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-   -   Ironhead One jug under the line... (

shgrier 14th May 2019 21:56

One jug under the line...
OK, now for my latest conundrum:

After getting the frame back from powder coat, I tore the top end off the motor (head/rocker assy) and all the guts out of it that i could to make it as light as possible to reinstall and not scratch anything. Install went fine.

I installed the front and rear jugs over the slugs, torqued to proper spec with new base gaskets, installed new .016 copper head gaskets, and installed the heads (with the rocker assy's still installed on the jugs). Went to put the pushrods in, and my pushrod cover clips won't fit on the front jug (rear jug is just fine).

Hmmm, I said to myself outloud. with the pushrod covers up, I tried rotating the motor, and I seem to be getting springbind on the front cylinder. If I loosen the front lifters by about 2 full turns, all is good.

What could I have done wrong? The bike was running before I pulled the motor out to powder coat the frame, so nothing has been changed on it. What, other than a thinner base gasket and/or head gasket and/or rocker gasket would create an overly short assembly? Since the lifters are 32tpi, two full turns of relief would be ~.060".

I'd had springbind originally with the new R5 cams, so I got the Manley Valve springs and the Andrews low profile bottom collars, and fixed the springbind problem before removing the motor (the motor had run fine before the removal). I have no springbind on the rear jug, and the pushrod cover clips fit flawlessly on the rear.

What am I missing. The only fix for this seems to be an extra thick rocker gasket, but that makes no sense! Nothing changed between running/removal/reinstall.

Any help for a neophyte I/H mechanic?

Thanks in advance!

Ferrous Head 14th May 2019 22:45

There should be plenty o clearance for the push rod clips to slip in.
The push rod cover tubes need to be seated correctly in the lifters blocks and the rocker boxes. I would guess that you don't have the tubes seating in the rocker boxes. This is the most common point of misalignment.
Also. make sure you haven't put two seals/gaskets in anywhere. When installing new sea;s I have sometimes forgotten to take the old seals out of the rocker boxes.

ezmerf 14th May 2019 23:22

?'s did you test your springs while you had them out?Did you file every thing were when you put it back together went back where it came from?

SHAKY DAVE 15th May 2019 04:16

you sure you don't have an extra o ring on the head side seal.i've done this before:dohso don't be as dumbass as me some times.this brain damage from my spill last july sometimes get to the way I run oring on top and cork in the lifter for me

randy3934 15th May 2019 04:37

did you install pistons with the relief for the intake valve facing the intake valve?

randy3934 15th May 2019 04:46

if not the intake valve will hit the crown of the piston seeming like spring bind.

shgrier 16th May 2019 21:05

All good input. I'll triple check all this tonight, but there's only one rubber pushrod-tube gasket in each rocker box location, and the pistons are installed correctly (The one with the R is in the rear with the R to the back of the cylinder, and the one with the F is in the front with the F towards the front of the cylinder).

I'll also check spring length, but given I removed and reinstalled the heads with the rockerboxes still attached, I can't see where I would have changed anything related to them.

I'm trying to find a root-cause that answers both questions: binding coils with properly adjusted pushrods, and too-short pushrod tubes...:headbang

Ferrous Head 16th May 2019 21:50


my pushrod cover clips won't fit on the front jug (rear jug is just fine).


and too-short pushrod tubes..

OK. So, O thought your problem with the tunes was that you weren't able to install the lips because you weren't able to compress the springs far enough to install them

properly. Now your saying they are too short ?

Make sure the inner tube can slide freely insife the outer tube. Thr inners are prone to rust and crud making them difficult to extend ot collapse easily.

Bent pushrods will make the clearances change. I haven't iven much thought avout why but I found on my last ace engine that I could adjust the front intake, roll the engine over a couple times and it would be too loose. Tried to adjust the push rod several times and finally pulled the rod and discovered it had bent.

If you had a problem after installing higher lift cams you might well have bent a push rod discovering that fact.

randy3934 18th May 2019 01:28

so you didn't remove the pistons? the jugs are marked "F" and "R" not the pistons, new rings and cylinder honing?

shgrier 20th May 2019 18:07

OK - I think I killed both gremlins with one move.

Looks like it was NOT spring-bind but, as Randy3934 pointed out, an intake valve touching the piston. The KB 292 pistons have a unique squish design to them that is fatter on the right side than on the left side, and that's where the intake valve was touching.

So to recap, I had taken a running motor out of my raw frame, so I could get mounting tabs and such welded on, then the whole frame powder coated. Before reinstalling the motor, I took everything off of it to lighten it up to ease in the install (didn't want to scratch the new powder coat). Then as I was reinstalling everything, I discovered my forward jug pushrod tube clips wouldn't clip in (too long?), but the rears were fine. I was also getting resistance to spinning the motor when the front pushrods were adjusted, but that resistance went away when I turned them in by about 2 full turns. (what I incorrectly thought was spring-bind).

The only difference between when I built up the motor the first time and this time was that THIS TIME, I torqued the front head down BEFORE installing the intake manifold - I then loosely installed the rear head and aligned the manifold and torqued the rear head down.

So, in the course of troubleshooting this, I removed both heads, installed new copper gaskets (.030" vs. the .022 ones that were on it originally), and LOOSELY assembled the heads on the jugs, and aligned the manifold with BOTH heads loose.

What I noticed was, in order to get the manifold properly aligned, I had to rotate both heads inward in the middle. Looking from the top of the bike, the rear was rotated counter-clockwise, and the front was rotated clockwise. The alignment of the manifold looked best this way.

I think what happened when I did it this way was that the intake valves are now rotated AWAY from the dome of the piston by just the right amount, and therefore my resistance is gone with the pushrods properly adjusted.

The WEIRD thing is that now all 4 of the pushrod tube clips fit properly! I don't EVEN understand that one. The additional .008" of copper gasket couldn't be the cause of that (I had about .040-.050" of clearance I needed for the front clips before). The only thing I can think is that rotating the heads modified the geometry of the heads to the tappet blocks, so now everything fits.

At this point, I can only say "OK, whatever" and move on. :tour

Thanks for everyone's input. These I/Hs are sure a learning platform... :geek

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