[FloridaKat]

as I undertsand it , the "closer" cable is mainly a failsafe , so that if needs be , you can close the throttle manually if the return spring should malfunction , or some such . If it's snapping shut , then it's doing it's job . However , a lean mix , which can be caused by dirt in the pilot circuit , bad settings , or an air leak , makes it return to idle a little slower . See , it COULD be a few things . This is why it's good to go for the easier/more likely culprits first .

OK...the "closer" cable failsafe makes sense.

Let me ask you, how would running lean cause the throttle to return to idle slower? Also, if you were to itemize the things (on order of easy/likely culprits) what would you list?

Here's what I'm thinking...

(1) Run the bike for a while letting the Seafoam work it's way through the entire circuit. If that doesn't work then...

(2) Lubricate the throttle cables from the lever end. Should I spray lubricant to the springs on the throttle rail (where the cables run to)?

(3) Pull the carbs, remove the EPA plugs and enrichen the mixture.

(4) Upgrade to an Ivan's jet kit (which might replace #3, above).

[md86]

Well , if it's stock , you shouldn't really HAVE to tinker with the EPA caps . It'd help a little , but you'd just be masking a potential problem . Good for getting you home , but bad in every OTHER sense .
I can't really get into the whys of lean making return to idle slower . I just know it DOES . Seen it before .
Yeah , start with the Seafoam . But go through a whole tank of gas with the stuff first . Like ..... throw some in at the gas station and fill up . Ride it home (hopefully that's a few miles at least) . Let it sit . You SHOULD now have the Seafoam/gas working into the carbs . Let it sit a bit maybe (like overnight) , then run it some more , like most of the tank would be good : . If the pilot circuit DOES just happen to have a little crud in there the Seafoam CAN clean it , that oughtta get it . If that don't help , then it's something else . Of course ,this IS just one possibility .

[The CyberPoet]

I can't really get into the whys of lean making return to idle slower . I just know it DOES . Seen it before .

You know, I'm not sure I'm exactly sure of why it does it either (in the sense of being able to diagram it out step-by-step why idle hangs in returning to a lean-idle condition on CV-carbed bikes), but I know it has to do with the nature of the engine to try to reach a steady-state condition in regards to fuel-vs-vacuum levels and as a result try to hover at the lowest steady-state it can maintain correctly. When the idle passages are too lean, it tends to hover for a little while around the RPM level where the needle hasn't quite closed off the needle jet yet.

In my experiences, cable binding from over-tightening is still usually the culprit, but there is a second culprit in the form of fuel that was left in the carbs far too long (esp on a hot engine at shut down), such as parking for a month or more at a pop -- the waxy paraffin in some fuels clog up the smallest passages creating an artificially lean mix. Any product with a parafin stripper (such as ketone) should be able to clear it out -- if you actually run the bike (it won't do any good just parked with the stuff in it -- the ketone will simply evaporate and you'll be back where you started).

Theoretically, water in the float bowls could also make the mix go lean, by depriving enough space for sufficient fuel...

Cheers,
=-= The CyberPoet

[FloridaKat]

In my experiences, cable binding from over-tightening is still usually the culprit

After manipulating my throttle cables and seeing a direct relationship between the idle position vs. cables position (as it sits above the cross-member), I would agree that binding is the most likely culprit. I was able to find a position that seemed to be a "sweet spot" for the throttle cables. I found myself having to play with the lever adjusters, idle speed screw and the choke setting until I got her back to "norm".

[Newbie2it]

It's actually nutted from both sides -- there's a nut under the bracket and a nut over the bracket, with the two holding it tight to the bracket.

Cheers,
=-= The CyberPoet

CP, Would that apply to the post 98 kats? Reason I ask this. I just ripped into mine tonight to do some maintence things, I pulled the carbs and removed the throttle cable. The throttle cable only has one single nut. The carb fitting where the cable slides thru the slot is part of the carb, not as a bracket in the above image (I thought mine was a bracket simular. There is no way the extra nut can be removed from the end of the cable, unless it was cut off purposely. Mine is on a Pre its a 93. I tried to look it up on Ron Ayers, but they dont show a shot of the cables for the throttle. Maybe the double nut is for the push/pull dual cable so if one cable hangs it cant accidently knock the other side off?

If its supposed to only be a single nut then the nut needs to be on the top for adjustment and as I had thought originally, the previous owner must have screwed up putting it back on.

[md86]

THe nut on the pre goes underneath . The cable end has threads which thread into the carbs , which is how you adjust the slack . The nut is a locknut .

[frosti108]

but there is a second culprit in the form of fuel that was left in the carbs far too long (esp on a hot engine at shut down), such as parking for a month or more at a pop -- the waxy paraffin in some fuels clog up the smallest passages creating an artificially lean mix. Any product with a parafin stripper (such as ketone) should be able to clear it out -- if you actually run the bike (it won't do any good just parked with the stuff in it -- the ketone will simply evaporate and you'll be back where you started).

1st off id like to say that this thread is very interesting and im trying to take in as much as i can. 2nd, what products have ketone in them>??

i have old gas in my bike and ketone sounds like it will be good to use while cleaning the carbs out. would dipping the jets in ketone work well to clean them out? or would i just need to dump ketone in the gas and run it?


and i think i made a mistake because i had my friend synch my carbs when they probly just need the valves adjusted. so when i actually adjust the valves, ill probly need to resync lol

anyway, whats the link to the valve adjustment for older 750 kat? i think ive seen it before...

[md86]

Well , if you're taking the carbs apart to clean them , blow some brake cleaner through . Cleans better than about anything I've tried .

[Newbie2it]

THe nut on the pre goes underneath . The cable end has threads which thread into the carbs , which is how you adjust the slack . The nut is a locknut .

Taking this to another thread so as to no longer Hijack threads like Nero , Look for another post about this. Will include pictures as a reminder.

[The CyberPoet]

what products have ketone in them>??

Ketone is the main ingredient in most fuel system cleaners, such as Techron (my preference) and Seafoam (loved around here).

i have old gas in my bike and ketone sounds like it will be good to use while cleaning the carbs out. would dipping the jets in ketone work well to clean them out? or would i just need to dump ketone in the gas and run it?

Drain out the old gas, put in some fuel system cleaner and fresh fuel and then run the engine to make it liquify the deposits and move them into the combustion chamber to be burned off. Note that ketone and most other very light petroleum products evaporate fairly quickly out of unsealed fuel storage devices, and the motorcycle on a gas tank qualifies as an unsealed fuel storage device.
If you're trying to figure out what to do with the old gas, mix one gallon of old fuel in per 5 gallons of new fuel in your car, and burn it off that way.

anyway, whats the link to the valve adjustment for older 750 kat? i think ive seen it before...

The link for the 750 is the same as the 98+ Kats... you can find it on my website here:
Katana GSXF nut-adjuster valve adjustment procedure including pictures. If you're not familiar with how to use feeler gauges correctly, see CyberPoet's "How to use Feeler Gauges to adjust nut-adjuster valve systems on motorcycles and non-hydraulic (very old) cars."

Cheers,
=-= The CyberPoet