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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: beemerphile on October 26, 2016, 05:48:49 PM

Title: Unfixable K1100?
Post by: beemerphile on October 26, 2016, 05:48:49 PM
I went to a local airhead specialist shop today to get some dirt bike tires mounted and I told the owner whom I have known for 35 years that I had recently acquired a K11RS.  He began a tale of one that they have been unable to fix for four years.  It idles fine, but when you give it throttle, it dies.  He says they have checked everything and that issues like this with bricks are common.  He is convinced that it is an electrical controls problem.

I haven't noticed this in my readings.  It seems that most things have been fixable using normal techniques and shared knowledge.  Anything to this, or is it misinformed chatter?

thx
Title: Re: Unfixable K1100?
Post by: Bill on October 26, 2016, 06:31:38 PM
Sure sounds like a challenge !  If all else is good maybe the bike in question can be had for a good[bargain] price ..... :dunno
Title: Re: Unfixable K1100?
Post by: Chaos on October 26, 2016, 07:05:15 PM
I'd dismiss that as the demented ramblings of an airhead lover
Title: Re: Unfixable K1100?
Post by: riots100 on October 26, 2016, 07:26:01 PM
I'd say that issues like this with bricks are not common.  I would be skeptical of an electrical controls issue.  Too many things it could be beforehand.
Title: Re: Unfixable K1100?
Post by: kennybobby on October 26, 2016, 08:22:40 PM
Well here's another opinion for ya to consider...

Since the mid 80's i have repaired hundreds of failed automotive Motronic units.  The most common issue is cracked solder joints on the big transistors used for the ignition and injection control. 

In the recent years i have found the same problem in Jetronic units used on the K75.  From my experience controllers are quite reliable, but they can and do fail.

The troubleshooting flowchart seeks to rule out all the mechanical culprits first before pointing to a controller failure and that seems to be a good approach for the majority of cases seen in the forums.
Title: Re: Unfixable K1100?
Post by: beemerphile on October 26, 2016, 08:40:10 PM
They swapped in a known good Motronic.  Funny my spellchecker wants to replace Motronic with "moronic".

Possible break in a harness or connector?  TPS sensor, as it idles ok but dies with throttle? They claim to have changed fuel pump and lines.  Buying it from them for a song is a good thought.
Title: Re: Unfixable K1100?
Post by: kennybobby on October 26, 2016, 09:06:11 PM
If it has set up for any time, the injectors are likely clogged and need to be cleaned.  This is consistent with the symptoms of stalling when the butterfly valves are opened letting in more air than the dirty injectors can pass. 

The throttle is completely closed at idle and only a tiny amount of air gets to the motor, so a tiny piss of fuel will let it idle.  The entire fuel system must be checked and cleaned and verified from beginning to end--you can't cherry pick certain parts and call it done. 

Maybe if you let him know that you might be interested in taking a crack at it when he's done messing with it...
Title: Re: Unfixable K1100?
Post by: beemerphile on October 26, 2016, 09:32:43 PM
Maybe if you let him know that you might be interested in taking a crack at it when he's done messing with it...

Oh, I think he is very done messing with it.  I'm warming up to the idea of buying it as a parts bike if I can get it insanely cheap.
Title: Re: Unfixable K1100?
Post by: kennybobby on October 27, 2016, 01:58:48 AM
Oh, so that's why my garage is so crowded--buying those cheap parts bikes
Title: Re: Unfixable K1100?
Post by: TrueAce on November 01, 2016, 09:53:47 PM
If you clean up the fuel delivery system, it will run. Fuel starvation is causing the faulted.
Title: Re: Unfixable K1100?
Post by: beemerphile on November 02, 2016, 06:15:24 AM
If you clean up the fuel delivery system, it will run. Fuel starvation is causing the faulted.

That would be nice.  I can do that.  I'm going out there today and wll try to buy it for $500 as a parts bike.  If I get it, I will try to get it running before I dismantle it for parts.  The guy ought to be pretty sick of it by now.
Title: Re: Unfixable K1100?
Post by: TX brick on November 02, 2016, 07:00:42 AM
A bad airflow meter will not allow the RPMs to go above idle.
Title: Re: Unfixable K1100?
Post by: Inge K. on November 02, 2016, 08:21:52 AM
A bad airflow meter will not allow the RPMs to go above idle.

K11's doesn't have a airflow meter.
Title: Re: Unfixable K1100?
Post by: beemerphile on November 02, 2016, 09:49:18 AM
Turns out the machine was a dog for spares.  I don't want a parts bike that I have to recondition everything before I can use it.  I'll leave it for them to resolve as they wish.
Title: Re: Unfixable K1100?
Post by: Vespa no more on November 04, 2016, 01:26:04 AM
In situations like these...

some time ago, I was driving to work with a mate and at a big intersection was some poor bastard crouched down at the back of his old VW Beetle with the engine (hood?) lid up. I was running late but offered what help I had at hand and got my passenger to toss a box of matches to him with the words "This should fix it" before driving off.

Low act I know and maybe demoralising but had been itching to do it for years after my brother once got the same advice.

Normally I do stop and share the pain... help if I can.

Honest.
Title: Re: Unfixable K1100?
Post by: TrueAce on November 04, 2016, 01:51:25 AM
Confessions are good for the soul......
Title: Re: Unfixable K1100?
Post by: beemerphile on November 04, 2016, 06:30:47 AM
...I was running late but offered what help I had at hand and got my passenger to toss a box of matches to him with the words "This should fix it" before driving off.

Was that you?  ya feckin bastid.  turns out i was gonna take a cig break and didn't have a match. so thxalot!