Briggs & Stratton powered Falco

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fatboy · #31 Post by **fatboy** » Sat Jun 14, 2014 6:38 pm

You seem to have ruled out fuel and spark issues so that leaves compression, wouldnt be surprised to find it is a valve problem.
Are you 100% convinced the lump was running 100% before it came to you ?

KitchenSync · #32 Post by **KitchenSync** » Sun Jun 15, 2014 1:17 pm

Motorised Bicycle Repair Man is yet to arrive - I just put the new battery in and it's nice to hear the thing turn over at a healthy lick. The previous gel battery never did match this new Yuasa.

Anyway... pulled the injector plugs out and with one of the rear spark plugs out my finger nearly got sucked down the hole as I turned the engine over.

Not an exhaustive test - I really should go and get a compression tester but it gets expensive buying tools for one use.

I've been assured by the guy that this engine is fine. He's got a good reputation for Aprilia parts and we spoke on the phone the other night. His instinct was coils, but I've switched one around and it's made no difference. I guess I could try some QuickStart but in an hour of chugging away this hasn't once tried to catch on the rear.

Just started raining so I guess I'll not get much done now but if it stops I'll pull the front valve cover and see what's what with the cam positions.

fatboy · #33 Post by **fatboy** » Sun Jun 15, 2014 6:57 pm

Hopefully MBR Man can make some sense of this.
You getting full voltage to rear coils ?
This is really odd, Ive had several elctrickery issues causing non starting, never got the bugger to start on one cylinder only.
Some have had the Falc turn into a big single because of the kill switch,blast a bit of cleaner in there?

Aladinsaneuk · #34 Post by **Aladinsaneuk** » Sun Jun 15, 2014 7:05 pm

Try swapping the coils over - front to rear etc

KitchenSync · #35 Post by **KitchenSync** » Sun Jun 15, 2014 7:09 pm

I did have it kicking over with both spare plugs in the rear leads... could see the both clicking away as it turned over.

Then I did the inner plug leads from both front and back to see if the sparks were the comparable. I got the impression that the rear spark wasn't quite as energetic as the front - but that's difficult to gauge.

I did get a jolt from one of the rear plugs, when I was messing about, and it didn't hurt like it should, though it may just have not be a well contacted.

I wonder if there are any spare ECUs about I could borrow and subsequently purchase if it turns out to be the problem?

Aladinsaneuk · #36 Post by **Aladinsaneuk** » Sun Jun 15, 2014 7:13 pm

Humour me

Try swapping the coils

I suspect on of the rears is degraded

KitchenSync · #37 Post by **KitchenSync** » Sun Jun 15, 2014 7:24 pm

Have done already. Nada.

But I've found this reference to running on one cylinder in the Mille Training Manual

But what the hell is an igniter or for that matter IGF11/12/21/22 - I can't see what that refers to.

Answers on a postcard please....

zoidberg · #38 Post by **zoidberg** » Sun Jun 15, 2014 7:25 pm

i also think the leads should be inspected if they havent already

fatboy · #39 Post by **fatboy** » Sun Jun 15, 2014 7:39 pm

Having a substitute ECU is a good idea, can make diagnosing cheaper than a plug in. Sorry but Ive just cooked two of em !
A lot of the wiring you need to look at runs through the ECU and the shut off relay

KitchenSync · #40 Post by **KitchenSync** » Thu Jun 19, 2014 9:56 pm

Replacement ECU has made zero difference.

I'm moving on to the alarm now - wondering if the disturbance of the loom during the switch has exposed a splice point.

Gawd knows quite how the alarm would be stopping the rear from firing when I've got fuel and a spark but the guy I had come round to review things was similarly stumped.

Still... the walking is doing me good - but the fortune on train fares isn't.

Bah humbug!

fatboy · #41 Post by **fatboy** » Fri Jun 20, 2014 8:12 pm

Tis now time to study wiring diagram, I would be looking at shut off relay/alarm circuit and giving Griff @ Aprilia Performance a bell.
Cant fault your determination on this one dude
You may have a short or open circuit giving you all the hassle, while you are twiddling thumbs and thinking about throwing bricks through windows, get a can of contact cleaner spray and sort as many of the multi pin connects as you can

KitchenSync · #42 Post by **KitchenSync** » Sun Jun 22, 2014 12:58 pm

So stripping it all back... I just had to take the covers off to have a snoop - but there doesn't seem to be anything amiss here.

I checked the resistance as the magnet passes the cam sensor and it spiked as it passed. Interesting that there are scratches on No.2 piston like someone has had a screwdriver down there checking for tdc AND the crankshaft plug was only finger tight. Not sure that means anything.

Yes those ARE spots of rust - this engine was sitting in garage over winter before I had a chance to switch. When I say engine, I should of course say "engine".

Off for some contact cleaner... more later

KitchenSync · #43 Post by **KitchenSync** » Sun Jun 22, 2014 1:02 pm

How can I verify that the injectors are actually injecting - if I turn the bike over with the throttle bodies not seated would I see them squirting fuel slightly out of sync?

fatboy · #44 Post by **fatboy** » Sun Jun 22, 2014 6:51 pm

Didnt you report a cloud of petrol smelling vapour blasting out one of the rear plug holes?
I agonised over making a test rig for the injectors (but my TB's were still fitted), I took them to an injection specialist, tested and cleaned for about £30 and they confirmed the injectors not to be the cause of my 1 cylinder/0 cylinder running issues.
Yes they are the same as ones fitted to cars.
Give Griff a bell, the man is a legend !

KitchenSync · #45 Post by **KitchenSync** » Sun Jun 22, 2014 9:54 pm

Yup - I shall do. Another day wasted stripping everything down without finding anything awry.

I guess I could get another set of coils but there's a spark!

As for the injectors, I've two set of throttle bodies and swapping them makes no difference (I'm currently on my original Falco engine's). That mist puffing out of the plug hole could just have been from petrol sloshing around in the bore, but I guess you'd need an oscilloscope to see whether there was a correct signal getting to the injector - or a fault code (and I don't get one).

I've still not remove that Datatool from the loom - just removed the circuit board and bridged the two immobilising circuits. I guess I should just do that to eliminate it from the equation but I'm no where near a power socket to solder it back together.

At the back of it all - I know this is going to be something really simple but by the time I've thrown a bundle of notes at getting this sorted I'd have been far better flogging the whole thing and just buying a fresher, less leaky Falco.

Live and learn... would be a useful maxim. But I probably won't.