1978 Vespa Bravo Won't Start

Dillon Zahrt /

Apr 05, 2020 08:05PM

My buddy just got a Vespa Bravo. When you hold in the clutch and pedal, it starts turning over, the lights turn on, and it gets a spark, but won't start. We cleaned the tank, fuel lines, and carb, but it still won't start. I have three questions. 1. What is this black switch on the rear hub that apparently changes from free pedal to pedal start? I can't find where this is located. 2. How do I go about starting with a power drill? 3. What could the reason be for not starting if I have fuel/air/spark/and what seems to be good compression? Is there any timing adjustments that need to be made, perhaps?

Thanks in advance.

Re: 1978 Vespa Bravo Won't Start

pat splat /

ggspeed

Apr 05, 2020 08:33PM

the lever your pulling is the decompression lever, not a clutch. How to start, Choke on, on switch on, petcock gas on, jump on, pull decompression lever n start pedaling once the motor starts spinning then continue pedaling like crazy and let go of that lever, keep pedaling and then throttle pedal pedal.

leave the switch on tranny hub alone if it turns the motor over

forget the drill start unless your a smoker.

Re: 1978 Vespa Bravo Won't Start

Seth B /

sibryan

Apr 05, 2020 11:36PM

Yep. Won’t start with the lever squeezed. Release it once the motor starts spinning. Also, Vespa is very picky about air/fuel mix, so if it’s missing the stock air filter box, it won’t run.

The black button/switch.- push in the button for bicycle mode, like when you run out of gas and have to pedal home. The switch/lever releases the button, and puts it back in motor mode.

Re: 1978 Vespa Bravo Won't Start

Seth B /

sibryan

Apr 05, 2020 11:38PM

Oh, try not to drill start Vespas. The crank threads/variator nut threads are only 8mm, and they strip out easy. Then you’re done.

Re: 1978 Vespa Bravo Won't Start

Dillon Zahrt /

kawazukiyamahonda OP

Apr 06, 2020 09:35PM

Thanks guys, this is extremely helpful and greatly appreciated. We were holding in the decompressor the whole time, so that may have been the issue. I will keep you guys updated once I get over there to give it another go.

Re: 1978 Vespa Bravo Won't Start

Darrin LaSarge /

oldschoolped

Apr 08, 2020 04:50AM

Hi everyone. I have a pair of 1978 Bravos that haven’t ran in at least 8 years. They are 98% complete but Neither one will start. I can do anything mechanical but electrical issues have always killed me. I can’t get any spark and I’m not sure I want to stand back and throw a bunch of money at them in the form of everything spark related. What would be a good place to start replacing electrical parts and where is a good place to get them. I’d really like to have them running for the summer for my kids or me and the wife to take for a spin.

I’ve read a lot of the posts here and I know you guys know your stuff so thank you in advance

Re: 1978 Vespa Bravo Won't Start

pat splat /

ggspeed

Apr 08, 2020 11:10AM

Read and state what you have done, don't just look at it.

Re: 1978 Vespa Bravo Won't Start

Seth B /

sibryan

Apr 08, 2020 11:50AM

The best place to look if you have no spark on a Vespa is the brake light bulb.

Then points. Then, the (busted)wire that runs thru the rolled lip of the rear fender (the one that powers the brake light).

Those are the biggest culprits on Vespas. I’ve dealt with all of them.

Vespa has external ignition ground, meaning the ignition coil’s negative (ground) side runs thru the brake light system. If the brake light circuit is broken anywhere, no spark.

Unless your Bravos have blinkers. Then it’s internal ignition ground, and nothing I said above applies. They have different wiring systems. (edited)

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