What is the total thickness of the 4 shims?
I've recently noticed development of a single sputter and stumble on my '07 when I roll on the throttle while cruising in third gear and sometimes in first on takeoff. The bike sputters, stumbles then accelerates when this occurs. I'm running with a 130 main jet, 4 shims on the needle, pilot screw 2 & 3/4 turns out and the bike was running STRONG till now. I just pulled the snorkel last night hoping to give her a little more air as I'm pretty sure she's running rich once this stumble developed. I was thinking I should back off 1 shim and see what happens but I know you guys know a lot better than I do so here I am. Should I be concerned about any other possibilities here? What would you guys recommend me trying? Thanks all, I know I can get this straightened out quick with your collective help and extensive knowledge, good to be back! Hopefully I'll have a hollow mod pictorial to come soon if time allows!
First thing to figure out is why it's running rich all of a sudden. Did you check the plug to verify? Smoke from the exhaust? Change source of fuel? Air filter dirty?
If it ran strong then developed this symptom, something changed. Plug, fuel supply, debris in the tank or within needle valve inlet, type of fuel, or change in temperature/humidity/low pressure/etc. How long had it been running strong? Any noticeable environmental changes? New gas station?
I'm making a big assumption that the shims are 0.010" but, if so, bring it down to 0.030". You may actually be running fat until the air can catch up to the fuel.
Plug tip was actually wet and dark when I pulled it, definItely running rich. I know my air filter definitely needs cleaned so I'll get on that, I dropped 1 shim off (total of 3 on now) and I'll turn the pilot in 1/2 turn from nearly 3 out. My fuel source is fine and the same, no exhaust smoke, I've been running rich for a while now I suppose. I'll ride a bit tomorrow and see how she's responded to the change, stay tuned for a swift update and more questions for you. LOL Thanks for all the response fellow Dubsters <--- (I'm coining that term)
Hey Qwerty, so I dropped to 3 shims, turned pilot in to 2 1/4 turns out and the 130 main is still in place. I cleaned my air filter, did a valve adjustment, got new gas in the tank and changed my oil. Still suffering from this stumble. I figure I've been running it rich for some time now, I've never cleaned the carb on the bike yet, I've had it since '08 bought new and I've got 4k on it. should i drop down to the 127.5 I have and clean the carb out? When winter hits I always run it dry, add stabil then run dry again before I store for the winter. What should be my next move at solving this?
Clean it all. Use compressed air to blow any debris back out the ports within the carb. Don't forget to take the slide out, clean its sides up (recommend soapy water as it's plastic and not sure on the strength of carb cleaner you have), clean the needle, clean the diaphragm (soapy water again is needed for it's rubber) and make sure diaphragm seats properly before re-assembly. Also make sure spring is seated properly. When done use your finger to slide the slide and make sure there is no obstruction.
Oh and check for cracks on the carb boot, just to be safe.