Back on an Airhead - 1975 BMW R90/6

Discussion in 'Airheads' started by tete, Aug 27, 2012.

  1. tete

    tete clown shoes

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    Can I use a regular tender with it or you are pretty much stuck with a $100 charger?
    #41
  2. Biebs

    Biebs BMW Airhead

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    Just years of experience with motorcycles, Cars and Batteries that start them.

    Trying to help someone out from having to buy a new battery every season. You can always go to Walmart and get a battery for $44.95 but I feel the PC680 is a wothwhile investment. I have a 1974 R75/6 4+ years on current PC680 I am sold - trying to help a fellow out with good advice. Had the same in my 1981 R65 worked great until it was sold.
    My 1989 R100GS - had a westco battery when I bought it - replace with a battery from Batties + (not PC680) had to replace in less than a year got a free replacement not a PC680 but it will fit and will be my next battery for the GS. So lots of experience just good advice!!:freaky


    TETE - you can use a regular battery charger with that battery - if you ride at least 1 once a week 15 or more miles you should never need a tender.
    If you do need a tender than something is wrong with your charging system of you have to much load on it. Easy to check with bike running check with volt meter across battery terminals should be above 12.5 up to 14 volts depending on engine RPMs.
    #42
  3. tete

    tete clown shoes

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    I think I'll take the Toyo battery as I need to save money where I can. It looks like many have been successful with it here. I'll pick up the battery, a tender and buy a seat off another member for the price of just the oddessy. I admit. i have heard from many, when you want the best, buy the oddessy. I can accept something pretty close at less than 1/3 the price. I appreciate all the input. The tender will be needed as the summer here in AZ can bring difficult times. I plan on riding the bike 4-5 days a week. All my previous bikes I road more than I drove.

    Unfortunately that means I will have to wait till next week to probably start the bike because the shipping time for the battery. Thats fine as I have many things to order. I have decided that im in the bike for the long haul. If I get in there and need a complete rebuild then so be it. Thats another reason I am wanting to save money. In the event that is the case.
    (from the looks of it mechanically I am confident) the PO son said the problem with the bike, to his re-collection, are all electrical. Alternator / Starter / something on that level.

    I am impressed on how many people on here know so much. Not only that many offer products that will help my bike run better, smoother and look the part. I plan on paying you guys back by supporting your products. I appreciate all the help.

    I've decided to go with the R90/7 tank I have and a seat from another member on here. I also plan on having a custom seat made. One for travel and one for kicking around town. I'm really liking something on this level but funds will determine he end result. obviously the bike has some features I could never match.

    http://www.returnofthecaferacers.com/2012/07/bmw-r80-by-workshop-maquerelle.html
    #43
  4. disston

    disston ShadeTreeExpert

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    Everybody is hooking their batteries up to these trickle chargers and leaving them. That is not the same thing as charging the battery once in awhile. If you ride once a week you don't have to charge a battery. If the battery gets a little low a battery charger hooked up for an hour or two will charge it. It doesn't have to be plugged in 365/24 which is what people want the little chargers for.

    I think Wirewrkr has 6 years currently on a Toyo battery? Or was it 5?
    #44
  5. rufusswan

    rufusswan Been here awhile

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    He said 6 yrs. I've had mine going on 4 years. Seems like a rock solid little battery. Never had to use the charger on it, though sometimes I park it in the house for a month or two if it's winter.
    #45
  6. tete

    tete clown shoes

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    I found this battery locally, it seem to be the same in terms of output.

    Do you guys think this would work?


    SLA BATTERY


    I wasn't looking for the least expensive but this was the only one they said available nearby. I have this weekend open and would like to get alot done if possible. A battery would be needed to maximize my time.
    #46
  7. tete

    tete clown shoes

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    I looked at your link and it stated it was 18 Ah? thats where I got that figure from. So higher than 18 is all good? Also do I need to adjust the valves prior to turning it over initially?
    #47
  8. disston

    disston ShadeTreeExpert

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    Let me go look again. I thought it was more.

    Much later:

    You are right. I don't know where I got 22 from. Maybe that is original. I haven't used this battery yet, I got the info from another inmate, and I have ordered one on his recommendation. So I will find out if it works along with you.

