Pinned FZR250 3LN1 carb service and tune

After reading such thorough and informative posts about such things, I thought I would add to the wealth by documenting my carb service.

Pics and settings to come.

Please feel free to comment or add from own 3LN1 experiences

 

YKU carb 2 & 3 /// YKS carb 1 & 4




LiteTek Viton kits A & B









Needle from carb 1. Obvious signs of corrosion.

Clip 3rd notch from top.




Questionable detritus.

 

Needle jet from carb 2. also showing wear & corrosion.

Both needles are marked 5TC7

 

To save trawling the forum posts again...I remember there was mention of an irreplaceable spring somewhere in the carb setup.
Anyone with more info?

 

Carbs 1 & 4 have jets 102.5 and carbs 2 & 3 have jets of 100.

All four carbs also run 37.5 jets.

 

Are these supposed to be one way [PCV] air filters?
The detritus in the diaphragm housing has either got there from the one way filter not working or perhaps the actual filter itself breaking down over 23 years?

They look like they should have additional tubes but in every photo I've seen the just hang off the carbs as is.

 

Is there a particular method for removal of emulsion tube other than gentle drift [tap tap]?

 

Nice work... your gonna love your bike after this rebuild .. I just did the needles and emulsion tubes and clean at this stage... and Wow!

 

Gentle tap downwards is the win. Thought they came out upwards. The black seal was actually dirt at the base of the emulsion tube.

 

Anomaly.

Carb 1 Emulsion tube has a very small nylon washer. None of the other carbs have a similar part.

 

OEM Emulsion tubes are stamped 638 and N-6

The replacement ET's and needles have no stamp whatsoever.

 

Idle mixture needle. All four showed wear & corrosion.

Also note washer which sits above spring.

 

Cheers Grey!
Totally would not have realised those rubbers were down in the bowels without that post!
All 4 successfully removed

 

Removing the slide housing to fit slide housing O ring [LiteTek OR-018 that replaces 003] is currently baffling us.

Result = Put finger in and pull!

 

Slide housing and well rigid O ring.

 

Choke plunger set up with Viton replacement. Hoping not to have the split the carbs if possible.

 

Float needles.

Before. No bounce.




After. Bouncy, bouncy



I imagine if the rest are the same then the excess fuel / bogging issue would have a lot to do with this...Not cutting off fuel supply, rich mixture etc etc.