Main jet 1-2 lean / 1-2 rich = ??? By gy6fandan (Read 444 times)

[gy6fandan]

After an upgrade ( still tweaking ) finding jet size an issue.

Carb is PD24J on 150cc.

#120 is simply too rich at running speeds (10mph +)

#115 is great at idle and performs decent at running speeds (10mph + 35mph). Runs awful over 35mph

However the #115 causes temperature rise of 300 deg in a few minutes
during 5 minute test ride....... The 300 deg temp is off the cylinder head / under the spark plug - not oil temp.

Sooooo, anyone know where I can find a PD24J main jet between the
#115 and #120 size ?

Thinking a #117 - #118 would be the perfect medium - but where to get it ?... Anyone

[Bashan]

Want to see a really simple way to directly check your oil temp? Ride the bike until you're sure it's fully warmed up...then shut it off and quickly do this:

I call it the Martha Stewart method. I got that one at BB&B for 8 bucks. Don't trust the head temp, you want oil temp. Up to 260 is acceptable. Now you can take a 115 and drill it out. There's not an exact equivalent for it but you can guesstimate:

I'm assuming you thought you were running lean and that made the bike hot? Check the oil temp to be sure. But the plug is the way to tell your mixture.

Black is rich, bare is lean.
Nice light brown makes a mean machine.

[gy6fandan]

I had considered using some of my old smaller jets and using the micro drill method. I may have to do that before it over with but I would really prefer a factor smooth one.

[Alleyoop]

Do you people every google, geez like a bunch of little kiddies, SPOON FEED ME PLEASE

www.ebay.com/itm/like/300941943591?lpid=82

[gy6fandan]

Alleyoop ----> Thanks for the link


Dealing with a Ebay buy hassle from a seller who posted an item with some mis-leading pictures and some seriously lacking facts about their item.

Not to keen on the photo of the item not showing the # on the jet - but I will send them a note (ask a question) and ask them about the item / specs and another photo possibly.

Thanks again.

[jct842]

I would have to guess that the needle height and mix screw to be off if there is that much difference in jets. Or the jets marked wrong.

When I tuned my 150cc I only used the jet it came with and ended up perfect. I bought 2 sets of orifice drills. I kept drilling it out bigger till I went too far then soldered it shut and re-drilled 1 size smaller than too big. It lasted over 5000 miles till it was wrecked.

[jct842]

And if you should drill them you need to use a pin vice and light finger tip pressure to avoid breaking the tiny bits.