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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: woodgeek on February 10, 2018, 11:53:33 PM

Title: Rebuild questions, probably first of many
Post by: woodgeek on February 10, 2018, 11:53:33 PM
So, I’m tearing off everything relevant to the intake above the engine block to begin a rebuild.

First some thoughts. In thirty years of riding, this is my first fuel injected motorcycle, so I’m a little nervous. Working on this engine is like working on a car—which it sort of is since BMW sourced it from a car.

Questions: if the FPR is a Bosch unit, it’s safe to assume it’s been replaced at some point in its lifetime. I’m hoping it’s good as I can’t test it. I’d like to relocate the FPR to a location above the coils. Has this been by anyone before?

I was researching the prices on radiator hoses—crazy $$$?! If they’re not cracked, is there any sense in replacing them? Even though the bike hasn’t been titled in 18 years, the coolant is still clean.

There’s 50k on the bike so out of curiosity I pulled the starter to clean it. It was very clean inside. I’m beginning to think this was a well maintained BMW until it was mothballed.


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Title: Re: Rebuild questions, probably first of many
Post by: Laitch on February 11, 2018, 12:02:04 AM
I was researching the prices on radiator hoses—crazy $$$?!
You were? (http://www.motobrick.com/index.php/topic,1563.msg91146.html#msg91146)
Title: Rebuild questions, probably first of many
Post by: woodgeek on February 11, 2018, 12:08:11 AM
You were? (http://www.motobrick.com/index.php/topic,1563.msg91146.html#msg91146)
Thanks Laitch.  I knew I should have checked the alternate parts page. Rockauto is becoming my new best friend.[emoji4]
Title: Re: Rebuild questions, probably first of many
Post by: The Mighty Gryphon on February 11, 2018, 10:01:17 AM
Are you sure you need to replace your hoses?  I now have four 90's vintage bricks crammed in the garage, and can confidently say that the parts least likely to show the age of the bike are the coolant hoses.

Even if you have a damaged hose that demands replacement, I would not hesitate to take a chance on a used part from the interweb.
Title: Re: Rebuild questions, probably first of many
Post by: woodgeek on February 11, 2018, 10:51:45 AM
Are you sure you need to replace your hoses?  I now have four 90's vintage bricks crammed in the garage, and can confidently say that the parts least likely to show the age of the bike are the coolant hoses.
That was certainly part of my question. I don’t want to replace them if it’s unnecessary. I pulled three of them off to make room to work on the intake. They don’t feel brittle and they don’t show any cracks. I’ll probably use some 311 UV protectant on them to clean them up and call it good.
Title: Re: Rebuild questions, probably first of many
Post by: F14CRAZY on February 11, 2018, 11:02:43 AM
The hoses on my K75 are original according to the dates stamped on them. They still look and feel fine. I wouldn't hesitate to run to U-Tall with them
Title: Re: Rebuild questions, probably first of many
Post by: rbm on February 11, 2018, 11:58:03 AM
Rubber parts can be rejuvenated with essential oil of wintergreen.  This combined with IPA, soak the part will restore the flexibility of the material.

http://v4musclebike.com/forums/showthread.php?t=13477

Wintergreen oil is available at any health food boutique.
Title: Re: Rebuild questions, probably first of many
Post by: The Mighty Gryphon on February 11, 2018, 02:21:03 PM
IMO, unless the parts have hardened up to the point where they are getting brittle I would avoid using any applications to soften them up.  These compounds have solvents in them that will eventually break down and remove the plasticizers that were compounded into the part when it was manufactured.  This will significantly reduce the life expectancy of good parts.