Modern Buddy

Some friends and club mates have a pair of 170i's. One had damage from encountering an abandoned bicycle laying on the middle of a dark road. We used some panels from my Pamplona project to fix it.

The other one had been sitting for several years due to a lost key. When I recently fixed a St. Tropez for another friend, we found that it's ignition issue was due to having the wrong key switch. I fixed that scoot and saved the switch. It happened to be for a 170i, so I got an extra blank from ScooterLounge and had it cut to match this key switch.

The plan yesterday was to pull the front end open and swap the ignition. The job was a bit fussy due to the steering being locked, but the transplant was successful.
Next job was to pump the ancient gas out of the tank. It smelled horrible and had me concerned about the pump health. There was a brown scuzz in the bottom of the tank that formed a bathtub ring, but I was hoping the pump was OK. We added a gallon of fresh gas and installed a non-dead battery. Time to test!

The scoot powered on and the CELP lit. We didn't hear the pump. Had to toggle the kill switch a few times to get the starter to crank. The scoot turned over but we never heard the pump.

Next job was to pull the lower panels, the under seat bucket and the tail panels off to access the pump assembly. The job was easier than expected due to poor reassembly by a prior mechanic and a missing rear rack due to damaged mounts. I removed the rear rack support and pulled the pump.
The tank looked worse inside with more daylight and the pump out. There was about 1/4" of what could best be described a as "rotten brownie batter" in the bottom of the tank and I was able to confirm that the pump was clogged with sludge.
I had an appointment, so I took the tank and pump assembly along so I could clean it later. I filled the tank to the scuzz line with acetone. The filter and pump received an acetone soak as well.
Hours later, I poured out the acetone and some loosened scuzz. Tank was then rinsed and I sprayed in some SuperClean Foamer to continue softening the scuzz. After another hour, I drizzled in some dish soap and poured in a kettle of boiling water.
Once that cooled a bit, I poured out the tank again. Now, I just need to finish removing the black sediment that was under the brown goo. I also need to free up the scuzzy fuel sender. New pump has been ordered and I'll swap it out later this week. We'll try starting the Buddy again next Saturday and I hope the injector is OK.

Pump shipped today. Used a 10-1/2" parts cleaning brush and more SuperClean to scrub out all the nooks and crannies that I could access. Rinsed it repeatedly and dried the interior with a hairdryer to prevent flash rust.
I'm calling the tank clean.
Also used a soft plastic bristle brush and some CRC electronic parts cleaner to de-scuzz and free up the fuel level sensor. According to multimeter, the rheostat still works. Yay, one less part to buy!

The difference is amazing. I guess that's possible when you're not dealing with rust. Well done.

ohiomoto wrote: ↑Wed Jan 08, 2025 12:23 am The difference is amazing. I guess that's possible when you're not dealing with rust. Well done.

Thanks! Even if there's rust, I try to get the old fuel out first and get the inside as clean as possible. Then I use EvapoRust to address the rust. Once it looks good, I drain it out, rinse the tank thoroughly, dry it quickly and spray the inside down with WD40 to prevent flash rusting.

You got lucky with the rust being 1: Removable without any serious issues and 2: The tank being removable. I did a PUCH moped tank not long ago, the model that the tank is part of the frame. What a PITA! Since we stripped it down for a full overhaul and paint I could at least hang the frame from the rafters. I had to use Kreem but luckily didn't have any pinholes on the bottom portion of the tank.

I spy a Prima pipe on that scooter. I love those pipes but had a bracket snap on a first gen model, plus I always scrape the down pipe. Shame as they are so nice looking. I have a plain jane NCY pipe hanging in the garage for the day my OEM gets damaged.

Quick dumb question: Does the 170i have a chipped key? If I lost my key to my Buddy I'd just order a new ignition assembly UNLESS it was chipped and cost Vespa money. I'm assuming this 170i was more of a play around toy and not a daily, so when the key went MIA the scoot ended up sitting.

You truly do the Lords work with these unloved scooters. I'm dreading my next oil change because it finally got cold out and my garage isn't heated well enough to not freeze my hands off. I suppose I could use a bay at my local Honda motorcycle dealers shop if needed or better yet, let someone else change my oil, NEVER! I still have a hard time trusting others working on my scooter.

sc00ter wrote: ↑Wed Jan 08, 2025 2:12 pm You got lucky with the rust being 1: Removable without any serious issues and 2: The tank being removable. I did a PUCH moped tank not long ago, the model that the tank is part of the frame. What a PITA! Since we stripped it down for a full overhaul and paint I could at least hang the frame from the rafters. I had to use Kreem but luckily didn't have any pinholes on the bottom portion of the tank.

