xj700x engine revs stay high while changing gear

xj700x maxim 1985 Hi, My Engine revs just hang when i close the throttle to change gear.
This is obviously connected to my idle tick over setting , because if i completely back off on the idle adjustment screw, all then works ok.
So the question is, how do i maintain my idle 1050 rpm , and be able to drop engine revs to change gear ?
Thanks Guys :twisted:

 

Assure that the Carbs are Cleaned in the manner of cleanliness this Forum demands.
Polish Diaphragm Piston Bores
No air leaks.
No cable issues.
Bench Sync using 3X5 Card, Resume' Paper or Strips of 35mm Film.

ColorTune or Struggle-By-Ear to get the Bike to IDLE steadily on Pilot Mixture Screw settings supplying Idle Mixture without Throttle Support.

 

idle speed is probably wayy to high. loosen that up somewhat until you get engine braking or notice the revs dropping at an apropriate speed between shifts (now your bike really wont idle but dont worry about that now) then start working with idle mixture its probably lean. diligence is key with carbs i suggest removal and cleaning

 

Thanks Rick and tdryan for your help.
Issue now resolved,tdryan you were spot on,way excessive idle speed and
idle mixture to weak - mixture screw out 1.5 turns , now nearer 2.5 turns.
Rick i took your advice, removed carb rack, stripped and cleaned carbs, polished bores, set fuel height etc, color tuned,vacum sync, and bike now runs just great with steady idle @about 1000rpm.
However i have noticed something not quite right with the petcock.
Engine off - no vacum - petcock set on , fuel pipe removed- as expected no fuel flow, but if i move petcock to primary - again no fuel flow, but i get fuel flow if petcock set to reserve. So looks like the primary and reserve positions are somehow reversed !
It may be that the p.o has rebuilt the petcock (i have had bike a few months) incorrectly , if that is at all possible. Before i strip the petcock could anyone offer any thoughts / advice ?

Thanks
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85 xj700x maxim x

 

How much fuel is in the tank?

Pri is for PRIME not primary. This should flow fuel with the engine off.

On is vacum operated

RES is also vacum operated but draws fuel from lower on the the stack filter inside the tank.

 

Tank is full

Engine off :- prime position - No fuel flow

on position - No fuel flow

Reserve position - Fuel flow

Bike idles and runs ok, i could just ignore it but i don't want to as something is obviously screwed up.

___________________

85 xj700x maxim x

 

Been sitting here examining my petcock (rebuilding) and the only way I can see for it to be backwards is if the name plate was put on upside down.

Unless I'm not seeing something that's the only way the valve would work that way.

 

On all of my stockers, the postions are ON=straight down; RES=Left, and PRI=right. The plate says "FUEL" across the top.

You're not "mis-reading" the lever are you? The handle IS the position, not opposite the position, like a selector switch. In other words, when the handle is to the left the petcock is in RES. When the handle is to the right, you're in PRI. (Look closely at the edge of the lever, there's a little arrow cast into it pointing outward.)

 

I've seen a couple instances where the Petc0ck's Tower Filter was hacked-at and put-on backwards.
There's supposed to be a Cylindrical "Neck" that inserts into a receiving hole.
Some PO's thinking its just a Filter, that fell-out ... mod-it and install it backwards.
(Rare)