1971 Sportster Ironhead Chop - Redo it Right

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  • bpeak
    Senior Member
    • Nov 2012
    • 553

    1971 Sportster Ironhead Chop - Redo it Right

    Hey guys and gals. Been a lurker on the site for a while since I didn't really have much to post/contribute. Until now. I've had a few projects over the years, some that died on the vine, but have mentally-designed hundreds of bikes (don't we all?). This past summer I grew more and more desperate to get back into the scene after a rough step-out from motocross (longer story). So here it is.

    Managed to score this bike from a local shop. It's already well on its way to where I want to take it. Was planning on buying an ironhead donor but this one already had the hardtail, oil tank, and drum rear setup I was after.

    I have a bunch of parts stock-piled for it too, bought specifically for this project. Got a narrow 12 over springer, tall risers, drag bars, the grips and controls, wheels, tires, spacers, exhaust, gas tank, neck cup kit, and a few other nic-nacs. All of it ready to go. Doing my own engraving, paint, pinstripe, and basic fab. Should be interesting.

    Got massive respect for ChopCult and the CC community. So I figured I'd start a thread to join the party. Also got the instagram going @bpeak82 and a youtube channel "bpeak82" doing videos of the purchase, parts, build, fab, etc. I am by NO MEANS a shop or good fabricator or anything. Just an average schmo trying to make something cool to ride.

    Much more to come. Cheers!

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  • Dragstews
    Senior Member
    • Sep 2010
    • 13738

    #2
    Hell of a foundation to build up from...

    71 Sportie was the first year for the wet clutch, Harley did a few up-grades to it during it's run...
    Last year of the 900's ....

    Check under the sprocket side of the trans case ... Being the 72 and back models was bad for case blow-outs due to the speedo drive was made into the case....
    If it hadn't been repaired, ya might think about adding a bit of beef with making up a press-on reinforcement ring for the C/S bearing case bore.... Could have already been done ..??
    Take my 45 and outrun em all ..

    Comment

    • bpeak
      Senior Member
      • Nov 2012
      • 553

      #3
      Awesome advice. It's stuff like that that makes chopcult what it is. I will definitely look into the crankcase bit. It's evident to me that the previous owner, or owners, did a lot of "backyard engineering" to this thing. Definitely got my work cut out for me. Not the least of which is a gigantic wad of steel wool chore-boy shoved inside the air cleaner cover to act as an air filter. It was wedged in and blocking the choke butterfly and probably restricting airflow. That might be why it wasn't holding tune. Oh well. Plenty of long nights ahead.

      Comment

      • brooklynbomber
        Senior Member
        • Sep 2011
        • 1944

        #4
        Great base, sounds like your parts list should be making it look just right. Keep us posted!

        Comment

        • bpeak
          Senior Member
          • Nov 2012
          • 553

          #5
          Ok so I officially have a ton of questions. I've searched online... researched... poked around on the bike... and ultimately = still searching for sanity. I just need to know what I'm in for on this bike before I start taking it apart for the re-build. I'll try to keep the questions easy with pics, but it's all about the oil system on this bike and the current oil leaks.

          BTW - yes, I have the service manual and have read it. Still got tons of questions.

          FIRST THING'S FIRST - THE BAD LIST
          1. Slow oil return to the tank. Going to do a full oil change and flush. Even going to replace the oil lines themselves since some of them look a little less than fresh. Will make sure it's running warmed up. And will check return flow again. It IS pumping. Just slow. Hoping the slow return is just due to old oil and old lines.
          2. Leaking slowly near or around the oil pump underneath. There is a missing or sheared off mount bolt on the oil pump housing. Will need to replace. Possibly leaking from that? Not a tight seal on the bottom cover plate? Might do at least a basic rebuild kit to replace the bottom-most gasket... the ball valve and spring... and pressure switch. Just to know that those things are tight before diving any further into the oil pump or cam cover. Hopefully that, and having all the mount bolts... will seal that up.
          3. Biggest issue so far is oil leaking from the primary in odd spots. More on this in the next post.

          SEOND THING'S SECOND
          The oil routing diagram vs. what I got. I marked up a grayed out image of the bike to properly illustrate:
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          Questions:
          1. Any concerns?
          2. What about the cam cover vent being blocked off? That needs to be venting back to the oil tank right? Take a look at my next post to see the issues I'm having in the primary side... could this be a factor in that?
          3. I normally see the oil coolers a bit lower in the front. Is there any issue with its height or the way the hoses loop around like that? I know the ironheads dont run a whole lot of pressure - but maybe this is ok? I have a fear of some sort of plumbing-air-trap happening?
          Attached Files
          Last edited by bpeak; 01-25-2018, 9:55 AM.

