G/S PD + some R-dubb goodness

Discussion in 'Airheads' started by R-dubb, Mar 30, 2013.

  1. mike54

    mike54 You don't get me

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    I was going to suggest leaking intake boots. Had it happen to me before. I like Lornce's suggestion better.


    This photo with the 2 different valve covers kind of bothers me though. :D

    [​IMG]

    Very nice job. I like these kinds of builds where it looks fairly stock to the casual observer but if you look a while and talk to the builder you find that there are many well thought out tweaks. :thumb

    I predict you will enjoy this bike mucho. I know I would. :D
    #41
  2. R-dubb

    R-dubb Dubbious Adventurer

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    Lornce,

    Pretty sure you are on the money regarding idle. There are no leaks I can find. The bean can was well lubed and in excellent running order when I went through it during the build. The issue is most likely timing. I was in a little too much of a hurry to balance carbs when first firing her up. It was running rough initially so I may have bugger'd the timing in my haste to make other adjustments. I'll recheck soon when I have time to get back into it.

    I tried the stock springs and found them way soft. Did some research in other threads and saw that other were advocating for stiff springs. They worked out just about right.

    Nice to hear from you. Cheers!
    #42
  3. R-dubb

    R-dubb Dubbious Adventurer

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    Mike, your right, I'm gunna like it a bunch. The hardest part is getting over the fact that it looks all new and perfect and won't stay that way if I go for few real rides :evil

    So yeah, that photo of the cases was pre bead blast. I took in a pair of each style since I wasn't sure what I wanted her to look like at the time :1drink

    I'm telling you crank balancing is a wonderful thing. Makes for a sweet ride. :deal
    #43
  4. bgoodsoil

    bgoodsoil Dare to be Stupid

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    Who did your crank balancing?
    #44
  5. Ras Thurlo

    Ras Thurlo Desert Lion

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    Also interested to hear more about this.

    Does the balancing need to take into consideration what pistons will be used, or is it a crank only piece of work?

    Had believed part of this is a balancing of weight on the crank to take out manufacturing imperfections, but also to reduce overall weight if lighter pistons are used.

    I know that the latter point does not apply to this bike as your keeping her stock.

    Are there many people out there that will do this job?
    #45
  6. ontic

    ontic

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    Yeah, I'd like to know more about the balancing too. I was planning to do my own piston and conrod balancing, and then after reading a bit about it have considered I should be digging deeper and doing it right with the crank and clutch as well...
    this was a good read
    http://www.advrider.com/forums/showthread.php?t=420346

    When the time comes and with the parts on hand I'll probably call around my local specialists and see what it would cost to pay a pro to do this.
    #46
  7. Beemerguru

    Beemerguru Beemerguru...G/S guy

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    Any chance you used Armando in Sunnyvale?

    I had the entire engine (crank, rods, pistons, wrist pins) done to a tenth of a gram..both K bikes and airheads.

    You just have to wait while he finished the 246GT Ferrari, 904 and 906 Porsches, etc,
    #47
  8. R-dubb

    R-dubb Dubbious Adventurer

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    I have used Gromm Racing in San Jose (near air port). Bob runs a very old school, cash only shop. He is meticulous, and I've been very pleased with both jobs. He starts with weighing and shaving from the con rods up. Then he spins and balances the crank, and flywheel bits, lightening as he goes. Don't know the lightening formula. I've been totally please with the smoothness of both builds. Very reasonable price and quick turnover.
    #48
  9. R-dubb

    R-dubb Dubbious Adventurer

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    I think many good, racing oriented machine shops are equipped to do the balancing and lightening along the way. They produce a report of what was done in terms of the weight values for each part including material removed from the crank. The machine work is certainly money well spent. Very low risk, high reward.

    The catch, if there is one, is that you've got to get the crank out of the block in the first place. That's the tricky business as it requires a few simple tools, some heating, and technique. That's where the risk lies, cause you can F'up the whole motor if not prepared for the task.
    #49
  10. R-dubb

    R-dubb Dubbious Adventurer

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    I got a PM asking about geometry, ground clearance, forks, tire clearance and such. I thought I would post my comments here for others:

    #50
  11. Airhead Wrangler

    Airhead Wrangler Long timer

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    Just curious, what spring rate did you go with for your forks?
    #51
  12. R-dubb

    R-dubb Dubbious Adventurer

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    .54kg/mm - They are stiff. Maybe a tad too much, but they feel good as long as the damping isn't set too heavy, especially on the compression side. I have them fit with zero preload, just long enough that they don't rattle. In the 43's, I don't think it is feasible to go much stiffer since the wire diameter is snug to the damper and might bind to the slider at full compression if it were any bigger. The one complaint I have is sticktion. No better or worse than on the KTM, so that's just the way it is.
    #52
  13. Stagehand

    Stagehand Imperfectionist

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    54's are big!
    #53