I picked up some torco gp-7 100% fully synthetic pre mix. I'm going to do a ratio 40:1 mainly cause I ride trails and I don't have high rpms on the trails. I read "spankys jetting guide" and " sponge 101". I guess my biggest concern is adjusting the carb/jets. The terminology makes me nervous. Afraid to blow it up! If there was a video on you tube of how to do it I feel more comfortable. I learn from seeing rather then reading it and second guessing my self. If anyone knows of a video on how to jet can you post it. Thanks for all the help and answers everyone!
Mate...you'll learn from feeling rather than seeing and get use to the terminology!!!
How to adjust the airscrew, grab a screwdriver, mark one side of the edge and turn that air screw in (clockwise), and count how many times that mark goes around. From factory, it should the set to 1.5 out. What does 'out' mean? Well, if you have the screw all the way 'in', this effectively shuts out the air into the carb circuit...in fact try and start your bike with it all the way in..guess what, it won't start. This is because this little screw controls or regulates the ratio of air to petrol that the carb will receive and is very important if you riding in differing altitudes and temperatures...the higher you go up or hotter it gets, the less air density so your carb needs to breathe more , so you turn it 'out' to allow more air. Very important, this little screw is very sensitive, a 1/4 turn here and there makes a difference!!
Understand jetting is complicated at first but you must, repeat MUST start to feel what the bike is doing at each part of the throttle (rev range) which are : Idle(0), 1/4, 1/2, 3/4, full or WOT (wide open throttle)....sitting there revving the crap of the bike doesn't do nothing but foul a plug. Also, each part of the throttle zone are all connected, if you are too rich (too much petrol) around 0 to 1/4, then from 1/2 to 3/4 will be effected as the bike will not smoothly make this transition as the richness travels through this range until you can clean it out by virtue of engine temperature and air velocity but sometimes, you'll foul a plug as the spark plug cannot generate enough heat due to the build up of a rich (oil) mixture.
33:1 vs 40:1 vs 50:1...It's the ratio of oil and a well tune bike can run any of these ratio's even 70:1 but it's dependent of how you ride....ride 70:1 in the desert or MX track where the motor is revving it's tits off and you will likely seize the bike due to lack of lubrication in the mixture and the opposite in tight technical trail riding, use 33:1 and you are only in 1/4 to 1/2 for 80% of the time and you will likely foul a plug or have a heap of spooge coming out the pipe....my golden rule is that after a good ride, you should have a little bit of spooge, if it's dry then the bike is running too lean (more air than petrol) and in the danger zone of a seizure and if it's too much and it's dribbling like a 1yo baby, the bike is too rich (more petrol than air) and while you probably won't seize the bike, you'll probably start fouling plugs and get frustrated.
Grab a notepad or sticky note and pen and write down what you feel e.g @1/4 to 1/2 it felt kinda hesitant until 3/4. Also always, ALWAYS write down your settings e.g 1.5 turns out, main jet is a 178 etc etc...if you don't write anything down you will tie yourself in a knot as you don't have a base to start with, nor do you know what the bike felt like before and after a change (helmet cam's are great for this)!!
I may be coming across as harsh or direct but l and we all share your frustration and fear of the first time in carbs and jetting and all the terminology that comes with it and posting on forums can be daunting when members start asking about needle height, type of needle, type of carb etc etc etc yet every person in this forum is very helpful but you really need to feel what the bike is doing in each rev range before changing this and changing that as this is when the frustration's build and it becomes hard to help you if you yourself don't know what's going on.
