Hello everyone, I have a 71 ironhead and it has a problem I can't seem to be able to figure out. This summer it was running fine, over a few days it would not run right unless the enrichment **** was all the way out (Keihin CV carb). Then it would not accelerate at all. Found a broken flyweight spring which solved the not accelerating problem but it still won't run right unless the enrichment is full on. I have been thru the carb several times and all looks well and I can't find any air leaks!! Help!! Any suggestions on what to check would be greatly appericated. Thanks, Bob

 

have you checked the flow out of the petcock? sounds like you either have a fuel flow problem or a very bad air leak, you say you checked the carb, what about the intake? they are a problem area sometimes hard to find

 

It could be something as simple as a fouled plug from your previous tuning issue.

 

My rule of thumb --> on an otherwise good running '71 motor, 90% of suspected carb problems, are ignition problems.... so fix your ignition, before you mess with the carb.

..... which means you need to address things like:

1. if your points are questionable, replace 'em
2. set your points gap..... both lobes should be @ .018
3. if your condensor is questionable, replace it
4. gap your spark plugs correctly
5. if plugs are wrong heat range or questionable, replace 'em
6. set your timing (not just static timing)...... put a timing light on it (borrow a timing light if you have to)
7. go thru the advance unit, & ensure the springs & pivot points are solid & lube'd properly
8. replace anything else in your ignition that you know is flaky

Bottom line, you need to be 110% certain your ignition is solid BEFORE you mess with your carb..... otherwise you're just chasing smoke.