    The one you found is listed as a replacement or substitute for the Toyo. And is the same size. I was operating in a fog I think.
    #48
  9. chasbmw

    chasbmw Long timer

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    I think that the /5 bikes came with a 18Ah battery, they also had a kick start, so when the battery ran out of juice then you might get lucky and get it stated, when BMW went to the /6 series the kick start became and option and battery size went up to 24 AH. People often fitted 28 or 32 AH battery's but these batteries are more prone to internal shorts and sulphating as the plates were crammed close together. Thankfully with the use of electronic ignitions and valeo starters battery sizes have got smaller.

    The PC680 works fine on my bikes, they don't need trickle charging as they keep their charge, overwinter, just disconnect the battery from the bike and it will start up well in the spring.n any charger will do with pc680, only if they get down to Avery low voltage then you might need to use a car sized charger.
    #49
  10. tete

    tete clown shoes

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    I went ahead and ordered the 12v 18Ah one. Should be here next week which give me plenty of time to get all the other stuff going.
    #50
  11. tete

    tete clown shoes

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    I tried to find BMW AZ airhead club but instead it lead me to a page that had no been updated since 2008? Does anyone from the club attend these forums that could advise me. I don't mind paying for the membership but I'm not looking to send someone money for nothing. Especially when the last update was 4 years ago. Maybe Im looking at the wrong place.

    Also isn't there a manual / guide made by an American that is suppose to be the best ?

    thanks
    Vic
    #51
  12. chasbmw

    chasbmw Long timer

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    There is stuff on the website but for members only, worth signing up for the email list to give you a flvour of the coversations. Best if you live in an area with active arheads groups
    #52
  13. tete

    tete clown shoes

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    Yeah after looking into it I think I will go ahead and get the BMWMOA membership instead. Seems pretty active and some good info to be had.

    ALSO: I plan on taking the carbs apart, cleaning, putting new gaskets, diaphram etc and then re-assembling them hopefully tomorrow. (my two years old is pretty sick so it depends on how he's doing)

    However I was told that I need to remove the butterfly and that re-assembly in particular to a couple screws need to be addressed. First, if the butterfly moves freely and is clean is it needed to remove it. and if I do what are the particulars with these screws?

    Please advise
    #53
  14. Horsehockey

    Horsehockey A GPS? Huh?

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    Two screws hold the butterfly plate to the throttle shaft. Often, those screws are "peened" or purposely mushroomed on the threaded end by smacking 'em with a hammer and a drift to prevent them from ever backing out and being sucked into the intake manifold. What that means is if you're not paying attention and try to simply remove the screws by unscrewing 'em, you'll ruin the soft brass threads in the shaft and you'll be buying a new throttle shaft. So I think most guys don't bother renewing the o-ring on the throttle shaft unless it's actually leaking. If you can fire the engine up now, I would spray carb cleaner at the exterior of the throttle shaft while the engine is running to see if you've got a vacuum leak (rpms change). The other thing to check is to observe the fitment of the butterfly plate to the perimeter of the carb plenum. The plate is the door to the cave...you don't want any daylight around the edge of the door. Got it? Back off the idle speed screw fully so the plate can "seat" fully around the edges. You should see no daylight around the edges of the plate when the throttle is fully closed. If you see daylight, then back the two screws off just enough to shift the plate a little to close up the daylight, then hold the plate in that position while you tighten the two screws. If you do this, you might want to put a little smear of loctite blue on the screw threads before you tighten 'em nice and tight. Again, if you don't have an air leak, just leave the throttle plate alone and replace all the little o rings and the diaphragm elsewhere on the carb.

    There is no "American" airhead manual. The two bibles are either Haynes or Clymers. Both have some errors and are not infallible, just like the real Bible. Oak Okleshen in Chicago has a "top end" manual that is invaluable if you end up doing some engine work (valves, pushrod seals etc).

    I've been a member of both the BMWMOA and the Airheads Beemer Club. In general, I've found the BMWMOA to be way more focused on newer bikes and on farkles and gear, and the ABC to be devoted to Airheads. That's why I'm an ABC member and not an MOA guy anymore, but to each his own. I've found that a combo of the AdvRider airheads forum and the Micapeak "airlist" to be the best source of airheads tech support.
    #54
  15. tete

    tete clown shoes

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    @Horsehocky thanks for all the clear insightful information. I'd rather throw my money at a forum and community that supports this cause. Once again you guys continue to be an invaluable resource. I will look into Airheads group asap. Thanks Again.
    #55
  16. Horsehockey

    Horsehockey A GPS? Huh?

