1995 K75 barely runs at idle, dies when throttle is applied....

[avandyke]

Hey everyone,

First post! Thanks to everyone for the great information on this site, but I finally have to ask a question myself.

I'm having a hard time getting my K75 to run well. If I start the engine with no "choke", and really crank the starter, I can get the engine running at idle for about a thirty seconds or so, then it will die. If I apply any throttle, it dies. If I increase the "choke", it dies.

I've verified that I have fuel, air, and spark, so I'm suspicious of the mixture. I've looked around for ways to test the mixture, but haven't been able to find anything yet. Does anyone have any suggestions on what my next few steps should be to ensure I am getting the right mixture into the engine?


Items done already:

Check FI computer connection
Check 4 pin connection under tank
Replace spark plugs
Test and clean injectors
Replace fuel hoses
Replace fuel filter
Replace old fuel with new (this was my first suspicion, so I did it just to make sure)
Check air filter and verify air is getting to cylinders by testing with starter fluid
Checked for air leaks at throttle body by testing with starter fluid
Check throttle position sensor
Check crankcase ventilation hose near TPS (could use replacing, but is still airtight)
Check air filter and box



Thanks in advance!

[Laitch]

Welcome.

Please put the year of the bike in your profile too. How long have you had the bike? How many miles on the odometer. Have you tried the No Start procedures in the Workshop?

[The Dude]

There is a "no start"flowchart,somewhere on this site.go through that.Too complex an issue to diagnose with out all the info.Fortunately myK75has not missed a beat in 30 years of solid riding so I'd be hopeless sorting that out.By the way,the "choke"is just an idle speed increaser.
All the best.

[avandyke]

Can't believe I forgot the year, my apologies. I even reminded myself to do it, then promptly forgot. *facepalm*

As for the no start board, I hadn't looked at it, since it does start, then just has issues spinning up/running for longer than 30 seconds. However, I did actually check the connection to the injector computer, and the four pin under the tank, just to make sure. And the starter engine is just fine, though I will run it in reverse a bit to clean it up for the future.

[The Mighty Gryphon]

Right behind the throttle position sensor is a short zig zag hose that goes from the engine block to the air manifold.  Remove it and check carefully for cracks, especially near the clamps.

[Laitch]

However, I did actually check the connection to the injector computer, and the four pin under the tank, just to make sure. And the starter engine is just fine, though I will run it in reverse a bit to clean it up for the future.

It's always helpful to the readers if you list everything you've done already so we don't strain our keyboarding muscles in futility. You should be keeping an updated list.

[avandyke]

Okay, I've modified the original post to a more checklist-y format. Should be easier to read.

[K1300S]

You need to go through the entire tune up procedure.  Tb balance, fast idle adjust, idle adjust, mixture adjust.....and check for vacuum leaks.    Once done with all, report back.

Process is detailed in several threads, and in your service manuals.

[avandyke]

The fast idle adjust was recently done. I'll do a TB balance and mixture adjust next. Thanks for the next steps.

[Laitch]

If it only runs for thirty second intervals it will be difficult to warm it sufficiently for TB balancing. It's getting fuel but maybe not enough fuel so the pump output should be suspected, too.

[avandyke]

Okay, that makes sense. I'll check the fuel pressure to ensure the engine isn't getting flooded. Thank you!

[The Mighty Gryphon]

Which hose?

[JimVonBaden]

Right behind the throttle position sensor is a short zig zag hose that goes from the engine block to the air manifold.  Remove it and check carefully for cracks, especially near the clamps.

That was it exactly. Broke off pipe shoved on and it ran perfectly. I ordered a replacement from EuroMoto Electric.

[JimVonBaden]

That was it exactly. Broke off pipe shoved on and it ran perfectly. I ordered a replacement from EuroMoto Electric.

Installed and ran great. Even the TB sync was perfect!