Modern Vespa

Hi all, I sold my GT a while ago but happy to now have a 2007 BV250. This is a carb model.

It will not start. The battery is new and charged. I flushed the fuel and cleaned the carb, unplugging the jets and ensuring that the diaphragm is intact.

Unfortunately it still won't start. A few times when I tried to add starter fluid it fired a bit but never took. I did replace the spark plug (and gapped).

Has about 12000 miles. Was used but not terribly abused.

I did check that fuel is flowing. I cleaned the two series filters.

I have not checked compression as I don't have the right adapter and have not yet checked spark. The plug is securely placed though.

The hose that goes to the evap was deteriorated so I did the evaporator bypass.

Any suggestions on getting this beast running?

Thanks!

Did you clean the jets out good, blowing high pressure air threw them and using jet cleaning bits?

As Web-tech said clean the carb. If it will start with fluid then it has 2 of the 3 things it needs, spark and compression. You just need it to get fuel for it to run. Have you replaced the fuel and Vacuum hoses? On a 2007 scoot its time to do that. You didn't mention a new spark plug. That can't hurt.

It pops with start fluid, so spark is there, hopefully at the right time. So you are looking at fuel delivery or compression. You went thru the fuel system, but was the spark plug wet with fuel when you tried it a few times? Have you checked the valve clearances? Borrow a compression tester and give it a check.

I think there are a couple possibilities.

The spark plug was replaced and gapped.

I did clean the carb and every possible orifice, pulling the jets. The jets were both so clogged it became structural support for the carb! I had to use a wire brush bristle to unclog the slow jet. But they are all clean.

I think I may have pinched the diaphragm when I put it back together. I've done that on different bikes probably 15 times before but I had to watch a video on the youtubes that showed me a different way that looked better. If it ain't broke...

I overthink things incredibly so I want to go back to basic and make sure I didn't leave bad fuel in the lines. What I'm going to do is start with a separate line of totally fresh fuel. Additionally, fully drain the tank and all the filters/valves. I will also check that I have good seal on the intake.

Will also try to score an adapter as I already have the compression tester.

Hope to get back to it this weekend.

You won't get an accurate compression reading because these engines have a decompression valve. Its possible to disable it but I don't have that info at my fingertips. I forgot to ask if you checked the valve gap.

The valve gap is on the list for next time I'm at it. It was maintained in a way that makes me think that may have never been done!

Thanks.

You have air coming out the other side when you blow air through the jet passages?
I had a carb I ended up sending out to get cleaned in an Ultra Sonic bath to get the idle fixed on an ATV. I thought it was clean too. The ultra sonic cleaning fix the problem.

I habe a 2007 GTS. I think they take the same battery. My replacement was Yuasa YB10L-B. I got It online fir about $65-$70. Hope this helps, i also live in the Midwest, nearest dealer is 3 hours away in Madison....

Yep, I used carb cleaner to ensure the channels in the carb were flowing.

The new battery (from Wally World) seems ok but I've been beating it up. I charge it up between sessions on the Battery Minder. It's an AGM so we will see how it goes.

Kill switch on or defective. Not sure if this is relevant or not? Side stand switch?

Making progress!

It actually ran today and it sounded quite nice. It would not rev very high but I think the fuel supply is anemic. I did an ultra-scientific mouth vacuum test on the vac hose that leads to the fuel pump and I noticed there is a leak.

On the vacuum port of the fuel pump - should that not be sealed with no air passed? Is this device the equivalent of a motorcycle fuel valve? Piaggio CM120901

At first the fuel delivered to the carb (when I was not successfully starting) was strong, but not it's virtually non-existent. I think it could be due to the fuel pump but is there anything upstream of the fuel pump that could slow down fuel delivery? Looking at the "complete coupling" in the parts catalog - it looks like that could be a screen which if blocked could inhibit fuel.

OK I replaced the fuel pump and now it pushes big volumes of fuel.

The current symptom is that it won't hold idle.

It will start and try to idle but won't rev and will die out.

I tried using some carb cleaner around some parts to see if any of them cause it to change. When I spray near the air input of the carb - it does indeed rev up. I can rev it just like I want to for a few seconds then it dies down again.

So I'm thinking something to do with the intake side may be the problem. I hope I don't have to pull the carb again. It does seem the side that connects to the manifold is sealed well.

Any suggestions on what could be going on? I suspect it's very close at this point but still no cigar!

And there it is - it was the Automatic Starter Coupling (gonnecticazoink to me). I figured it might be misaligned - and it was.

Now it revs just great. Idle is low - but I suspect PO might have futzed with it due to poor running. So wish me luck - I think with a few more turns I have a working BV250! Can't wait to blast around.

I have a 2008 BV250 so I have the style of yours with Fuel injection. Enjoy your new ride, I love mine.

Awesome 14Perry. Have you tried adjusting the valves yet? That looks like a contortionist act! I'm going to get a few miles before doing that.

Only have 6,000 miles on mine. Lucky to live in San Diego so I have Robot @ Scooterwest for my service needs.

The old lines for fuel and vacumm can crack causing all kinds of problems. Replaced all of that on my BV200.