Pushrod Adjustment Anomoly

[IronMick]

The exhaust pushrods have the habit of getting too tight after only a couple days riding. Has occored twice now for each. The adjusting nut is not moving so something is wearing [valve?, valve seat?] such that it starts off ok then slowly gets too tight.

What is wearing? What problem is causing this?

Thanx AGAIN!

[Fisherman]

Hew, Mick. How'd the choke cable work out? As to push rod loosing adjustment, The only thing that could wear that would make it tighter would be the valve to valve seat match. Anything else would tend to loosen it up. Or else the wheel & rollers on the bottom of the lifter are out of round. But, I've never heard of that. I'm stumped, Mick. Just so long as the engine is cool when you set them, they should remain adjusted.

[Fisherman]

Now wait a minute. I had a thought. (it's a miracle). No, really. The engine is heating & cooling. Could it be that the head is compressing the head gasket a little as it's new & settling a little & messing with your adjustments? Have you re-torqued your heads yet?

[IronMick]

... Have you re-torqued your heads yet?

No i have not. This is a new idea for me. Re-torque the heads, eh!? Sounds like another one of those things i would like to have known about ahead of all this. Ok, tomorrow.

I must have forgotten to get back to you about the choke cable. Sorry about that. It has worked out VERY WELL. But it took me about a month of fiddling to get it to go. The main problem was that it was pre-shaped to fit not-my-bike, and i had new, bigger manifold clamps that were in the way, and it kept messing up and it took quite a bit of fiddling, mostly chasing the wrong thing.

Many thanx again.

[flathead45]

that won't cure your problem tho

getting too tight sounds like your adjusters are not locked down tight and slowly spinning up are you using both a 1/2 and a 7/16 to lock em down with ?

[bamf_shadow]

For one, check the head bolts to make sure they are tourqed right. As far as the tappet wheels being out of round, I suppose it could happen. You might try adjusting them, then rotating the engine a few times and check them again.

[IronMick]

... getting too tight sounds like your adjusters are not locked down tight and slowly spinning up are you using both a 1/2 and a 7/16 to lock em down with ?

I am considering buying a new pair of 1/2, 7/16 wrenches; something with longer handles to give better purchase. With my current wrenches i am getting them as tight as i dare. That is why i am wondering what else it might be.

In the morning i will check them again. We had an all-day ride today, and from the end-of-day performance and exhaust sound i would guess the exhaust p-rods are too tight again.

[Y2K]

I think Flatty is on to it Mick,I can't imagine anything else making them get tighter like that.I had 'em come loose many a time from hot rodding but never tightening up as you describe.I do remember having to crank that lock nut down tight as hell though.I'd definately check the head bolts and even the cylinder base to be sure they're torqued properly.
Y2K :smoke

[Fisherman]

Mine aren't that tight. Maybe 15 lbs torque. Not really hogged down.. Pun unintended. Adjuster loose, turn counter clockwise 'till fit achieved. Then lock nut clockwise until locked down. (Just thinking to myself, so to speak) Perhaps you should take one of the adjusters out of the lifter & see if the threads are good. Run the lock all the way up & down the adjuster to make sure it's not 'locking' on a bad thread? A thought. When you have to re-adjust, are the adjuster lock nuts still tight? Do you have to 'break them loose'? I am completely stumped. If it was the adjuster, it would get looser. Either the rocker is moving down or the lifter is moving up. I assume the little 'ball' on the bottom of the adjuster lock nut fits into the 'cup' on the lifter well? I'm sorry, Mick. I've lost sleep trying to figure this out for you but, I'm at the end on my train of thought on this one.

[IronMick]

I just checked them this morning. They are now tight.

When i adjust them i set them so that i can just rotate the p-rod with my fingers, then loosen it more by "1 side" of the adjusting nut [recommendation of local inde mech]; then i tighten the lock nut, then check to be sure the adjustment has not moved. Then i rotate the engine again [maybe twice] and check it again. It is still good.

Then the same for the other. It runs real good after this adjustment.

Did this Sat nite to prepare for Sun 160 mile ride. At the end of the day i could tell they were tight by the heavy exhaust sound [exhaust valves not closing, can hear the fuel burn] and low idle speed [stalls at intersection, too much "rap" on decel]. Just checked them [now Mon a.m.]. They are tight. The locknuts are tight - have not moved.

So, do we perhaps have the valves slamming against the seats causing rapid wear? Bent stems? Some other nitemare? I'll probably have to open 'er up for a peek to solve this one.

[IronMick]

... are you using both a 1/2 and a 7/16 to lock em down with ?

Yup, using both. And setting them real tite! I have been thinking of getting some longer wrenches but i don't think that will solve this problem.