          Comment

          • bpeak
            Senior Member
            • Nov 2012
            • 553

            #6
            THIRD THING'S THIRD
            About this primary oil leak thing. When I first saw the bike with the previous owner, they fired it up. Within a minute, a slow trickle of oil started to ooze out the vent hole of the primary filler plug. About the same time, I noticed oil leaking from the vicinity of the top side of the motor behind the rear cylinder.

            When I inspected everything back at home (after buying the bike as-is), I noticed more details.

            The primary filler plug's mesh wad was SOAKED with oil. check it out after I yanked it free...
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            And as for the leak from the top side of the motor it looks like oil is coming out of the seam/gasket area where the starter case mounts to the inner primary case. See image:
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            These leaks are slow, but constant, when the bike is running (sitting at idle or riding down the road). I had the bike started once to let it warm up and check oil flow and carb settings but didn't ride it. Then a few days later I started it... let it warm up... and rode it around the block a few times (maybe 5 minutes of riding). Leaked both times. After the short ride time, it ended up using 2 paper towels to clean the leak from the filler plug and left about a 4" diameter puddle from the top-side-leak-running-down-the-back. So to me that's a pretty substantial leak.

            I read a bunch on this. Thought it might be case oil transferring over to primary. The transfer valve issue. Main shaft seal from crank into primary. Etc.

            Honestly I thought maybe the previous owner just WAY overfilled the primary (seen some other dumb stuff on this bike already). So I purchased a new filler plug and clutch cover plug (the current ones were WAY chewed out). Last night I pulled them both off (and took the photos above). I thought it was going to flood out in a gushing stream of overfull oil.

            Nope. Oil level in the primary looks about right. I didn't remove the "check level screw" yet for fear of threads. But looking down in the primary, the oil level is just covering the bottom of the clutch sprockets (the chain dives under-oil just as it gets to the clutch end). It's definitely not so full as to be leaking out of the vent hole due to overfilled... right?

            On to the transfer valve. I did confirm that on this bike, the transfer valve between the case and primary was REMOVED and filled in with some sort of JB Weld. I was hoping this wasnt the case. I was hoping that oil was draining from crank into primary while sitting due to a faulty valve. Easy enough to replace. But nope.

            (for some reason this image keeps getting rotated upside down. But you can see the JB in there)
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            I also seem to understand that at normal situation - the crank case operates at negative pressure and actually sucks air from the primary (if at all). That being true, then the primary filler plug hole and mesh wad is meant to relieve NEGATIVE pressure in the primary, right?

            So...

            QUESTIONS
            1. Could the lack of cam cover venting somehow be playing into this?
            2. If the transfer valve removal JB Weld isn't totally sealing that hole... it could still be leaking from crank into primary right?
            3. Even so - why would oil so readily (and quickly after starting) leak out the vent hole and starter block gasket?
            4. With the whole talk of pressures - if the transfer valve stays JB'd (or repaired JB to seal it up) - What would happen to pressure in the primary? Would the primary stay naturally pressure flat? Or go positive?
            5. What are the chances that a fresh primary filler plug/mesh/oring and a fresh starter block gasket fixes these two leaks?
            6. When the bike is running with the correct amount of primary oil, does it really fling around enough in there that bad to force its way through the old SUPER-SOAKED mesh wad and up around the starter?


            PS - I understand that a severe case crack or seal issue is possible. I also know that this weekend I'm going to try to do the oil change, replace the hoses, new filter, (might bypass the cooler for a try), and run the new filler/clutch plugs. So we'll see what happens after that. But I'm hoping to get some sleep between now and then and these questions are killing me. (I really want to learn and I don't currently have the answers to the riddles).

            As always - thanks for the help guys. I know that was a lot. But any help you could offer would be good help.

            Cheers!
            Last edited by bpeak; 01-25-2018, 10:05 AM.

            Comment

            • Dragstews
              Senior Member
              • Sep 2010
              • 13738

              #7
              Originally posted by bpeak

              2. What about the cam cover vent being blocked off? That needs to be venting back to the oil tank right?
              What the ?!?! .. ??

              Think most of your oil leaks is due to this problem...
              Look behind the rear of the cam cover, there should be a 5/16 barb fitting ... That vents the oil tank to the motor with a line that runs from the barbed fitting to the top of the tank...

              Need to have the crank-case vent working in the cam cover (It vents into the air).. On that model the gen has a washer that acts as a baffle and I think you will find a spring plate in the cam cover that works hand in hand with the washer...

              Now onto the oil pump ...

