Vespa Bravo Has Compression/Spark Won’t Start

We have a Frankenstein Vespa Bravo. Replaced rings and head gasket and got it to the point where the spark is strong, gets fuel from a separate moped, has compression, but won’t fire. It has loose wires so my guess is it’s a wiring issue. Check video

Re: Vespa Bravo Has Compression/Spark Won’t Start

I was expecting a video showing the spark, I'm disappointed. If you have good spark how could it be the electrical, ya dig?

Re: Vespa Bravo Has Compression/Spark Won’t Start

Sounds like it wants to start so I would suggest timing or crankcase vacuum leak

Re: Vespa Bravo Has Compression/Spark Won’t Start

My apologies, as far as electrical, I meant maybe a kill switch scenario, or improper wiring that would affect timing. Idk, usually I know what to do but I’m at a loss, and these loose wires have me perplexed.

Re: Vespa Bravo Has Compression/Spark Won’t Start

How do I adjust timing on this?

Re: Vespa Bravo Has Compression/Spark Won’t Start

You have to cut the crank to adjust timing. Check your points (I think I saw the inspection window on the flywheel)

Re: Vespa Bravo Has Compression/Spark Won’t Start

Dirty30 Dillon /

> Bob Loblaw Wrote:

> -------------------------------------------------------

> You have to cut the crank to adjust timing. Check your points (I think I

> saw the inspection window on the flywheel)

No, you don't change your ignition timing via crank cutting, that's how you change your intake timing.

Points need to be gapped, and set. Most likely you've sheared or slipped the woodruff key.

Re: Vespa Bravo Has Compression/Spark Won’t Start

> Rebel Moby Wrote:

> -------------------------------------------------------

> Sounds like it wants to start so I would suggest timing or crankcase

> vacuum leak

This one.

Vespa has fixed timing and on a stock bike as long as they open and close it should run.

If you have spark at the spark plug and it's good, then none of the other wires matter until you need lights.

If gas flow is good, and compression is stock, then the last thing is air leaks. Crank seal is an easy fix and makes a huge difference. The other common leak point is the carb.

Re: Vespa Bravo Has Compression/Spark Won’t Start

This is greatly helpful, and much appreciated. I'm gonna' try and take a look at it today.

Re: Vespa Bravo Has Compression/Spark Won’t Start

what are u using to spin the motor? i mean there is usually a nut that holds the flywheel on and it's not there. those vespa crank shafts are easy to shear, being m8 or so. i'd say it's slipped timing off that small woodruff key.

spark compression fuel timing n points, isounds like it almost wants to start.

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