The rehabilitation of Sir Gustave Sebastian

Discussion in 'New Zealand' started by Box'a'bits, Aug 22, 2010.

  1. Mark_S

    Mark_S Fair Weather Faggot

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    "Actually I found the old Whanga Rd to be in pretty good nick overall. There weren’t any sections that I struggled with..."


    You did appear to have the odd moment of discomfort....

    [​IMG]

    [​IMG]
  2. Box'a'bits

    Box'a'bits In need of repair Supporter

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    No discomfort. Sometimes caution is better than aggression, especially on slick / sloppy clay. The road seemed much better than previous rides. No bike swallowing ruts or culverts. Gus is better suited to the more open farm tracks in Aotuhia Station, up to the boundary gates.

    Great photos. Cheers.

    Here's Andy Mac's video of the stream crossing. Has more of the bikes going thru than Michael Breen's video.

  3. Night Falcon

    Night Falcon Structural Failure

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    Excellent Video - river is up a bit since I was last through there, Glad you got Gus across Steve, conkin out in rivers really rips my nightie
  4. Box'a'bits

    Box'a'bits In need of repair Supporter

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    We seem to have resolved the carb & electrical stoppages. Now we need to work on the clutch, which was the issue on the 42nd...
  5. Mark_S

    Mark_S Fair Weather Faggot

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    well you will be pleased to know that there was no way you'd ever get that left side jet carrier out with a spanner.
    I got it out with a deep socket but it was super tight the whole way out - I was worried I was going to shear it off.

    cleaned the crap out of both sides and put it all back together - need to take the bike for a decent ride to see if its ok
    in hindsight I suspect some sort of fuel restriction - either vacuum in the tank or crap in a fuel filter etc - time will tell

    We must have encountered a few wasps on the way (aside from the one that stung me in the head) as my airfilter was a veritable wasp graveyard
    I also cleaned all the crap out of the oil cooler as I wondered if it might have contributed to the slow speed/hot running in the old whanga rd
  6. guzzitony

    guzzitony Guzton

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    20161106_150749.jpg Well.the poor old Marlboro is well ensconced up in hahei . got the Quota down from Whangarei in 3 rainy days.have made a few little changes for my comfort. has a heindinau trail type tyre on back which I thought was pretty mint on gravel but after my first exploratory run up the hill (Mt Hutt) not so sure. have toys squeezed into shed for adjustments.
    Te Hopo and Combatscoot like this.
  7. Box'a'bits

    Box'a'bits In need of repair Supporter

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    Nice. What's been your impressions with the Quota so far?

    Thread dredge from page 3!
  8. guzzitony

    guzzitony Guzton

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    Haha. yeah I saw that.6 years later . ...
    I don't think the Q will be quite as robust as the Bim but I'd still have a go thru the makairo etc . typical Guz power so would probably (officer ) sit on 80mph all day, USA bike , that's about 100 kmh right?
    Early fuel injection but seems to have been set up nicely by P.O.s as no snatchiness like say a 990 adv.feels modern beside beem and even my LM.
    Dare I say comparable to a 950 adv without the outright grunt. but may go see if I can scare the odd one of those . the front seems planted but I'll have to do a few more kms on gravel , maybe fit old rear tkc to get better idea. ya coming to brass next year?
    Still orig muffler so very quiet , makes it a bit harder to ride on gravel as by the time you can hear it I seem to be going sideways haha. working on that.
    Box'a'bits likes this.
  9. Box'a'bits

    Box'a'bits In need of repair Supporter

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    TOP END REBUILD:
    The issues:

    Post the Makiro Run (Jan ‘16) Gus really wasn’t running well. I wondered if I’d bent a valve or rod when I hydrauliced the right cylinder trying to start him after I’d tipping him upside down in gully.

    I rode him up to Eddie’s Central Plateau ride, & whilst we completed that okay (about another 1k kms), it was apparent something wasn’t right – no real low rev engine braking. So he got parked in the back of the garage pending further investigation, & the sidecar assumed main bike running.

    Fast forward to the Pink Ribbon ride where an Airhead run (sans sidecars) was suggested. So I dragged Gus out, fired him up, & took him for a test ride out Ohariu Valley Rd. Guess what! Time hadn’t resolved Gus’s issues. So time to look at compression to test that bent valve theory.

    Diagnosis:
    That was a good news / bad news scenario. Good news was that the suspect right side had good compression. Bad news was that the left side was down to 50% of the RHS. I pulled the heads, & it became apparent the valves were not sealing, & further, that they were too worn to provide a short term ‘valve grind’ solution.

    So after a discussion about the situation with a well known enabler, the heads were sent off for extra holes to be bored – just in case I might want to use a twin plug ignition system at some later time. I also got an insert put into the RHS head to allow the valve cover OEM central stud to be used (I’ve been using a temporary ‘longer stud & cut down nyloc nut’ almost since I bought Gus – worked well enough).

