Heads - Rebuild

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49bones
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Heads - Rebuild

#1

Post by 49bones »

If i wanted to strip of the cylinder heads from my 57 panhead, give them a good clean up, check the valves are closing, change anything that i need to change etc...

What advice can anyone give me on this? What problems can i expect to run into? What parts would you change?

Bikes running good, but i feel it can be better, the plugs match in colour, but sometimes i can't seem to lean it off a bit without getting a misfire, if i run it how it is (Rich) then its ok but blacks the plugs up after a few hundred miles. Got a good seal on the inlet.
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Re: Heads - Rebuild

#2

Post by 48Doc »

Why not pressure test first. An accurate test would give you some idea as to the the condition of the valves, rings, and head gaskets. Have you done a compression check? Just a few thoughts. There are some very skilled, experienced, and knowledgeable guys on this site, hopefully they will chime in. Sometimes the enemy of good is better!
Doc
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Re: Heads - Rebuild

#3

Post by 49bones »

48Doc wrote:Why not pressure test first. An accurate test would give you some idea as to the the condition of the valves, rings, and head gaskets. Have you done a compression check? Just a few thoughts. There are some very skilled, experienced, and knowledgeable guys on this site, hopefully they will chime in. Sometimes the enemy of good is better!
Doc

Ok 48 Doc i guess you are right - A compression test would provide me with what i want to know in fact. It doesn't smoke at all and rides good, i have run it rich and in my head i guess that i have blacked up the combustion chamber and valve ports etc. Does that happen?
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Re: Heads - Rebuild

#4

Post by 58flh »

Bones---Absolutely Bubble test as was mentioned.If your bikes plug look as you say /Thats GOOD!--you rather be slightly rich then running white or light-tan plugs even scare me.When & If you need to pull the heads /You may encounter the usual a crack from plug to seat (normal )/But must be fixed as olny the milage packs on the seat & head will get worse!.EX.-I know of heads that ran with cracks like that for a few yrs./but they were mostly weekend warriors,so they got away with 600 miles a year or whatever.-When you pop the springs look for a nice thin shiny ring on the valve-seats.If you have it then there holding pressure./Check spring pressure & make sure there all in spec./OK naturally you will probably get NEW guides ,valves & seals ,Springs.Send the heads to a shop that DOES PANHEADS & have a good rep./unless you have the eqipment,then do it yourself,Its not hard if you done this type of work!/Just have to treat the heads GENTLY as you know there POUROUS & have a zillion miles on them which make them BRITTLE.Check your spigots for cracks & inside the EX.-ports for cracks after a good cleaning.(When cleaning Dont use anything CORROSIVE as in strong detergents!,it will change the color of your heads & may even eat some brittle finnage away.I use spray carb. cleaner ,a nylon brush,& rinse immediately with a solution of water & SIMPLE GREEN.Spray a little area at a time & Rinse.Valve & spring height must be checked after the valve-job & olny then you will know how much the valves need tipping.The star fasteners should not protrude past the gasket surface.Always check for flat gasket surface.& sand on a piece of glass with fine (preferably used paper & go in a circular motion.You olny need remove enuff matieral until the suface is FLAT!.Some of your pan-cover screws may be stripped.You can fix with Heli-Coils/or they may need to be tigged-up & machined again.Everything I told you /you can check at home so you have a good clue going into the head restoration.As your saying the bike is running good/Then its a HUGE PLUS.After bubbletesting & fixing that if it needs it/If its not burning oil,Ride the Bike.(If its not broke dont rip into it.).ONLY YOU know if work is needed!-Take compression readings & do a leakdown test before you jump into anything.ALL the BEST!--Respectfully---Richie
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Re: Heads - Rebuild

#5

Post by 48Doc »

I concur with Richie. What I called a pressure test, he called a leak down test. I believe he used the correct terminology. If you are not familiar with the procedure you can see it on U tube. Preformed correctly, and with a compression test, you should get a pretty good idea as to what you have. Good luck.
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Re: Heads - Rebuild

#6

Post by 49bones »

Thanks all, i'll give that a go. I might give my carb a re set up too when i am next with my bike. Whats your thoughts on the linker base settings and then re dialling it back in using the plug colour and feel of the bike?
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Re: Heads - Rebuild

#7

Post by 48Doc »

Once again I'll premise the following by saying, this is what works for me. There are many guys on this site with much more experience. I'm running a Linkert 74b on my 48FL, standard bore, FLH cam. Five turns out on the low speed needle, and three out on the high speed needle, gets me in the ballpark. With a cold engine, two prime kicks at full choke, ignition on, choke off, fires on the first kick. After she fires, I start dialing in the low speed needle. With the 74b I believe the high speed jet is fixed and I haven't noticed much difference with adjustment. The initial adjustments are just that, and only necessary after overhaul, carb rebuild, etc. I often make slight changes in the adjustments, depending on changes in temperature, speed (town vs. open road), elevation, humidity, and fuel. I'm using HD 3-4 plugs, and most of the time unleaded regular gas. My plugs are generally brown, but sometimes change with different gas brands and octanes. When I adjust, to the bikes best performance in a given situation, the plugs usually look right.
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