needle clip

[FileStyle]

when you install the throttle into the slider barrel , should the needle clip be above or below the c - shaped washer? I have run both ways and seems to do fine either way but just looking for a census!

 

[Pablo]

when you install the throttle into the slider barrel , should the needle clip be above or below the c - shaped washer? I have run both ways and seems to do fine either way but just looking for a census!

How could it work either way??? The needle could "float" up if not in this order:

See: http://motorbicycling.com/f30/motorized-bicycle-carburetor-install-rebuild-302.html

 

[stude13]

very nice paul

 

[Pablo]

I just stole Norman's pictures.

 

[MarkTur]

Oh...and I thought you were an upstanding individual!
(kidding)

 

[Pablo]

Naw I'm a natural plagiarizer and general clown about town and can be found outstanding in my field. But other than that, I'm a fine and serious dude.

Hey why re-invent the wheel?

 

[MarkTur]

LOL

Dude, help me out...I richen up my motor, and all of a sudden I can hit 35mph...but my idle is barely running with the screw turned all the way in. 35:1 AMSOil, NGK plug. The low end is HORRIBLE. I moved the clip to the third slot down from the blunt end. It was on the last slot - lean - before, and I had decent low end, but great mid, boggy high.... I know the high end now was too lean, but I guess the way I was riding it (half throttle) it was rich enough to give me a nice brown plug.

I'm actually ready to move on to a better bike and new motor, but don't know what to buy, or who from, and who's got anything in stock. But before I do anything, I want to get my motor right.

I ported both ports like you suggested, so that's no longer any type of bottleneck. I also have an o-ring in the carb to prevent air leaks - but I'm ready to pull it out and let some more in if nobody can give me a better suggestion.

Thanks!
Mark

 

[Pablo]

So have you actually ported your engine?

Or just matched the stock exhaust to the port? Or did you get an expansion pipe?

Same with intake? Port/gasket/manifold all match?

Is your engine well broken in? How many full tanks of fuel have you used?

Have your jets arrived? Have you measured your stock jet?

I need a better baseline - because it's quite odd going two clicks rich makes it run better. Especially at WOT.

 

[Pablo]

Sometimes the O-ring if too fat, makes it worse.

 

[Bikeguy Joe]

I have found that when I get an optimal full throttle mixture, the bottom end is too rich. Good off idle and mid? too lean at WOT.

I taper my needles to fix that. Not for the faint of heart.....

 

[Pablo]

I have found that when I get an optimal full throttle mixture, the bottom end is too rich. Good off idle and mid? too lean at WOT.

I taper my needles to fix that. Not for the faint of heart.....

So you chuck the needle up.....how much do you remove?

.....what grit emery paper for how long, etc.....

 

[Bikeguy Joe]

That's why it's not for the faint of heart....you have to take it out, use 320 paper and sand it a little at a time (chucked up in a cordless drill) then put it back and test, repeate....over and over until it's right. You can only do this if you can hear the difference. I usually take a little off until I can see it on the paper, then test.

I get the engine set so it runs well at idle and part throttle cruise, then start tapering the taper from there.

 

[ran49]

I have done the same thing by chucking the needle in a drill press using 600 grit wet/dry to start with.What I was trying to accomplish was a uniform steeper taper by removing most of the material from the tip.I found if you remove too much from the the top of the taper(fat end)
It may run too rich at idle at any setting.Fix= new needle.Like Bikeguy says,little at a time and mostly from the tip.Ron

 

[Pablo]

I'm gonna give it a go. I have a whole spare carb AND pocket bike clone carb on the way from BC (soon!!)