Sorry guys, I've never tuned for alky, almost did a while back, but never got to it.
all I have is second hand info frim THEBOM, he has tuned many many.

 

The specs your at now sound way too rich. Mine backfires on deceleration and it was dyno tuned. It might be a trait of alky.

 

i know it sounds rich to mee as well, but when i started at a 60 pilot, the air screw wanted to be about 1/3 from seated, and a 75 was about 7/8 of a turn from seated, and the 84 is about a turn and 3/8 from seated.

The main started with a 300, and tried a 338, as that was the next size bit i had at the time, but i will tune more tonight. I brought home a tri-head gas monitor, it tells you the LEL of the atmosphere being tested and the oxygen percentage. With this I might have better luck.

Oh well we'll see what happens I guess.

 

if i read it right you said it was 5 deg celcius? thats 41 deg. now thats cold for alky! in a fourwheeler. i know in the sleds they ran when its that cold but it was running out of the tail pipes. iv never had good luck colder than 60 deg. crazypainter is right on with the jetting, and the alt here is the same up there "2000 ft".

 

it's gonna get a lot colder than that too, say about -35 celcius...lol

Anyways, got the needle to run a lot better on the bottom groove (richest), went from a 330 main down to 296, ran better, but still too rich, for ***** and giggles, threw in a 240, and will see how it likes that tomorrow. Next size I have is a 254 or 256 or something. Pilot is still 86, and only about 1 turn out. that tells me still a bit lean no? And if it;s more than 2 1/2 turns out, then it's too rich....

I'll throw in a 60 pilot again tomorrow and see what that does. work around there, and if nothing, then I'll have to go richer yet. I know big jumps here, but I need to start seeing some sense of direction.

Oh, and I've already accomplished owining that yfz450, and to top it off, he just put on an edelbrok carb as well....so I definately have gains.

 

Its real difficult to tune alky in cold weather. I would suggest you run a hotter thermostat in your engine. Your engine needs to be at a good operating temperature before you even start jetting.


With my old Tm45, I had my best gains running .075 pilot,and drilled my main jet out as big as possible. The Needle was on the richest setting. But this was in the HEAT of Summer, so its a whole new ball game at 30 degree's and below.





Bigger.

 

This i have noticed.....i would like to run alky all year round for 14:1 comp. I'm headin out now to tune some more and will get back to you.

 

When it's below 60deg, you have trouble building enough heat to burn the alky complety. It will be down on power. My bikes jetted out around 280 +or- in the summer.

 

Thanks for the info guys,
The BOM, that just makes me feel better about sending it to AA last night. Back to premium I went. I didn't have a 30 pilot, but i'm at 162.5 main, 96 needle second clip, 40 pilot, and air screw about 2 1/2 turns out. does anyone with a numbered set of bits know what a 30 pilot is? I have the bits, but no numbers as to what they are. the bit is approx. 0.0110709 inches. So what number is that? Thanks guys