Re: 1980 Vespa Grande, no fuel

Hugh Goldspiel /

Why don't you chill out? Huh?

Re: 1980 Vespa Grande, no fuel

Hugh Goldspiel /

I think my grande will beat yours cheetachrome

Re: 1980 Vespa Grande, no fuel

Hugh Goldspiel /

Isn't this fun? Isn't this what were here to do ? I've been doing porting work on vespas for over 20 years. You don't know what I've developed or what I'm running. Would you like to put your money where your mouth is and race? Say for $1,000? Winner takes all?...

Re: 1980 Vespa Grande, no fuel

Downhill Harvey (OFMC) /

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Re: 1980 Vespa Grande, no fuel

Hugh Goldspiel /

Poser

Re: 1980 Vespa Grande, no fuel

Aimee Delin /

Steve Clark Wrote:

-------------------------------------------------------

> Watch out for one thing with the drill starter,

> sometimes when it starts the nut might fly off

> with the drill attached, don't loose it or the

> washer if there is one.

Wow no joke, I sprayed fuel into the cylinder via the plug hole, put the drill to it, and it fired up like a bat out of hell (carb removed so it was beyond wide open) the bolt, washer, and "harmonic balancer"? shot off with the harmonic rolling a good way across the yard.

One bad Cadillac!™ Wrote:

-------------------------------------------------------

> I still can't tell if you just cleaned the carb

> many times, or in fact did a rebuild. If you just

> cleaned the 30 plus year old carb parts many

> times, you need to rebuild it instead because you

> can suspect all 30 year old carb parts including

> the intake seal. And if you did not rebuild it,

> it'll never be a reliable machine once it is

> running.

I rebuilt it with new seals and jets, reused the casting, throttle, and float/needle.

Hugh Goldspiel Wrote:

-------------------------------------------------------

> You'll know what I'm talking about when your crank

> taper breaks off, or you loose a ton of speed

> because you tweaked your crank out if true. Then

> what are you going to do with a bike that has a

> broken crank?

Can you please explain how using a drill to turn over the engine could do such catastrophic damage to the crank? The starting mechanism on the bike uses centrifugal force to do the exact same thing, but in a hammer like manner which would exhibit much higher bursts of torque than a drill. In fact I have used impact wrenches in the past on small four stroke engines with no ill effects, the only issue with that is they are too loud to listen for variations in engine noise, didn't think of a drill because the engines I have used the impacts on were all too large to be turned over with a drill, at least I thought, now I want to try it.

And to the lot of you, if you want to engage in childish bickering that is why the forum has a PM function, if you are going to offer information or advice about my issue, then feel free to reply.

Re: 1980 Vespa Grande, no fuel

Hugh Goldspiel /

The needle has to be chanced too , if it's worn it'll hard start

Re: 1980 Vespa Grande, no fuel

to aimee, you never replied if it fires on a shot of fuel in the plug hole.

are you familiar with the idle passage on the sha?

it's tiny and easy to miss.

if you totally cover the carb inlet with your hand or a rag, choke it hard, any results?

i'd be checking to see if it was pulling any vacuum there cranking.

my thought is primary (crankcase) compression, either the seal is popped out, or there's stories of people over enlarging the intake.

this prevents a tight seal between the crank and intake port.

lastly, how is the exhaust, if it's plugged bad enough, it could do the same.

unhook the pipe to test fire, but don't go for a joy ride if it does start.

sorry for the rude induction to moped army, greetings anyway

Re: 1980 Vespa Grande, no fuel

Aimee Delin /

I did get it to fire last night spraying fuel directly into the cylinder, not sure if I will get the chance to work on it today, but this weekend I'll turn it over and make sure there is suction on the intake. If there is I'll go over the carb one last time with compressed air and cleaner, would it be possible for you to get me a picture of this easy to miss idle passage? I replaced all the jets and seals, but it sounds like the passage is in the casting which I am reusing. I have tried to start it as full choke, full throttle, and everywhere in-between and the only time I ever got it to fire was when I sprayed fuel directly into the cylinder and cranked it with a drill.

When I drill started it last night I noticed even with the drill at very low the engine turned over much quicker than when I attempted to pedal start it, the belt looks like it may be original, and while grips it does have a lot of slack, is it possible the belt it to worn and slipping rather than turning the engine over at the speed it requires? I had the carb off last night when I drill started it, so I am not sure if a high starting RPM would create the suction required to pull fuel. I distinctly hear the engine turning over when I pedal, but it's more of a chug-chug-chug (faster but you can clearly hear every compression stroke) oppose to the blending of the strokes into the buzzing sound you hear when you pull start a small two-stroke.

