1972 r75/5

Discussion in 'Airheads' started by assquatch20, Sep 20, 2012.

  1. assquatch20

    assquatch20 Hoss Cat

    Joined:
    Jan 31, 2010
    Oddometer:
    1,136
    Location:
    Alpine, TN
    Answers/advice appreciated for the statements in bold text. The rest is details to help us both.

    So a few months back a buddy sat on my little Honda and liked it. His folks were giving him a /5 one of them had bought, but the little dude didn't like the weight and style of the thing, so I'm selling him mine and bringing his home, while making a little profit to dump back into the thing. 52,000 miles.

    [​IMG]

    So I guess I should get started with a proper thread on it so I know how to approach the thing and feel like it's roadworthy. I took a look at it the other day, and it now has a battery. Sidecover tabs are there, but no covers. Passenger pegs, as someone (east_high) pointed out to me before, have been moved but it looks like a clean job. From what I can tell, it has Wixom luggage and the Avonaire (thanks pfestus1) fairing. My fairing knowledge isn't enough to be sure if it's from the /2 or the multipiece kit for the /5. (It's the 2-piece specifically for /5's)

    I couldn't get it to start, but I don't know the intricacies of the process. It would chug a time or two, but no idle. Had gas, left fuel tap on (or at reserve) and seemed to do worse if I put the choke on. I still won't have it home for a few weeks and probably won't hit the roads much until next year, but I'd like a head start. The carbs are not the flat tops, but I'm not sure which they are (can ya tell I'm new to white people bikes?). As well, the tank is definitely gonna need a POR15 run, but I can't see any external rust or pinholes, etc. Carb and petcock rebuilds look easy enough. I did notice the right side petcock would rub and was unable to turn all the way up. I'm thinking there's an internal spacer in there? And where should I go for a complete jet set?

    In fact, it looks clean from maybe 5 feet off. Up close you notice how chrome isn't one of those things that stays pretty, so there's a lot of cleaning work to do. Not sure if it has the factory tool kit, but I'm hoping so. Where could a guy buy a /5 tool kit as an all-in-one bundle? Doesn't have to be OEM or NOS or other acronyms.

    The needles on the clocks look pretty rough, and the lights inside as well, but seem to be operable. I've seen where folks rebuild them, but too rich for my blood right now. What I'm worried about is undoing the lighting reroute for the fairing. The signals were taken off the stems and mounted outboard, same deal with the headlight of course, so I'm hoping it's not hard to undo. If the front lighting is a total mess, which harness(es) would I be needing to fix that?

    The Wixoms will probably get a resto at some point, but they're in pretty good shape. Latches and hinges look totally usable. My understanding is I can still find a key that fits those, correct?

    I got lucky and saw an ad for a local guy that's a certified airhead mech. which is pretty rare here, but more opinions could help. My base question is, as a newbie to BMW (and a novice in general), what are the first and most important things to do when you get the bike home? What procedures would you go through? What would you have to buy with most certainty?

    And also, would anybody be interested in the Batmobile fairing?
    #1
  2. Kt-88

    Kt-88 I like everything.

    Joined:
    Sep 9, 2012
    Oddometer:
    1,017
    Location:
    SLC area, Utah
    Out of curiosity, which honda did you trade? That's how I got into my r90, too.
    #2
  3. assquatch20

    assquatch20 Hoss Cat

    Joined:
    Jan 31, 2010
    Oddometer:
    1,136
    Location:
    Alpine, TN
    It's a CB-1. I made a deal that I'll get visitation rights.
    #3
  4. Kt-88

    Kt-88 I like everything.

    Joined:
    Sep 9, 2012
    Oddometer:
    1,017
    Location:
    SLC area, Utah
    A cb1000?
    #4
  5. assquatch20

    assquatch20 Hoss Cat

    Joined:
    Jan 31, 2010
    Oddometer:
    1,136
    Location:
    Alpine, TN
    Oh no, a CB-1. Kind of a rare naked 400 brought over here in '89 and '90.
    #5
  6. disston

    disston ShadeTreeExpert

    Joined:
    Mar 22, 2011
    Oddometer:
    12,368
    Location:
    Silver Spring, Md
    Good. You more than doubled your CCs.

    Welcome to the asylum.

    The earliest petcocks are not too easy to rebuild, they are the ones called Everbest. They can be worth a few $s because working ones are getting scarce. But it looks like a Karcoma petcock in the pic, can't be sure, too far away. The Karcomas are rebuildable if they only need rubber parts. Some of the other tiny pieces inside the petcock are NLA. We sometimes can come up with used parts.