Oh, believe me man, I know moped frame tanks. That's why I like my JC Penny Pinto more than the old Maxi; tank is way easier to service! I'd argue that the worst moped tank to deal with is the Piaggio Grande/Gilera CBA.

One upside of the EFI tanks is the bonus opening thanks to the fuel pump well. the extra access really helps!

sc00ter wrote: ↑Wed Jan 08, 2025 2:12 pm I spy a Prima pipe on that scooter. I love those pipes but had a bracket snap on a first gen model, plus I always scrape the down pipe. Shame as they are so nice looking. I have a plain jane NCY pipe hanging in the garage for the day my OEM gets damaged.

I didn't inspect the pipe too much, as I figure that even if this runs, there will be a lot of other routine maintenance that it will need to be caught up on. The oil filter looks a bit vintage and there was only a drop of oil on the very end of the dipstick.

sc00ter wrote: ↑Wed Jan 08, 2025 2:12 pm Quick dumb question: Does the 170i have a chipped key? If I lost my key to my Buddy I'd just order a new ignition assembly UNLESS it was chipped and cost Vespa money. I'm assuming this 170i was more of a play around toy and not a daily, so when the key went MIA the scoot ended up sitting.

No chip on the key. It's the same blank as every other Buddy. Not sure why they never got around to replacing the keyswitch; but I suspect it has a lot to do with mechanical aptitude. It was ridden regularly until the owner had a back injury and then the only key was lost. I did nudge them a bit to get this resurrection started as I hate dealing with scoots that sit dead for too long. Especially EFI bikes.

sc00ter wrote: ↑Wed Jan 08, 2025 2:12 pm You truly do the Lords work with these unloved scooters. I'm dreading my next oil change because it finally got cold out and my garage isn't heated well enough to not freeze my hands off. I suppose I could use a bay at my local Honda motorcycle dealers shop if needed or better yet, let someone else change my oil, NEVER! I still have a hard time trusting others working on my scooter.

Thanks! Just trying to keep the Genuine flame alive here in the Dirty T. They've all but disappeared from the roads around here since ScootOver closed down. My ulterior motive is to get folks back out for club rides.

New pump has been fitted into the assembly. Ready to reinstall on Saturday. Hope the injector works!

Debating if I should pop the pressure relief valve section apart, but I don't have a spare 2.5 bar regulator to install.

Sometimes, resurrecting a scooter is a game of inches.

I met up with the Buddy's owner this morning, ready to fire the scoot up. I reinstalled the fuel tank, bolted in the pump, connected up the fuel sender and pump power leads. The fuel line was snaked back through the frame to the injector feed and clamped down. Now it was time for fuel.
While the owner ran out to grab a gallon of gas, I proceeded to change the engine oil and the oil filter. Man, I am not a fan of the oil filters that need the special removal tool. I used a 3/8" piece of square stock to loosen it, but the skid plate for oil cooler assembly and the bodywork made this trickier than it should have been. My kingdom for a pair of slip-joint pliers! I did finagle it off and replace it with a new Prima filter with a hex on the end. Topped it all up with Motul 7100 10W40 and we were ready to test.
The bike powered up and the CELP lit briefly. We still didn't hear the pump...rats!

I started the diagnosis by finding the pump relay. It's on the right side of the scoot, under the seat bucket. By looking at the lead colors at the pump plug and ECU, I figured out which pair powered the pump. Jumpering those leads powered the pump while the scoot was switched on. We primed the fuel line until we heard the pressure relief valve open, then tried cranking again. Still no start.
Next, we tested the relay itself. When switching the ignition on, we
thought we could feel the relay clicking, bit we still weren't getting pump power.

Note: I had checked the fuel pump fuse prior to pump replacement and it passed a continuity check. Still looked good today.

Next, we tried feeling the injector to see if it was firing when cranking, but we couldn't tell if it was operating or not. I pulled the plug to see if it was getting wet, and to check spark. The plug was dry and when I tried cranking with my finger over the plug hole, it stayed dry. I also noticed that despite being grounded, we didn't have spark while cranking.

Taking stock of observations, I suspect an electrical issue. The ECU powers up, as evidenced by the CELP light. The lack of pump operation, injector operation or spark is far too suspicious to be coincidence. I did check the ground lug on the frame; the connections were clean, but the ground wire from the coil had a damaged casing and signs of some corrosion. We wrapped at this point, as we both had other commitments.

