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Thread: Fuel filter ? 78' R100/7

  1. #16
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    Quote Originally Posted by Darryl Cainey View Post
    Are they not upside down?
    Looks that way to me, too. But I can't see the arrows, and those are different than the ones I have.

  2. #17
    Registered User godfather's Avatar
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    Quote Originally Posted by Darryl Cainey View Post
    Are they not upside down?
    NOT UPSIDE DOWN...the arrow points from tank to carb...thats why I asked in my original post, it just did not look right.
    Attitude is everything!
    1978 R100/7
    08' V-Strom 650 great light weight tourer

  3. #18
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    Look upside down to me too. My guess is that the arrow points "up" and does not refer to fuel direction.

  4. #19
    Registered User godfather's Avatar
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    Quote Originally Posted by cseltz View Post
    Look upside down to me too. My guess is that the arrow points "up" and does not refer to fuel direction.
    The word "FLOW" is actually embossed in the arrow and I have them pointing from tank to carbs.
    Attitude is everything!
    1978 R100/7
    08' V-Strom 650 great light weight tourer

  5. #20
    Registered User godfather's Avatar
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    Look close at the filter, you can see the pleated element does not fill the entire plastic filter case from top to bottom. The fuel flows into the case above the element and surrounds the element and is filtered through it, then passes to the center of the element and exits to the carbs trapping any contaminants on the outside of the pleated element. If the flow was the opposite going from inside the element to the outside it seems the flow would be somewhat restricted and you would not be able to see the contaminants.

    I don't know if it matters, but this kind of makes sense to me.
    Attitude is everything!
    1978 R100/7
    08' V-Strom 650 great light weight tourer

  6. #21
    Registered User lkchris's Avatar
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    Just because nobody's mentioned it yet ...

    ... these were not factory fitted nor are any such filters available in the BMW parts system.

    And, they're completely unnecessary.
    Kent Christensen
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    '12 R1200RT, '02 R1100S, '84 R80G/S

  7. #22
    Registered User godfather's Avatar
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    Quote Originally Posted by lkchris View Post
    Just because nobody's mentioned it yet ...

    ... these were not factory fitted nor are any such filters available in the BMW parts system.

    And, they're completely unnecessary.
    You may be right, but an ounce of prevention...
    Attitude is everything!
    1978 R100/7
    08' V-Strom 650 great light weight tourer

  8. #23
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    Quote Originally Posted by lkchris View Post
    Just because nobody's mentioned it yet ...

    ... these were not factory fitted nor are any such filters available in the BMW parts system.

    And, they're completely unnecessary.
    So they're not original BMW, but they ARE necessary!

    These have saved a lot of leaky carbs where a spec of dirt got through the system and lodged in the float needle causing an overflow.

    I sort of wonder why Max's BMW, RePsycle, and probably every other shop sells them. At $2 each, cheap assurance.

    There was a reason why nobody mentioned it yet. Can you guess why?

  9. #24
    Registered User lkchris's Avatar
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    Quote Originally Posted by jimmylee View Post
    So they're not original BMW, but they ARE necessary!

    These have saved a lot of leaky carbs where a spec of dirt got through the system and lodged in the float needle causing an overflow.

    I sort of wonder why Max's BMW, RePsycle, and probably every other shop sells them. At $2 each, cheap assurance.

    There was a reason why nobody mentioned it yet. Can you guess why?
    Rode my RS for 27 years and still riding my G/S after 28 and never had that happen. The petcock screens are fine enough. Have no psychological need to prove I'm better than BMW. But I agree, the filters are cheap and make you look like a genius if you need that.
    Kent Christensen
    21482
    '12 R1200RT, '02 R1100S, '84 R80G/S

  10. #25
    Sir Darby Darryl Cainey's Avatar
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    Never used fuel filters on my RS either and never felt the need in 27 years.
    My (New to me) GS has them, when I take off the SHED System I won't put them back on.