[79iron]

i don't think you need longer wrenches. i don't tighten my locknuts down that tight and never have a problem. definately check the threads and make sure something's not screwed up there.
you are checking them when everything is dead cold right? like not-ran-all day type cold? i don't know what else it could be. you said you double check the adjustment after you've tightened the lock nut, so that's good. i don't know man.
i've been having non-stop problems with the same oil seal all summer too, so you aren't alone in your re-occurring problems. if i didn't love my bike so much i'd have an evo by now for sure. i try to talk nice to it but it doesn't seem to help. i think my bike's just pissed off at me for test riding that buell and new sportster this spring. i keep telling it i'm sorry, but it just ignores me.
i'm tired and should stop writing now. :tour

[The_Bishop]

The only thing that pops into my mind right off that might cause that is valve seat recession. :frownone

[flathead45]

recession would have to be drastic to tighten the pushrods asmany times as mick says it has , by now he would have lost a valve , and those old ironheads are not known for loosing seats

if the problem continues I would try new adjuster screws and lock nuts

[Fisherman]

Mick. Are these new valves? How good a quality are they? Could they be cheap Chinese valves & the valve stem is stretching?

[IronMick]

Update on tight p-rods:

Talking with a friend recently - he has worked with many 1980s BMW motorcycles. He said that those bikes, like the ironhead, were designed to run on leaded gas. He said it was common for the valves to go out of adjustment tight within a few hundred miles just as mine have, and that using lead substitute was the solution to the problem.

Also talking with one of the tech reps at CraneCams, he suggested adjusting them "two sides" rather than "one side" so they would be looser, perhaps a touch noisey, but still ok.

Unfortunately i implemented both of these suggestions at the same time. The problem has gone away. I do not know which did it.

I did re-adjust the exh p-rods to "1,1/2 sides" as "2 sides" was tooooo noisey for me.

[hawgzotic]

well after reading this whole thread, and not seeing anybody mention "valve lash" i am going to jump to the wild conclusion that you have hydraulic lifters (as opposed to solid lifters).

your problem is

a) hydraulic lifters will pump themselves up (thats why they use them , so you will never have to get the feeler gauges out and gap the valve lash)

b) when you are setting them, they are getting compressed by the camshaft ... try this

put bike on lift, in gear so you can rotate the engine by spinning the rear tire.
spin the rear tire until the lifter for the intake on the rear cylinder starts to rise.
set the rear exhaust pushrod

spin the rear tire until the rear exhaust lifter starts to rise

set the intake pushrod.

repeat for the front cylinder

[IronMick]

well after reading this whole thread, and not seeing anybody mention "valve lash" i am going to jump to the wild conclusion that you have hydraulic lifters (as opposed to solid lifters) ...

It's an ironhead - solid lifters. I appreciate the thought tho.

[jamman]

as in another thread of yours, these problems are probally hand and hand ( the sputtering) You may Have a worn seat, Broken spring( rotating to bind and rotating to loosen up again) or a worn and spun or spinning out of round rocker bushings...













0

[hawgzotic]

It's an ironhead - solid lifters. I appreciate the thought tho.


in that case you should have lash settings for hot or cold

just did my triumph t110

they are set cold

ex 0.004
in 0.002

with a note for cast iron heads to be set at 0.001

while a vrod is
0.22 +/- 0.025mm intake
0.32 =/- 0.025mm exhaust

whats your manual say?

[Takingabreak]

Hi Mick.

Ok, what's going on here is the exhaust seat is burning off, and the valve is being beaten into head do to no lubrication.(Lead)

So, the way to fix this is not to use a lead substitute, but to pull the heads and have harden seat installed and unleaded valves.

[IronMick]

in that case you should have lash settings for hot or cold ...

We always adjust the pushrods with the engine stone cold; usually first thing in the morning. No info available for setting when hot - burn your fingers off trying anyway.

[IronMick]

Hi Mick.

Ok, what's going on here is the exhaust seat is burning off, and the valve is being beaten into head do to no lubrication.(Lead)

So, the way to fix this is not to use a lead substitute, but to pull the heads and have harden seat installed and unleaded valves.

What do you mean by "the exhaust seat is burning off"? I think the valve seats are part of the cast iron head, not some part attached separatly [tho i may be wrong here].

I do think you are right about the correct solution to the problem. I will wait until winter project time [December] if i can get away with it.

[jamman]

The seat is a Malleable alloy pressed into the cast head, Can be changed and new ones are unleaded fuel ready..

[BobboJama]

Mick,
jamman is probably correct... If your not running leaded fuel or a lead substute your exhaust seat is erroding. It happens slowing at first, Taking some to wear through hardened surface of the seat area, About 1/16" of an inch. Once the is gone your exhaust valve will retreat up into the port. You are going to need new seats. If you can if a small dental mirror, you may be able to see where the valve sits through the spark plug hole. The edge of the valve should match the contour of the combustion chamber... Not sit in a pocket... Good Luck!

[nmaineron]

I think you are simply adjusting them to tight.They have to spin free without any lash and they will be a bit noisey.It's the nature of the beast.If they are running open as soon as they expand then you may be collecting enough carbon on the seat to cause your tight condition.Be careful that you don't burn a valve.Better to run them a little noisey.