I just wanted to seek a second/third/forth etc opinion before I send my bikes ECU for repairs and have to sell a kidney to pay for it. The saga so far:
Some time ago when warm the engine would not idle reliably when it stalled it would be reluctant to start. At the same time the rev counter would not work at low revs, it would stay on the stop until the revs got above 2000 ish and then start working again. From a cold start things would be fine again. Sometimes all would be well and it would run fine for a whole trip.
Lately the problem was becoming more frequent until the other evening is stopped and refused to start. There was no spark on either cylinder. It was a very hot evening and after an hour of cooling it still would not play and I called the recovery people.
The next day I got it running, again it’s was fine until it got warm and then started to play up.
I have checked all they connectors between ECU coils injectors etc, all the earth connections are fine and I have removed and tested the oiland air temperature censors which were both fine.
This all points to the ECU having a fault I think. Have I missed anything?
Before you do anything change all the relays under the side panel. The bit you haven’t checked is the crank position sender take it out and ideally fit a replacement they can fail when hot
Regards keith
An update on the saga…Having had the ECU tested (no fault) replaced the crank position censor (expensive) all appeared well. Started well ran OK when hot started again several times on a couple of road tests. Then it all started to go wrong, first sign of trouble was the rev counter became erratic then it was difficult to start then refused to start at all.
Going back to square one, plugs removed, no spark. All connections re checked removed CPS and double checked clearance, still no spark. Tried selectively cooling things with air line-nothing. Then for want something else to do swapped the ECU relay for a new one. Big spark and engine ran on they other cylinder. Several start stops later all well.
Tested the suspect relay and found that it had resistance across the contacts (about 70 ohms) all the other relays had no resistance. The next day the relay tested fine, needless to say I have not refitted it.
So far after a couple of hours of mixed use and a lot of start stops all is well, although I am not entirely convinced that I have seen the back of they problem.
I am beginning to wonder if there were two separate intermittent faults. I now plan to test the CPS, but before I can do this I a data sheet so I know what I am testing. If anybody knows where I could find one please let me know.
On the hottest day of the century I was out on my Cali Vintage, after about 25 miles I shut off at a roundabout and it cut out, tried to start it and it was banging and popping, after 15 mins of cooling down under the shade of a tree it started gain, another 30 miles or so same stuff, I managed to pull into a garage, I filled up and went to start it again, one almighty bang and 8k on the rev counter, switched off in a nano second, bike had to be recovered.
The reason was, the hose and clip between the injector and inlet manifold had expanded in the heat and was leaking air and finally detached itself hence 8k revs, It’s just a suggestion but check the condition of the hoses.