    A complete tool kit is going to cost some serious money and if you want the correct original tool kit the price will keep going up. There are tool kits, used, listed as "original" be careful. There are specific items that belong in the "original" tool kit.

    How many miles on bike? Is there any ignition modification or addition? What else non-stock is on the bike?

    Start with just changing all the fluids and tune up items. Set the valves. Replace worn or cracked rubber pieces. You will find plenty to do.
    #6
  7. assquatch20

    assquatch20 Hoss Cat

    Joined:
    Jan 31, 2010
    Oddometer:
    1,136
    Location:
    Alpine, TN
    I just want the tools I need to use. Doesn't have to period correct or anything, but I'd like to know where I could get some of the specialty stuff on a decent price and throw it under the seat.

    52k miles AFAIK. Not sure on the ignition, but there's two gigantic horns mounted by the downtubes and what looks like a big solenoid valve for each. Probably not good on the charging system, but I'm no expert. Being no expert, I can't say with certainty if there are other mods, but that's all I noticed. Oh, the tank badges look to be the adhesive type or something, as I didn't see screw holes. Is that right for a '72?
    #7
  8. disston

    disston ShadeTreeExpert

    Joined:
    Mar 22, 2011
    Oddometer:
    12,368
    Location:
    Silver Spring, Md
    You would do well to contact Hucky's and see what he can get you a complete kit for. Find Hucky's on the Web but call him to place orders. He will explain to you. Get as much stuff as he has in stock that you can afford right now. Get the Clymer's or the Haynes manual now. If you can't afford the complete new tool kit then tell us do you own metric tools?

    If Hucky's only sells the BMW shop manual don't get that one. It is too much money for something not very useful for a beginner.

    http://www.bmwhucky.com/

    Look for "tool" on Ebay. You may find what you need. Hopefully, but I just did that and did not see a reasonable /5 tool kit in the lot.

    The problem is that it is an on going evolving thing. The "tool kit" under the seat is only a start. You are going to need a lot of other tools as time goes by.

    The German tools made for the bike are good tools. It would cost just as much to make the tool kit up at the Sears store.

    There are several ordinary wrenches needed but there are also a couple of special wrenches you should have. These are hard to find if Hucky's doesn't have them. Recently we have sent riders there to get the specialty wrenches.

    I think there is a picture of the tools in the manual. Please get a manual right away so we know what we are talking about.
    #8
  9. disston

    disston ShadeTreeExpert

    Joined:
    Mar 22, 2011
    Oddometer:
    12,368
    Location:
    Silver Spring, Md
    Supposing that you have some of this stuff already we will try to make a list of everything that belongs in the basic /5 tool kit. Remember there are other tools you will need but this is the on board tool kit. To begin;

    5 Hex Key wrenches also called Inner Hex wrenches. You need 3 mm, 4 mm, 5 mm, 6 mm and 8 mm. Ordinary good quality hex wrenches will work fine. But not cheapo ones, they will round off.

    Several special tools are needed in the on board tool kit. 71 11 1 237 857 is the ring spanner that fits the swing arm nuts on one end, 27 mm, and the other end fits the center nut and other parts of the front forks, it is 36 mm.

    Another special wrench you will need is the hook spanner with pins for the top covers of the fork tubes. It is # 71 11 1 237 858

    There is a third special spanner for /5s but I don't have one so I don't know the #.

    You need a socket for the spark plugs. The tubular one in the stock kit is a good one. It has a Tommy bar that can also be use to remove stubborn axles. The spark plug socket is #71 11 1 237 856 the Tommy bar is #71 11 2 301 357

    There is a special feeler gauge that is still available and belongs in the on board tool kit. It is shorter and makes it much easier to do some of the operations needed. It covers all the sizes needed for the setting of valve lash, ignition point gap, spark plug gap and a setting needed on the brake master cylinder (used only rarely when replacing, rebuilding the MC) It is part # 71 11 9 090 154

    You need a test light, a continuity light. They are a common tool for tracing wiring problems. There is a German one made by Stahwillie and is a nice one but a common test light will work fine.

    It is recommended to carry a couple of short tire irons. I one several and a long one too. And if using tube tires, which you will be using, a tube patching kit. There is an on board tire pump that has a special place to store on the bike.

