Resurrection of a Mongrel /5

Discussion in 'Airheads' started by cameron110, Apr 25, 2013.

  1. disston

    disston ShadeTreeExpert

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    I spent several hours last night searching for the authoritative version of what I said earlier. I fell asleep.

    This is all I'm suggesting and the reason. Some cylinders have longer spigots or some cranks have bigger throws. Not sure which is the case but it's vintage dependent, or, only happens if x vintage crank is used with y vintage cylinder. So dry fit the parts and check the clearance of the crank to the cylinder spigots as the crank rotates. If the crank hits or is very close, grind some notches at the offending place in the cylinder.

    I have really heard this, that there can be a problem. There are many things that should often be dry fit anyway.

    Your using the O-ring makes for a better assembly. It will leak less.
    #61
  2. Lornce

    Lornce Lost In Place

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    Ummn, yeah. That step winds up in the pile of chips when you turn the spigot to fit the 97mm openings in the /5 block.

    All the 500cc through 1000cc cranks are dimensionally identical (except R65 and R45 which is it's own animal). I promise you, there isn't a counterweight clearance issue.

    :stoned
    #62
  3. disston

    disston ShadeTreeExpert

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    OK. I'll try to remember to check and if I see any reference to this I'll copy you. No offense, I still think there is a problem but can't remember the particulars.
    #63
  4. cameron110

    cameron110 Been here awhile

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    I was in the shop today and I made some progress, the mongrel now looks like this

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    I mentioned a few posts ago a small hiccup while installing the cam carrier. I am using the updated carrier which uses hex bolt and the bolts contacted the back of the timing chain sprocket. I little time on the grinder and the problem as resolved.

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    and here is the photo I promised of the step at the base of the spigot behind the o-ring groove.

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    If you've been following the build you know I didn't turn my jugs so I ended up having to account for that step when having the portals enlarged to 99mm

    I forgot the camera again today so you all have to suffer the crummy cell phone pics above. The upshot is that I forgot the photo below was on my phone from last week.

    I did this on the PD on the way back from Asheville, it is a pretty good prelude to this winters project,

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    Time for a midlife refresh
    #64
  5. cameron110

    cameron110 Been here awhile

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    I didn't compare cranks today, but I did measure some spigots and surprisingly I found the opposite of what I was expecting. The spigots on the /5 jugs were a few mm longer than several nikasil cylinders which I measured. Now that you have that information logic will lead you to conclude what I found which is that with a 1970 r75/5 block and crank I have no clearance issues with the length of spigots on a pair of 800cc nikasil cylinders.
    #65
  6. AntonLargiader

    AntonLargiader Long timer

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    In terms of stroke, yes. Externally, no. You have early cranks that only fit eyebrow cases, and later cranks.
    #66
  7. cameron110

    cameron110 Been here awhile

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    Sorry I have been remiss in keeping up the build log. I am hoping to have the bike rideable by the middle of next week or so.

    I think I left the story off at the crank install. I set everything out for the long block assembly.

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    I took a little time at the press

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    and found the valves to be nice and tight. Unfortunately someone before me had been a bit heavy handed when tightening the lock nut against the rocker arm and had stripped out the threads on 3 out of 4 adjusting bolts. the threads were bad enough that I couldn't back them out through the rocker arm without risking the threads on the arm so it was time for a bit of grinding.

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    with the heads ready to go it was time to finish out the shortblock

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    if you have been following along you might recall some advice not to reuse the wrist pin snap rings. With the decision to upgrade to the 800cc nikasil jugs the newer pistons are machined for circlips.

    It all went together nicely.

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    then the trans went back in

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    and I started to work on the wiring

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    I fabbed up a little dash to mount the idiot lights and hang the headlight from and then really set to work. The left control perch was seized onto the broken stub of bar but a little time in to oven and off it came. I took the opportunity to snap a shot of odd construction of bar that came on the bike.

