Sprint Veloce blowing bulbs
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Molto Verboso
1979 P150X, 1983 P200E, 1987 T5, 1996 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 1558
Location: Veria, Greece
Sat Jul 28, 2018 7:25 am quote
Hi all. A friend brought me his beautiful Sprint Veloce. It's been blowing up bulbs for a long time now and he doesn't know what else to do. The only thing he knows is that the guy that restored it, had changed the coils. So far I have taken off the tail light and discovered it had a 12V-21W for the rear light and a 12V-10W for the brake light. Probably to avoid blowing them up, but they blew up anyways. The 12V-21W also burnt the bulb holder so I'll have to come up with something to repair the tail light. I wanted to measure the coils output but can't seem to find any info on resistance and max voltage when they're disconnected. It's a EU spec 6V Sprint without a battery or rectifier...

Any info??

The wiring diagram and the beauty itself...

Wiring.jpg

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Ossessionato
1976 Super (x 2), 1974 Primavera (x 2), 2006 Fly 150
Joined: 26 Sep 2013
Posts: 4814
Location: So Cal
Sat Jul 28, 2018 7:47 am quote
Mmmmm mmm that is a beauty.

I had the same issue with my 6v batteryless PV. I spent weeks trying to balance the load by swapping (and blowing) different wattage bulbs.

Finally ran a simple single wire 6v regulator to the tail light wire at the junction box. The spec’d 6v bulbs now glow reliably, and not one has blown since.
Molto Verboso
1979 P150X, 1983 P200E, 1987 T5, 1996 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 1558
Location: Veria, Greece
Sat Jul 28, 2018 7:56 am quote
That's what I am thinking as a last resort. He has already brought me a 6V regulator but won't I be needing two of them?? One for each coil??
Ossessionato
1976 Super (x 2), 1974 Primavera (x 2), 2006 Fly 150
Joined: 26 Sep 2013
Posts: 4814
Location: So Cal
Sat Jul 28, 2018 8:02 am quote
Possibly... but try one first on yellow (tail-pilot-speedo circuit). That did the job for me.
Hooked
'65 Sprint 177
Joined: 28 Oct 2013
Posts: 423
Location: Dorset, UK
Sat Jul 28, 2018 8:20 am quote
+1 for popping a regulator in series. Piece o cake

If you know your way around a multimeter(voltmeter) then its no harm to get someone to rev her up and measure what AC voltage is at the offending bulb sockets? They generally blow because they see too much voltage, and if you have 12's in there already then chances are the voltage is going over 15-20VAC
cheers
Kevin
Member
1965 150
Joined: 06 Jun 2018
Posts: 25
Location: Wiltshire England
Sat Jul 28, 2018 8:43 am quote
will be following this one as im still having a similar problem with my 1965 super, tail light is getting 4.22v but the brake light is getting 22.17v

iv checked all i can and still haven't found the reason for it.....hate electrics lol !!!
Hooked
'65 Sprint 177
Joined: 28 Oct 2013
Posts: 423
Location: Dorset, UK
Sun Jul 29, 2018 5:42 am quote
Chris,
Do you have a regulator fitted? This seems to tell me the rear light coil is poor (but possibly going through a regulator) and the brake light isnt going thru the reg.
Stop me if youve heard this before but the regulator (if a 6v version) will only clip the voltage at 6v. Anything under that it'll simply pass right thru..

Kevin
Member
1965 150
Joined: 06 Jun 2018
Posts: 25
Location: Wiltshire England
Sun Jul 29, 2018 7:14 am quote
cheers Kevin

theres no regulator fitted, tbh i think the stators well past its best, when i had it apart the wirings insulation was rock hard so i suspect thats the issue,
going to be fitting a new 5 port reed vlve lml engine in couple of weeks so a rewire will be needed anyway - and that sounds like a complete nightmare
Hooked
'65 Sprint 177
Joined: 28 Oct 2013
Posts: 423
Location: Dorset, UK
Sun Jul 29, 2018 8:11 am quote
No problem....yes it does!

Shame cos its so sunny outsid......oh hang on
Molto Verboso
Joined: 15 Nov 2008
Posts: 1895
Location: Seattle
Sun Jul 29, 2018 8:35 am quote
'popping a regulator on it' isn't as good a idea, nor as straightforward as it sounds on these.

since there is no true ground, you'll merely end up overloading another part of the circuit even worse, unless you tie in three regulators. witch is silly.

start off by putting the proper bulbs in it. 90% of the time this fixes that system's issues, as the output of the system depends on what the load attached to it is.

load it wrong by using improper wattage or voltage bulbs, and you'll blow them. put 12v bulbs on it and you'll get 18-24 volts out instead of 6v.


start with a 6v 5w tail and pilot, and a 6v 10w brake.

if that blows, go to a 15w tail and a 10 or 15w brake light bulb and omit the pilot.

in all my years working in shops, i can count on one hand the number of bikes that this didn't fix the bulb blowing that used this style of system.
Molto Verboso
1979 P150X, 1983 P200E, 1987 T5, 1996 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 1558
Location: Veria, Greece
Sun Jul 29, 2018 9:33 am quote
@Rob...

