Forum

[Dean]

picked up a new EFI B5 a few weeks ago and notice that the idle is a bit low - it will occaisionally die at traffic signals unless I feather the throttle a bit. the dealer is out of state and doesn't seem to know much about the very bikes he is selling. new to the EFI technology - how do I increase my idle?

[Michael]

If it is under warranty, get them to look at it (it is common on these bikes I am afraid). If you want to tinker, there is a brass flathead screw in a very inaccesible plae, under the seat on the rear end of the throttle body - it is the idel adjust screw. Quarter turn at most!

[Dean]

thanks Mike - will pull the seat and see what I can do. dealer is almost 400 miles away. thought by upgrading to the EFI my "tinkering" days would be over.

[Dean]

Mike - does the brass screw have a pretty large head?

[Michael]

Yes, large single slot head I think. Its on the right hand side, right near the back of the air intake but of the injector manifoldy thingy. Cant recall if the head faces upwards or to the right of the bike, but you can just about get to it with the seat still on

[Michael]

The head faces upwards... it sits in a kind of recess. Tiny turns are all you need

[Alan R]

Hi DEAN----------- just to add to the others info......... It's like adjusting a carb's idle air mixture... Imagine that the visible face of the screw head is divided into 8 off, 45 degree segments...Let's suppose that the screw thread is 1mm pitch ie}--- for 1 complete revolution the screw advances or retreats 8 segments which is 1mm..For 1/2 revolution it's 4 segments = 0.25mm movement and for 1 segment it's 1/8 revolution = 0.125mm moved......................Using this approach you can now quantify what you are doing.............And as per a carbed bike, do these adjustments when its' up to running temp.............Trouble for you is that an EFI has a temp sensor linked into the "Brain" which if faulty could be sending info saying that the eng. temp is still low and thus the fuel enrichment will stay on longer and give a rich mixture when it's not required........... You really need to get it hooked up to an appropriate analyser and get it sorted......

[Frank]

Aren't these supposed to be very sensitive to the type of spark plug which can cause problems at idle? Think it's been discussed here before.

[Michael]

How did you get on Dean? A ciuple of things to note... these bikes often dont idle too well, cutting out etc isn't uncommon. It probably isnt a faulty sensor but rather a poor quality sensor. The EFI unit is, after all, a gerbil blowing as hard as he can!!! Also, check the manual bistarter-ey choke-ey cable is seated properky at both ends. This can enrich the mixture when you dont want it, causing poor idling.

[MickB]

Hi Dean, as Frank says it might be worth looking at the spark plug. My EFI came with a Bosch WR7DDC4 plug (India made) which was quite black and sooty when I removed it. Replaced it with an NGKBPR6ES and the difference was quite noticeable; more responsive, smoother and slightly faster idle and also cured an annoying backfire problem. Plug colour is also spot on.