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    Anytime. My pleasure. I'd join the ABC for the "Airmail" the monthly newsletter that has a lot of fun airhead articles and tech information from Oak, the premier guru. Be patient, it's all volunteer and takes something like two months for your first issue to arrive. At worst you blow $25. At best you have access to lots of good info, including the name and phone number of the AZ "air marshall"....a guy who can clue you in to all things AZ airhead.

    Meanwhile, for free you can join the technically unaffiliated "airlist". This is a message board/forum exclusively for stupid tech questions, which will be answered by people who actually know what they're talking about. More edgy and snarky than the ADV Rider forum and less "fun" because of that, but you'd be smart to at least lurk on the airlist to learn lots of good tech info. It's free. I recommend signing on to the "digest mode" first...that way you only get one email (with a collection of poster's emails) rather than stuffing your inbox with separate posts. Your choice.

    http://micapeak.com/mailman/listinfo/airheads
    #56
  17. disston

    disston ShadeTreeExpert

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    If you want to join only one club then it should be the Airheads Beemer Club. The BMWMOA tries to stay active with the Airheads but every year now there are more issues with no Airhead content. The membership of MOA is probably 30 to 1 the newer bikes to the older ones. It seems almost all the Airheads now belong to guys that also own other bikes. People like me and Bill, Horsehockey (where'd he get that name?), can be found here on Adventure Rider or on the Airlist. You can join the Airlist for free, the Email club, but the printed version of the ABC is available to members of the ABC only. So most of us, like Bill (HH) said are members of both. But if you want to join only one then make it the ABC because you have only one bike. The reason for getting the Airmail is that here is where you find Tech Answers from Oak. You may have heard of him. He is sometimes on the Airlist but he answers 5 or 6 Tech Questions every month in Airmail. It seems 100% of the membership agrees that the cost of getting Airmail is made up for by Oaks articles.

    On the Airlist you will find most of the Gurus. They are mostly active professionals and some retired professionals involved with Airhead repair. A few of the Gurus are here on Advrider but not all. (actually I know of only one Guru here on advrider but there may be others I don't know of)

    Find http://micapeak.com/ and go through the table of contents till you find the page where you can join "Airheads". This is the Email club that is very active. You may want to receive the digest at first but there is a big disadvantage to "digest". This forum is peopled by Only Old Farts that will jump up and down if you ever, ever, make the mistake of responding to a digest and thereby sending an entire digest to the forum. (a lot of Old Guys are still using a dial up modem and it is slow) So be careful of your Band Width over there.

    BTW some Old Farts don't like the ABC because of the left wing politics associated with it's founder and political commentator in every issue of Airmail. Most of the rest of us either like it or ignore it.

    Good Luck
    #57
  18. tete

    tete clown shoes

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    Well, tonight I took apart the right side carb. Pretty gummy blackish stuff throughout. I only had time to get one side apart. [​IMG]
    In the past w Honda carbs I've had success w simple green so I went ahead and soaked all the parts in SG over night. We'll see how it
    looks in 8 hours when I get off work ( Iwork graves in a hematology lab).
    The jets look a bit gummed up as well but re-usable as they are brass it looks like. Cleanable, and in theory should clean up well. Floated the float. Etc
    I decided not to mess with butterfly till tomorrow. I'm not going to disassemble it. I will simply clean it as Good as Possible

    The diaphram looked like new, but will be replaced of course. I was wondering if I should keep it in the event of a road trip the new one fails for whatever reason I at least may have something to get me home.

    After seeing the gummed up stuff it made me thing how nasty the combustion chamber must be. What could I spray in there prior to start up to break some of that stuff down? One person said Wd40 would be good to free up the rings a bit. I imagine the gunk will burn out initially as it should be just old gas?
    #58
  19. Horsehockey

    Horsehockey A GPS? Huh?

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    You're on the right track. That thang is filthy and the other one is prolly the same. Yes, keep the old diaphragm as a backup but they don't store too well - mishappen and dried out. Yes, from the looks of it, your combustion chamber is prolly carboned up too. To clear out the carbon, use Seafoam in your first few tankfuls of gas. Seafoam will also help clear out your idle and main jets in the carbs. Not a miracle in a bottle stuff, but real formulation designed specifically to attack carbon. Keep up the good work.
    #59
  20. tete

    tete clown shoes

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    I have a question. is it needed to remove the spring assemble on the butterfly / throttle connection and remove those parts to clean? I used some carb cleaner and removed most of the gunk.

    Also where do i get rweal seafoam? and also how much do I add per gallon of gasoline? what is the dilution.
    #60