#4 - R90S Powered /2 Conversion Period Hot-Rod

Discussion in 'Airheads' started by Solo Lobo, Jun 17, 2020.

  1. bmwrench

    bmwrench Long timer Supporter

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    The brake pedal has a grease fitting ('70-'80), one of those conical things the Germans like so much.

    Oh, boy. I'd try Loctite 290 there.
  2. black knight

    black knight Long timer Supporter

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  3. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    not sure if the gaskets I sourced from Motobins were OEM, but they didn’t seal.

    it could also be that the Briel oil cooler surfaces are the issue.

    mom going to add belt and suspenders so I don’t have a leak again. Plus, the chance I need to pull the oil pan again in my ownership are (hopefully) very low
  4. black knight

    black knight Long timer Supporter

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    read Brook's article about using a heavy glass pane and sanding the whole surface flat
  5. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    I think that said it all, no book needed.

    The better answer would be machining the surfaces. That’s my backup for next summer if needed
  6. bmwrench

    bmwrench Long timer Supporter

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  7. Pokie

    Pokie Just plain Pokie.

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    "The brake pedal has a grease fitting ('70-'80), one of those conical things the Germans like so much."

    Yes, and not many folks have a pointed grease gun, so that gets overlooked along with the swing arm bearings.
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  8. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    I just ran across this photo from 1995. A good friend from Seattle told me his dad had seen an "old BMW motorcycle" while passing through the town of Auburn, NE so when I was visiting my grand parents with my folks my dad and I jumped into the car and drove the 80 miles to see if the "old BMW" was still there.

    We ended meeting the owner, who was a local attorney who built this bike and owned lots of others... super nice guy, but wouldn't sell me anything that day.

    I was ready to buy an old pickup and drive this one home if he had agreed. That would have been a great adventure.

    This is also proof that I did in fact have hair at one time, lol

    [​IMG]
  9. black knight

    black knight Long timer Supporter

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    I would love to go see an old dear friend in Auburn, NE
  10. Plaka

    Plaka Brevis illi vita est

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    this beats machining. no Gaskets to buy, permanent, leak and weep proof. Follows the slightest deviation in the mating surface with minimum torque on the fasteners. I've been doing this on my rocker covers for some time. Very good results. It's a cast in place silicone gasket. Only downside is that it is dedicated to the surface that it was cast against. Recasting it not so easy because the old gasket must be removed and this is not so easy although certain chemicals may help.
  11. Plaka

    Plaka Brevis illi vita est

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    Pointed push greasers are used on the nose sprockets of chainsaws. Available everywhere. Dump the chainsaw nose sprocket grease and fill with your favorite whatever. Pointed tips for ordinary grease guns available everywhere too.
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  12. Pokie

    Pokie Just plain Pokie.

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    I guess those folks that don't have a pointed grease gun also don't have chainsaws. We used to carry grease gun points just to satisfy those that didn't.
  13. black knight

    black knight Long timer Supporter

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  14. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    Had the opportunity to ride the /2 down to a local motorcycle bar last night, what a real pleasure it is to ride this bike... the engine is really smooth, flexible, powerful, responsive..

    After the ride, I found at least one oil leak.

    I am guessing my new rear main seal is leaking, and if that is the case it is the first rear main seal fail I can remember having in the last 25+ years... doubtful it is the oil pump cover (but also possible) as that had a new o-ring and sealant.

    The oil filter cover doesn't seem to be leaking (yet) and I need more miles of testing.


    [​IMG]

    For now,. I will do a few more miles and watch for more leaks. I'll change the oil and filter but not pull the oil pan and spacer... sometime this winter I'll pull the flywheel and see what's what in there.

    I used a rear main sourced from Motobins, and will probably grab one from my local dealer for the replacement. =

    To the best of my memory the flywheel did have some slight marking where the lip of the rear main rode, but it wasn't a channel or gouge. Have to confirm that.

    [​IMG]
  15. tennessee thumper

    tennessee thumper Long timer Supporter

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    SL,

    For what it's worth---had a similar oil leak scenario after resealing my 90S.

    Turns out it was the trans output shaft seal leaking---not the RMS or OPO (oil pump o ring)

    Did you replace the trans output seal during the rebuild?

    I was thinking, same as you when I saw oil on the shelf.... how odd it would be for the RMS to fail or have been improperly installed but still assumed that was the cause.

    Worth pulling / checking that trans seal---which you'd do anyway---before assuming its the RMS and ordering another.

    There is a chance your OPO could be the culprit, as well.

    Guess there is something to be said for having trans oil a different color than engine oil. If it was, in your case, you'd know the source of the leak.
    I've heard trans smells different but my sniffer could not tell the difference.

    Good luck
  16. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    Thanks TT - there's no gear oil smell, and I really hate the smell of gear oil so I think the output shaft seal may be ok. Also, the trans had zero miles on a rebuild by Matt Parkhouse rebuild (it did sit on a shelf from 2005 to 2020.
  17. tennessee thumper

    tennessee thumper Long timer Supporter

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    I could never tell the difference in smell.

    Either way, just an anecdote for you to consider.

    Here's hoping for a quick, painless repair.
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  18. bmwrench

    bmwrench Long timer Supporter

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    If you can't smell your gear oil, it may not have enough Sulphur in it to adequately protect your gears. Or you don't have a good sniffer.
  19. Chad M

    Chad M 14880

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    I've got the Royal Purple in my gearbox, no mistaking where a leak might come from!
  20. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    First up today was fixing the turn signal indicator, or more correctly getting it to work. With the LED's installed in the Hella bar end's with a bulb (LED or incandescent) both bar ends would flash at the same time.

    I received help in another thread, and was advised to put a diode (1N41001) in each turn signal line, attach to the same terminal and ground the second terminal on the bulb socket and that did the trick

    [​IMG]

    Next up was chasing the oil leak, and I ordered a replacement rear main seal but don't have it yet. Figured since rain is in the forecast all week I would tear the bike down today and see what's what.

    I have had a sneaking suspicion that there was a chance the "oil" I saw was break cleaner mixed with dust from cleaning the bike before I rode it...

    Start of the job - I had my suspicions here that this was going to take a while due to having to drain the tank. I wasn't sure what it would take to get the transmission out yet either

    [​IMG]

    [​IMG]

    It took more that I anticipated to get that trans out... Photo evidence below

    [​IMG]

    Not sure I see a smoking gun here, but the oil was clean I only traveled 220 miles. and the cases were clean.... some of the grunge is spline lube that was kicked out and I did wipe a not so clean rag around in there a bit

    Brook Reams had a leak where oil was sneaking up the treads of a flywheel bolt...

    [​IMG]

    Back of the trans

    [​IMG]


    Untouched rear engine, haven't cleaned anything yet... no smoking gun visible to my eyes

    [​IMG]


    Flywheel as pulled and uncleaned, the bottom of the flywheel is on the bottom of the photo

    [​IMG]

    So at this point, I think I will just replace the rear main. I don't see a leak, but since the oil is clean as are the cases it may be there, small and hard to spot. I don't remember what I did on the rear mail seal depth and need to research that before I install the new replacement. The flywheel is back on with the bolts while I wait for the seal to arrive.

    Thinking I'll do that and reassemble the bike, clean the engine again and do some miles. I do need to change out the oil and and filter and may just go ahead and replace the oil pan gaskets as well.

    Seriously considering removing the Briel oil cooler to remove possible causes of the leak... I really like the look of it, but don't think they add much and if it is the source of the leak I would rather not have the Briel and have no leak. That, and I can reinstall it later if I decide to.