MOPED ARMY

four stroking. downjet by single numbers until it stops.

what kind of filter are you running.

hey man I am having a similar experience in a similar thread on the main perf tuning page but with a 19 del and 65 metrakit... I think we just gotta down jet slowly...

4 stroking huh??? I could be a little rich still. When i take off from stops it kinda bogs for a second and then rips. It will also almost die at idle if I dont keep it slightly revved. So... too much fuel.

Im just worried about down jetting because at WOT my plug if fairly clean to light beige. And if my plug looks like that how could i be four stroking?

wait why would it be a snagged throttle cable? wouldn't that keep it from opening up thus being leaner?

Contrary what some people just told you, you are NOT four-stroking. You are running lean! Upjet if you don't want to seize the kit.

Four-stroking is running rich. You notice this by a rumbling/sputtering engine at full throttle.

You are running lean. You notice this by the bogging down when you go WOT. The last 1/4 of throttle only adds air, no extra fuel. So at 3/4 throttle it runs right and when you give it more throttle, the engine goes BWOAAAAA and feels like it's stalling.

Trust me on this one, upjet. And you don't want to have your plug a light moccha, you want it dark coffee with just a hint of creamer.

Unless, like Roald said, its not sputtering/choking but the smooth bwwwooooaaahh sound then thats a lean bog. Try going up to like a 90 or 92 first and see if it gets better or worse. Then you'll know for sure.

^ ?

i have but the differences are so minimal at that speed

ok i will try that before. thanks man.

one more thing-

blue tinted smoke while cruising but not really at idle.

and there is definitely wetness on the end of the estoril. blackish oil.

seems rich to me. I just cant imagine down jetting with such a large carb and a cylinder that is 70cc's though

Sounds rich unless your timing is retarded. Did you advance your timing with the kit?

eh, im over it. ill figure it out.

thanks

yah i did. it looks im the only athena with a 21 dellorto.

I hear this can be a tricky setup.

Your too rich. Obviously. If you upjetted and it got worse, then obviously you need to go back down, and then down some more. If you top speed is less than full throttle than that means you are too rich.

21mm is not too big for that cylinder, it is tricky to tune tho. 88 to 94 in jets makes a big difference in that carb, so try a 90 or 92 and see how that goes.

For example: My Puch Maxi with 70cc RGD tuned, 21mm Dell'orto PHBG and Proma LowBoy rides good with a 96 jet, but 4-strokes with a 98 and runs lean with a 94. That's how close it can come when you take your carbsize to the edge of what is possible.

About needle settings and such:

The performance in the low to midrevs is set by a different part of the carb than the performance in high revs.

Have a look at this:

This tells you what to alter for what rev range. My suggestion: Get your main jet in order first, then fix your needle and then work on the idle.

Good luck getting it tuned :)