Modern Vespa

Background 2004 BV 200 Have ridden every day since the 4th of July. 1800 miles on it. Gassed it up last Thursday. Rode Friday and put 75 miles on it on Saturday. Didn't ride on Sunday.

This morning it started up but the idle seemed a little low. Whenever I rolled on the throttle it died. Let it warm up a bit and then it let me head down the driveway. When I got to the end of the driveway it died. Wouldn't restart. Pushed it back into the garage. Waited a bit and started it up again. Same thing happened. Pushed it back into the garage and took the truck to work.

What should I start checking on ?

H.T. cap, lead & plug.
Try to see if there's any water in the petrol, might be dodgey fuel.

Don't think it's the fuel as I ran 2 days and 100 miles smooth as silk after the fill up.

I think it's fuel related though. Not getting enough to where it belongs.

Does the BV 200 suffer from the "replace the rubber hose" like some of the other Vespas ?

Have you tried it with the petrol cap off?
It could be an air lock.

Nope. I'll try that when I get home at lunchtime. Be nice if it's that simple.

Now that's it's daylight I can see I've got a gas leak. Same symptoms. It'll idle but dies on the throttle.

Can anyone point me in the right direction on the leak ?

That's leakage from the air filter - where's the little plastic bubble that is supposed to be there?

I don't know when/if you have ever cleaned the air filter - but I would start there. There are far smarter people here who could also assist.

I think we are experiencing something similar. I also have a BV200- 2005. Check my thread titled "Anyone experience this- starting problem". I just tried a bunch of stuff and now it's not starting at all. I am beginning to think it is in the ignition. I'm kinda lost right now. I'll let you know if I find anything out.

Bob

I've never cleaned it. Only had it since the 4th of July but I'll check it tomorrow. Don't know if the previous owner ever cleaned it.

Never had a little plastic bubble on it.

Not 100% positive but it might be the Emissions stuff. Fuel backed into the charcol canister causing what you're experiencing. The blowby going through the air filter is most likely because your charcol canister is filled with gas instead of vapor. I think mine is fixed now but it's pouring outside so I can't take a test ride. Starts right up each and everytime and idles better. I'll keep you informed if my fix does indeed work.

Bob

Please let me know what the fix was ?

I haven't had time to take anything apart yet, but tomorrow I hope to start. I'll look at the canister first and see what I find.

Thanks

Good luck with that guys. Hope you get them sorted.

Took the afternoon off to try and get the BV fixed. Took off the side panel to look at the air cleaner and didn't find any foam in there. Will have to see what's supposed to be there. Opened up the pet carrier to see if I could see a leak.

Fired the scoot up but didn't see any fuel leaking anywhere. Nothing leaking into the air intake but it still wouldn't rev up and died when I tried to roll the throttle.

Checked the canister and no fuel in there.

Checked the plug and the gap was a little wide so I fixed that.

Fired it up again and it died on acceleration.

Put in some Stabil Fired it up again and let it idle for awhile. While idling I noticed that a lot of air was coming thru a pinhole in the air intake. Held my finger over that and let the pressure build up. Really "puffed" when I took my finger off.

For whatever reason, it now runs fine. Did a run around town. Stopped a couple of times and it starts right up. Idle is where it should be.

So it's fixed but I don't know why. Dirt in the main jet ? I have no idea.

Well it's happened again. 2 days after a fill up the BV 200 is back to it's old symptoms. Ran great on Friday, Saturday and Sunday.

Will start but won't keep running when I roll on the throttle. Finally after playing around with start re-start re-start. It acted like it was going to run. Ran 2 blocks and quit. Couldn't get it restarted. Starter cranks just fine but it won't start.

Same symptoms as 2 weeks ago when I filled it. So it must be the EVAP system I'm thinking. Can anyone point me to the correct hose to disconnect on the carb ? I think the BV 200 carb is the same as the GT200.

Can anyone confirm this ?

TIA

Have you over-filled the gas tank?

Over filled the tank ?

I don't think so. I've been filling it the same way I've done for the last 3 months. Only had problems with the last 2 fill ups.

You don't necessarily have to overfill to the point of sloshing over, but trying to fill up to the bottom of the neck can still allow raw fuel to enter the evap system.