    Just sayin'
    Ambassador BMW MOA Ontario Canada
    President Niagara BMW Riders #298
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    1977 R100RS, (Retired) 1993 R100GS (just getting started)

  11. #26
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    Better look like a genius and fail than to talk like a fool and succeed!

  12. #27
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    I agree with lkchris - fuel filters not necessary or even desireable by design if good screen in tank and or aditional screen in fuel tap (some verticle drain types)

    One possibility especially if the filter pictured is a paper type or very fine porous material - water and gas do not mix well.
    If you are unlucky enough to get a bit of water in bottom of tank that wets a dry filter first with water then gas will not pass through it till it drys out - you could blow back through it (adding more moisture from your breath if by mouth) and just make things worse.

    Another reason to get rid of the filters - a slug of water will make the engine stumble but probably not shut you off like a water contaminated filter will.

  13. #28
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    Quote Originally Posted by 44006 View Post
    I agree with lkchris - fuel filters not necessary or even desireable by design if good screen in tank and or aditional screen in fuel tap (some verticle drain types)

    One possibility especially if the filter pictured is a paper type or very fine porous material - water and gas do not mix well.
    If you are unlucky enough to get a bit of water in bottom of tank that wets a dry filter first with water then gas will not pass through it till it drys out - you could blow back through it (adding more moisture from your breath if by mouth) and just make things worse.

    Another reason to get rid of the filters - a slug of water will make the engine stumble but probably not shut you off like a water contaminated filter will.
    I doubt that any of this applies to this filter situation. The filters I have are sintered bronze and will not do as above suggested even if it would be true of a paper-type fuel filter. All one has to look at, is to examine the bottom of the float bowls when no filters are being used to see that dirt and stuff does, indeed, pass through the system. If the filters would ever clog up from dirt, then are you saying that it is better NOT to use them and have all that dirt clog the carbs?

    The fact is, is that if one simply DOES use the filters, which do definitely work or they wouldn't clog up, but make sure that they are replaced every 10,000 miles (or less, as they are cheap insurance!) one will be able to catch the dirt, not clog, and save that engine/carbs all of that dirt.

    I would bet that if you have not used filters for all those years, then your engine has been sucking in all of that grime and burning it, and the grime does do damage that you just can't see.

    In my opinion, better to use these in-line filters (sintered type from Max's BMW) and change once per year. Cheap insurance.

  14. #29
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    Gas filter thread

    I'll bite. Couple years back, float bowls always had rusty stuff in them. bothered me. All screens in place including with Dels third screen at carb fuel inlet. Put on Fram inline filters, next spring float bowls still had red stuff in the bottom, only very fine. So, with tank screens, petcock screens, Frams and Del screens, the bowls still had the red stuff.

    At this point it was getting anal, like "what kind of oil should be used", but kept filters except petcocks, went to ninety degree units, and made an aluminum tank. this fall checked float bowls, finally, nothing. Success, but at a price. Redkote likely would have worked out real nice except that my old tank was coated with some kind of peeling yellowish sealer. FWIW that's the story. Time to order the pizza.

  15. #30
    Registered User godfather's Avatar
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    Here is a follow up....Today I was able to get out for a 15 mile ride. Everything seems to be ok. The fuel filters filled and stayed that way. The bike ran strong throughout the rpm range...actually I am impressed at how strong it pulls from 5000 to 6000 rpm's in 3rd gear.

    The last two miles I ran at 4000 rpm, pulled in the clutch, hit the kill switch and coasted into the garage. I removed the spark plugs to see how they looked...





    I adjusted the idle to 1000 after replacing the plugs....smoooooth!
    After I get the idle/mixture tweaked a bit, I'm sure it will run even better.


    Thanks to everyone for your input. It's great to hear so many varied opinions.
    Attitude is everything!
    1978 R100/7
    08' V-Strom 650 great light weight tourer

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