    There will be more, to be continued.
    #9
  10. disston

    disston ShadeTreeExpert

    Joined:
    Mar 22, 2011
    Oddometer:
    12,368
    Location:
    Silver Spring, Md
    #10
  11. assquatch20

    assquatch20 Hoss Cat

    Joined:
    Jan 31, 2010
    Oddometer:
    1,136
    Location:
    Alpine, TN
    Much appreciated, disston. That's the stuff I'm looking for, the bike-specific tools that make the job easier. There's still a chance the kit is on there, I didn't check. I might go have another look at it next week or wait until I bring it home.

    I was considering getting the OEM, Clymer, and the Haynes as it seems they're always missing something, but it looks like those prices are ridiculous and I'm not that helpless. By good luck I've never had to tear into a gearbox but I'm not opposed to it. I've done plenty of engine maintenance and top end work though, so I don't think anything will blow my mind. Would you still say the BMW manual is too complicated or should I have it? Is the owner's manual necessary as well?

    Mostly I'm worried about getting into something I desperately need to fix and then not having the tools or parts to complete the job. Obviously I don't know what "jobs" I'll end up having to do, but the feeler gauges and special spanners look like a good start. I suppose a syncing gauge would be handy to have around as well, considering the fuel system work I'm looking at?

    My weak point is definitely electrical stuff, so still a little nervous about undoing the fairing wiring and/or throwing new wiring in there. Any advice in that arena is greatly appreciated.

    Hopefully somebody can read this thread in a few months and see a nice little transformation.
    #11
  12. disston

    disston ShadeTreeExpert

    Joined:
    Mar 22, 2011
    Oddometer:
    12,368
    Location:
    Silver Spring, Md
    If you want more than one manual get the Haynes and the Clymer. The OEM is not too complicated, it's just not really needed with the other two and the internet. The OEM does have more torque values an explanations about what pistons and which cylinders are made, 30 years ago. I'm not against people getting this, I have one myself. but you can get the OEM manual next year or the year after. And they do show up on Ebay and at Flea markets. October Fest is almost here.

    The owners manual is nice for a lot of basic info. I have one somewhere. There may be one on the bike. These are often with the bike.

    Good, you may have a tool kit. I did learn tonight a bit about posting pictures tho.

    There is a simple method to sync the carbs that doesn't use an expensive tool. You may want to get one of the expensive tools but you don't need it now. I'll describe how to make the shorting tool and explain a little about it's use, but later I'm about to turn in, big day tomorrow.

    We do a lot of transmission stuff on these bikes. And then after all the bother and sweat and money, more tools, we end up with something that shifts like a John Deere. There will be transmission work in your future or you will send it out, the option that really is best for most riders. But if you are one of those that are driven, or think you can handle it or want the experience then we can help a little. The one thing you don't want to tell yourself is that you want to rebuild a transmission to save yourself money. Not very likely that anybody ever saves any money doing the first two or three transmissions. And the guys that have done a few hundred of them, there are a few, they know stuff we can't learn, they will do a better job than any part timer. Just the way it is. But some of us just want to do our own, that's me, and we are allowed.

    When's the bike get to you? Does it run? Any known problems? Mileage?

    BTW, I've been meaning to tell you. I think you might have something of a rarity in that fairing. Would like to see more pictures of that set up.
    #12
  13. assquatch20

    assquatch20 Hoss Cat

    Joined:
    Jan 31, 2010
    Oddometer:
    1,136
    Location:
    Alpine, TN
    I'll be bringing the bike home in a little over 2 weeks. My buddy will get back from AIT and want to get on with the trade I suppose. I couldn't get it to run myself, but I'm told it does. The owner wasn't there when I looked to help me out. Seems like just a clogged jet or old gas. No known problems aside from the fuel stuff. I'll definitely need POR15 for the tank. Mileage is 52,000 miles.

    It does certainly seem like the fairing is hard to come by, but I don't know if that means anyone will want the thing. I kinda like it and I've read it was the best of the best for its purpose, but I'm not so sure it'll stay with me.