You mentioned not finding a foam block in the filter case. Is there anything in there? If not, you are running unfiltered air through the engine.

If the previous owner removed it, there is a good chance that he had overfilled a few times and got tired of having to clean the filter every time, so he pitched it.

When you take off the large black plastic panel there is no foam in there.

Where should the foam (air cleaner element) be located ?

As you can tell I'm fumbling around here. The owner's manual and shop manual aren't the clearest manuals I've ever run across.

Thanks for your patience !

There is supposed to be a foam filter in that black box that is in your photo. You're saying that it is missing?

Just in front of the battery is a plate that covers up the roll over valve. The roll over valve to a small plastic tank that has a standpipe that will close off the vent hose that attaches to the carb. The plastic tank (roll over valve) can be disassembled by rotating the end 90 deg like a camera lense mount. Clean the tank out cause id bet is got gas in it. Also make sure the the little ball in the standpipe is not stuck. When you blow down the hose at the bottom of the little tank it should be clear. reassemble and u should be fine

I am going with Benito on ths you need an air filter that's properly oiled, and a new clear drain cap put on the opening. You may have to get you fuel system cleaned out (carb).

Get into the parts breakdown for a BV250 and look at page 61. The tank im talking about is part number CM028201 ( Number 2)

Got it.. I took that tank apart the first time this happened but didn't find any gas in there.

Charcoal canister was good too.

I'll check it and see what condition it's in.

Thanks

on my wife's bike the the Tee (number 10) was plugged. Blow down the tube and make sure its open. Thats why people tell u to pull the vent tube off the carb. If the venting system is plugged the piston in the carb will not move freely. Thats why your bike will not keep running

OK I'll check that tonight after work.

I did get the scoot running. Had to start it multiple times. Finally I remembered what I did last time. Just let it idle for 3 or 4 minutes.

Now it runs like a top again. Go figure.

If you do decide to disconnect the evaportive hose, the hose on the BV is black, not clear like on the GT, and it has a clamp. Be careful that you don't snap off the tube on the carb. It is easy to do - just take your time.

Bob

Those clamps are funky looking. What's the best way to loosen them ?

I used a very small screwdriver to pry it open. There are little teeth that hold it closed. I slowly lifted them while supporting the hose near the carb and it popped loose. Then I just pulled the hose off. I haven't had any problems at all since I removed mine. I've put about 400 miles on it since. Curiously enough, I also started using mid-grade gas as soon as the tank I had in there ran out. It seems to run even better. Might be in my head, but I thought I'd share.

Bob

Thanks.. I'll see if I can find the right hose tonight.

I'll keep ya posted.

Is it the hose on the "southwest" corner of the carb ?

I do not know if there is an archive on MV however I do as a dealer know a little about this old BV problem.

There is a fuel line under the right floorboard that is looped poorly and the gas can't make the turn. The fix was to remove the line, cut some off to soften the curve and reinstall with a new clamp.

Please advise if you can't find the archive or need further assistance.

Best,
SDG
Vespa Thousand Oaks

How come it only happens 3 days after a fill up ? That's what's got me buffaloed. And it only started happening with the current fill up and the one two weeks ago.

Try this link. It points to the hose. I think it's "clear" in the photos here, ours is black. I zip-tied it to a hose near it to keep it in place.
Bob


https://modernvespa.com/forum/topic86

Not the one I was referring to however maybe that would be helpful also. It is located under the right floorboard of the scoot.

Best,
SDG

You're referring to the actual gas line correct? I was referring to the evaporative hose in the emissions system.

Correct. It is looped around in such a way that it can become problematic. I know about a year ago when the BV200 was a little more in the loop (no pun intended) we fixed 2-3 of them with this repair in short order. It has to be looked at as part of this repair.

Best,
SDG

Thanks for the tip! I never heard of this one. I'll take a look at mine over the Winter when I put it away for the season.

Bob

Same here. I'll look at mine over the weekend and see what I can see.

I looked at the link on the carb but mine doesn't look like that. But I do think the EVAP hose attaches at the same place.

Under the right floorboard boys, near the fuel filter. You will see, you can always call Spencer at our shop for a walk thru. 805-494-1918.

Remember, dealers are here to be helpful, haha. Just ask Jess !!

Best,
SDG

Did you plug the hose ? Did you put anything over the port on the carb ?