LANCER
Serious Thumper Alliance Member
Offline
Savage Beast Performance Parts
Posts: 10618
Oklahoma
Gender: 
|
wearsabrowncoat wrote on 05/06/13 at 14:07:36:Hello, Just sent a PM regading a Jetset.
I was going to ask about tuning in the PM but perhaps other members may benefit from this public Q&A.
I have a 97 and live 300 feet above sea level. I just did a blue collar boober kit install incuding their muffler. After install this gave me a little more backfiring and I have been tinkering with the idle mix screw. Still seems slightly more lean than when stock.
When I perform the pilot swaps I plan on also adding a chinese cone filter. What would you recommend for a starting point with the pilots and spacer? I've not used the BCB muffler but from others who have it appears the jetting for the pilot circuit is on the 52.5/55 line, so start with the 52.5 and with the pilot screw at 1.5 turns out. Expect the need to go more on the rich side. Do not go beyond 3 turns out if the engine continues to increase in rpm as you turn the needle out. If/when you hit 3 turns out then go up to the 55 pilot and start the screw back at 1 turn out and tune again.
You are looking for the "sweet spot", the screw position where the engine is at the highest rpm, and if you turn the screw in either direction the rpm decreases. Expect for this position to cover from 1/8 to 1/4 turn, or perhaps slightly more, with the engine not changing its sound/rpm. Just set the screw in the middle of that range.
The pilot circuit (low throttle range) is set.
For the BCB muffler, which is fairly high flowing from the reports of it, will benefit from using all 3 washers in the JETSET to replace the white spacer on the needle. There is not often difficulty with this "mid throttle range" and using 3 washers. If there is then we can deal with it at the time.
For the main jet, start with 152.5 and see how it runs.
Find an area where you can open up the throttle to wide open in 3rd or 4th gear and allow it to go to redline.
If it pulls good and clean without stuttering and without a flat spot then it is usually good to go. If there is erratic running or a flat spot then to up to the 155 main jet and make the run again at wide open throttle. It must be absolutely wide open and at the throttle stop to be sure you have it there. If it pulls strong without problems then you are good. If it bogs down then the jet is too big, so back down to the 152.5.
Always make sure that the engine is fully warmed up by riding for several miles if possible before starting the jetting/tuning. If you cannot ride it then let it idle for a good 10 minutes.
Those are the basics.
|
Pages: 