Re: 1980 Vespa Grande, no fuel

Hugh Goldspiel /

If there's good spark, compression,and a seal , and if it fires up and doesn't idle you need a good in line cone fuel filter from treats, and clean the tank out as well. Sounds like it's getting instantly clogged. It doesn't have an idle circuit I thought, it has one or two tiny holes along the brass adamizer tube, and one really small hole right under the slide. Those are the ones that need repeated hard blowing of air. Soaking it over night before would help. Be sure to replace the float needle too, those are more important to replace. Your bike will not run if those are clogged it real easy to miss that. Other than that you should get to know what a good condenser is like, it has a different color than a bad one.

Re: 1980 Vespa Grande, no fuel

you can see the tiny hole in the casting in line with the brass tube in this pix.

the idle hole in the brass tube is smaller then the others you can see.

http://www.mopedarmy.com/mediawiki/images/2/22/SHAcarb13.JPG

there is some gearing via the pedals to help start, different then a pull start.

the three motor mount bolt holes are slotted, you have to remove the rivets from the rear one to be able to adjust the belt.

chug-chug-chug sounds good, not slipping, but may be too slow, i roll start rather then just pedal (as a good rule)

i omitted top end compression as a cause, but it would have to be really non-existant to not pull fuel.

Re: 1980 Vespa Grande, no fuel

Hugh Goldspiel /

Careful of the needle, don't get cleaner on it. Soak the carb really well in cleaner, then go to an auto place and use their air with the cone shaped blower, hold it really good in your hand cause it's gonna blow really hard, then you wanna put the tip of the blower as close as you can to that hole, and also the of there's holes too, then blast the fuck out of it repeatedly . That's what I've had to do a few times.

Re: 1980 Vespa Grande, no fuel

Aimee Delin /

I have managed to get the bike to start, it doesn't seem like it ever reaches top RPM, but it runs smooth. It stalls out within 5 seconds of starting it, longest I ever had it running was about 10 seconds. Everything is wide open so I believe it stalls due to fuel delivery, going to clean the tank, any ideas on the best way of doing this? Anything else I should look at or do while I am at it?

Re: 1980 Vespa Grande, no fuel

simple test, run the fuel line into a cup, measure how well it flows in each lever position.

typical the selector gasket disintergrates and blocks flow.

rebuilding is possible, but the thickness, and fuel resistance is critical.

Re: 1980 Vespa Grande, no fuel

Another simple test..........Once you do what Glen said,loosen and drop the float bowl a half inch(you'll get gas on your fingers,so wear gloves).Fuel should run out generously.

Once you've established fuel THRU the float needle valve,just push up the float bowl and screw it back tightly.Yer done! don-ohio (:^)

Re: 1980 Vespa Grande, no fuel

Aimee Delin /

Okay so here is where we stand after today. I got it to start via drill starter, it won't go above 10mph even though it's a 30mph model, it sounds like it is running strong but I think it may be running rich. I say this one because it bellows out way more smoke than you would expect from a 2-stroke and also because after I manage to get it to start it will run at anything above half throttle for as long as I wish it to, but dies if brought below and refuses to start again for about a half hour.

When I cleaned the tank and petcock, the previous owner had the petcock reassembled with a hail Marry, it's scrap now, I have it kluged together with a rubber fuel line straight to the tank, my theory on why it won't idle is the carb is clogged again due to dirty fuel so tomorrow I plan to clean the carb out again.

I have made much progress from where I was a week ago, it'll run now just not steady or at max power output, where should I go from here? I am considering ordering a new carb when I order the petcock, as I have said before my knowledge on carbs is lacking, to get where I am now I am pretty happy with myself, but really just want it running. Where should I look to fix my current issues, or where is the best place to buy a new carb for it? It is a Dellorto SHA 12/12

Re: 1980 Vespa Grande, no fuel

Hugh Goldspiel /

Did you try to adjust the idle screw? Give it a few clockwise turns then see what it does

Re: 1980 Vespa Grande, no fuel

Hugh Goldspiel /

Get a cito plus pipe

Re: 1980 Vespa Grande, no fuel

Aimee Delin /

Hugh Goldspiel Wrote:

-------------------------------------------------------

> Did you try to adjust the idle screw? Give it a

> few clockwise turns then see what it does

I messed with the idle screw a lot, no change at all, and it's odd because it's not like it stalls, the engine is still spinning when brought below half throttle, and even if snapped back to wide open it just dies out, does not even try to restart.

Re: 1980 Vespa Grande, no fuel

Hugh Goldspiel /

Change the condenser

Re: 1980 Vespa Grande, no fuel

Hugh Goldspiel /

Check points gap too

Re: 1980 Vespa Grande, no fuel

Aimee Delin /

In the final stages of reassembly and I appear to have lost spacer on the crankshaft before the drive pulley, I have tracked it down as part number 103241. It is my hope that someone knows the specs of this spacer so I can find a replacement.

Re: 1980 Vespa Grande, no fuel

Aimee Delin /

Nevermind, it appears I was smart enough to stick it to the magnetic tray, just not smart enough to remember it wasn't in the box with the rest of the parts.

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account