carb question

[redranger08]

i recently just got my new/used 08 250r and i noticed that down low in the lower rpms before take off, it would kind of lag and you would have to rev it or give it gas in order for you to have a nice and smooth take off, it would hesitate in the higher rpm range 8k to redline and poor fuel mpg. first thing that came to mind was maybe the carbs are dirty and for the poor fuel mpg i thought it was due to the large sprocket(49t) the previous owner had on( i dont know why it needed such a large sprocket, maybe previous owner trying to stunt it? LOL). so i decided to take the carbs off and clean them carb/brake cleaner. while cleaning them one at a time, on one of the carbs i notice that one of them did not have the copper piece that sticks out into the carb underneath the slide.( not sure what it is, first carb motorcycle ever) i put the carbs back together, put it on the bike and took it out for a test ride. the low rpm take off is still there but the hesitation in the higher rpm is gone and i changed the sprocket out to a stock 45t and fuel mileage has improved.

will missing this piece(circle in red in the pic) affect anything on the motorcycle? also ive been searching around on the forum and found that shimming the needle with 1-2 washer or turning the mixture screw 2.5 turns will help with the low rpm take off.

sorry for the long post! any help or advice will be appreciated.

thanks!

[RacinNinja]

Yes, both carbs should have that part. I would not tune further without it.

16017
JET-NEEDLE,#6
16017-1417
$27.39

http://www.ronayers.com/oemparts/a/k...rburetor-parts

[HoneyBadgerRy]

Racingninja is correct, the part is a needle jet, and it is an essential part of the needle system.

[redranger08]

could that be the issue with the poor fuel mpg? would not having this piece cause any problems at the moment as im getting this part ordered? its starts fine cold with a little bit of choke in the early mornings, temps in the mid 50s. it idles fines and i ride it 200 miles round trip to work and back.

[HoneyBadgerRy]

Originally Posted by redranger08

could that be the issue with the poor fuel mpg? would not having this piece cause any problems at the moment as im getting this part ordered? its starts fine cold with a little bit of choke in the early mornings, temps in the mid 50s. it idles fines and i ride it 200 miles round trip to work and back.

I'm supposed the motor even runs last 1/4 throttle. Yes it could lead to horrible fuel economy and running bad.

[ducatiman]

With the needle jet missing, it impacts assembly and performance of related parts. Your "main jet holder" aka emulsion tube is screwed too far, your main jet (the fuel pickup) is too high....your fuel atomization (spraying an atomized mix into the venturi)....is not occurring...the main mixing chamber is not able to..errr...mix.

These are very common to go MIA during carb disassembly when the emulsion tube is removed and carbs turned rightside up....they can fall right out....in silence.

ALWAYS double check the venturi for their presence during the assembly phase of a carb clean.

Tip...the emulsion tube threads should not bottom out on its carb orifice....anyone in the know would catch the error *right there*. This will become apparent to our OP when he replaces.

[redranger08]

Fixed the problem! Bike runs very good now! Also shimmed the stock needle and wow! It made it such a different bike! No more revving it up to 4k rpm just to take off from an idle. Took off the snorkle as well and it growls. Super nice!

[ducatiman]

good deal, mon.

[redranger08]

Originally Posted by ducatiman

good deal, mon.

thanks for the help! i appreciate each and everyones reply.