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Thread: No Spark, I need HELP!!!!

  1. #1
    Rodney Aiken Ctrod's Avatar
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    No Spark, I need HELP!!!!

    I have a 73 R75 /5 that on and off for about 2 years I've trying to get running.
    It was sitting in a garage for at least 12 years. It needs a lot of TLC and my plan was to get it running, ride it around a little and figure out everything I need to do to it and go through it over the winter but I've haven't been able to get it started.
    I've cleaned and creamed the tank and rebuilt the carbs and I was getting a spark untill some point after changing the points, now nothing.
    I changed the points without disconneting the battery and have read this is a good way to burn out the diode board, is there a way to test this. It's been a long time since I've worked on anything with points and I'm not sure if I'm doing something wrong or just missing something.
    Any idea's?

  2. #2
    Administrator 20774's Avatar
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    Generally, the diode board and starting have nothing in common. The diode board is for charging; the starter runs off the battery....the bike will run without a functioning diode board...for a while.

    I would go back to what you did last...the points. Most likely, you have either too much gap or not enough. Both situations will result in no spark.

    Another thing that might be an issue is the coils...you had the tank off and the leads to the coils are very near the underside of the tank. Make sure they are not in contact with the tank.

    Check your kill switch and your battery ground.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  3. #3
    ABC,AMA(LIFE),MOA,RA,IBMW MANICMECHANIC's Avatar
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    One other item to check, did you put the front cover back on before attempting to start the bike? If so, then take it back off and see if you pinched the wire to the condenser, grounding the spark.
    F.O.G.Rider, Rounder #6,
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  4. #4
    Registered User lmo1131's Avatar
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    All good points (pun intended).

    It would also help to know if you were sold Chinese-made ignition points with the taller than OEM rub-block; they're junk.

    Shceck this article -> http://forums.bmwmoa.org/showthread....6-not-starting

    DISCONNECT the battery ground cable BEFORE you remove the front cover. The front cover does not have to be on for you to run the engine. As per MM, if the engine was running BEFORE to replaced the cover and it would not run AFTER replacing the cover you more than likely pinched the condenser lead.

    Check your kill switch ...
    There is none.
    "It is what you discover, after you know it all, that counts." _ John Wooden

    Lew Morris
    1973 R75/5 - original owner

  5. #5
    Registered User lmo1131's Avatar
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    P.s.

    Have you adjusted the valves?

    Did you have the flywheel at the correct position when you set the point gap?

    Are your coils properly grounded?

    Are the HT plug wires and spark plug terminals in good condition?
    "It is what you discover, after you know it all, that counts." _ John Wooden

    Lew Morris
    1973 R75/5 - original owner

  6. #6
    Rodney Aiken Ctrod's Avatar
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    Thanks for all the input so far. I haven?t worked on anything with points in about 20 years, this is also my first Airhead, I had to go to MAX?s to verify what the switches on the handlebars do, so any point no mater how small is appreciated.
    The flywheel seems to be installed in the correct orientation. I didn?t have it apart but I?m assuming that if I adjust the points at the high point on the cam they should be right?
    The kill switch on and the tank grounding out the coils is a good possibility. The switch was apart and I had put the tank back on after installing the points.
    The starter doesn?t work so I?m trying to kick start it. I tried to get the starter out but the transmission has a flange on it that doesn?t let me get a socket on one of the bolts. I checked the repair manual and it doesn?t show this flange so I?m wondering if it has the right transmission in it. It would make life a lot easier if I could get the starter to work

    Thanks again for the input.
    My plan is to work on it all day today, or untill I can't kick it any more.
    I'll keep you posted.

  7. #7
    Administrator 20774's Avatar
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    That "flange" to get at the rear starter bolts is definitely a pain. I seem to recall I had to go to a 1/4" drive ratchet with a swivel head on the socket. I think once it's out, you can reverse the direction of the bolt and make it easier next time.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  8. #8
    Registered User kentuvman's Avatar
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    Quote Originally Posted by Ctrod View Post
    Thanks for all the input so far. I haven?t worked on anything with points in about 20 years, this is also my first Airhead, I had to go to MAX?s to verify what the switches on the handlebars do, so any point no mater how small is appreciated.
    The flywheel seems to be installed in the correct orientation. I didn?t have it apart but I?m assuming that if I adjust the points at the high point on the cam they should be right?
    The kill switch on and the tank grounding out the coils is a good possibility. The switch was apart and I had put the tank back on after installing the points.
    The starter doesn?t work so I?m trying to kick start it. I tried to get the starter out but the transmission has a flange on it that doesn?t let me get a socket on one of the bolts. I checked the repair manual and it doesn?t show this flange so I?m wondering if it has the right transmission in it. It would make life a lot easier if I could get the starter to work

    Thanks again for the input.
    My plan is to work on it all day today, or untill I can't kick it any more.
    I'll keep you posted.
    Northwoods Airheads sells a nifty tool for adjusting the points gap
    http://www.northwoodsairheads.com/Tools.html

    Good Luck & ket us know what you find!
    Ken Tuvman
    Excelsior, MN
    K75s, R65LS, R60/5

  9. #9
    Rodney Aiken Ctrod's Avatar
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    I have spark but not fire YET.
    The no spark problem was unique to my bike. At some point the ignition switch must have went so the original owner replaced it with 4 toggle switches and 3 of them have to be on to get spark, not just the one labeled ignition. At some point I?ll have to replace the whole wiring harness and switch.

