Intermittent starting issue (help pls)

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gavhowe · #1 Post by **gavhowe** » Wed Oct 24, 2012 6:03 pm

Hi I have 4 Falcos over the past 8 years, but have struck upon a starting issue with the current one:

Went to start the bike to comute to work, and it just span over on the starter motor with no sign of catching. Ended up flooding the engine then the battery got low, so got jump leads out, all this achieved was a bang and smoke out of the exhaust and from air filter (must have been flooded so bad it compressed the fuel and set it off) and to top it off the engine kicked back damaging the sprag spring. The battery was on its way out anyway so put the issue down to a s**t battery.

So purchased a new battery and fitted it after work, the bike still just span over (but with some noise from the sprag), but would still not catch. I put this down to it still being flooded. You could still smell fuel. I fitted some other spark plugs and still would not start (I forgot to check for a spark at this point).

So a day later I had another look at it and first on my plan was check for spark. I pulled a lead and connected a spare plug, and while staring at the plug I pressed the starter. And guess what it started on the button no fuss at all. So at this stage I had concluded it was a bad battery that had caused it to flood and this had taken time to dry off.

So 4 days later after my race weekend, I went to start it and would not start but lots of noise from the sprag. I stripped it down and shorted the sprag spring. The bike now started perfectly multiple times.

The following morning I plan to commute on it again, got up early to make sure it still started and all was fine, started and stopped it 3 times. So rode it 15miles to work with no issues.

However at 5pm when I want to come home it was not playing ball again. It is back to the original issue of just turning over. It has no alarm or imobilizer so its not that. My plan tomorrow is to take a spare plug into work with me and see if there is a spark. My only thoughts are that it was left outside all day in the damp and it may be an electrical issue.

Sorry for the essay but wanted to give you all the facts. Please could people offer me some advise as what to look for next??? I mean if there was no spark, what could cause this??

Thanks

Gavin Howell

fatboy · #2 Post by **fatboy** » Wed Oct 24, 2012 7:29 pm

When you say catching and turning over do you mean not starting/motor not turning over ?
Get some of those nifty little lights that fit twixt plug an cap, they flash with every pulse from coil so you dont have to remove plugs every time.
Also as others have said the Kill Switch on the RH can give some wierd problems
When you try to start, check both the pos and neg leads, if they are hot to touch then you got probs on those circuits,check for clean tight connexs
Good luck

gavhowe · #3 Post by **gavhowe** » Wed Oct 24, 2012 7:55 pm

I mean the starter motor is turning the engine over (spining it), but nothing else happens. As the engine is twin plug it is easy enough to check for spark without removing a plug. I will have a look at the kill switch though

blinkey501 · #4 Post by **blinkey501** » Wed Oct 24, 2012 8:15 pm

Firstly... Whilst recently having some work done by Griff he moved the wires that sits across the back cylinder and re routed them between the throttle bodies.
He told me that he had done this has wiring problems have occured in the past due to the outer sleeve of the cables fraying and earthing out on the engine.
I am wondering if anyone has any electrical faults it might be a good starting point

. I would advise cornish mafia to take this approach also with his fault on his bike.
Hopefully this will solve the problems and has these bikes are getting older it would be feasable to take this aproach.

Secondly...A chap who i used to work with has a mille and when i showed him the falco he pointed out there is a multiplug under the seat/rear panel where your right bum cheek would be if you was sat on the bike that is also renowned for problems if people ride the aprilia in the rain on a regular accasion. So with this in mind i would be tempted to splt the joint and check for loose contacts and perhaps spray the multi plug with contact cleaner before pushing the plug togeather.

Worth a try fellas

Falcopops · #5 Post by **Falcopops** » Thu Oct 25, 2012 1:22 am

IIRC the kill switch will result in no action when you press the starter, but could be wrong.

This is tricky, I'd be looking at the safety circuits. Side stand switch, clutch switch and neutral switch.

