Tapering the needle...

[Guest]

Here's a discussion that lead to me giving it a go-

http://www.motoredbikes.com/viewtopic.php?p=12805#12805

The details are in my last post there.

 

[Guest]

Just got back from a decent ride to check the actual running across the spectrum with the needle tapered....WOW is all I have to say.

I was so happy with the results that I told Randy the K to take 'er for a spin. He came back and said "Dude, it's like at least a thousand times better than it was!"

And he LIKED it the way it was.

 

[spunout]

ok, my symptoms are 100% exactly the same as yours (pre-taper). i have an extra one, so im going to check it out. my needle clip has always been at the 2nd from top position and ran perfectly until the recent partial-throttle misfire. now, my qeustion is if you taper, lets say 1/32" off the needle, and then move the clip up a notch, whats different? the distance from clip to end of needle hasnt changed.

 

[Guest]

First- I think I removed around a few thousandths or maybe a 1/128th, it doesn't take much.

The reason for tapering it is so it got richer sooner-(mine was running lean everywhere but WOT. I made the taper more pronounced. If you raise the needle then it just gets richer across the whole range, this way it starts off a little richer, as you go through partial throttle it's still richer, then by WOT it is pretty much stock.

Simplified, I sanded off a few thousandth from the bottom half to bottom third of the needle.

That's why I say take your time and do a lot of test runs.

 

[JosephGarcia]

Can you take pictures, or maybe draw some kind of diagram to better understand?

 

[Hugemoth]

I don't know if this have been mentioned but the key to adjusting the taper of the needle is this:

Warm up the engine, then take it for a ride. At whatever point in the throttle position the engine is running too lean, carfully leave the throttle there and shut off the engine. Pull the air filter and mark the needle with a sharpy or something where it goes into the needle jet at the bottom of the venturi. Remove the needle and take off a very small amount of material from the point right around the mark. Repeat the process until you get it right.

I've found that just spinning the needle between my fingers and using 400 grit wet dry sandpaper works just fine.

Moth

 

[Guest]

I doubt the difference will show in a photo, but Hugemoth has a good way of being a little more accurate- as long as you have a way of leaving the throttle where you need to. I kinda did it by the "close guestimation method". I listened to the engine at various throttle settings for each "adjustment". I just took some off the tip and went from there.

I chucked it up in my drill and did it with two grades of paper.... the details are in the other thread.

Take your time, test a lot and you'll likely do fine.

Also, make sure your plug is new or nearly so before you start. A bad/old/crappy Chinese plug will cause problems.

 

[spunout]

ok. already it seems i had plans to take off too much.

I did it! i'm so proud of me :mrgreen:! i took off just a miniscule amount, and i mean just a tiny bit. Vroooom! went the motor through the entire throttle range. But i got a scare when i pulled clutch in and the revs skyrocketed. hit kill button, turned the idle screw down a turn or so, and now its perfect.

my hat's off to you, gentlemen 8)

 

[Hugemoth]

Yes, leave the point alone. Changing the shape of the point won't make any difference. You'll find you need to take off only a VERY TINY amount of material along shaft just at those places where it is running lean.

Moth

 

[Guest]

I did it! i'm so proud of me :mrgreen:! i took off just a miniscule amount, and i mean just a tiny bit. Vroooom! went the motor through the entire throttle range.

I'm proud of you too, spun! Glad you tried it and were successfull.

my hat's off to you, gentlemen 8)

Well dang, gee whiz and all that, you're welcome!