Lancer,
Thank you for your post. I'd just convinced myself I need to return completely to stock and start over. I've never had this bike stock!
LANCER wrote on 08/25/09 at 16:13:16:Since your bike is an '07 model, I assume that it has not had any extended down time which could have left gunk in the carb that would clog any of the tiny passageways, which would affect tuning and cause odd symptoms.
Longest down time I'm aware of is Nov - March. I did use fuel stabilizer.
LANCER wrote on 08/25/09 at 16:13:16:You have checked and/or adjusted the float to proper level.
I have not. I've managed to avoid pulling the carb up to this point. Later in the week I'll have time to get some smaller ID tubing and retry that trick.
LANCER wrote on 08/25/09 at 16:13:16:You have a stock engine with stock carb and a dyna muffler, which is mounted properly and has no air leaks, which would mess with your tuning efforts otherwise.
Correct.
LANCER wrote on 08/25/09 at 16:13:16:With those issues eliminated, you should be able to jet & tune the carb normally. The majority of others with a stock engine, carb and dyna muffler end up with a #52.5 pilot, 3 washers on the needle, and a #152.5 main jet. A few engines like a #55 pilot vs the 52.5, but as long as the engine responds to the tuning process normally then either is fine. Ex: A #55 with the screw at about 1 turn out, or a #52.5 with the screw at about 2 turns out, can supply an equal amount of fuel so there is no real difference. Though Mikuni does say somewhere that if you have a choice, it is better to go with the smaller jet @ 2 turns out vs the larger jet @ 1 turn out. Anyway, as long as you have the right size jet so that when turning the screw you DO have a "happy point" that yields a max rpm at idle, and if you turn either right or left then the engine slows. That tells you that you have the correct setting. Also, it is not unusual to have a small range where turning the screw does not seem to change the rpm. Like you mentioned earlier that between 3/4-1 1/4 turns out there was no change. This does happen at times, and if so then set the screw in the middle of that range ... in this case at 1 turn out.
At 1/2 turns out it slows slightly. It is less than 1/4 turns out when it really starts to bog. It doesn't stall even at 0 turns out.
Back to the original topic: Which is better for the engine when it's warm out and the engine is cold...
a) Choke to first notch - idles rough, but runs OK
b) No Choke - idles OK, but runs rough
LANCER wrote on 08/25/09 at 16:13:16:The main jet that gives you the highest speed @ WOT if you have a road you can do that on. IF not, then the largest main jet that does not bog the engine down @ WOT and near redline rpm in 3rd gear is the one. Keep going larger until it bogs; then drop down 1 size.
I don't have a road I can safely do more than 70 on. I'll try redlining 3rd gear later in the week with the 150 main.
LANCER wrote on 08/25/09 at 16:13:16:If you go through this process and it is still not working correctly, and you know that you have good ignition, then pull the carb and tear it down to look for the problem. Something is clogged. There are several very small passageways and a single small grain of sand can easily clog them.
I don't think that'll be necessary. Part of the problem is that I'm attempting to understand why, rather than just follow instructions.
Thanks for the help.
-D. Dwarf
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