Hey guys,
Been reading the forums for months now, but truly have no idea of what i'm doing with a 2 stroke. I bought a basket case 87 LT500 Zilla that had every problem you could think of. After a complete teardown of the motor, I decided to take it to a shop and have it built properly. Everything internally is new and has had a couple of proper heat cycles so far. My question is about jetting with the particular setup I have. I have a brand new Mikuni TM38SS currently with a 22.5 pilot, 400 main with the clip on middle notch. The motor is an 87 with an 87.5mm Wiseco, Hotrod, head is o-ringed and squish is set @ 60cc/.0525. Stock reed cage, clean up port (very mild) AAEN pipe with ceramic coat and non-spark silencer. Also has a K&N with outerwear. Setup is running 110 octane @ 32.1 ratio. This bike is being set up to run @ sea level in the Oregon dunes. Can anyone tell me if my jetting is way off? I just want to get through the heat cycles without nuking this thing as i'm pretty deep financially! I will do a plug chop after the heat cycles and go from there. Thanks in advance, Bill
Welcome to the sight!
Where in oregon are you?
For jetting I was explained that its all about throttle position. How does the bike run? At idle, 1/8, 3/4, and full throttle and that determines what needs to be changed.
Thanks for the reply! I am in Oregon City. I haven't even hit the throttle yet, so no idea of how it runs off idle. I does seem to idle pretty good though. Sunday will be my get into it and see what we've got!
Someone correct me if I'm wrong but I believe that idle to 1/8 is your idle screw, 1/8-3/4 is your pilot jet, and 3/4-WOT is the main.
I'm in Salem, Its nice to see some other Oregonians getting into the classic quad racers.
1/4 pilot 1/2 is the needle jet needle to 3/4 main jet from 3/4 to wot
I'm running a 420 main in mine at the coast. Would have to check my jet box for the pilot, can't remember at the moment. but I think you are close.
See obh I knew someone would be able to set us straight. Should take a video of when you get to ride it and post it up. We'll be able to help out a little better. Also we like videos
I'm at 800ft in cincy and have pretty much the same setup as you (bore 87.5, q pipe, k&n, mild port, my carb is bored 41.5mm and I have v2 reeds) my jetting is 30 pilot and right now a 540 main needle clip 3rd position. My main is super fat and needs tuned more pilot is just right. Here are videos of my idle circuit tuning
25 pilot 2nd needle clip
http://youtu.be/jfMLHURiXe427.5 pilot 2nd needle clip
http://youtu.be/LHBDAdPDJjU30 pilot 2nd needle clip
http://youtu.be/TYyKQbWYN2830 pilot 3rd/middle needle clip air screw out about a 1/4-1/2 turn too much though
http://youtu.be/9T_577nQwHk
I'm flowing more air then you having the bored carb and v2 reeds so I'd say my guess for good jets for your setup would be a 25-27.5 pilot air screw 1.5 turns out 3rd needle clip and a 420-450 main. Start fat work your way down on the main, pilot idle should have a nice chug to it you don't want it racing it will almost sound like it wants to stall but it won't.
Nice videos helpful for me.
I'm flowing more air then you having the bored carb and v2 reeds so I'd say my guess for good jets for your setup would be a 25-27.5 pilot air screw 1.5 turns out 3rd needle clip and a 420-450 main. Start fat work your way down on the main, pilot idle should have a nice chug to it you don't want it racing it will almost sound like it wants to stall but it won't.
This 25-27.5 pilot, start at 450 jet and work down. 400 is probably to lean.