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Thanks.

I found a new set on ebay for $47.

But Im thinking, after the whole ordeal with the crank sensor on my car, I'm wondering if it could be more of the same. It still doesn't seem logical for throttle angle to play a huge role if its the coil packs. However, bad ignition timing seems like its possible, to me.

FZR does not have a crank sensor.


Mine was cured with coils, and a higher float level..
 

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The 1998 R6, best I can tell, has an individual coil on plug design and the FZR600 has two coil packs with 4 plug leads.
The YZF R6 was first released in 1999 and was a totally different design than the YZF 600 or the FZR 600 and is FAR superior to both in virtually every way.
The first YZF R6's were/are a completely different animal than its predecessors. As you discovered the R6 uses "stick coils". That's not the only difference.
R6 parts do not interchange with the YZF 600 or the older FZR 600.

Troubleshooting with used coils is risky. If it still acts up with the replacements the question becomes... Are these coils bad too?

I keep thinking something may have been missed in your carburetors. The jet blocks have intricate passages going up into the carb body. Having found "jell" in the pilot jet I would expect to find plugging in the jet block and in the smaller passages in the carburetor bodies themselves. Those smaller ports (passages) in the jet block and carb body control fuel metering in the RPM range you are experiencing poor running.

I would recommend setting/checking the carb
synchronous first (with fresh spark plugs) then if needed verify the internal carburetor ports are all clear before spending money on electronics that can not be returned.

S F
 

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You can have a now clean pilot jet (good idle) but still have more trash in transition circuits, whatever serves as the small holes that expose when the slide lifts. NOT the one hole for pure idle that is downward of the slide. The holes right at the slide add fuel like baby accelerator pumps and provide the fuel used at low cruise and low rpm just past idle until the main system and needle come on line. Often those holes are fed from a small chamber casted or drilled in carb body and it may have a plug over it to allow drilling the small feed holes. That chamber can have grunge in it to then pull up at engine vacuum on the holes and block off your necessary fuel there. and the chamber is very hard to guarantee getting 100% open.

I'd look close at that area. With SF on this.
 

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Emulsion tube. ... I think that's the term you are searching for.

Correct sir!


You can have a now clean pilot jet (good idle) but still have more trash in transition circuits, whatever serves as the small holes that expose when the slide lifts. NOT the one hole for pure idle that is downward of the slide. The holes right at the slide add fuel like baby accelerator pumps and provide the fuel used at low cruise and low rpm just past idle until the main system and needle come on line. Often those holes are fed from a small chamber casted or drilled in carb body and it may have a plug over it to allow drilling the small feed holes. That chamber can have grunge in it to then pull up at engine vacuum on the holes and block off your necessary fuel there. and the chamber is very hard to guarantee getting 100% open.

I'd look close at that area. With SF on this.
If he had any emulsion tube blockage he would never acheave full throttle/rpm. thse tubes are responsible for mid to high rpm fuel draw. His issue is an mid rpm issue.

OP, I still say its a spark issue. But GL!
 

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Emulsion tube. ... I think that's the term you are searching for.
This bike doesn't have what we usually think of as the 'normal' or 'regular' type emulsion tube.
Look at #35 (jet block) and #31 (main nozzle) in the carburetor parts diagram. Number 31 would be the emulsion tube (as it relates to the jet needle) but it has to work with the jet block to function the way a normal emulsion tube would function. (Mixing air/fuel). Several different Yamaha models used that type of set up. Lots of nooks and crannies for trash to hide inside that stinking jet block. Not the best way to make a carburetor IMO.


S F
 

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Discussion Starter · #48 ·
Thanks everyone.

I had a planned surgery on my wrist a week ago so I won't be able to do anything on this for a month or two. I will definitely update this when I do, though.
 

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Went back and looked at my post and I used the word slide instead of butterfly and I corrected the text. Dunno what I was thinking of.

The discharge point I refer to can definitely affect the complained about problem.

Looked at the carb pic and the part I'm talking about may be the OTHER jet block, or part #17. I'd have to have a carb in front of me to tell for sure so I could trace out fuel passages. The holes could be drilled in carb body and something in the bigger jet block #35 may feed them. There could be emulsion tubes pressed into the jet block too. You may have to pull a plug to get to them like some Holley carbs do.

There is almost always a low volume intermediate fuel feed to feed partial no load throttle like low cruise and it serves as a go-between pure idle and main system startup at needle. The engine will idle fine then go to **** at opening throttle more, then straighten out to run fine at higher loads when needle is online.
 
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