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The Motobrick Workshop / Re: Banging Noise at Idle
« Last post by John Lang on Today at 07:36:37 PM »Thank you for the prompt response, Laitch. I will listen to the alternator, inspect the clutch rod piston as you suggest and report. - J
Community of BMW K75 K100 K1 K1100 Indestructible Flying Brick Riders
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The Motobrick Workshop / Re: Banging Noise at Idle
« Last post by Laitch on Today at 05:08:14 PM »Extracting the push rod bearing assembly for inspection may help lessen the suspect pool. If you're ok with contortion, by crawling under the Brick—if you don't have a lift—you should be able to extract for inspection: a) the piston, the piston bearing, the spring, and maybe even the push rod bushing (#2 in the drawing) if it is the old style assembly, or b)the one-piece piston/bearing assembly (photos #2 and #3).
A problem with an alternator bearing cannot be ruled out yet. Remove the plastic shield covering the alternator, place the tip of a long screw driver on the alternator body then put your ear against its handle to determine if the alternator is the source of the noise.
old style clutch piston assembly
clutch side
boot side
A problem with an alternator bearing cannot be ruled out yet. Remove the plastic shield covering the alternator, place the tip of a long screw driver on the alternator body then put your ear against its handle to determine if the alternator is the source of the noise.
old style clutch piston assembly
clutch side
boot side
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The Motobrick Workshop / Banging Noise at Idle
« Last post by John Lang on Today at 04:23:46 PM »The attached audio file is labelled 'pushrod noise' but that is an assumption. Reading through the site I see various other possibilities. Have a listen. The knocking noise abates somewhat when the clutch is disengaged. I hope that makes worn monkey nutz, faulty valve clearances or something dreadful inside the engine less likely.
Will visible inspection of the pushrod thrust bearing -- aka throwout bearing or 'puck' (Chris Harris) -- reveal whether that easy solution will solve it? If so, I would like to take the part from my 1987 K75C parts bike. I understand, however, that there was a change in pushrod design that might disqualify this attractive option.
My 1992 K75RT has about 100,000 km on it, the 'parts bike' has about 225,000 km on it but no knocking sound..
Advice welcome. - John L
Will visible inspection of the pushrod thrust bearing -- aka throwout bearing or 'puck' (Chris Harris) -- reveal whether that easy solution will solve it? If so, I would like to take the part from my 1987 K75C parts bike. I understand, however, that there was a change in pushrod design that might disqualify this attractive option.
My 1992 K75RT has about 100,000 km on it, the 'parts bike' has about 225,000 km on it but no knocking sound..
Advice welcome. - John L
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The Motobrick Workshop / Re: Where to get a Tank Sender - UK? My K75 Broke down on me
« Last post by bluebossa on Today at 11:45:14 AM »Thanks Laitch... Yep resigned to buying new now, no point in gambling on a second one from 1994 at the same price!
so thanks for the link... Will source a fuel gauge when it's done too as believe they fit straight on, bizarre they didn't fit from Factory...
Correct hose on its way, expensive but yep submersible... Plus EFI clamps, check..
Thanks for the link...
so thanks for the link... Will source a fuel gauge when it's done too as believe they fit straight on, bizarre they didn't fit from Factory...
Correct hose on its way, expensive but yep submersible... Plus EFI clamps, check..
Thanks for the link...
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The Motobrick Workshop / Re: Where to get a Tank Sender - UK? My K75 Broke down on me
« Last post by Laitch on Today at 11:04:11 AM »New fuel level senders are the same price in the States as in the UK and Europe. Used ones are a gamble and uncommon as well. Get a new one like this one from Kparts Holland. Soak the tank in white vinegar a couple of days, clean it with a plastic brush or nylon scrubbing pad then rinse it out.
Be certain you replace hoses inside the tank with SAE J30 R10 or NBR/NBR submersible fuel injection hoses and fasten them with screw or pinch clamps made for fuel injection hoses. Don't use that hose for outside hoses. Those would be SAE J30 R9 or equivalent fuel injection hoses.
