Greetings - hoping for some help and advice on my new-to-me Softail.

The prior owner was very fond of aluminum crimp butt-splices and 25¢ a roll electrical tape, using them to "tighten" just about every wire on the bike. This has lead to multiple oddities in behavior, for the most part tracked down to rotten wire (Al+Cu+road salt/water) or just plain bad work ("extra" wires he didn't understand left to dangle or grounded).

As I've been working through the mess, one of the repairs /replacements I've had to do is the ignition (which was also modified, with the P.O. removing the VOES for some reason - now replaced).

Now that I have a new DynaTek 2Ki installed and timed (static by TDC mark, then dynamic to the timing mark), I'm having a dickens of a time getting the rear cylinder to play nicely.

Every exhaust cycle on the piston, there is a strong "suck" from the tailpipe back in towards the engine. I've lurked around here searching for any similar issues, and searched Mr. Google and either didn't set up my search correctly, or this is a weird /Zebra sort of problem.

So, in summary:

1984 FXST with EVO 80 engine (appears stock beyond orangutang "work")
Stock 4 speed transmission
DynaTek 2000i ignition with 3 Ohm coils
Operating environment - high country Colorado (6500-8000 ft above sea level)

Front cylinder fires as expected and exhausts fully
Rear cylinder reverts during exhaust and pulls air in, causing random odd hiccups and hesitations

Any further data I can post to help diagnose, further advice, cautions, alarms (e.g. "Stop riding now and get to a full shop before your piston comes through the seat!!!"), or other help will be most appreciated!

 

Hi from the UK and welcome to HDF. I recommend you visit the Evo section where you will find plenty of fellow owners and our experts, who can help you sort this out!

 

Can do - just figured to start in the "Tech /Ignition" area since that appears to be the causative modification.

Thanks for the advice!

 

I understand, but far fewer members call into the Tech section than the model-specific ones. You should get better results in the link.