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Fuel filter ? 78' R100/7

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.
 
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?
 
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.
 
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'
 
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 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.
 
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.
 
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.
 
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.

Looks great to me. I am SURE you will not regret the filters. Too much prevention? NO. Not for a few bucks a year!
 
Have you always run the BP7ES which is the coldest plug (equivalent to the Bosch W5DC)? I tend to run the W6DC plug in my R100/7, which is one step hotter. I think either will work fine...it could have an impact on the plug color as well.
 
Have you always run the BP7ES which is the coldest plug (equivalent to the Bosch W5DC)? I tend to run the W6DC plug in my R100/7, which is one step hotter. I think either will work fine...it could have an impact on the plug color as well.

I've only had the bike for 6 weeks...When I ordered the parts, Beemer Boneyard said these are the recommended plug. I will try the 6's next time though. Thanks.
 
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.

I also had red stuff and carb floats sticking and leaking. I cleaned out the tank, removed petcocks and screens, thoroughly cleaned, replaced fuel lines, and added two sintered filters. Also cleaned and dressed float needle seat. NO MORE dirt in carbs. No more leaking, and 9,000 miles later. Just checked bowls a few weeks ago when replacing jet needles and needle jets, no residue or dirt whatsoever.

As one other poster does, I only open the left petcock when riding so one filter feeds both carbs until that side of tank goes empty. Then I open right side. When that side goes empty, I put both petcocks on reserve. This way, I kind of get a double warning about low gas level.

All of this to show that a clean in-line filter will flow plenty of fuel to BOTH carbs. Key is to replace them regularly - perhaps once per year.

"An ounce of prevention is worth a pound of cure"
 

Godfather,

So . . . what was the final outcome? Were your old fuel line filters, in fact, the problem, presumably because they were plugged?

If so, that is a sign that the filters do, indeed, need installed. If they hadn't stopped that dirt the carbs probably would have, or worse, the engine itself would have sucked it all in.

JL
 
Godfather,

So . . . what was the final outcome? Were your old fuel line filters, in fact, the problem, presumably because they were plugged?

If so, that is a sign that the filters do, indeed, need installed. If they hadn't stopped that dirt the carbs probably would have, or worse, the engine itself would have sucked it all in.

JL

There was no visible sign of contaminants in the filters. They were new with less than 100 miles on them so I will assume there must have been water in the gas that caused the paper element filters to plug up. I blew through them comparing airflow to the new(est) ones and the air flow was restricted in the problematic ones.

I am a believer in prevention and will continue to use the inline filters until someone can prove they are detrimental.

Thanks again to everyone that contributed to this thread.
 
There was no visible sign of contaminants in the filters. They were new with less than 100 miles on them so I will assume there must have been water in the gas that caused the paper element filters to plug up. I blew through them comparing airflow to the new(est) ones and the air flow was restricted in the problematic ones.

I am a believer in prevention and will continue to use the inline filters until someone can prove they are detrimental.

Thanks again to everyone that contributed to this thread.

I would suggest that you should use the sintered bronze type next time. Mine came from Max's.
 
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