Be certain you replace hoses inside the tank with SAE J30 R10 or NBR/NBR submersible fuel injection hoses and fasten them with screw or pinch clamps made for fuel injection hoses. Don't use that hose for outside hoses. Those would be SAE J30 R9 or equivalent fuel injection hoses.
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FS WTB WTT ~ Bikes ~ Parts ~ Gear / Re: WANTED - FUEL SENDER for K75 UK 1986 Bike
« Last post by daveson on Today at 09:04:03 AM »If you can't get an original one, you could try a non original one. One of my bricks had a fuel pump from an AU Ford Falcon which worked without problems. The previous owner had a fleet of AU Falcons and used one of those from his spare parts stash. It's just a pump, no big deal.
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FS WTB WTT ~ Bikes ~ Parts ~ Gear / WANTED - FUEL SENDER for K75 UK 1986 Bike
« Last post by bluebossa on Today at 05:20:44 AM »URGENT - anyone in the UK got a Fuel Sender unit?
PLEASE - DM me
PLEASE - DM me
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The Motobrick Workshop / Where to get a Tank Sender - UK? My K75 Broke down on me
« Last post by bluebossa on Today at 05:15:56 AM »Well, my new to me K75C, recommissioned and stood for 16 years packed in and broke down on me this week!
I set off and the Red light wouldn't go out... then it died - and I had to push it 1 mile back home.
Fuel Pump died... 10amp fuse blew when I checked, but replacing it and still nothing so I stripped the tank to find the following - though it initially looked pretty good inside...
I could see lots of rubber and black bits... yuk.
All Rubber disintegrating - pipes corroded, the pump holder vibration rubber - dead, all sitting in the bottom of the Tank.
It was just all too much for the Bosch fuel Pump/Filter combo, the Pump gauze was also knackered so it was sucking everything up
Though I may have accelerated things as I added a set of Fuel system cleaner from Wynns to go through the EFI and degunk it... I think this hastened its end... any thoughts on that one?...
I had done 300 miles on it, but now its awaiting all internal parts.. full tank strip/clean and rebuild with new Pump, Filter, internal Piping and sender Gasket...
However finding a replacement Tank sender is proving a challenge.
That's all OK - though I had to walk it back to my house - it died within 2 minutes of leaving home - so I was lucky I wasn't on a big trip.
Anyhow - trying to find a replacement Fuel Sender - is like finding the proverbial Rocking Horse SH1T.
Why are they so expensive second hand $250 - £200 - E200 for a Second hand unit on EBay, with nothing available new?
Witness - https://www.ebay.co.uk/itm/365440946110?_skw=BMW+K100+Tank+Sender&itmmeta=01KR8JQWC6HZVQYNWCQJ2HEJTF&hash=item5515fa4fbe:g:aVYAAOSwH8pnyD9p&itmprp=enc%3AAQALAAAA0GfYFPkwiKCW4ZNSs2u11xBVaOnSW4k7Nt%2FbGx0585n13htWlVxGVyMjHZyoygkjc35K%2FqX0PPKE%2FXeuXOu9qXeHuSuLsAQodilaGVdmBqXbS%2F2tqFGSsRIMUYIexemocFEC9fD2cTCDyvfu4Ro3T9%2FMD8Adp%2FyRzsnOtab2kMs2wDuAd30cBQvHlCgxRxvyMoyzNF5%2BydHd0oypeXBmWeLkkoOE7oGF%2B6IV%2FeEgtHON9MMlF3kG40Nl%2BxgcdDw%2BFUSCrQl6%2FqpBt6wwO30hvaQ%3D%7Ctkp%3ABk9SR7DG35LCZw
Motoworks have no S/H units in stock - though I am going to ring them on Monday - any ideas?
