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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: pinhead on March 24, 2022, 05:39:36 PM

Title: General question on common major repairs as the miles on a K bike go up
Post by: pinhead on March 24, 2022, 05:39:36 PM: I have a 1985 BMW KRT100 and it has about 85000 miles on it. Was thinking of doing some long distance touring and wondered if there are commonalities of certain repairs (like the fuel pump maybe) as the mileage gets higher on these great bikes. So far it has never failed me over the 50,000 miles I have rode it. Any thoughts or observations out there?
Title: Re: General question on common major repairs as the miles on a K bike go up
Post by: Laitch on March 24, 2022, 06:57:48 PM: To start this off:

The transmission input splines and the final drive pinion shaft splines get lubricated periodically. When is the last time you did those chores? Adjust the clutch free play. Bleeding brakes two times a year is good maintenance. Check brake pads and rotor thickness to spec. Clean the ground point on the frame backbone beneath the tank and all terminals attached to it, if that hasn't been done. Replace the fuel filter if there are tens of thousands of miles on it and check the integrity of the fuel lines. Replace the z-tube if you don't know its age. Clean and lube the throttle cable gears. Replace all the fuses.
Title: Re: General question on common major repairs as the miles on a K bike go up
Post by: The Mighty Gryphon on March 24, 2022, 07:15:31 PM: Clean all the electrical connections with Deoxit, flush the radiator inside and out(there can be a lot of bugs blocking the airflow), lube the clutch splines every 3-4 years, check valve clearance every 3-4 years, run two tanks with a half bottle of Techron in each through the injectors once a year.

Change transmission and final drive oil every two years as well as the coolant(60%water 40% coolant). Drain and fill the forks every two years as well.

Once a year, take an hour and check the torque on all the drive train and fork bolts and screws. It wouldn't hurt to put a little copper anti-seize in the threads, either if you aren't sure they have it.

It goes without saying that keeping the bike clean helps keep it reliable.
Title: Re: General question on common major repairs as the miles on a K bike go up
Post by: Chaos on March 24, 2022, 07:36:48 PM: Old bikes (and cars) seem to fail in unexpected ways. I'd suspect anything rubber or electrical, hydraulic or mechanical. And I'm sure I'm forgetting something.
Title: Re: General question on common major repairs as the miles on a K bike go up
Post by: frankenduck on March 24, 2022, 09:11:09 PM: It should still be very reliable at 85K. The final drive 1985 Z16 splines are much longer lasting than the later Z20 splines.

Just ride. Worrying about what might fail is just wasted negative emotion.

The four most important things to carry:

1) Spare throttle cable
2) Spare clutch cable
3) A roll of Rescue Tape
4) Emergency TP

A tire repair kit isn't a bad idea either.
Title: Re: General question on common major repairs as the miles on a K bike go up
Post by: pinhead on March 25, 2022, 03:18:05 PM: Yes I do the splines every time I replace the rear tire which I just completed yesterday. Was surprised to see them all still well lubricated with the black grease I used. Apparently has great sticking potential. called Coastal premium moly grease. Changed and flushed coolant, checked trans and differential. lubed throttle, and of course, engine oil change. Did a brake fluid change a few years ago. How long does a fuel pump last on these bikes? I guess I will start with short trips under 500 miles Rt total and see how it goes. The damn thing just keeps running beautifully! I don't understand why you can still buy these so cheaply.
Title: Re: General question on common major repairs as the miles on a K bike go up
Post by: frankenduck on March 25, 2022, 03:26:23 PM: Fuel pumps usually don't fail unless the bike sits and the gas in the tank absorbs moisture from the air.

If it's running well now then there is no need to worry about it.
Title: Re: General question on common major repairs as the miles on a K bike go up
Post by: Chaos on March 25, 2022, 06:01:40 PM: I've still on my original fuel pump, 35 years and 200K +
Title: Re: General question on common major repairs as the miles on a K bike go up
Post by: Laitch on March 25, 2022, 07:11:29 PM: Quote from: frankenduck on March 25, 2022, 03:26:23 PM
If it's running well now then there is no need to worry about it.
Worry is pointless anyway no matter its object. It just creases your face, churns your guts and makes you a less likely copulation opportunity—if that's important. :laughing4-giggles:
Title: Re: General question on common major repairs as the miles on a K bike go up
Post by: The Mighty Gryphon on March 25, 2022, 10:51:42 PM: Quote from: pinhead on March 25, 2022, 03:18:05 PM
Did a brake fluid change a few years ago.

For the moderate time and cost involved, you should be doing it every year. Brake parts aren't cheap, especially front brake master cylinders. DOT 4 is only a couple bucks.
Title: Re: General question on common major repairs as the miles on a K bike go up
Post by: Scott_ on March 26, 2022, 08:58:28 AM: Note on the cooling system flush, when you refill, use DISTILLED water.
You will get much less mineral buildup in the internal passageways and water pump impeller.
Also I agree with MG, brake fluid flush/change every year(2 at the most if you live in a drier climate).

At the age the bike is now, there shouldn't be any original hoses(brake lines, fuel lines, vacuum lines) remaining... They should have been replace by now.