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post #1 of 11 Old Sep 14th, 2008, 12:26 am Thread Starter
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85 K100rt

I just had a co-worker drop off his 85K100RT, I told him I'd take a look at it and see if I could get it running and road worthy....This bike is a basket case.
His son dumped it a few years ago and took out the RH crash bar and tore up the lower fairing. That isn't so bad in itself. What is bad is that there is NO spring back and no resistance when the front brake lever is pulled, it just flops around. He dropped off a Clymer manual kinda for the bike (it covers 83-89 K100's 2 valve and his bike is a 4 valve) From what I've read so far on the brak system, if the brake lever is bad or master cylinder on the handlebar is bad, you have to replace the entire throttle grip, master cylinder, switches and all as a unit (from what I can see he does not have the "newer" ABS systerm).
Once I get power to the bike I'm going to attempt to bleed the brakes and see what happens.
The question of the minute is...does anyone have any ideas why the brake lever is flopping around and is it fixable without having to replace that entire grip assembly? Of sourse replacing the whole assembly may fix the throttle staying where ever you left it when you took your hand off.

Thanks for any insights.
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post #2 of 11 Old Sep 14th, 2008, 5:29 am
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Re: 85 K100rt

Ken

Is the master cylnder plunger (part 23 here broken or it is missing? Sounds like a nice project.

Regards

Graham Wintersgill
On the bonnnie bonnie banks of Loch Lomond

2001 K1200LT

1995 K75RT now deceased
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post #3 of 11 Old Sep 14th, 2008, 10:51 am Thread Starter
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Re: 85 K100rt

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Originally Posted by grahamw
Ken

Is the master cylnder plunger (part 23 here broken or it is missing? Sounds like a nice project.

Regards
If I am looking at it right (I removed the lever) it appears that the plunger is fully compressed and stuck. All I see in there is a black rubber piece, I assume that is the cover over the plunger? Or maybe it is the rubber end on the plunger?
I was hoping that it was just out of fluid and that was what was causing it to stay bottomed out...no such luck, the master cylinder is full.
I finally got the battery charged enough to power everything up..the fuel pump isn't running
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post #4 of 11 Old Sep 15th, 2008, 7:00 am
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Re: 85 K100rt

85 K100 does NOT have ABS unless someone changed the brake system.

Sounds like something in the master cylinder is broken or stuck. Right side crash he may have hit the front brake also.

If it has been sitting idle for some time may be cheaper and easier to just replace the master cylinder.

Other things to consider if the bike has been sitting:

Gummed up fuel pump, injectors and pressure regulator.

Good luck

Roy

Roy Gregersen

Ride Slow, Ride Fast, Always Ride Safe
85 K100RT sold
02 LTC DOA 9/21/14
12 R1200RT
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post #5 of 11 Old Sep 15th, 2008, 7:20 am
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Re: 85 K100rt

Ken

If I remember correctly the end of the plunger is metal and the plunger is held in by an internal circlip. If it was stuck compressed then I imagine the brakes would be jammed on. Is the circlip still there? Do you have tihin enough pliers to grab what is visible and try and pull. I think I have an old plunger at home if photos of it would help.

The fuel pump is in the tank - check supply and try it off the bike?

Regards

Graham Wintersgill
On the bonnnie bonnie banks of Loch Lomond

2001 K1200LT

1995 K75RT now deceased
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post #6 of 11 Old Sep 15th, 2008, 8:51 am
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Re: 85 K100rt

Just a thought.

This bike has no collector desirability. Parts are expensive. It has been neglected and sounds like it is in fairly poor shape. It is 24 years old.

Is it worth the effort?

Bob Chapman
Virginia
2000 K12LT
1978 CB750A (Automatic Cafe Racer Ratbike)
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post #7 of 11 Old Sep 16th, 2008, 1:35 am Thread Starter
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Re: 85 K100rt

Quote:
Originally Posted by bigbear
85 K100 does NOT have ABS unless someone changed the brake system.

Sounds like something in the master cylinder is broken or stuck. Right side crash he may have hit the front brake also.

If it has been sitting idle for some time may be cheaper and easier to just replace the master cylinder.

Other things to consider if the bike has been sitting:

Gummed up fuel pump, injectors and pressure regulator.

Good luck

Roy
Yes, the piston is stuck in the M/C but supposedly not from the crash. He claims it was working until a year or so ago.
I've already pulled the pump...it is locked up with corrosion, all of the rubber parts in the tank are dissolved and just a black gummy mess.
I suspect the injectors are gone as well, and the regulator. The regulator I may be able to save by soaking it in naptha. But if not E bay is always an alternative.

About the ABS....The book says it doesn't have ABS but on the instrument panel it has the ! in the triangle which according to the book is for the ABS along with a tiny light right above the clock, which it has.
Also, it is supposed to be a 2 valve engine but the valve cover has the 2 humps just like the LT's twin cam engine, it looks nothing like the 2 valve engine's valve cover...maybe someone transplanted the engine???

