Pistons Seizing or ???

[oklahoma]

Runs great on start up, pulls strong, feels smooth but then when it gets hot it dies. It doesn't lock up but loses power and then once I roll to a stop its dead. If you try and start it back up hot, the kicker is difficult to push thru, like the pistons are seizing slowly. If you wait for it to cool down it seems fine again. By hot I mean not just warmed up idling but ridden hard and after atleast 5+ fast highway miles. Didn't have a temp gauge to check with but seems like it is over heating. Haven't done a top end in a long time so maybe its time for a bore.

Anybody have experience with this? Anything else to look for. Gonna pull the top end tonight I think.

I read Kings's Seized Motor (Seized motor) issues in the knowledge base but mine turns over freely after cool down so I am pretty sure its a different issue all together.

[old52pan]

I have to ask the obvious, do you have oil return to the tank? That's the first think to check. Is the motor blowing smoke? Do not run it any more than to do brief checking of the systems. Tim

[oklahoma]

Yeah I have not changed oil lines and have been runnin this way for maybe 10,000 miles as it is. Stock style oil tank and just rubber lines.

[NightShift]

Dear Oklahoma,

Odds are it is getting too hot from sucking air somewhere like the manifold.
Thats if your points aint closed up or valve adjustment wacked, of course.

'Spectful,

[oklahoma]

So could sucking too much air make it over heat enough to cause the seizing pistons? The plugs look clean would the too much air make it run lean?

[NightShift]

So could sucking too much air make it over heat enough to cause the seizing pistons? The plugs look clean would the too much air make it run lean?

Dear Oklahoma,

Yes, yes, and before you even ask, Yes.

'Spectful,

[Bosheff]

If it's suckin air, it's gonna run lean. If it's runnin lean, it's gonna run hot. If the top end is loose, it really shouldn't be seizin pistons should it?....bosheff

[oklahoma]

Ok so I pulled the top end and it does look like it was pretty lean. Thanks for the help guys. How much end play should be in the front rod? (This pic of rods is not of my bikes I just used it for reference on the measurement). End play where the piston connects is about 1/8" play.

Rod_End-_Play.jpg

Here is a pic of my front piston too.

IMG_0015.jpg

[NightShift]

Dear Oklahoma,

I woulda said just fix the air leak, but your piston says it was too late anyway.

Thats the worst wear on the top of rods I've ever seen ever on anything. I gotta show a pic of those to everybody at the bar!

'Spectful,

[Bosheff]

How in the ---- could the top of the con rods wear like that? Over the years I've seen some pretty beat on rods, but never anything like that. Can anyone explain?....bosheff

[FlatHeadSix]

my guess is that those rods did not wear that way, somebody did that intentionally. Trying to change a balance factor maybe? I guess you could get away with removing metal in that area to reduce the reciprocating mass, most of the thrust is on the bottom half anyway.

but it still looks dangerous to me

jmho

mike

[oklahoma]

If you notice I put "(This pic of rods is not of my bikes I just used it for reference on the measurement)" Harley did that and its a much later model than a Pan. I was just using the image which I pulled off the interwebs for a point of reference on the back and forth measurement. I guess that was not very clear.

[Bosheff]

Who in or out of their right mind would do that intentionally, and think it would not cause a problem sooner or later. (Probably sooner)....bosheff

[Cotten]

Who in or out of their right mind would do that intentionally....bosheff

Apparently Harley Davidson did.

You gotta make them wear out somehow if you want to sell more of them.
Why do you think Shovels were invented!

...Cotten

[steinauge]

I cant see the pictures but I imagine you are talking about the late style rods that almost arent there at the top of the small end.The reason for that is allegedly to promote better small end oiling.Sounded like bullshit to me.