Tuning question

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
Ok that makes sense. I was thinking of the fuel addition via the screw as something constant but your right feathering the throttle (increasing idle) “opens” or adds both fuel and air. The screw setting simply gives you a max setting to optimize the mix of fuel and air once opened.

Makes me wonder if setting your TX to only 1/3 throttle and tuning the LS would be easier than how we do it. Sorta bypass the HSN completely and just deal with each screw on its own. The HSN wasn’t hard at all to tune but the LSN seems to be the mystery. I am terribly hard of hearing at 47 yo so I don’t feel great doing things totally by ear. Plus without someone else around who knows better I have a hard time distinguishing the correct sounds I am looking for. It all sounds similar to me, just a loud obnoxious 2 cycle.
 
You just want to make it idle, if you bump the idle too high, you'll be getting into the transition ports in the carb. Set your idle, and tune it. The rpm fluctuation is from being too rich or lean. Your just looking for the happy middle ground.
 
This thing is running amazing now. I stayed slightly rich and smokey on my LSN and it still jumps up in rpm when the HSN kicks in. I can remove all that "jump" by going a literal hair more lean and I have a very smooth linear acceleration from low to mid to high. I find it hard to determine by sound the affect of the HSN feeding fuel when set that way.
I loved how it ran but I figured why not keep it a little more rich and not risk the engine just b/c most of my runs have been under 1/3 throttle in front of the house at low to mid rpm and for just a few minutes each run (neighbors get annoyed if I blast around to much). I'll lean it out slightly once I get more room to run. I don't know if its necessary at low to mid RPM's to be on the rich side but at least now I know where it needs to be. I also ordered a DDM v2 dominator pipe so I am anxious to see how that affects things.
 
Rich setting ate safe, just hard on plugs. Once you get the feel for how it runs you'll lean it out a bit more.... and just a suggestion you should go read the walbro manual I posed over in the carb page. The jets don't "kick in" it's a progression at the butterfly opens up. They have pictures in the manual that explain it far better then I can. You "jump" in rpm is the engine hitting its power band.
 
Back
Top