i have recently purchased an old ironhead that had been customed out by the previous owner and dont know much about old harleys. I took it to a local bike shop and had them get it road ready and the bill was 1700 bucks(i know its a lot but they did do some much needed work, eg tapits n lifters and a few other things) anyway i changed the neck bearings, throwout bearing and chain tensioner myself. anyway got it back from shop and has ran great (put about 500miles on it) but im starting to hear a lot of top end noise when im cruising, especially when i downshift and the motor quiets down i can hear it,,almost like somethings tapping on the bottom of the gas tank. i do have some oil dripping..although very minimal from the jugs so im assuming i need to change head gasketts at some point but this noise is new and i dont wanna continue to drive it and have it cause more damage than simply replacing an easy fix and have another 2 grand bill , its like i hear a loud sowing machine on the top end of my engine if that can describe it , please dont think im stupid i just dont know a lot about old harleys and i know they are loud and rattle so i just need some advice on what a 72 ironhead is supposed to sound like , so any advice wld be a big help..thanks schmitty 72 ironhead 1000cc

 

for $1700 you should basically have a new motor.. what exactly did they do?

 

Listening to this video, at first you can hear mainly the exhaust sound, but when the camera is close to the top end, that is the sound of properly adjusted valves and a well tuned up IronHead engine ...

http://www.youtube.com/watch?v=dwgzY...ure=plpp_video

If you want some feedback on the $1700 you could scan and post the invoice or type it in. Labor cost is typically $50 to $100 per hour, and when you add in parts and taxes it adds up pretty quick. It cost me ~$1000 first shop day for mine. Now i do everything i can first then just bring in the parts needing service. This is basically what we all do.

somethings tapping on the bottom of the gas tank could be the right sound or it could be one of many things. First check the gas tank mount bolts and the tank itself. I rubber mount mine with ~3/16" slices of 5/16" or 3/8" ID rubber oil/fuel line; the rubber gets squished into the bolt holes in the tabs on the tank; have to be re-tightened after each of the first 2 or 3 rides ...



What is the throwout bearing? Whatever it is it is called something else on an IronHead.

Exactly where on the cylinders is the oil dripping from? Post a pic to make it clear.

a loud sowing machine on the top end of my engine - this is what it should sound like.

You need these two manuals ...
99484-78 Factory Service Manual
99451-78B Fatcory Parts Catalog
Buy these thru a local indie bike shop, HD dealer, eBay, various internet sellers, J&P Cycles, etc etc. Put the part numbers into the Google and eBay searches.

Here are some notes, first on using a mechanic's stethoscope to listen to your engine, then on adjusting the pushrods. You should do both of these procedures, yourself of course ...

IronHead Noise Analysis

The "sound" can be quite disturbing, very much like the engine is going to blow up. Litterally like a tin can of marbles. What you need to do is to determine if it is the normal sound or if something is wrong.

The best way to do this is to listen with a mechanics stethoscope. You can use a screwdriver or a length of hose but the real tool is much better, and can be purchased inexpensively at Princess Auto or Harbor Freight.

With the engine at idle listen at ...

• all 4 rocker ends, both sides of the engine
• all 4 pushrods, top, middle and bottom
• all 4 lifter blocks
• all 4 cams, listening thru the gearcase cover
• both ends of the generator

All similar points should sound about the same, like rotating steel parts. The generator should be 2 or 3 times noisier than the other points.

If a pushrod is too loose you will hear a louder click sound at its lifter block. If you adjust the pushrods according to the looser option in the notes you will hear this click on the exhaust pushrods - slightly louder than at the intakes.

It is worthwhile to do this process a couple of times a year, just to keep track of stuff. It is a very good idea to do this when the engine is running well so that you know what running well sounds like thru the stethoscope.


Ironhead Push Rod Adjustment

Do this procedure with the engine stone cold. I usually do it first thing in the morning, [but i do steps 1 thru 3 the night before] ...

1. Remove the spark plugs. Remove A/C to make room to work.

2. Using a flat blade screwdriver pry the spring keeper off of each push rod; the bottom of the keeper pops out first, then the top. Alternately, use a 3/4" open end wrench to push down on the top of the spring retainer, then pry out the spring keeper with the screwdriver.

3. The lower push rod covers may be stuck tight against the bottom o-rings, but they can be loosened by pinching between thumb and finger [or carefully using a shop rag and a pliers] and twisting or rotating. Lift these up and secure each with a tall-S-shaped piece of 12 or 14 gauge household wire [not cable] [or a long piece of Plumbers solder such as 95/5 hooked over the rocker cover and under the push rod cover.

4. Jack up back end of the bike so that rear wheel is off the ground, shift to 2nd gear, rotate wheel until it clicks, repeat until you get to 4th gear. Now by rotating the rear wheel you are rotating the engine. Almost impossible with the plugs in; very difficult in lower gears.

5. To adjust a particular push rod, its valve must be fully closed [the valve spring is relaxed]. Valve position for a particular cylinder is determined by observing the corresponding push rod of the other cylinder. For example, when the rear cylinder intake valve tappet is raised [valve fully open, spring compressed], the front cylinder intake valve is fully closed, and the front intake push rod can be adjusted.

6. Check [and adjust if necessary] the push rods:

[a] use the rear wheel rotate the engine so that the rear cylinder exhaust push rod tappet is fully raised. The front cylinder push rod is adjusted correctly if it has no vertical or horizontal play, and you can just rotate the push rod between thumb and forefinger with no trace of binding or dragging.

[b] to adjust if needed: hold the adjusting screw in place with a wrench; with another wrench loosen the split locknut. Then turn the adjusting screw using fingers only until the pushrod's ball end is seated in the tappet with a "slight amount of play". Then tighten further as follows:

Option 1: Adjust on the tighter end of the range: There should be no vertical or horizontal play, and you should be just able to rotate the push rod between thumb and forefinger with no trace of binding or dragging.

Option 2: Adjust on the looser end of the range: Set the adjusting screw to finger tight so that you cannot turn the push rod between forefinger and thumb. Undo it a tiny bit so that it is just barely loose. Then loosen it 1 "side" for an exhaust or 1/2 "side" for an intake. "Side" refers to one side of the 6-sided adjusting nut.

EDIT: Experience here is that Option 2 is the better and most likely the correct choice.

[c] hold the adjusting screw in place with the one wrench; with the other wrench tighten the locknut.

[d] recheck the adjustment; it is common for the adjustment to go out as you do step [c], in which case [b] and [c] must be redone.

[e] repeat for the other push rods.

7. Use a flat blade screwdriver to push the upper push rod covers up, and seat them into the upper o-ring or cork washer.

8. Install the spring keepers, top end first, by prying them in under the bottom with a flat blade screwdriver.

 

do what mick said as far as valve adjustment , but piniongear said it right before, these bikes sound like "thrasher" machines just the nature of the beast