Ironhead Just some thoughts....

[vyper202]

Well I was a little bored last night and was reflecting on my past sportys... a 1960 that was stroked and a 1973 that was stock except for 20 thousand over pistons/jugs.... The 1977 we have now, that has 750 miles on it since a total rebuild, engine and trans, just doesnt seem to be as strong as I remember the others. Im not comparing to the stroker, but the stock "73... they are set up almost identical... same carb and jets, same stock cams, same 2" open drags, same sprokets and rider weight almost identical. It seems the 77" is just weaker, dont get me wrong, its pretty darn peppy and runs great but the "73 would eat its lunch on takeoff and a 30 roll. So after reading some post and a little research, all info says the ironhead runs better with 1 3/4 drags with lollipops instead of the 2". I have installed the eye bolts in the 2" and it made no differance at all.
So last night I took an old set of 1 3/4" drags I had, cut the length down a little so they were the same length, installed the eye bolts and mounted them on the scoot half azz with old clamps so I can ride it a little to see if this changes anything.
Maybe there is just a differance in the early "70s sportys compared to the late "70s? for a little more power.... I know there is a slight horsepower differance in the year models...maybe Im just crazy... maybe I was just bored and wanted to find something to tinker with in the man cave... maybe I should just ride my Softail and leave my sons sporty alone....

[chevelle]

I.don't have much experience w/ drag pipes (for a reason) but...

Your right about eye bolts, they don't do a thing.
What you need is restrictive plate (large fender washer tacked to a bolt) in the pipe.
The lollipops needs to be about 3/4 the area of the open exhaust pipe.
If the plate is adjusted to be parallel to the pipe opening that will give you a noticable low end increase, but will hurt topend.
To get a happy medium, adjust plate to varying degrees until you are happy.

Originally Posted by vyper202

Well I was a little bored last night and was reflecting on my past sportys... a 1960 that was stroked and a 1973 that was stock except for 20 thousand over pistons/jugs.... The 1977 we have now, that has 750 miles on it since a total rebuild, engine and trans, just doesnt seem to be as strong as I remember the others. Im not comparing to the stroker, but the stock "73... they are set up almost identical... same carb and jets, same stock cams, same 2" open drags, same sprokets and rider weight almost identical. It seems the 77" is just weaker, dont get me wrong, its pretty darn peppy and runs great but the "73 would eat its lunch on takeoff and a 30 roll. So after reading some post and a little research, all info says the ironhead runs better with 1 3/4 drags with lollipops instead of the 2". I have installed the eye bolts in the 2" and it made no differance at all.
So last night I took an old set of 1 3/4" drags I had, cut the length down a little so they were the same length, installed the eye bolts and mounted them on the scoot half azz with old clamps so I can ride it a little to see if this changes anything.
Maybe there is just a differance in the early "70s sportys compared to the late "70s? for a little more power.... I know there is a slight horsepower differance in the year models...maybe Im just crazy... maybe I was just bored and wanted to find something to tinker with in the man cave... maybe I should just ride my Softail and leave my sons sporty alone....

[bobber58]

Depending on how they were/are set up, gearing has a big impact on this as well. The older XLCH's had deeper gearing in the transmission than the XLH, and there's a noticeable difference in roll on power between a 21 and 23 tooth front sprocket as well. So it may not be a weaker engine, it may just be a more parasitic way of getting the power to the rear wheel.

[hugie03flhr]

Exhaust make a big difference but are the bikes geared the same and are you broken in yet on that motor? Some moly rings take 2-3000 miles before they are broken in and seal up.

[tracbike]

I agree with gearing, the early bike may have had a smaller sprocket. which would explain that punch at 30

[bobber58]

Originally Posted by hugie03flhr

Exhaust make a big difference but are the bikes geared the same and are you broken in yet on that motor? Some moly rings take 2-3000 miles before they are broken in and seal up.

If it takes 2-3000 miles to seat a set of moly rings, you have the wrong surface finish on the cylinder wall when you honed it. I've never seen a moly ring take more that about 30 minutes to fully seat. On a race engine using moly rings once they are fired up and the engine tuned it is ready to go. The rings are seated in the time it takes to check the carb and timing.

Now standard cast iron rings will take some time to seat, and can take up to 500 miles or so

[Motorhead52]

Ever try dry top end rebuild? thats what I do

1 minute run at 3K RPM let cool over night

the rings seat and motor is oil tight for a long long time

cylinders are washed and dried ( flash rusted ) heads installed oiled, cylinders/piston and rings dry

motor can be used up to 70% of throttle for 250 miles then full 100% after

I use this method for all rebuild, its fast and reliable

[leadfootlambert]

Maybe the 73 had different cams than the 77? Just a thought.

[vyper202]

Like I said guys, its not weak by any means, just doesnt seem to as strong as it should. Maybe Im just getting older and want MO POWER! Im sure its fine for my 16 year old son...

[85mm]

Originally Posted by leadfootlambert

Maybe the 73 had different cams than the 77? Just a thought.

Good thought. I think Q-cams were stock for 77, P-cams stock for 73.