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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: redwolfstudio on January 11, 2022, 07:09:10 AM

Title: Alternator rubber blocks,
Post by: redwolfstudio on January 11, 2022, 07:09:10 AM
Here’a picture of my alternator and these rubber blocks look really worn to me.
Is that of any concerns or should I replace them.
And while its out would you recommend I take the thing apart and clean everything?
The previous owners assured me the bike started,3-4 years ago.
Many thanx all!
Title: Re: Alternator rubber blocks,
Post by: The Mighty Gryphon on January 11, 2022, 08:56:17 AM
Those "Monkey Knutz" don't look too bad.  I would probably use them.

No reason not to clean up the alternator.  I don't think it has enough km to need any rebuilding, but you might want to take a peek at the brushes.  You could take it to an automotive electrical shop to have the electrical output and the bearings checked as long as you have everything apart.

When you put it back on the bike, put some liquid soap on the monkey knutz to help them slide onto the drive dog on the engine.  It's one of the hardest jobs in assembling an engine.
 
Title: Re: Alternator rubber blocks,
Post by: frankenduck on January 12, 2022, 11:56:06 PM
The monkey nuts will let you know (start making noise) when they need to be replaced.
Title: Re: Alternator rubber blocks,
Post by: redwolfstudio on January 13, 2022, 03:35:32 AM
Great! Thanx for your answers:-)
Title: Re: Alternator rubber blocks,
Post by: Martin on January 13, 2022, 04:18:35 PM
I just replaced mine at 180,000 Km's I could have left them, but while I had the alternator off I thought that I'd replace them. I had no trouble fitting them, I used a smear of silicone grease to hold them in place and lube between the blocks. I marked the alternator cup with a black marker where the gaps were in the blocks. I then rotated the engine so I had a good view of the vanes. I aligned the mark with the vane on the engine and on it went first go.
Regards Martin.
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Title: Re: Alternator rubber blocks,
Post by: The Mighty Gryphon on January 13, 2022, 05:02:44 PM
Martin, where are those knutz from?  They look a lot better than the official BMW version.

Also, does anyone know of a service limit on those damn things?  Seems there should be a spec on the gap for the drive dog vanes.  Hard to believe the Teutonic engineers don't have one for those parts.
Title: Re: Alternator rubber blocks,
Post by: Martin on January 13, 2022, 05:53:40 PM
Gryph they came from Motorworks UK I don't know what the predecessors looked like but as stated a piece of pie to fit. I've had them in stock and I believe they were cheaper when I bought them with a spare still unused cup. Seeing as though the first ones did 180,000 K's I believe these will outlast me.
Regards Martin.

Alternator cush drive rubber 3 required | ELA64877
Fits K75, K75S, K75C, K75RT, K100, K100RT, K100LT, K100RS, K100RS 16v... Show All...

Associated BMW part: 12311464877 (12 31 1 464 877)
This is an upgrade part with better quality rubber and more precise fit than the originals extending its service life.   £11.16 INC VAT
£9.30 EX VAT


Title: Re: Alternator rubber blocks,
Post by: redwolfstudio on January 14, 2022, 04:25:25 AM
Great, just ordered a bunch of parts from motorworks.uk, think I’ll add those too.
Also, I have a stupid question for all here. Am trying to open my alternator and its proving a lot tighter than I expected. To the point where am confused which way to squeeze or pull away??
See my pic:-) thanx for your input!
Title: Re: Alternator rubber blocks,
Post by: Martin on January 14, 2022, 02:04:43 PM
Hold the shaft with the Allen key and undo the nut counter clockwise. The long Phillips head screws holding the two halves of the alternator body together can be hard to remove. Spray the threaded part with a good penetrant not WD40 and allow it to penetrate. Then supporting the alternator so it's stable use an impact screwdriver  to loosen the screws.
Regards Martin.
Title: Re: Alternator rubber blocks,
Post by: redwolfstudio on January 14, 2022, 03:54:47 PM
Oh crap! What’s wrong with WD40?
Title: Re: Alternator rubber blocks,
Post by: Martin on January 14, 2022, 04:04:31 PM
WD40 is not a rust penetrant it's a water displacement fluid.
"WD-40" is abbreviated from the term "Water Displacement, 40th formula", suggesting it was the result of the 40th attempt to create the product. The spray, composed of various hydrocarbons, was originally designed to be used by Convair to protect the outer skin of the Atlas missile from rust and corrosion.
Regards Martin.
Title: Re: Alternator rubber blocks,
Post by: redwolfstudio on January 14, 2022, 04:09:12 PM
Thanx for the info! What is recommended for K75 work? 
Title: Re: Alternator rubber blocks,
Post by: Martin on January 14, 2022, 05:05:43 PM
I've got know idea what's available in Sweden. Try going online for recommendations.https://www.carcareninja.com/best-penetrating-oil-reviews/
Regards Martin.
Title: Re: Alternator rubber blocks,
Post by: The Mighty Gryphon on January 14, 2022, 05:42:31 PM
Make your own penetrating oil. 

50/50 mix of acetone and any automatic transmission fluid(ATF).
Title: Re: Alternator rubber blocks,
Post by: Past-my-Prime on January 14, 2022, 10:59:21 PM
Can you get PB Blaster?
Title: Re: Alternator rubber blocks,
Post by: redwolfstudio on January 17, 2022, 06:07:13 AM
Thanx very much for all your replies!
Title: Re: Alternator rubber blocks,
Post by: frankenduck on January 18, 2022, 01:34:33 AM
WD40 is not a rust penetrant it's a water displacement fluid.
"WD-40" is abbreviated from the term "Water Displacement, 40th formula", suggesting it was the result of the 40th attempt to create the product. The spray, composed of various hydrocarbons, was originally designed to be used by Convair to protect the outer skin of the Atlas missile from rust and corrosion.
Regards Martin.

Shame on you.  Using The Internet to spread actual truth.
Title: Re: Alternator rubber blocks,
Post by: Martin on January 18, 2022, 04:56:14 PM
Duck sincere thanks for pointing out the error of my ways. I know not what I doest and I will humbly seek forgiveness' from the Gods of Vahalla. I will spend the day in contemplation and penance and hopefully amend my evil ways.
Regards a chastised Martin.