Um ok... seriously you guys need to stop coming up with these bs things and stay on the subjects.

And another thing where are the freakin admins telling people to stay on subject and telling you freakin whinning baby's to SHUT THE F##@ UP.

 

BOY, you guys/kids can turn a nice informative post into a buch of BS in a hurry!

Start a thread with something like "let's talk ****" and you guys go on there and duke it out verbally.

 

I am with you on that one swy. I normaly have a blind eye and a deaf ear when it comes to this kind of stuff. After having my bike for almost 3 years the one thing that has evadid(sp?) me, until recently, is how to correctly jet. This was all because I didn't properly know how to read a plug. Some poor soul might need the info on this post, like I did, but doesn't want to wade through all the junk to get it. Now one person has caused John Doe Raptor rider to lose valuable information.

BTW to answer a question brought up earlier to get a mod all you have to do is click on the thumbs down icon on the right side of the screen. Why, do YOU think it needs to be done?

 

ok gentlemen,

I have finally started down the road of the endless jetting task...my motor came back from Sparks with 35 mm FCR'S with 142/145 mains, 48 pilot, and fuel screws at 1 turn out...and needle clip at 3 slot from bottom.....it ran great for about two months...when the motor finally was broken in...( i didnt ride it that much )...i started to develop a 1/2 to full throttle miss, with hesitation, poping and crackling sounds (i.e. preignition and detonation)...1/8 to 1/2 throttle was fine....the plug reading told me I was very lean...had black and silver specks on the plug..(not good)...but and get this...the ground strap color change was perfect and the base ring was a little on the blackish side and the porcelin insulator was blackish...i went to 178/180 mains leaving everything else the same....still had a 1/2 to 3/4 throttle miss, but not as bad...this told me i am moving in the right direction...if i rolled on the throttle slowing up to redline the motor didnt miss....if i roll on at 1/8 to 1/4 throttle and then punch it...(like i am racing)...the motor will miss....i then went to 185/190 mains, turned the fuel screws to 3 turns out....had terrible stumble 1/2 to full throttle...plug reading told me too rich....i backed the mains down to 180/182 with fuel screws at 2 turns out....still have the mid throttle miss and the plug reading was as follows...the strap was all one color...the base ring was backish....porcelin was white....this tells me i am lean....i turned the fuel screws to 3 turns out...and still had a 3/4 throttle stumble....right now i am pulling me hair out....my last adjustment was to turn the fuel screws to 2-1/2 turns out....and put another fresh plug in and go riding...i know what i am doing is the right road to go down...and it does take time..but it's driving me nuts....what i am looking for here is a little encouragement...and maybe some insight to information i may be missing...please keep in mind...i have a built motor...i am in Connecticut at about 300 feet above sea level...and i burn c12 (108) octane fuel....here is my question....does running race fuel throw off the plug readings?....i have read extensively on this "jetting" issue...please..someone help me.....damn i can do a jetting change in 30 minutes now....and that's with full plastic installed....heeheh....getting good at it...

herbdon out........

 

Herb,

I would say to put the air/fuel back to where it was originally. Play with just the main, until you get it close, then go back to the air/fuel for fine tuning. I have found this to be the best way. If you get to adjusting too much at once, you end up where you are, pulling your hair out.

Start rich with the mains, continue down until you get it close, then adj the air/fuel. From what I have learned, the air/fuel is a fine adjustment-as long as they are within a full turn.

IF you find that you still can't get close with the mains (too rich, then all of a sudden too lean). Go back to where you found it to be a bit too rich and adjust the needles.

Again, adjusting the air/fuel from where they were when you got them should not be necessary at this time. You want to be close with the mains, then needles, then air/fuel. Start with the mains (get it close), then the needles (should be really good by now), then air/fuel for final dial in.

Keep us posted as to how you make out. I too will have the FCR's on by Friday.

Swy

 

Herbdon,
It sounds like your needle position is off. When you get your 3/4 to full throttle right without hesitation or missing (sounds like your were there with the 180/182) using the main jets, then work on the needle height to get the correct 1/4 to 3/4 throttle response.

There was a great article in the April issue of Dirt wheels that gave some basic jetting tips based on engine behavior and not plug readings. They say to start really rich on the mains which should get you a skipping behavior at 3/4 to full throttle. Then move down one main jet size at a time until the skipping is gone. Then work on 1/4 to 3/4 throttle engine response using the needle height (and taper/length if the height alone doesn't get you where you need to be). A soft hesitation without a hard stumble anywhere from 1/4 to 3/4 probably means too lean and a hard stumble probably means too rich.