    I got the starter to work with a bump switch that I?d forgotten I had witch is a big help to the balls of my feet. I?ll have to replace the handlebar switches also at some point.
    I put the tank back on with a little gas and both carbs leaked so I adjusted the floats and fixed that.

    Now when I turn the motor over it jerks and I get a noise like a squeaky hinge. So I?m going to put a little Marvel Mystery oil in the cylinders and have an early lunch while the battery charges and the gas fumes air out.
    I think now that the starter works I might go get the motorcycle lift at Harbor freight I?ve been looking at.

  10. #10
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    The squeaky hinge noise is probably the crankcase breather. You can take the breather housing off and verify, its the piece the breather hose attaches to at the forward end, next to the starter.

  11. #11
    Registered User lmo1131's Avatar
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    The no spark problem was unique to my bike. At some point the ignition switch must have went so the original owner replaced it with 4 toggle switches and 3 of them have to be on to get spark, not just the one labeled ignition.
    This I HAVE to see. Post some pics please. Of all the BMW models to have to replace the entire wiring harness on, the R75/5 is the cheapest; around $150 if I recall correctly. If you had a /6, or later model you'd be looking at $600+ (OEM from MAX, Hucky, etc.) - buying "used" on eBay or elsewhere is a waste of time and money. IMO

    As I mentioned, the R75/5 does NOT have a kill switch. If your's does, the PO put it there.... .
    "It is what you discover, after you know it all, that counts." _ John Wooden

    Lew Morris
    1973 R75/5 - original owner

  12. #12
    Rodney Aiken Ctrod's Avatar
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    IT?S A LLLIIIVVVEEEE!!!!! ? Gene Wilder, Young Frankenstein?
    After 12+ years of sitting it ran
    It wasn?t pretty but it ran for about 10 minutes. A mouse must have built a nest in the left exhaust pipe. When it started black chunks started to blow out of the pipe, I thought rust or carbine build up but it was birdseed. Hole cow I've never smelt anything quiet like a mouse nest burning.
    To adjust the point I loosened them up slid the feeler gage in far enough that it didn't hit the alternator, pushed it snug with my finger, tighten it up and then pulled the feeler gage out.
    I turned the motor over with the plugs out to get most of the Marvel out and then put the plugs back in.
    I used the light method to time it but I must have had it advanced to far because I hit the starter button and there was a big backfire and the motor locked up. I took the plugs out and was able to turn the motor backwards and it freed up but the starter wouldn't engage.
    I took the starter out after a couple trips to Harbor Freight for tools and cleaned the starter bendix with WD 40, added a little grease and put it back together. It turned over so I put the tank back on, squirted a little lighter fluid in the carbs and holly crap it started right up. It?s not ready to ride around the block yet but it RAN!!!!
    This is just too cool! I have to admit I was suprised by how emtional I got when it started.
    Here?s a picture of the wiring inside the headlight buck. It doesn't show the switches but will give you an idea of the mess.
    I'll take soom pictures tomorrow afternoon and post them.


    Headlight bucket.jpg
    Last edited by Ctrod; 09-26-2013 at 08:34 PM. Reason: typos

  13. #13
    Registered User kwb210's Avatar
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    Emotions are good!!!

    "This is just too cool! I have to admit I was suprised by how emtional I got when it started."

    There is simply no explaining how you can feel when a project you have sweated over fires up! Even 10 seconds is a triumph!
    I have a slash 5 (well, a couple of them) but one in particular that has really whipped me. I just prod along when I have the right frame of mind to work on her. I have tackled one area at a time, so its little by little. Right now I have pulled all the wires out of the headlight housing to clean out the PO mis-guided experiments. This will be the last project on her. I have pretty much gone over every component on the bike. My point here is that these 5's are a joy to work on. And then...the riding is fun too. This past summer I rode a 1973 R75/5 to the Rally in Salem. Absolutely enjoyed it. My regular ride is a 1977 R100/7. They are two different BMW's.
    So keep at all the components and you will have a gem of a ride!
    Best Regards,
    Kurt
    1977 R100/7 1971.1972.1972.1973 R75/5
    1974 R90/6 multiple boxes
    Airhead Revival
    "Objects in the mirror appear to be losing" unk

  14. #14
    Rodney Aiken Ctrod's Avatar
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    This is what the PO did with the switches. I put the lables on with the blue tape. I wasn't getting any spark because the ones I labled ingnition, headlight and tail light all had to be on. You can see the the speedo is in KPH witch I like.
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  15. #15
    Rodney Aiken Ctrod's Avatar
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    Heres a picture of the bike now. It's still has the frame mounted tire pump.
    Attached Images Attached Images

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