For starters, this is what I'm planning. I took apart the scooter yesterday and I've found a lot of problems in the harness. The "restorer" guy did an awful job on it. Most of the terminals are corroded, hanging from threads of wires and the black wire is almost disintegrated at the harness junction under the tank. What he also did was to install a brake light switch for the disc brake, wired parallel to the foot brake switch, which of course can't work cause one switch is a "shutter" and the other one is an "opener". I'll probably take out the whole harness and fix the problematic areas before trying out new bulbs. One thing also missing is the green control light above the speedo. Should I install one or leave it as is?? And what kind of bulb should I put in it?? Thanks for any feedback...

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Hooked
'65 Sprint 177
Joined: 28 Oct 2013
Posts: 423
Location: Dorset, UK
Sun Jul 29, 2018 10:04 am quote
My 'popping on a regulator' was really a solution to blowing the bulbs and limiting the voltage. Im also assuming the regulator will have a 'good' ground ie same potential as the root coils. Its a sticking plaster really to the problem upstream ie stator related
Kevin
Veni, Vidi, Posti
74 50s x2 78 P200 84 Cosa 58 AllState 68 Sprint 80 50special + projects
Joined: 22 Nov 2010
Posts: 7054
Location: seattle/athens
Sun Jul 29, 2018 10:22 am quote
Thank you Piaggio for your clever 'load balanced system' ! If it's still working and you pop one bulb, better replace it quick or others will quickly follow.
rob hodge wrote:
'popping a regulator on it' isn't as good a idea, nor as straightforward as it sounds on these.

since there is no true ground, you'll merely end up overloading another part of the circuit even worse, unless you tie in three regulators. witch is silly.

start off by putting the proper bulbs in it. 90% of the time this fixes that system's issues, as the output of the system depends on what the load attached to it is.

load it wrong by using improper wattage or voltage bulbs, and you'll blow them. put 12v bulbs on it and you'll get 18-24 volts out instead of 6v.


start with a 6v 5w tail and pilot, and a 6v 10w brake.

if that blows, go to a 15w tail and a 10 or 15w brake light bulb and omit the pilot.

in all my years working in shops, i can count on one hand the number of bikes that this didn't fix the bulb blowing that used this style of system.
This. Regulator works well if you are completely rewiring an older bike with a different stator(ie P200 w/ single power out) but what Rob says usually works. In addition to the problematic wiring you found, you "discovered it had a 12V-21W for the rear light and a 12V-10W for the brake light." so that's already backwards even if it's been rigged to 12V somehow. Your pilot lite should be 3 watt and is probably expected to help maintain proper "load", but as Rob suggests, omit it if you try the bigger bulbs.
Molto Verboso
1979 P150X, 1983 P200E, 1987 T5, 1996 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 1558
Location: Veria, Greece
Tue Aug 07, 2018 12:32 pm quote
Update time. Lots of problems in the harness. It was supposedly a brand new Italian repro harness. Anyways, I fed a new ground wire everywhere, replaced the broken brake light switch, gathered the ground wires under the tank where they'll be connected to a central key switch (for safety / anti-theft purposes) which will be mounted beside the choke lever. I used new terminals everywhere and wire ferrules at the light switch. I've also repaired the tail light (burned by the 21V-21W bulb) and tomorrow will start the engine to see what I've achieved so far. Fingers crossed, no more blowing of bulbs.

Few photos. Last one is for Terry cause he loves COSAs (this one has another story)...

Before...












Seriously???


Feeding new ground wire...


Repairing harness and feeding new wires to the headlight...








Tail light repair...




Headlight wires ready...


Finishing up...












Wire ferrules kit...


COSA (for Terry)...
Veni, Vidi, Posti
74 50s x2 78 P200 84 Cosa 58 AllState 68 Sprint 80 50special + projects
Joined: 22 Nov 2010
Posts: 7054
Location: seattle/athens
Tue Aug 07, 2018 12:42 pm quote
Thanks. Lemme see the handlebar on the other side. There's gotta be a master cylinder there somewhere. Cosa looks to be in fine (original?) condition and same color as mine was. That front brake isn't original though.

Also, you are very good at rewiring! Them bulbs should be happy now.
Molto Verboso
1979 P150X, 1983 P200E, 1987 T5, 1996 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 1558
Location: Veria, Greece
Tue Aug 07, 2018 12:56 pm quote
V oodoo wrote:
Thanks. Lemme see the handlebar on the other side. There's gotta be a master cylinder there somewhere. Cosa looks to be in fine (original?) condition and same color as mine was. That front brake isn't original though.

Also, you are very good at rewiring! Them bulbs should be happy now.
Thank you for your kind words!!

About the brake on the Cosa. It has a PK Brake Lever with a manual choke (e-choke was ditched) and uses a typhoon brake master cylinder inside the horncover. So it's a 50-50 disc brake system. The scooter's not original. It was restored last year by a friend, for another friend, but the engine seized after 500Kms. The friend that built it, doesn't want to work with it (although he's responsible), so I must be the detective on this one. Anyways, it's next after the Sprint is finished...

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Molto Verboso
1979 P150X, 1983 P200E, 1987 T5, 1996 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 1558
Location: Veria, Greece
Sat Aug 18, 2018 12:48 pm quote
Looks like we have a SUCCESS!!! Main switch was eventually mounted besides the luggage hook (most flat space on body). Finished up with the rest of the harness / connections. Fired her up and everything seems OK. No blown up bulbs so far...







And a small video...

Addicted
Honda elite
Joined: 19 Jun 2007
Posts: 534
Location: California
Sat Aug 18, 2018 4:12 pm quote
wow that looks so clean. The switch looks great too it turned out nice. Where is the USB port?
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