On the injectors...does anyone know the flow rating of the K100's injectors? I have a set of eight 19# bosch/Accel injectors sitting around. I can't imagine they would be larger than that.

Last edited by Morley; Sep 16th, 2008 at 1:43 am.
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post #8 of 11 Old Sep 16th, 2008, 7:36 am
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Re: 85 K100rt

Quote:
Originally Posted by Morley
Yes, the piston is stuck in the M/C but supposedly not from the crash. He claims it was working until a year or so ago.
I've already pulled the pump...it is locked up with corrosion, all of the rubber parts in the tank are dissolved and just a black gummy mess.
I suspect the injectors are gone as well, and the regulator. The regulator I may be able to save by soaking it in naptha. But if not E bay is always an alternative.

About the ABS....The book says it doesn't have ABS but on the instrument panel it has the ! in the triangle which according to the book is for the ABS along with a tiny light right above the clock, which it has.
Also, it is supposed to be a 2 valve engine but the valve cover has the 2 humps just like the LT's twin cam engine, it looks nothing like the 2 valve engine's valve cover...maybe someone transplanted the engine???
The red light with the "!" symbol is for warning that the rear brake light bulb is burned out or not functional. When you first start the bike you must apply both brakes and then this light will go off.

2-valve Vs 4-valve: Both engines have two cams and the valve covers do look similar. I guess you will know for sure when you pull the valve cover off. 4-valves per cam easy valve adjustment. 8 valves per cam more difficult valve adjustment.

Injectors: http://www.ibmwr.org

there is a section on this site listing alternative parts for these models.


May want to check all the vacuum hoses, fuel lines, throttle body mounts, coolant lines, etc. for cracks. These parts can add up to over $1,000.

Depending on when or if the water/oil pump seals have ever been replaced this can also be an expensive item. I think around $350 or more. On the 85 K it usually cheaper to replace the entire pump assembly Vs attempting a rebuild since most of the parts have been superseded and they don't interchange well.

Roy

Roy Gregersen

Ride Slow, Ride Fast, Always Ride Safe
85 K100RT sold
02 LTC DOA 9/21/14
12 R1200RT
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post #9 of 11 Old Sep 16th, 2008, 12:04 pm Thread Starter
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Re: 85 K100rt

Quote:
Originally Posted by bigbear
2-valve Vs 4-valve: Both engines have two cams and the valve covers do look similar. I guess you will know for sure when you pull the valve cover off. 4-valves per cam easy valve adjustment. 8 valves per cam more difficult valve adjustment.

Injectors: http://www.ibmwr.org

there is a section on this site listing alternative parts for these models.

That explains the valve cover...but why do some not have the twin hump cover? Ah well, no matter. Once it is off we'll see.
I've been to ibmwr and looked around at their alternate patrs lists and I've found a few others as well. I was just hoping to find something that stated the flow rating on the K100's injectors. With the flow rating in hand there are several places to look for injectors, since all multi port injectors are the same physical size (more or less) it gives more & better options.

I'm planning on taking all of the fiberglass off the bike and stripping it naked so I can fully assess what all is going to need replacement. Once I have that I just need to look up parts & prices and let him know what it is going to run for parts. All he's told me so far is he doesn't want to spend 2k in parts for it...that could leave a lot of room for restoring.
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post #10 of 11 Old Sep 16th, 2008, 12:07 pm Thread Starter
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Re: 85 K100rt

Quote:
Originally Posted by Bob204bc
Just a thought.

This bike has no collector desirability. Parts are expensive. It has been neglected and sounds like it is in fairly poor shape. It is 24 years old.

Is it worth the effort?
the "effort" isn't the worry...its the cost of parts that is going to be the limiting factor. If he can do it for less than the value of the bike in good running order, then it is worth it. If not I'll tell him to just cut his losses, part it out on E bay and buy another one.
Since the engine turns over and all the electrics seem to be in working order the major stoppers are taken care of.
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post #11 of 11 Old Sep 16th, 2008, 1:25 pm
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Re: 85 K100rt

Quote:
Originally Posted by Morley
the "effort" isn't the worry...its the cost of parts that is going to be the limiting factor. If he can do it for less than the value of the bike in good running order, then it is worth it. If not I'll tell him to just cut his losses, part it out on E bay and buy another one.
Since the engine turns over and all the electrics seem to be in working order the major stoppers are taken care of.
You're right. Checking out the electrics is a good first move on a bike of this age and type.

I really wonder what the current models with their massive wire bundle will be like in 20 years......

Bob Chapman
Virginia
2000 K12LT
1978 CB750A (Automatic Cafe Racer Ratbike)
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