I just did the Wiseco 1200 conversion on my 2003 sportster. (9.5 compression pistons, no head work, rejet 45/175, se a/c and pipes) I do get some pinging every now and then and one backfire. I thing I need to adjust the timing - maybe retard a few degrees. Any thoughts?

Frank

Under what conditions do you get the pinging...how bad is it? I would say that retarding a few degrees might help you out...do you happen to know what your timing is set at right now? Did you check it after the conversion?
John

I have not touched the timing. It is not very bad, every now and then, when under load, such as accelerating up an incline in 2nd gear.

Try using hi octane gas. It might help.

Stock cams with 9.5:1 compression is going to have a tnedency to want to ping if the timing is in stock location (20 degrees at 1000 rpm idle) and you are running 87 octane. First thing to do is switch to 91 or 93 octane, then use an adjustable timing light and set your timing to about 17 or 18 degrees at 1000 rpm idle. That'll fix her right up and most likely reduce the vibes:)

G'day Frank

Tha 883 ignition module has a more aggressive advance curve than a 1200.

So you need to take a touch of timing out ususally.

Just knock it back a couple of degrees and see how ya go.

If it pops out the intake, when does it do it??? When the bike is cold it may mean ya need to use the choke a bit longer...if it does it hot the ya may need a shim under the needle.
What throttle opoenings does it do it at???

G'day Frank

Tha 883 ignition module has a more aggressive advance curve than a 1200.

So you need to take a touch of timing out ususally.

Just knock it back a couple of degrees and see how ya go.

If it pops out the intake, when does it do it??? When the bike is cold it may mean ya need to use the choke a bit longer...if it does it hot the ya may need a shim under the needle.
What throttle opoenings does it do it at???

Just turn it counterclockwise a "bit" ?
Running on 95 octane