              Ya missed it by one year...
              In 72 when Harley started making the 1000cc motors they redesigned the oil pump with larger gears to move more oil in & out...
              You can fit the 72-76 pumps to your motor... After/market took it one better with a A/M pump that has the 72 size gear but added .080" more to the gears on the "get it out side" and rerouted the oil path ways to be less restricted to flow... Ain't that nice of them Boys .. ???
              Last edited by Dragstews; 01-25-2018, 10:31 AM.
              Take my 45 and outrun em all ..

              Comment

              • bpeak
                Senior Member
                • Nov 2012
                • 553

                #8
                Just saw this on the "Questions to the Max" thread... might apply to me...?

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                Given that my vent is blocked off...

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                ...that might be causing some of my oil problems eh? Sounds like the previous owner of my bike bought/installed a brit oil tank on this sportster?

                Comment

                • Dragstews
                  Senior Member
                  • Sep 2010
                  • 13738

                  #9
                  Think so ....

                  Say .... The way that bike was built ...
                  It would have a killer look using a "TIME BOMB" oil tank from Sucker Punch Sally ...



                  Just a opinion ...

                  Last edited by Dragstews; 01-25-2018, 10:48 AM.
                  Take my 45 and outrun em all ..

                  Comment

                  • bpeak
                    Senior Member
                    • Nov 2012
                    • 553

                    #10
                    Can't argue with that tank. Those bombs look awesome!

                    The previous owner of this bike cracks me up. So the mount bosses on the top of the oil tank. He didn't use em. They remain undrilled untapped. They hung the oil tank with 3 giant band clamps. Ugh. Gotta be kidding me.

                    I'm going to get this tank off and clean it up. Add some bungs/bosses. Mount it properly. Run new hoses the right way. Change oil/filter. Use the new primary plugs. And see where it ends up. Fingers crossed that this cures it.

                    --- looking forward to the weekend!

                    Comment

                    • mttm
                      Junior Member
                      • Apr 2016
                      • 24

                      #11
                      leave the oil filter out of loop.I got a 76 iron with oil filter in had many leaks with out not near as bad. the oil filter seemed to hold to much pressure in motor. replace primary seal also can't hurt.Mind my iron has about 200,000 miles.rebuilt 5 times over the years.oil pump 3 times.I'm still learning after 30 years with same bike.

                      Comment

                      • bpeak
                        Senior Member
                        • Nov 2012
                        • 553

                        #12
                        Originally posted by mttm
                        leave the oil filter out of loop.I got a 76 iron with oil filter in had many leaks with out not near as bad. the oil filter seemed to hold to much pressure in motor. replace primary seal also can't hurt.Mind my iron has about 200,000 miles.rebuilt 5 times over the years.oil pump 3 times.I'm still learning after 30 years with same bike.
                        Interesting. I know there are a lot of opinions on filter vs no filter. I appreciate your perspective. See... I come most recently from the motocross realm of 450 4-strokes where frequent oil changes are key. Im already used to that. With this bike... I would have no problem changing oil frequently to make sure everything is fresh. So would that be fine then to skip the filter?

                        Comment

                        • BlackCloudSalvage
                          Senior Member
                          • Jan 2015
                          • 633

                          #13
                          You are off to a good start on the right foot by tackling the motor stuff first. All the Fab stuff is a piece of cake. Go over the whole motor now so you don't have to pull it out 10 times later.

                          Comment

                          • garystaven88
                            Senior Member
                            • Mar 2014
                            • 347

                            #14
                            Originally posted by bpeak
                            Interesting. I know there are a lot of opinions on filter vs no filter. I appreciate your perspective. See... I come most recently from the motocross realm of 450 4-strokes where frequent oil changes are key. Im already used to that. With this bike... I would have no problem changing oil frequently to make sure everything is fresh. So would that be fine then to skip the filter?
                            Hmm. Not sure I agree with keeping the oil filter off due to “over pressurization/leaks”.

                            I ran a spin on style filter like yours and many others have as well. Keep the filter setup and address the leaks and venting issue.

                            Comment

                            • bpeak
                              Senior Member
                              • Nov 2012
                              • 553

                              #15
                              Originally posted by garystaven88
                              Hmm. Not sure I agree with keeping the oil filter off due to “over pressurization/leaks”.

                              I ran a spin on style filter like yours and many others have as well. Keep the filter setup and address the leaks and venting issue.
                              10-4. Totally makes sense.

                              I ended up pulling more apart this weekend. Actually found that the oil tank DOES have another topside bung... for the cam vent tube... that the previous owner just put a plug in. Sheesh. Why??? The plot thickens.

                              Got the oil tank drained. Going to clean it up, install all new clean fittings and hoses, and correct the vent tube routing first. Will run it as-is then and see how it goes. As you guys mentioned above, if I still have problems, then I can take care of them one-by-one as needed. Will report back.

                              Comment

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