Here's the story sold my last Harley wanted to go old school and so I got this ironhead. When I got it I put some new pipes on her and cleaned her up and some few cosmetic things looks great but here is when I started to get in the heart of this beast mind you ran good but I'm tryin to get all I can out of it. Right of the bat I have a intake leak on the front cylinder and a exhaust leak I found this out by the glowing pipe at night but still ran good so I fixed the intake leak to the best of my knowledge with a carb cleaner test not changing any rpms but could maybe have a small leak really small so then I fixed the exhaust no problem there. So then I had a valve tapped leak that I fixed and I also did a pushrod adjustment but I think my adjustment was shotty going to redo it. now the bike idles great when cold but once warms dies out after warmed out and I go to throttle it backfires I mean pops and also through the carb I pulled the plugs look good but also when I go to restart its a bitch I let it sit for three min fires back up but wants to be chocked a little. Then I adjusted my cab ss and its still back firing so here's the list

1.pushrod adjustment
2.compression(got to score a tester)
3.Timing(need to hone my skills)
4.carb(but don't think so do to running well a week ago)
5.ignition(coil condenser)
6.Back to intake leak but don't think so
7.battery contacts

FACTS
1. Runs good at idle
2. When I did the pushrod adjustment I did it in neutral and used the kick to move it I'm pretty sure I adjusted at the lowest point(plugs out)
3.bike ran fine a week ago but was hot in the front cylinder

Alright whos got any ideas thanks for the help or any you ironhead legends want to change my list around I'd appreciate it I'm just a young gun appreciate it

 

valve adjustment is done this way when one intake or an exhaust is lifted as much as it the cam can lift, you adjust the other intake or exhaust pushrod - you do them in pairs intake than exhaust -

you could have a tight valve or a fouled plug causing popoing its easy on an iron head to do -- check valve adjust first

 

I'm going to redo the pushrod adjustment first but my plugs are good

 

need to get the intake sealed up 100% first before moving forward, then move to the points checking for worn springs etc then re do the push rods make sure its stone cold

 

Thanks for the help guys. Not yet figured it out but any tips on finding a really small vacuum leak when I spray the carb cleaner all around I'm not pickin up any changes in rpm's

 

The shop trick we use that seems to always work if it is in fact leaking or not

take one clamp off at a time ( manifold to carb ) and just the o ring is in place as you look at it

take a piece of electrical tape ( not the china crap ) USA made and run it around the o ring so it sticks to the spicket metal on both the head and the intake manifold - than put the clamp back on and snug it - than do the other one - you will find the seal stays unlike just the o ring - its what we do in my shop just my take some may do something else -- jz

 

The way I check for intake leaks is to remove the carb.
Then stick your finger inside the intake manifold and feel around the entire surface of those O rings.
If you feel any irregularity anywhere on the rings, you have an intake leak.

As Shepdog said, fix the intake leak first, then make sure the valve adjustment is done correctly next.
Do this with a stone cold engine
Backfiring (or coughing) through the carb or exhaust pipes points to an intake leak.
Not idling smoothly and normally (at 950 rpm) is another sure sign of an intake leak.
pg

 

you did a nice job on the sporty

we did a C box conversion on this 69 XLCH not that long ago

my first bike was a 57 sporty -- jz

 

When looking for intake leaks, whatever you use, you have to spray a lot. Get the nozzle right in there close. Any change in RPM is a leak. In my experience it is always a decrease in RPM, never an increase.

You need something with very fine particles; this is why some guys have traditionally used WD-40. However, the best i find to locate intake leaks is to use propane, or some guys use butane.

Just don't light it!

You have to spray a lot. The gasses will find much finer leaks than the sprays, and they leave no mess.

I check mine a few times a year as part of regular maintenance.

Well, ya kno, ya always lite propane when ya use it for other applications. So it can be easy to do it accidentally. So that is why i mention it.

Another, and said to be the most preferable and reliable and precise technique, is to pressurize the cylinder heads and spray liquid soap on the joins looking for bubbles. But i have no experience to setting this up.

Something like this - remove exhaust pushrods so exhaust valves are closed, adjust intake pushrods so intake valves are open, apply air pressure thru spark plug hole. Just guessing here. And i9 do not know how much pressure to apply.

 

Backfire thru the carb on deceleration can be a result of exhaust system leaks. You can never get a good tuneup with these leaks.

Check for exhaust system leaks by pouring ~1/2 oz of oil into each cylinder thru the spark plug holes. Then run the engine at idle, you will get lots of smoke for a few minutes.

Smoke from anywhere other than the ends of the exhaust pipes is a leak that must be fixed. Best to do this out of the wind.

The most common leaks are at the cylinder heads, and these can easily result in a hole being burned in a piston. In my experience a leak at the join of the crossover pipes is an absolute disaster for a good tuneup. I am uncertain how bad is a leak at the muffler/header connection.