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    Those white bars that I have had on during the mockup are 7/8" so it took a bit of creativity to get the controls mounted up but I got them on there and started to get my connections made up for the handlebar switches

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    and then started to lay out the relays

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    Sorry I didn't get may photos along the way but I'll leave you with an old shot for inspiration and if anyone is interested in more of the details of any particular part of the build so far just let me know and I'll fill in the gaps.

    [​IMG]
    #67
  8. Plaka

    Plaka Brevis illi vita est

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    I put relays in that location on my /5 and had problems with them getting wet and corroding. I can't see if you have a flange forward of your ground nexus; I would do one. The red-tape voltage regs had a flanged bracket as well.
    #68
  9. cameron110

    cameron110 Been here awhile

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    Thanks for the heads up, I have a different part of the rt relay and fuse box that I cut up saved for the final install that has the relays surrounded on all 4 sides by plastic but given your experience it might be worth adding a little deflector plate on the steering damper mount to protect all the little shocky zappy bits on both sides. I am trying to build something durable for the long (and dirty) run.
    #69
  10. Plaka

    Plaka Brevis illi vita est

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    I have found making things maintainable gives a lot of robustness. They just get cleaned every few years. Relay sockets are convenient for changing a relay, but difficult to clean. individual female spades are the opposite.

    I have done some pretty bulletproof stuff---and then watched it fail. :huh I seldom try anymore. I do use potted sealed relays.

    I've also noticed that I end up changing enough stuff--every few years---that connects stay pretty new. Always some new feature to add and an old one to delete...

    It can be worth leaving goodly service loops in your wiring---enough so you can snip off a connector and replace it, several times, without banjoing the wires tight or needing to replace/splice in more wire. Sometimes a new connector replaces a bad one. Other times you want to expand and putting two wires on one (female) connector is the simple and clean way. If you dress it well, you can have a couple of inches of spare everywhere and it still all looks clean and crisp.
    #70
  11. cameron110

    cameron110 Been here awhile

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    You just summarized quite nicely why I (and many others) love airheads.
    #71
  12. cameron110

    cameron110 Been here awhile

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    [​IMG]

    A 1000 miles from home.

    I realized this afternoon that I owed an update on how the resurection and subsequent modifications have been going.

    After a bit of break in time I decided it was time for a bit of a trip so I repaired a broken and derilict tool tray with a bit of aluminum strapping and some galfer tape

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    traded some parts for and repaired some wixoms

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    one of the mounting plates had cracked over the years so I drilled out the rivets fabbed a new one and popped it in

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    This is was back in the early spring (it's still running great) and I was a bit worried about being cold so I soldered a subharness for my gerbing.

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    (the observant among you will notice from the previous photos that these little projects were done in the evenings, barefoot in the top photos and beer in 2 out of 4, man, I look like a jackass from those shots :lol3 )

    I rounded up a couple friends and we loaded up some camping gear and headed south.

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    We wound our way on back roads south through south west Virgina out throught the Cumberland Gap, to Nashville, then back east to Hendersonville, Asheville and back north to Charlottesville

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    It was a great ride and the bike did great
    #72
  13. cameron110

    cameron110 Been here awhile

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    For those of you disparaged by my slapping mismatched parts together with little regard for style, originality, or cleanliness on this build the 100,000 mi refresh on my PD is well underway and I'm fully at the other end of that spectrum.

    here are a few random teaser shots

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    I am stepping away from eom colors so if that bothers you now is the time to avert your eyes


    [​IMG]
    #73
  14. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    Thank you! A wonderful postscript to a great build thread.

    Not at all. Just don't go all anal on us...

    Here are two current popular build threads:

    So there I was, minding my own business when this bloke walks up and...
    http://www.advrider.com/forums/showthread.php?t=958640


    Elsa, Lancasters Frankenbeamer build...
    http://www.advrider.com/forums/showthread.php?t=982463

    --Bill
    #74
  15. cameron110

    cameron110 Been here awhile

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    Thanks Bill, I have been following and enjoying the one in AU but hadn't caught the one in the UK. I even had some photos that might help the guy in the UK.
    #75