still lean...
 

So today I FINALLY got my UNI filter! So I drove a few miles WOT (even though I know I shouldn't) and cut the killswitch and pulled into my drive way; essentially the whole plug chop process, with a BRAND NEW spark plug and freshly changed 92 jet. And this is what I got:

http://i42.tinypic.com/358swux.gif

It doesn't look quite as white as last time, but it's definitely still white.


Gonna try #95 next...

Give it a hotter coil?..

For real?! I thought that was for rich conditions??? I'm already running an orange one... D:

The tip is still white with a #95 jet but now there is the slightest of brownish tint to it. I think I'm getting closer. (This is with a BRAND NEW spark plug, mind you. Not the last sparkplug I used.)

http://i40.tinypic.com/v6nmev.jpg

Do y'all think I should go to #98?

For the sake of science I did another plug chop, but running for a few more miles this time.

I think #95 might be the one!

http://i43.tinypic.com/fnh4ww.jpg

You should take a GPS and measure the top speed on a level road with no wind you get with the various jets. One or two of them among your 92, 95 and 98 ought to give you a better top speed which will tell you what range you ought to be going for.

And the 38 pilot can be washing the plug clean. Are you able to adjust the idle mixture screw using the idle drop method? If not then you're too rich on the pilot jet and would be better off switching back to the 34. If your pilot jet is flooding your cylinder with gas at idle it can throw a proper plug chop off.

Because by the looks of it the 95 or 92 are actually closer to the jets you want. In fact it looks like the 95 you're getting carbon build up on the metal edges. On mine when I have them tuned perfect metal has no carbon build up and looks like a dull even brown no black spots or build up.

My apologies.. Your correct.
Ugh. been a long day. lol

So far my highest speed I've ever attained on the scooter is 58mph with the 95 jet and my performance seems great. There was the slightest popping with the 92, but no more with the 95. I think the 95 might be the one. I also think I was too anxious and didn't go for a long enough drive for the first plug chops - I mean you can still see the result, but it's not that clear on the picture.

My stock idle jet wouldn't come down from revs. No matter what a/f setting I had it on it just wouldn't come down after giving it throttle. It was hard to start, and it sometimes died at stops. So someone on the forum suggested I try the 38 pilot jet and I got it from AbsolutelyScooters and all my problems were solved. Now I can actually adjust my a/f setting. I'm a bit confused as to what size the stock is. Is the stock 32, 33, or 34? Because the stock for 150cc scooters is 35, correct?

No worries, lol. It's just that everything I knew about scooters was turned on its head for just a little while as I pondered your comment, haha.

Stock size is 34, it's possible you got a bad stock jet. You should definitely try a new 34 pilot jet.

And also when plug chopping the engine needs to be fully warmed up and up to temperature, usually 15 minutes of riding.

95....but to me thats reall clean....not that bad...but thats just my opinion.....

That's still very lean. You could try covering a bit of the air filter with some e-tape. I've found that a cone-style paper filter on my 90cc BBK 139 w 95 jet works best 3/4 covered with e-tape.

Is there any reason to avoid a larger idle jet? I'll order up a #35 from absolutelyscooters and see what happens since that's what they have in stock and they're the first ones I found that offer the extended length idle jet for easier starts. But I still don't understand the reasoning if my current setup seems fine, is there some chance I'm running too rich at 1/8 throttle?

The first few plug chops consisted of a five minute warm up in idle and a ten minute drive at WOT. The last plug chop was a longer drive because my mother asked me to go to the store for her - I got much better results with the longer drive, that's for sure. Sadly it just so happens that a lot of roads were flooded around town so I was confined to a small strip of road on 120 since my speeds are too high to do WOT around the neighborhood anymore.

Clean, or lean? It may just be your opinion, but I value your opinion Buford. :tup:


You think so? I've been running a restricted free flow filter for months now because I didn't have the proper jets. Millsc says I shouldn't have to go over 95 with jets and I'm trying to get the best performance possible - won't the restriction hinder that? I mean... the tip of my spark plug is white from my hotter coil, but the base is coffee colored - isn't that what I'm looking for?


In any case I'm ecstatic that I can almost hit 60mph now. I'll try a smaller idle jet for some reason, but otherwise I'm liking my setup so far.


Thanks for the input, Y'all!

A correct looking spark pluf should look gray colored, if your running too lean turn the a/f screw 1/4 turn richer (counter clockwise)

Here yea go.