    Then to continue the magical mystery tour, they went off (with a large amount of spendy new parts) to Ian at Headmaster. He has completed the following work for me:
    • Decarboned the heads;
    • Skimmed the heads 0.030” ea side to rid the heads of a warp (& coincidentally giving me the same compression increase Woodman has done – but I was working with 9.5:1 pistons already - I hope that's not going to tip things into detonation..). The warp was on the top side of the heads.;
    • Installed new guides;
    • Done a new 3 angle cut;
    • Reamed the guides to achieve the following clearance - Inlet 0.04mm, exhaust 0.06mm.

    [​IMG]

    Decarboning the pistons:
    Last time I did this it was a truely a shit job. I soaked the pistons in Simple Green, then scrapped the carbon off with a variety of scrapers, including an old chop stick. This time round I thought there would have to be a better way.

    I have done a test run on Gus’s old pistons, using Bunnings ‘Diggers’ Paint Stripper - which contains Methylene Chloride. A test in some aluminum foil tray showed no adverse reaction. Painted on the top of the pistons, & round the ring landing. The carbon scrapped off fairly easily in 20 mins or so

    [​IMG]
  10. Mark_S

    Mark_S Fair Weather Faggot

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    and?
  11. innathyzit

    innathyzit AKA Woodman

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    Good stuff, you need your own engine shop.:wings

    Your pretty bold raising the CR to 10:1 ish. Will be interested to see how Gus goes.
  12. Box'a'bits

    Box'a'bits In need of repair Supporter

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    It's a work in progress. You'll just have to wait until tomorrow
    Ian discovered the warping & asked if they could do the skim. After the skim we talked about how much had actually come off.

    I'm fairly sure that the actual compression ratio varies from the stated C/R. We'll find out if there is a huge detonation issue. If so:
    • The fall back is installing the twin plug ignition sooner, rather than later (spendy), & / or
    • I can reinstall Gus's original (lower compression) pistons.
    Zebedee likes this.
  13. Manakau.KTM

    Manakau.KTM Been here awhile

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    Working from home then? Jolly earthquakes are damned inconvenient I say.
  14. Box'a'bits

    Box'a'bits In need of repair Supporter

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    Yes. Because my unit was up & running so soon, & coped so well, we appear to be at the bottom of the priority list to be re housed. So sometime before Xmas is the timeline. Good & bad. The music & coffee is improved. But cabin fever sets in sometimes...
  15. Box'a'bits

    Box'a'bits In need of repair Supporter

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    TOP END REBUILD 2/2:
    The Pistons under the all the carbon are in better condition than Gus’s originals, & way better than the ones in the sidecar. No wear where they ride on the wrist pins, unlike the sidecar engine. No photos.

    [​IMG]

    Rods:
    While I had things pulled down I thought I’d change the rod bottom end bearing shells. I have the 12 point tool to pull the rod bolts. But I realised that I hadn’t ordered new bolts. Bugger. Clymer has dire forecasts about the consequences of reusing these. Fortunately I was able to contact MD who assured me that this was unnecessary.

    The shells have some scuffing & couple of smaller scores, so probably a good time to change them.

    [​IMG]
    Left side

    [​IMG]
    Right side.

    The crank looks good (from what I could see).

    The small ends look good. I have changed the wrist pins, as they have some discolouration.

    [​IMG]

    [​IMG]
    New bearing shells.

    Reassembly:
    Now have the barrels & heads back on. Tommorrow I’ll set the valves & complete the reassembly.

    [​IMG]
    Te Hopo and innathyzit like this.
  16. Mark_S

    Mark_S Fair Weather Faggot

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    "just in case I might want to use a twin plug ignition system at some later time"

    The things we put in our blogs to pacify those who read uninvited over our shoulders

    us guys know that 'at some later time' really means 'as soon as I can get away with it'
    globalt38 likes this.
  17. Box'a'bits

    Box'a'bits In need of repair Supporter

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    Just on the QT - ordered.
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  18. Night Falcon

    Night Falcon Structural Failure

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    I respect the enthusiasm you beamerers commit to the continual repair process that is beaemmuu ownership......you guys rock :D
    Te Hopo likes this.
  19. Box'a'bits

    Box'a'bits In need of repair Supporter

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    Remember - 25 yr old bike, 240k kms. Easy to work on. Time spent keeping Gus running well / improving / personalising him is part of the attraction of ownership. And depreciation - well if anything Airheads are going up in value.
    Te Hopo and innathyzit like this.
  20. Night Falcon

    Night Falcon Structural Failure

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    undoubted investment opportunity 4sure :rayof
    Muzz67 likes this.