I am truly stumped...

my 1980 Pacer with a Morini M1 won't fire below 1/3 throttle. The carb is totally clean, the condenser was just replaced, and the whole thing has only 105 original miles... so to recap: I have excellent compression, good spark at all rpm's, and gas flow to a clean carb, but the thing won't stay running unless the throttle is at least 1/3 open. The throttle cable has proper tension and it is not the idle screw. Above 1/3 throttle is runs so well I just don't get it. The only thing I can think of is maybe something is blocking the transfer ports? I don't know, HELP!

Re: I am truly stumped...

Does it do this with the bike on the stand, rear wheel free to spin, or just when you're riding it? Maybe your clutch is sticking and killing the engine?

Re: I am truly stumped...

Peter Chudzik /

it does this both on the stand and while riding it, 99% sure the clutch is not causing this.

This just in:

Peter Chudzik /

I swapped out the ignition coil for one that I know for sure works, and same problem. So the coil is out, condenser is out, carb is out... I'm thinking replace the points, check the reedvalve and transfer ports? Any more suggestions would be totally welcome.

Re: This just in:

clean your points

and clean the idle circuit in the carb like 5 times

make sure that is clean

that could be your problem

sometimes you ahve to use compressed air to blow the clog out

Re: This just in:

Peter Chudzik /

I've cleaned the points to no end, but is there a possibility that even though they look good they actually are not? I suspected the idle circuit and I blasted it for a while with carb cleaner. Is there more to the idle circuit than just that small lower hole in that brass rod which runs vertically up the "throat" of the carb? Maybe I missed something.

Re: This just in:

I have an 80 pacer with a M1 also. I havn't tried to start it yet, but one thing I discovered is that my exhaust was 100% completely clogged. Maybe yours is? Are your head/cylinder and exhaust gaskets good/sealing properly?

Re: This just in:

It's been a while since I've worked with a Dellorto carb, which I'm pretty sure you've got. If memory serves, the vertical tube is for the main jet (the small lower hole). I think there should also be an idle jet in another tube screwed sideways into the carb, I think by the air mixture screw. Did you also clean that one out? Speaking of the mixture screw, have you tried adjusting that?

Re: This just in:

If this is a reed motor (you did mention something about reeds) it sounds like you have some bad petals or something foreign found its way in and is preventing the reeds from sealing when the crankcase is trying to pump.

Re: This just in:

Peter Chudzik /

by "the lower hole" I don't mean the main jet, I mean the lower of the two holes drilled into the brass rod which you can see if you remove the air filter (holes are on the other side). The dellorto SHA carbs don't have a mixture screw.

Re: This just in:

Peter Chudzik /

This whole moped hasnt been ridden more than 105 miles in its entire life, but I will check the exhaust and everything else beyond the intake manifold, including the reed valves.

Re: This just in:

could be the following

Carb main tube is partially clogged pull the main jet in the bowl and using a piece of fine wire pish it up the tube.

The other thing could be bad seals on the crank. bet it in the carb though.

Re: This just in:

Can you change the timing on this ped?

Re: This just in:

Ben Van Zoest /

Most likely the brass spay tube like Freddie said, remove the carb, insert the reed of carburator cleanin fluid can into the tube and give it a couple of blast. Sometimes it needs to soak awhile. Considering it only has 100 mile I would not monkey with stuff that is irrelevant like 'the pipe' timing or plug.

How old is this thing and how long has it been unused you might have a murky gastank.

Re: This just in:

yeah, cant be the pipe at all with only 100+ miles on it.

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