Is your meter set to AC or DC? Since it's giving negative readings, I'd suspect it's in DC mode. Try in AC mode, and see what you get. If it's a DC generator, I'd expect to see zero volts everywhere, possibly with a flash of "some volts" when you first hook up.
I think we need to make a little table here, as I'm not sure of your readings.... First, please verify (for sure) that you've got AC or DC, then let's see the readings for each cell in this table.
Red Lead -> | L1 | L2 | R1 | R2 |
L1 | -- | ___v | ___v | ___v |
L2 | ___v | -- | ___v | ___v |
R1 | ___v | ___v | -- | ___v |
R2 | ___v | ___v | ___v | -- |
^^ Black Lead ^^ |
I'd expect some of those readings to be zero, assuming none of the 4 wires are joined.
HTH!
Ade.
PS: To replicate that table, copy the below into your reply, and replace each "___v" with the applicable reading
[table]
[tr][td]Red Lead -> [/td] [td]L1 [/td] [td]L2 [/td] [td]R1 [/td] [td]R2 [/td][/tr]
[tr][td] L1 [/td] [td] -- [/td] [td]___v[/td][td]___v[/td][td]___v[/td][/tr]
[tr][td] L2 [/td] [td]___v[/td] [td] -- [/td][td]___v[/td][td]___v[/td][/tr]
[tr][td] R1 [/td] [td]___v[/td] [td]___v[/td][td] -- [/td][td]___v[/td][/tr]
[tr][td] R2 [/td] [td]___v[/td] [td]___v[/td][td]___v[/td][td]--[/td][/tr]
[tr][td] ^^ Black Lead ^^ [/td] [/tr]
[/table]