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-   -   How do you know you got your jetting right ? (http://www.gasgasrider.org/forum/showthread.php?t=12764)

Krisden 07-01-2012 04:38 AM

How do you know you got your jetting right ?
 
I've just replaced my exp pipe because of a nasty crash crushing the old pipe
Now my bike seems faster and uses less fuel but the first part of the pipe have turned a gold color (heat ?)
I'm new to gas gas and im now questioning if my jetting was or is now right
how would i gauge that ? is there a right sound or ping ?
being new to gas gas i cant really tell if the power is right
any help would be nice six year off a 2t has made my a noob again :)

Jakobi 07-01-2012 04:47 AM

Hot topic. How lean is too lean?? Poor power, high temps, easily boils over, white spark plug, not much piston wash. Pinging under load. IMO a well jetted exhaust note sounds crisp and clean. A lean one sounds too tinny but more so lacks power under load. A rich exhaust note sounds wet and dull.

The easiest way to tell is to richen it up and see if it makes more power. If it does then it was a bit lean. If it gets too rich and starts to break up then switch back.

Krisden 07-01-2012 04:52 AM

its not over heating at all
sounds more crisp but band is weaker but that could be a pipe as its an
fmf gnarly
i was just worried as im getting 140 out of a tank when i only got 120 before
I just have nothing to gauge it off hence the question

wence 07-01-2012 06:10 AM

Jakobi is the man to talk too:D

Jakobi 07-01-2012 07:03 AM

Is that on the stock tank?? If so thats about twice as far as most people get. No one really has anything to compare against with their jetting, apart from other settings they have tried, which is why I suggested richening up the needle one clip and experiencing the change (which may be better or worse). Its all a very personal experience depending on what you want from the bike and the way you ride. When I jet I tend to go to somewhere with an incline and do runs in different gears at different throttle positions. Basically I'm looking for good response and having the engine take revs easily. As things get leaner the bike will rev faster but may also start to lack torque and take on more of a 125 feel where its weaker below the band and super responsive on it and needs more clutch work. As they get too rich you'll get a lot of 4 stroking and burble at light throttle or part throttle. Ideally I want my bikes to fall in between these.

Krisden 07-01-2012 07:20 AM

sorry fair call
have a Clark 12.5 tank gnarly pipe standard scotties jet set up i was after jetting info just after how do you know you got it right :)

Krisden 07-01-2012 07:45 AM

Quote:

Originally Posted by wence (Post 89766)
Jakobi is the man to talk too:D

\

Your our only hope Jakobi !!!


:)

Jakobi 07-01-2012 08:06 AM

Ha.. pfft. I know nothing about it other than what I've read and experienced.. If it feels close and you just want to confirm best method is probably to index the throttle and go and rip a few plug chops at varying throttle positions. From memory scotties was setting their Euro models up with 42 N3EJ#3 178 after setting the floats a touch lower than stock. I'd say its fairly safe even if the pipe did lean things out a bit. Especially if you haven't increased the compression ratio or tightened up the squish (IE stock engine). For me I just say the jetting is right when it feels right, and come to this by experiencing what is too rich, and what is too lean.

Krisden 07-01-2012 08:25 AM

i hate not knowing gas gas aust isnt too helpfull when you ask questions they just have a standard answer
and that's right what does too lean sound like :)
i hate not knowing
looks like i will have to rebuild soon just to be safe

Jakobi 07-01-2012 09:14 AM

How many hours you at now?

No one can really jet a bike for you on the phone or online, or tell you the answer. Its really one of those things you have to experience or feel for yourself, and once you do you'll know. My advice is that if the bike is still taking throttle and accelerating well when given throttle at any rev then the bike isn't too lean. Pinging will happen if you go too lean and will sound like bolts in the ehxuast and will be evident with the engine under load, and usually with flat power as well. I also think the turbinecoreII silencer produces a much raspier sounding exhaust note than the Q4.

If you're worried richen everything up until it rides like crud, then lean it off until it runs well.


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