    Also now that I think about it, my buddy slapped together one of the yardstick synchronisers, so I suppose that might work for me. I'm used to 4 cylinders so much that it never occurred to me.
    #13
  14. disston

    disston ShadeTreeExpert

    Joined:
    Mar 22, 2011
    Oddometer:
    12,368
    Location:
    Silver Spring, Md
    There are a number of little things about Airhead ownership and repair that are sometimes hard to explain even if I know the answer. You have a number of good qualities that make helping you out so much easier. It's amazing the number of times riders with no prior mechanical experience come to these forums for advice and help but they need to have their hands held because they won't buy a manual. The inexperienced beginner mechanic thinks that real mechanics don't use manuals. Little do they know that we read them from cover to cover in our spare time and revel at the quality of a really good manual. They are the back bone of what a lot of us do. So I just wanted to say again you're on the right track

    After the Clymers and Haynes manuals there is another that will prove very useful. It is the Bing Carburettors Manual. Mine was published in 2001 and I understand there is a latter edition with some up dates. I think this is the next after the ones already mentioned. Find the Bing Web page and get the phone #. I think you have to call them to order anything. But here's the caveat, do not make a big order of a lot of parts from Bing. You will get their price list with the new manual (BTW it's pretty cheap at only 10 or 11 dollars I think.) And from there it is easy to compare with the prices from other sources. Not to start the discussion all over again but the fact is Bing parts are cheaper at the dealers than from Bing. But get the book.

    Here is a link to one of the places that have after market tools for BMW. You may use them. There are others. They will sell you the adapters for the shorting the plugs method of balancing the carbs. You can also make your own, I'll give directions if needed later.

    [​IMG]

    http://www.northwoodsairheads.com/Tools.html

    (not sure why the pic didn't work)
    #14
  15. assquatch20

    assquatch20 Hoss Cat

    Joined:
    Jan 31, 2010
    Oddometer:
    1,136
    Location:
    Alpine, TN
    Went and had another look today. Guy said it was a '73, showed me the title, but I can't remember. If it is, it must be an early one. The tank badges aren't screwed on, which I think indicates a difference between 1972-73 and I don't think it's a LWB. Also noticed the dual airhorns run off some Sears brand compressor and are scary loud. I might have to hang onto those.

    Anyhow he got it running and it idles nicely once it's warm. Still needs a serious cleaning for the entire fuel system, but it ran. Looked like a tiny pinhole in that link pipe/connector thing between the headers, and an exposed hole on the motor beside the dipstick. What is that? Absolutely can't be good to have that open, oil change asap.

    I couldn't get the seat to lift, all the way, seemed like the luggage was in the way and the whole seat felt kinda loose. The trim around it needs replaced but the cover looks dandy. From what I could see, though, no tools/pan. In that case, what maintenance tools do I need? I know gauges and the exhaust nut spanners, but what else is necessary to lube the splines and change fluids, etc? Doesn't look like I'll be needing into the tranny/crankcase so that stuff can wait, I hope.
    #15
  16. disston

    disston ShadeTreeExpert

    Joined:
    Mar 22, 2011
    Oddometer:
    12,368
    Location:
    Silver Spring, Md
    Price sounds fine to me for 52,000 mile machine.

    An exhaust nut wrench will be needed sooner than later. The pipe you mention with a pin hole in it costs a hundred dollars, or there abouts. There are many options when it comes to exhaust wrenches. This one has the advantage of being able to be carried on the bike but then you still need the breaker bar to use it. Check out some other options too.

    http://www.cycleworks.net/index.php?main_page=product_info&cPath=29_33_51&products_id=346

    [​IMG]

    Then there's this one;
    http://www.northwoodsairheads.com/Tools.html

    [​IMG]

    The original BMW tool is hard to find, expensive and made of heavy cast iron. It's my favorite but I don't have a picture. Sorry.
    #16
  17. assquatch20

    assquatch20 Hoss Cat

    Joined:
    Jan 31, 2010
    Oddometer:
    1,136
    Location:
    Alpine, TN
    Disston, you're practically a library. I saw the Northwoods one and figured I'll probably order it. What I'm hung up on is the carbs. It has the black labels so I'm assuming it might be hard to make it run great. I'll have about $500 off the bat to blow on it, but I'm not sure I want to dump all that into Mikunis.

    Hell, I still don't know what I'm going to do with the thing. I might get overzealous and tear it all down. I hope I can avoid that.
    #17
  18. R85/8

    R85/8 Been here awhile

    Joined:
    Aug 20, 2011
    Oddometer:
    370
    Location:
    Highlands Scotland
    It may not be the carbs.

    Firstly, it's worth cleaning them out anyway, but I wouldn't do anything major to them until other things had been tried first, but a quick check of the diaphragms would be worthwhile.