Since you've had 4 Falco's I'd expect you've got the staring do's and don'ts well sorted, although each bike can be different.

Another thought is the wiring to the fuel pump, although that doesn't sit well with the flooding issue.

Good luck and keep us informed

gavhowe · #6 Post by **gavhowe** » Thu Oct 25, 2012 8:41 am

Ok an update on the bike, I got to work early this morning so I could start going over the bike. I checked the battery voltage and that was 12.9v so was happy to continue testing the bike. So I unpluged, the lower rear spark plug lead and fitted a spare plug I had. and guess what it started instantly on the button. So put lead back on the bike and it continued to start each time. The bike has been sat in a heated factory all night instead of a damp garage on outside.

Next I unplugged as many connectors in the tail unit and around the engine I could find and sprayed with contact cleaner. I did not find any suspect connections. So I pushed the bike back outside so I can leave it running to charge the battery.

I went back out to it after 10mins and it was reading 95 on the temp readout, so I thought I would leave it running till the fans cut in. However the bike got to 105 and they had still not come on so turned it off. So fans are not working.

Now the really strange bit, the bike was idling at 1500rpm and when I turn the key off the clocks went off as normal, but the rpm needle stayed at 1500rpm. It did not drop back to 0rpm. so I tried it again turned the key rpm needle went up to shift light point as normal and i turn the key back off as it got to 6000rpm. The needle again stuck there, it is sat outside at the moment off, but with 6000rpm showing on the clocks.

Any thoughts???

D-Rider · #7 Post by **D-Rider** » Thu Oct 25, 2012 8:48 am

A few on AF1 have reported that their tacho needle has become mis-aligned. They've taken the clocks apart, re-positioned the needle and then put it all back together.

gavhowe · #8 Post by **gavhowe** » Thu Oct 25, 2012 9:36 am

Hi, it is not misaligned as it will still do the full span and when running it idles at the correct rpm. And from a reset situation the span test goes to 6000rpm. Some how the stepper motor for the clocks is holding its position, I am thinking a earthing issue may be. This could be related to why it would not start and this is driven by crank/ cam sensor, so a problem on this circuit could stop a spark being made...... may be

Aladinsaneuk · #9 Post by **Aladinsaneuk** » Thu Oct 25, 2012 12:14 pm

certainly sounds like an earth / short issue

I have had a few issues with the right hand switch gear.... especially the engine on/off - though it did not have these symptoms....

MartDude · #10 Post by **MartDude** » Thu Oct 25, 2012 1:32 pm

Aladinsaneuk wrote:certainly sounds like a short issue

Tim should be able to help, then

Aladinsaneuk · #11 Post by **Aladinsaneuk** » Thu Oct 25, 2012 1:37 pm

very tempting to say that he is boring no and does not often rise to the bait......

#12 Post by **Kwackerz** » Thu Oct 25, 2012 2:02 pm

I saw what you did there....

*sigh*

if I wasnt painting the house and packing boxes i would have bitten..

and yes I have an extension handle for the roller, before the smartarsed nurse gets there.. and a ladder for the stairs walls..

Back to the subject of the thread, a lot of good pointers previously mentioned. if all else fails phone griff with the symptoms

D-Rider · #13 Post by **D-Rider** » Thu Oct 25, 2012 2:16 pm

Kwackerz wrote: I saw what you did there....

*sigh*

if I wasnt painting the house and packing boxes i would have bitten..

and yes I have an extension handle for the roller, before the smartarsed nurse gets there.. and a ladder for the stairs walls..

... and this is the house ....

Aladinsaneuk · #14 Post by **Aladinsaneuk** » Thu Oct 25, 2012 2:37 pm

surely not?

i thought of the hobbit hole in another thread

D-Rider · #15 Post by **D-Rider** » Thu Oct 25, 2012 2:41 pm

Aladinsaneuk wrote:
i thought of the hobbit hole

Pervert !