Maiden Voyage

discussions specific to the 906 Paso
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Giscard
Posts: 120
Joined: Thu Apr 28, 2011 2:56 pm
model: 906 Paso
year: 1990
Location: Cardiff UK and Dordogne France

Maiden Voyage

Post by Giscard »

Took the Paso out yesterday for a reasonable first test ride since I rebuilt the carb. Did about 72 kilometers. This was the first time I have had it on the road since I did 4 kilometers at the back end of last year. Very much a curates egg job.

Responsive on the throttle but a little hesitant at low revs and on pick up. I have yet to do the vacuum gauge and change the mixture settings as I wanted to see what the baseline was like before I played about with it too much.
It handles really well and is very responsive through bends and roundabouts. I thought with the 16 inch wheels it might tend to drop in to corners but I did not notice that at all. Probably helps that I have inflated the tyres to the correct pressure.

I did notice what felt like the engine misfiring, but I think I have identified the problem. Not necessarily how to fix it but at least identified it. When I tried the horn it did not work but the bike cut out. Didn't try that again. Noticed that it also missed when the indicators were used. When I switched the lights off the fault seemed to disappear. Anyway it is obviously related to the left hand handlebar switch, so I will need to sort that out before I try her again.

The battery is new and charges up nicely. The alternator is churning out plenty of volts.
By fiddling with the light switch I was able to eliminate the problem temporarily but it eventually came back. I am reasonably sure there is a fault with the left hand handlebar switch, ie a dead short brought on by pressing the horn or using the indicator switch. In the spares I got with the bike is a beaten up switch so I think the previous owner identified it as a problem also.

Nothing that a bit of time with the voltmeter won't cure.

Other than that - great fun.
Mc tool
paso grand pooh-bah
Posts: 1875
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Newzealand

Re: Maiden Voyage

Post by Mc tool »

Im picking the switch is ok , what is happening is every time you switch something on the load thru the very thin and often badly connected ignition wires goes up and the digiplex don't like that so it huccups. Have a look at the wiring diagram and you will see that everything is switched thru the ignition switch . The idea is to fit a main relay to the harness and solve this issue . If you want to prove the point connect a wire from the batt + to the power wire for the digiplex at the digiplex plug ( red wire , 6th from the left in the plug )and go for a ride and you will see that the problems have gone away. The other way to prove the fault is to connect the + probe of a multi meter to the batt + and the other lead to the digiplex red power wire and start the bike , with the meter switched to DC volts . What the meter is displaying is the difference between batt voltage and what is arriving at the digiplex , called voltage drop. Ideally the meter should read very close to zero but usually its one or so volts . Whilst watching the meter switch on various things like lights , blinkers horn and you will see that voltage drop increase to maybe 3 volts or more. This is telling you that the wiring harness ( all the plugs and switches and the wires themselves ) is not capable of handling the load . A combination of deteriorating connectors and the original skinny wires , the best way to fix is to fit relay(s). There posts and diagrams here somewhere showing how best to do this .
Image
Here is mine :) One relay is the main ignition one and the other feeds the digiplex and coils , there are 2 more relays up front which feed the Hi and low beam for the headlight
I wish I was young again............Id be heaps smarter than last time
User avatar
Giscard
Posts: 120
Joined: Thu Apr 28, 2011 2:56 pm
model: 906 Paso
year: 1990
Location: Cardiff UK and Dordogne France

Re: Maiden Voyage

Post by Giscard »

Thanks for the info. A few things to look at now.
Just a bit of extra information.
The horn is working now. It was due to a loose connector on the horn. Why would the engine cut out when I pressed the horn switch when one wire was loose but not touching anything ?
Started the bike yesterday and on tickover switched the pilot light on, with no problem. As soon as the headlights were switched on it cut out. If I revved it up then I could switch the light on. :mad:
Mc tool
paso grand pooh-bah
Posts: 1875
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Newzealand

Re: Maiden Voyage

Post by Mc tool »

Mine was the same , specially with the head light ( highest load ), if I switched beams while on the move the digiplex would take a big dump and for a split second the bike would die then do a massive backfire ( flames an all .... lit up the road at night ) and away it would go again , now I aint going to try and tell you that the ability to backfire at will wasn't fun ( no shit ... it was like a couple of shotgun blasts ), but things deteriorated and the bloody thing would do it in time with the blinkers ... which was not good trying to get round a roundabout lurching and banging, and soon it got to the point that it would boom and bang while trying to start it .... so the anonaminity was gone ( shit I had some fun tho :evil: :evil: :lol: :lol: :cool:... spent days lookin' for a girl on a horse :twisted: an a whole paddock full of deer 2 feet of the ground looked pretty cool :lol: and O A P's ...... ).
Seems that as the voltage to the digiplex suddenly drops as some other load is applied it will hiccup and then recover . I was down to 8.5-9 volts at the digiplex ( and probly everything else ) in the end, and I have had mufflers split and valve seats come out while delibrately backfiring in the past ( work vehicle :) ). Check and clean all the plugs and connectors , specially those multi pin molux plugs and even make sure the terminals are correctly fitted to the wires , I found several where the factory crimping tool had cut thru most of the strands of wire , usually between the wire crimp and the insulation crimp , but relays are really the best way , one each for the headlight beams and one main one :)
I wish I was young again............Id be heaps smarter than last time
User avatar
Giscard
Posts: 120
Joined: Thu Apr 28, 2011 2:56 pm
model: 906 Paso
year: 1990
Location: Cardiff UK and Dordogne France

Re: Maiden Voyage

Post by Giscard »

Brilliant, unlike my bike at the moment. I know what you mean about the backfire although to date I have only had one when I was trying to start it. Sounded like a cannon going off. It upset the quiet of the village to say the least. I had expected to see the silencer shredded. :D
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paso750
paso grand pooh-bah
Posts: 5558
Joined: Sun Jul 18, 2004 12:00 am
model: 750 Paso
year: 1987
Location: southern Germany

Re: Maiden Voyage

Post by paso750 »

Mc Tool shouldn`t there be two 25A fuses and one 7.5A ?

G.
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