    Back in the day I had an R75/5 with a maddening problem. It would run ok for a while - like several hundred miles - and then just become cantankerous at low revs. I would check the cleanliness of carbs etc but they would usually only have a little dirt in them (the bike did most of its mileage on dirt roads). I diagnosed the problem to be a loose bit of dirt stuck in the jets somewhere that would get sucked into the jet, stay there for a while, and then drop down. No amount of searching found it, and I must have had the cleanest carbs in Oz.

    Then one day as I was doing a U-turn in front of a truck, the bike just died. I only just avoided the same process. :)

    I'd long since given up using the starter motor because it had been barely able to turn the engine over, even with a new battery - this should have been a major clue.

    The problem was as simple as the earth lead. Where it attaches to the engine, the lead had gradually been breaking, strand by strand, just inside the insulation. Even though I cleaned and polished the bike regularly, this break was invisible to the eye.

    A quick roadside repair and suddenly my starter motor was back to full strength, and the bike started idling and running like a new one.

    Since then I have always looked to electrical system first anytime I have had what seem to be carburettor problems, and in most cases it is electrical.

    Anyhow hope this helps, and that bike is a great bargain.
    #18
  19. disston

    disston ShadeTreeExpert

    Joined:
    Mar 22, 2011
    Oddometer:
    12,368
    Location:
    Silver Spring, Md
    I'm always surprised when a new Airhead owner gets this machine he knows very little about and the first thing he does is takes it all apart for "Restoration". So I am against that. The bike is designed to be worked on as it is. Some parts, if need be, can be taken off but 90% of anything this bikes needs to get it running will be done before the frame is painted. If you get my drift.

    If the carbs have the plastic black labels on the sides they are later carbs. This is a popular way to fix a problem the original carbs had. They can probably be made to work just fine. There are some numbers on the side plates. They will be of the order 64/32/??(?) The last digits being either two or three digits. Those numbers will tell us what they are. However they could have started out as R80 or R100 carbs and the jets will have to be examined. So when you get them off, start by telling us what the numbers are and then take one of them apart. Using a magnifying glass look at the numbers on the jets.

    You are going to have to use a parts microfisch to tell which jets are which. And I want you to use the correct names for things in the carbs. I'm on a life long mission to get everyone here to use the correct names for stuff in the Bing carbs. Our carbs do not have Pilot Jets. They do not have Air Screws and they do not have Chokes. Just to name a few.

    Learn to use this web site, you have to go through a few pages to get to 1...Motorcycles, 2...Archive, 3...find your model. Then enter the data till you get to the carbs. Learn to use this site first. There will be others;

    http://realoem.com/bmw/

    There is a place on Real OEM dot Com to enter the serial number and it will tell you when the bike was made. It looks to me like it is most definitely a /5 and because of the tank it is one of the last produced. Those tanks look like the /6 tank but they do not have the space for the brake master cylinder. Unless that really is a /6 tank. But still other things say the bike is a /5.

    Hopefully $500 will be enough to get this thing going. It should be but there are several expensive things you have not been able to check. 1...Compression on the cylinders would be a indication of the health of the engine and weather or not it needed any immediate internal parts. Engine work would eat up your $500 really quick. 2...Transmission repair comes to the Airheads awfully early sometimes. The trans are rather clunky but there are a number of things that we don't like to see at any time. The main thing being anything more than paste on the drain plug. No metallic particles allowed when the oil is drained. 3...Engine oil leaks bother everybody but they are usually an easy fix. Oil leaks from the trans or the final drive can be more expensive.

    Have you made a deal for this bike? And when are you bringing her home to show to Momma?
    #19
  20. assquatch20

    assquatch20 Hoss Cat

    Joined:
    Jan 31, 2010
    Oddometer:
    1,136
    Location:
    Alpine, TN
    Thanks for steering me away from a tear down. I'll get the carb numbers once it's home and go from there, but the bike runs strong once warm, so I don't think much more than a good cleaning is required for now, but I want to get an idea of how everything is doing. I'll lube everything, replace fluids, new air filter, and go from there I suppose. Still wondering what the hole is beside the dipstick. Pictures I've seen show what looks like a rubber plug in there.

    My buddy will be home on the 5th. I'm gonna take my bike up to his house, he gives me $500 and a /5, and I leave the Honda. I'm certain it's a /5, just unsure of which year, 72 or 73.

    Electrics seem strong, but seems like the fairing-mounted headlight isn't working. Starter cranks well, not sure on the charging yet.

    Could the link pipe (what is this actually called?) between the headers just have the pinhole(s) repaired and then I ceramic coat the entire exhaust system?
    #20