NEWBIE ALERT - some carb questions - probably overthinking as usual

[herennow]

Hi All,

I finally got around to checking the carb setup as plugs look too lean and the engine seems to run a bit hot for my liking (its a 2004).

Found it to be all stock except for the thick washer under the needle:

Pilot = 17.5    /  Mid = 60  /  Main = 127.5  / Needle = 5DH24  / one washer below 1mm thick

I'm thinking of beefing those up to the recommended ones of around 20/62.5/140 (or maybe 137.5).

I have a couple of questions though - peering into the slide I noticed a little lip at the bottom that the needle/washer seems to sit on, it does not seem to sit flat on the bottom of the slide... this was identical in both slides - see photo.    Is this normal?

Also, the PO seemed to have swapped over the float bowls, I am assuming the drain screws should point outwards? (he had them pointing inwards), pictures shows them as I think they should go. Is this correct?


thanks a million

HnN

[herennow]

Anyone?

[The Buddha]

Drain screws do point outwards. So you should swap em.
Also 137.5 140 ? what are you jetting for ? Cos those are not jets for any real combination we recognize.
132.5 for stock, and 147.5 for K&N lunch box and slipon.
Cool.
Buddha.

[herennow]

So, a few results,

Regarding the lip under the needle, I spoke to an old bike tuner I know who said that that he would guess that it is there to "chicken the needle" to one side to prevent wear. He said that with the air stopping every 1/5000-ish of a second when the intake valve closes, the needle normally flicks back and forward at the same frequency as the RPM. With the lip's location, the needle will sit slightly slanted towards the engine and rest on the engine side of the pilot jet. As the air blows past and stops /starts it will keep the needle in this position. This will reduce wear compared to the needle hitting back and forward all the time. If this is true its a nifty piece of work from the engineer who thought it up.

Regarding the rejet, the 20 pilots and 135 main work a treat! I know finally understand what people say about a bike being "cold blooded". She is running much better now and ready to pull away where previously I would have to downshift to get some oomph. The popping on engine deceleration is also completely gone.Wish I'd done this right when I got the bike!

The only remaining problem is what feels like an occasional misfire when under load. I'm thinking coils or possibly a bad connection relating to the ignition. Its harder for the ignition to spark under load (higher dynamic pressure makes it harder for spark to jump), but who knows -happens rarely enough to maybe ignore it for now. 

Bottom line bike is transformed - go out and jet yours now.

[user11235813]

The only remaining problem is what feels like an occasional misfire when under load.

Follow the wire that comes out of the bottom of the timing cover on the right hand side of the bike all the way around to where it forms a plug on the left side of the bike. Unplug it and spray it with electrical contact cleaner let it dry and plug it back in. Maybe unplug the CDI unit and spray that with contact cleaner too.