95 K75 only idles normal when leaned to left side

[squirrel]

Hey gang! First post so be gentle.
I have a 95 K75 that idles (lopes) when upright. Kicker: goes, and stays normal ONLY when I lean the bike to the left.
I have scoured the internet looking for this, and nothing. Hope to find an answer.
Thanks!
BTW, the only vac hose that has not been changed is the fuel regulator hose due to inaccessibility.

[Elipten]

What happens when leaned right?

What has been changed out?

That hose is not vacuum, it is a fuel line.  There are no vacuum lines or very few that I can think of.

[Inge K.]

BTW, the only vac hose that has not been changed is the fuel regulator hose due to inaccessibility.

That hose is not vacuum, it is a fuel line.  There are no vacuum lines or very few that I can think of.

The only vacuum hose on a K75 is between the fuel pressure regulator (as squirrel says) and #3 thottle body.

[The Mighty Gryphon]

Does it smoke when you lean it over?  The only significant thing I can imagine changing when leaned to the left is that the oil will supposedly get to the cylinder bores "below" the pistons.  It will help the compression in a weak cylinder, and make the engine smoke.

How many miles?  How is the compression?

How much fuel in the tank? 

[squirrel]

Thanks for responding everyone.  I apologize for the delay; I am in Hawaii, so it is 0530.

More specifics:  ~42000 miles, fresh gas and plugs.  Lopes/erratic when upright and leaned to right.  Bike generally doesn't smoke, aside from startup when left on kickstand too long.

I have changed all rubber lines on bike except the fuel reg one listed. A year ago, my fuel pump seized up from accumulated water in my tank thanks to a clogged drain line on my gas tank lid.  Removed it cleaned it (reverse polarity off a car battery did the trick) re-installed.  Sounds constant when doing the lean over. Poor man's check of squeezing line nets the same feel/feedback in any position. New fuel filter also. Regular FI cleaner thought it too.

I agree with Gryphon, I thought it was oil moving up to compensate, but here is a kick: It will idle fine at random times.

I swear I am chasing a gremlin.  Baffled.

[johnny]

im betting on the under tank electric connector is whack... or not enough suspension fluid in the right fork...

j o

[squirrel]

Lol, I will check both Johnny!

I had compensated the rough idle by adjusting idle screw and then throttle position switch.

I even thought I had a cable that was binding on something causing rpms to climb, but nope.

I keep thinking this is a fuel thing, but i will check fuel pressure and compression...

If I can post a video, I will.

[Motorhobo]

Maybe one of your spark plug wires is failing and it's arcing sometimes, sometimes not -- when you say it's 'loping' are you sure all the cylinders are firing? If you have OEM wires, you're probably the only motobricker left in the universe who can make that claim...

[squirrel]

I went down that road too.  I have my original set as well as two more sets of used ones that have tested good. 

As for the lope, when i coast to a stop, the engine rpms slow, fairly evenly, then as i stop, sit for a second (all happening as I come to halt) the rpms drop and then it goes: (slow) rUMp rUMp rUMp, instead of the slow purr.  Acts like my old Virago when the carbs where acting up.

And yes, says the "rump"  :yes

[The Mighty Gryphon]

Idle...?  How is the balance of the throttle bodies?  Not sure how leaning would affect it, but balance does affect the idle.

[squirrel]

I haven't messed with throttle body links. I think I will do a vacuum test off the fuel rain tonight and see what happens. Then I will test voltage flow at plug to fuel pump, looking for spikes and drops. I MAY pull the injectors, but I really want new seats in hand first.
More to come...

[The Mighty Gryphon]

Not talking about the linkages, but the idle air screws.  Check this thread:

http://www.motobrick.com/index.php/topic,364.0.html

3 pages, lots of information and some dyi balancer gizmos.

[squirrel]

Very cool!
Thank you!

[squirrel]

So, check this out... Rode home with half choke because it does that thing below 1000 RPM. Sat I driveway and ran throttle to 3k and held it. Proceeded to watch bike draw down to 2k on its own, throttle un moved.
?
Fuel system or the air mix?

[Elipten]

Could an air leak from the manifolds or the connections to plenum chamber?  Have you tried the carb cleaner method?

[squirrel]

I have, with no results. I noticed they were aged/ cracky, but I tried other sprays too, NAD not change.

[TimTyler]

> Rode home with half choke because it does that thing below 1000 RPM.
> Sat I driveway and ran throttle to 3k and held it.
> Proceeded to watch bike draw down to 2k on its own, throttle un moved.

So this has nothing to do with "left leaning" then?

How are your exhaust valves? I'm guessing very, very tight.

[squirrel]

Seems different but I think it is related.
As for exhaust valves, I haven't checked them in about 3-4k miles.

I am going to reset/balance the idle air and then see where that takes me. Gotta get the vac tester first.

I appreciate the input. I am flummoxed by this... Acts like it has carbs.

[Scott_]

I'd recheck the valves, before you mess with the air balance.......

[pfls]

Leaning the bike to one side or the other (I can't remember which way for sure) will affect the mixture. I think it is a result of gravity on the flapper door in the mass air flow sensor. If I recall, this came to light when two different CO readings (side stand vs. center stand) were obtained on a bike while on a gas analyzer. My guess is you have air leaks resulting in a lean mixture. Leaning the bike richens the mixture enough to smooth it out. K75's also tend to backfire a lot when lean.

[kylemb]

Leaning the bike to one side or the other (I can't remember which way for sure) will affect the mixture. I think it is a result of gravity on the flapper door in the mass air flow sensor. If I recall, this came to light when two different CO readings (side stand vs. center stand) were obtained on a bike while on a gas analyzer. My guess is you have air leaks resulting in a lean mixture. Leaning the bike richens the mixture enough to smooth it out. K75's also tend to backfire a lot when lean.

i am sort of having the same issues with this myself... my bike was running rough, the lean of the bike was changing the idle, etc.
i just recently replaced my cracked throttle body inlets and it seems to really have helped the initial throttle response but the sluggishness still persists. (but the inlets definitely helped a ton!)

when i had the air box off i noticed that the flap on the air flow meter would move very easily depending on its position. maybe the spring has gotten a bit lax after 30 years, but its got to be a gentle spring to move with the air flow. i would bet my money that is the reason why leaning the bike left and right moves the idle.

the next thing i plan to do is check the valves, hopefully this will smooth the rest of it out. ill post a couple videos of the idle before and after changing the rubber inlets. 

[kennybobby]

look up the troubleshooting flow chart and do the drill--change all the old rubber tubing, check all the sensors, and rule out odd ball things like water in the tank, rusty return line check valve, ants in the jetronic, cracked solder joints in the jetronic, etc.