on the bike.

Many thanks
Colin

Hi Colin..

You may have read some of my threads on the problems that I have had... ranging from the FPR not controlling the pressure to valves not being right. What is the Mpg that you are getting? I am around the 43 mpg mark. I would ignore the red light and work out the real Mpg as the red light is controlled by the fuel level sensor which is know to tell lies!!! With a full tank my gauge doesn't show full!

The only time I needed to give the throttle a feather was yesterday after I swapped valves around which meant the throttle bodies were out of synch. She is starting like a dream now.

Hi thanks
Im getting about 40mpg - and I ride quick off the lights!
I'm more inclined to look at the throttle body mounts next?? - I've noticed vibrations at footpegs getting moreso of late - revelation was changing the handlebar moubting rubbers..
no vibes there now!

It does sound like your in a very similar position to me then. All of the Rubber parts that attach to the throttle bodies on mine have been replaced, the reason was leaking air which was being unmetered. This normally presents itself as a poor idle I believe.

Due to the age of our bike's it wouldn't be a bad idea to replace all the rubber which air flows through due to it being hard at times to identify where there is an air leak.

Out of synch throttle bodies can cause extra vibrations...

I am also wondering if the winter fuel which is what we are using at the moment could be a partial cause! I am not to sure when the fuel mixture is due to change to regular fuel mind. But there maybe an increase in mpg at that point. Along with when the external air temp rises.

The vibration in the foot pegs is normally felt around the 4 - 4500 rpm mark.... I find it worst in 3rd gear as well! but then its not too bad.

I am thinking about replacing the last 3 original injectors on my bike (I had to replace one as it died). I have thought about reconditioned one's but have decided against it as they are never going to be as good as new... James Sherlock has them cheapest out of the normal 3 parts sellers here.

Thanks for your thoughts....I have read somewhere there are bosh injectors for other vehicles that k100 owners have tried with success and much cheaper...I was comtemplatinjg that route too. Has anyone any experience of this?

I usually find Shell petrol better than Tescos with a bit more mpg - but Tescos is more convenient!

The vibes start at just under 3k to about 4k
The bike seems "almost" perfect, but not quite!!
Colin

Sounds to me likw a leak at the TBs and it may be sealing with heat and that is why it will ballance the TBs because it is done hot.
As for fuel I will not use Shell fuel I have suspected it several times as the cause of problems and always use 98 RON which is the highest octane available here. Your engine is 10.2-1 compression and will not tollerate a lesser octane without long term problems like detonation which causes the nicasil bores to come apart.