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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: dantheman1956 on January 26, 2013, 06:00:13 PM

Title: 93 K75s won't start
Post by: dantheman1956 on January 26, 2013, 06:00:13 PM
Does the clutch switch have anything to do with the fuel injection system? The bike turns over .
Title: Re: 93 K75s won't start
Post by: Inge K. on January 26, 2013, 06:13:05 PM
The clutch switch just cuts the power to the starter button.
To get the starter to turn, you must either select neutral or pull the clutch.

Inge K.
Title: Re: 93 K75s won't start
Post by: K75RT Keith on January 27, 2013, 01:16:32 PM
Would you give some history about the problem please. 
Is this a new issue or, have you had starting problems in the past? 
Have you recently done work or, had work done? 
Has it been sitting for a long time?
   
Title: Re: 93 K75s won't start
Post by: dantheman1956 on January 28, 2013, 11:17:41 AM
Thanks for the feedback. Here is some history on the bike:
I bought it from a guy at a garage sale for $500. He road it daily for five years to work. One day it didn't start so he road his other bike. He put a new fuel pump, fuel filter and plugs. Still didn't start.
That was 2007. Here is what I have done:
Checked for spark – good.
jumped fuel pump with 12v and it ran. Didn't start.
Fuel pressure is 36 psi and  holds 32 psi for 5 minutes plus.
I swapped ABS relay(n/c) with the fuel pump relay(n/o) and pump ran. Wouldn't start.
I sprayed starting fluid into intake. It started and stayed running as long as I continued to spray.
I bought a used Hall Effect sensor on eBay and installed it. No luck.
At this point I am assuming that it is either the ignition control unit or the fuel injection control unit.
I have checked every connection and most had dielectric grease and those that didn't, I greased.
Any help would be appreciated.
Title: Re: 93 K75s won't start
Post by: frankenduck on January 28, 2013, 11:31:09 AM
Did you get the FIs rehab'd?  They were left with gas in them for quite a few years.  That gas turns to varnish and clogs them.

Getting Fuel Injectors Reconditioned (http://www.motobrick.com/index.php?topic=1064.0)
Title: Re: 93 K75s won't start
Post by: dantheman1956 on January 28, 2013, 06:40:13 PM
I will send them to Mr Injector after I figure out the fuel pump problem. When I press the start button the starter work, but the pump does not run. As noted earlier I can jump it.
I will see if I am getting power from the start button on pin#6 at the ignition control module.
Any other suggestions would be great.
Title: Re: 93 K75s won't start
Post by: K75RT Keith on February 02, 2013, 04:14:40 PM
Sounds like the FI brain.  Check the connector first and clean the contacts whit spray contact cleaner and let dry.  If it runs when you sprayed starting fluid, then it isn't the hall sensor.   You need 3 things to run.  Fuel, Spark, Air  Sounds like you got spark.  Air is there if it ran.  That said, I would replace the air filter on principal. I would check the fuel pump connector and clean the contacts then replace the relay with a new one. (not used but thats me) check the sock on the pump, replace the fuel filter and while the injectors are our, clean the fuel rail with carb cleaner   
Title: Re: 93 K75s won't start
Post by: dantheman1956 on April 16, 2013, 09:57:12 PM
I figured out that it was the fuel pump relay. I swapped it with one of the other relays and the pump runs when the starter button is pressed. I had my injectors cleaned by Mr Injector. Just put them in and she started up. Rough idle and can't accelerate. It dies when i barely crank the throttle. I let it warm up to operating temp. Cooling fan came on and off. Still bad. Then the bike stopped running. The battery went dead. I am charging it now.
Any suggestions?
Title: Re: 93 K75s won't start
Post by: JamesInCA on April 17, 2013, 01:48:58 PM
Have you replaced the 2007 fuel filter?  How about the rubber vibration damper around the fuel pump? They degrade and drop rubber particles into the fuel, which can get sucked in and clog the filter.

Could also be excess air entry. Check all the rubber parts past the air flow meter -- the big elbow coming off the air filter box, the rubber and plastic around the throttle bodies, and, especially, the crankcase breather hose, just sort of above and behind the throttle bodies.

Check the rubber vacuum hose from the rear-most throttle body to the FPR, and the little rubber caps that seal the same nipple on the other throttle bodies.

Also make sure the oil filler cap is on tightly and its o-ring is properly sealing. That's also an air entry point if not sealing.
Title: Re: 93 K75s won't start
Post by: dantheman1956 on April 17, 2013, 08:33:29 PM
I figured it out. The Mass Air Flow butterfly is stuck. Looks like it is crooked in there. It is very hard to move. Probably happened when I had a huge backfire when using starting fluid awhile back. Does it come apart so I can line up the pivot points again?
Title: Re: 93 K75s won't start
Post by: mystic red on April 17, 2013, 09:39:33 PM
Quote
I sprayed starting fluid into intake. It started and stayed running as long as I continued to spray.

Sorry I missed this but it was obviously nothing electrical if this was the case. Glad you got it sorted!
Title: Re: 93 K75s won't start
Post by: dantheman1956 on April 27, 2013, 03:24:58 AM
Put the used MAF sensor from eBay($48) and she is running like a champ. Changed all the fluids,  new tires and road all day!
Title: Re: 93 K75s won't start
Post by: WayneDW on April 28, 2013, 07:48:53 AM
Put the used MAF sensor from eBay($48) and she is running like a champ. Changed all the fluids,  new tires and road all day!
There ya go!  :clap: