Name That Part - 1991 FZR1000

[Demoni]

So... we were tearing into my buddies newly acquired FZR to check the plugs (man pulling plugs on an inline 4 is a pain in the ass :thumbdown). Came across this little box that two cables connect to. Only one of the cables is currently connected to the unit and both of the cables go no where and are currently zip tied to the underside of the frame. It is powered and when you turn the bike on the little nub that the cables attach to rotates back and forth.

Any wisdom would be greatly appreciated.

In addition there is a jerky condition with constant throttle applications (around 3-4k RPM). This issue varies from day to day and will rear it's head at varying temperatures.

 

[Cycle61]

Exup valve.

Blocks off part of the exhaust to generate backpressure at low RPM to increase torque. Opens up at higher RPM for free-flowing horsepower. Good stuff. Your jerky condition may be related to this.

 

[cletus]

darn i guessed it was a whatchamadohickey

 

[Cycle61]

darn i guessed it was a whatchamadohickey

They didn't start using those until 1994 :rofl

 

[kingmoochr]

well the bike has an aftermarket yamaha pipe on it. do you know of anyway to perhaps add it to the pipe, or do i just need to go with the oem one? id really like to be rid of this jerkyness (we checked all the usuals, chain, oil, sparkplugs for tune) and the bike runs real solid as long as im turning my wrist, id just like to be able to commute on it more comfortably.

 

[rapidrobbie]

the yamaha pipe,is it a slip-on?if yes the exup is still there,and you should make sure it is adjusted correctly.check valve clearances,and sync the carbs.these bikes have some carb wear issues that could be causing your problem,but these other things should be checked first....Robbie

 

[kingmoochr]

based on how hard it was to get 1 plug out, im definitely not looking forward to checking the valves. it is just a slip on, so the valve is still in the exhaust? what would they have done, just locked it full open? and what exactly wears on the carbs? i need the damn haynes

 

[Hooli]

based on how hard it was to get 1 plug out, im definitely not looking forward to checking the valves. it is just a slip on, so the valve is still in the exhaust? what would they have done, just locked it full open? and what exactly wears on the carbs? i need the damn haynes

Look at the headers. If the spot they all meet beneath the engine has an EXUP valve, then you have a slip-on, and yes, the valve should still be there).
The only real moving part on a carb that can wear is the slide needle and the emulsion tube that it slides into. The needles are usually aluminum and the tube is brass; over time normal wear and vibration can wear these out. Replace as a set (aftermarket suggested since you have a non-stock exhaust).

I would contact Elskipador for your valve adjustment needs, because if any valves are out of spec, the cam(s) must come out.

 

[kingmoochr]

i used to work at an auto machine shop, so as long as i have proper directions, i think id be able to tackle the valves. i have no clue what im looking at under the bike, other than there are some bits on the exhaust that dont need to be there unless they attach to something in the pipes, so i was assuming the valve is still there. im just unfamiliar with the techinque involved with disabling it, because its apparent that was either done, or is just sitting in there flapping around, as the servo is clearly no longer attached to it. the bike only has 13k on it, so im assuming/hoping there shouldnt be too much wear and tear on the carbs at this point.

 

[Cycle61]

Carbs should not be too worn out after 13k, mine ran like a champ at 28k still, with no work except oil changes. For the plugs, try removing the radiator, it makes accessing the top of the engine much easier.

And +1 on getting the Haynes Manual

 

[rapidrobbie]

the emulsion tubes wear out causing a rich low speed/part throttle condition.the exup should be spring loaded to stay open if no cables are connected,but if the servo motor works,and you can still buy cables,i would hook it up.if the emulsion tubes are worn out,factory pro makes replacements out of stainless that are much better,make sure you check the fuel level(float height)if this is off you will have driveability issues,usually the fuel level is too high(rich).you will need special tools to check the valves,extra narrow feeler gauges,and there is an attatchment for the end of the crankshaft so you can rotate the engine with a wrench,yes i have owned/tuned a few of these supatanks they are a pain in the ass to work on,but once dialed in they will take a LOT of hard miles with no problem.i would get a yamaha factory repair manual,fuck haynes and clymer,you should be able to find one online that you can download/printout ...Robbie

 

[Shears Cycles]

So... we were tearing into my buddies newly acquired FZR to check the plugs (man pulling plugs on an inline 4 is a pain in the ass :thumbdown). Came across this little box that two cables connect to. Only one of the cables is currently connected to the unit and both of the cables go no where and are currently zip tied to the underside of the frame. It is powered and when you turn the bike on the little nub that the cables attach to rotates back and forth.

Any wisdom would be greatly appreciated.

In addition there is a jerky condition with constant throttle applications (around 3-4k RPM). This issue varies from day to day and will rear it's head at varying temperatures.

That would be the electric servo motor that controls the exup valve in the exhaust pipe.

 

[kingmoochr]

ya. thats been covered. ive spent a few hours looking and the only fsm ive been able to locate is in german. do you know of any sites that might actually have or sell the fsm? at this point i dont care if i have to pay for it, i just need something. any chance you might have some factory info or tools you may be willing to part with seeing as you now have a gxsr robbie?

 

[cletus]

They didn't start using those until 1994 :rofl

i thought that was a thingamabobberwrong again:laughing