PLEA - Anyone in the UK have one for sale - I will post a Wanted Ad... meanwhile pictures of the mess I found inside attached...
I'm booked on a Charity Bike ride next Sunday for Mens Health in the UK and wanted to use this Bike, rather than my R45 Boxer - which is a little underpowered 2 up.
The K75C is of course 40 years old, so doing this is a must anyway to give it the next decade of running... so I'm replacing everything...
As you can see it's a wonder it did 300 miles for me...
I set off and the Red light wouldn't go out... then it died - and I had to push it 1 mile back home.
Fuel Pump died... 10amp fuse blew when I checked, but replacing it and still nothing so I stripped the tank to find the following - though it initially looked pretty good inside...
I could see lots of rubber and black bits... yuk.
All Rubber disintegrating - pipes corroded, the pump holder vibration rubber - dead, all sitting in the bottom of the Tank.
It was just all too much for the Bosch fuel Pump/Filter combo, the Pump gauze was also knackered so it was sucking everything up
Though I may have accelerated things as I added a set of Fuel system cleaner from Wynns to go through the EFI and degunk it... I think this hastened its end... any thoughts on that one?...
I had done 300 miles on it, but now its awaiting all internal parts.. full tank strip/clean and rebuild with new Pump, Filter, internal Piping and sender Gasket...
However finding a replacement Tank sender is proving a challenge.
That's all OK - though I had to walk it back to my house - it died within 2 minutes of leaving home - so I was lucky I wasn't on a big trip.
Anyhow - trying to find a replacement Fuel Sender - is like finding the proverbial Rocking Horse SH1T.
Why are they so expensive second hand $250 - £200 - E200 for a Second hand unit on EBay, with nothing available new?
Witness - https://www.ebay.co.uk/itm/365440946110?_skw=BMW+K100+Tank+Sender&itmmeta=01KR8JQWC6HZVQYNWCQJ2HEJTF&hash=item5515fa4fbe:g:aVYAAOSwH8pnyD9p&itmprp=enc%3AAQALAAAA0GfYFPkwiKCW4ZNSs2u11xBVaOnSW4k7Nt%2FbGx0585n13htWlVxGVyMjHZyoygkjc35K%2FqX0PPKE%2FXeuXOu9qXeHuSuLsAQodilaGVdmBqXbS%2F2tqFGSsRIMUYIexemocFEC9fD2cTCDyvfu4Ro3T9%2FMD8Adp%2FyRzsnOtab2kMs2wDuAd30cBQvHlCgxRxvyMoyzNF5%2BydHd0oypeXBmWeLkkoOE7oGF%2B6IV%2FeEgtHON9MMlF3kG40Nl%2BxgcdDw%2BFUSCrQl6%2FqpBt6wwO30hvaQ%3D%7Ctkp%3ABk9SR7DG35LCZw
Motoworks have no S/H units in stock - though I am going to ring them on Monday - any ideas?
PLEA - Anyone in the UK have one for sale - I will post a Wanted Ad... meanwhile pictures of the mess I found inside attached...
I'm booked on a Charity Bike ride next Sunday for Mens Health in the UK and wanted to use this Bike, rather than my R45 Boxer - which is a little underpowered 2 up.
The K75C is of course 40 years old, so doing this is a must anyway to give it the next decade of running... so I'm replacing everything...
As you can see it's a wonder it did 300 miles for me...
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The MBdotCOM Community Center / Re: K Bikes in Pop Culture
« Last post by daveson on May 09, 2026, 07:38:03 PM »
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The MBdotCOM Community Center / Re: K Bikes in Pop Culture
« Last post by daveson on May 09, 2026, 08:02:54 AM »A spin-off from the underbelly series, The Underbelly Files: Tell Them Lucifer Was Here. The opening scene.
https://youtu.be/yoNDEUnC2l4?si=h8tvcWVDd--eJ7lo
https://youtu.be/yoNDEUnC2l4?si=h8tvcWVDd--eJ7lo