I'm going to grab a wiring diagram and go back over with a meter. I suspect a safety switch or maybe even the ignition I replaced. The kill switch is also suspect, as it has to be toggled occasionally in order to get the scooter to crank over. Hoping we can make more headway next weekend.

At least we have a clean tank, fuel to the injector and a working fuel sender. Now we just need to run this gremlin down.

I know your trouble shooting skills are strong but I'd check the kill switch. If sitting outside it might be gummed up, it'll be in the run position but not be engaged on the inside. Vespa owners call it "Rocking the switch" when it gets hard to start. Had many a Zuma bug-eye suffer sticky switch from sitting outside.

I had a tip-over sensor get stuck after I righted my Burgman. I had to find it's hidden location under the panel, find a long screwdriver to reach it and whop it a few times. Those are the only 2 things my limited electrical knowledge can think of. The EFI Buddy's, while still very nice, are extra complicated.

Can you pull codes on a Buddy 170i with a OBD 2 sensor or does Genuine call for a proprietary system?

Brother, you have no idea how close to the mark you likely are.

I downloaded the manual and wiring diagrams last night before bed. This was bugging me enough that I woke at 1:30A this morning to analyze it more.

Firstly, I was able to confirm the keyswitch function is correct (close both circuits when switched to "On"). I also figured out that the tip-over switch is fine (it sits on the ground leg of a relay that supplies power to the 5A fuse for the fuel pump) since I can power the pump. If it was tripped or faulty, I'd have no pump power.

The "epiphany" came when comparing the main wiring diagram and EMS (Engine Management System, we usually call it an ECU) diagram. The diagrams are appropriate for a fuel injected Bubu, not a Buddy.

The finding lies with locating the main switch in the diagram (right hand side, near the middle). It calls for a red/white, orange, green and grey wire. The green and grey wired trace to a "antithef". If you pivot to the EMS diagram, the immobilizer, marked "burglarproof" (left side, below the middle) shows a grey and green wire coming out of it. One lead seems to be a common ground for the immobilizer and multiple sensors, while the other leads to EMS pin 29, marked "IMMO".
Here's my hypothesis: we know the Buddy 170i doesn't not have an immobilizer and the harness has a yellow and a blue/white wire in place of the green and grey immobilizer wires. I suspect that the immobilizer was just an intelligent switch for safing certain functions in the EMS. What we do have that the Bubu doesn't normally come with is a kill switch. I propose that the IMMO circuit disables spark, injector control and fuel pump command when open. A cruddy kill switch could also prevent that circuit from being closed.

The plan is to get back over next weekend and to check the switch. If it looks good, I'll jumper the IMMO lead to the SG pin and satisfy that requirement. Since there is no separate CDI on the scoot, I'm pretty sure this is my stumbling block.

If anyone needs the manual and the diagrams, look here:

http://www.epfguzzi.com/scooterpunks/manuals/

NOTE: You will need to rotate the diagrams 90° CCW to read them as I described.

Awhile back a friend bought one of those weird, but quality, used scooters for his son. It was a United Motors with all Hyosung undies. While making sure it was reliable he rode it to a store and when he came out and loaded it the scoot wouldn't start. He pushed it home and ended up calling me, plus I've yet to see it anyways. I get there and all looks good, plug connected, kill switch in correct position and no side stand with a safety switch. I had a hunch but the seat was stuck shut from being slightly overloaded. We finagle the seat open and something in the seat bucket pushed the "hidden" kill switch under the seat to the off position. It was in a dumb location so we just bypassed it.

I still find that wiring diagram weird with the Burglar Proof mystery box in there. I wonder if the overseas versions get a fob option or auto-start feature?

His son loved that United Motors scooter so much he's now a motorcycle owner (ZX6R) with a tuned 2-stroke Honda Spree of all things that's his pride and joy. That Spree is pretty quick! I never knew that anyone made tuning stuff for those. I have a friends mom who had a pink Spree with a pig face on the front and a little pig tail on the rear. I should look her up one day. There's no way that pink Spree is still sitting in her garage.....

What is the voltage on the battery? My Zuma 125 would still turnover but the fuel pump wouldn't turn on under a certain voltage. I forgot what the voltage cut-off was but it was something stupid, hence turning over but the pump not pumping. A very fine line of frustration!