Getting a Pipe is jetting necessary

[RevHappy]

I know on a street bike when you get a pipe you need to re jet but could I get away with just a pipe for this summer and re jet over the winter??? Any Pros and Cons I suppose the bike would run a lot leaner with the after market exhaust? :silly:

 

[G. Gearloose]

Only if you want practically free HP and throttle response ;)
The other advantage is you don't fill your nice new pipe with spooge.

 

[canyncarvr]

Why not rejet for a pipe (or any proper performance)..but wait for the winter? What's the five month wait for?

Honestly, a lot of what I say is tongue in cheek......cynical. In this case, I have no idea what the point is.

CDave has excellent write-ups on how carbs work, how to decipher kawi's needle numbers, charts, graphs....basically info out the proverbial wazoo.

Or..if you don't want to mess with the process and/or understanding anything about it, he lists jet changes for individual and multiple modifications. Sure...everybody's situation is different. I didn't ASK him, but I'm sure you'll never hear him say, 'This is what you put in all the time for every situation.'

STILL...it's an excellent place to start! It'll cost you maybe $10-15 bucks and take 10 minutes of your time (G-loose did say practically free)!

re: '..lot leaner with A/M exhaust.'

Sounds like a 4-stroke idea. 2-stroke pipes are going to effect jetting requirements not so much due to anything having to do with the pipe's ability to FLOW...but the pipe's pressure waves as tuned by the expanding/collapsing cone construction. A good pipe 'sucks' the exhaust gasses out, and then 'shoves' the fresh charge back in.

I'm not saying the AMOUNT of mixture effects the DENSITY of the mixture .......pressure would.

Anyway...given a stock kdx with original jetting, changing a pipe isn't likely to put you in a dangerously jetted situation. Well...unless you're riding at sea level in the sand. That might be close.

 

[slcyclerace]

Jetting's as easy as 1, 2, 3. If the pipe didn't come with instructions. you could call the manuf. for recommendations. You usually go leaner with aftermarket pipes. This is what I came up with ; The following works quite well on my 96 KDX: B8ES, Belray 50:1 with Sunoco 94 octane, 152 main, 45 pilot, center clip on stock needle, 1 1/4 out on air screw, Pro Circuit plat. pipe, P.C. Spark Arrester, 12/47 Talon sprockets, Regina Gold O-Ring, M78 Bridgestone. The only reason I change the plug is out of guilt from leaving it in so long. Never foul plugs, even on the slowest, sandiest trails.
When I added the Pro Circuit pipe I went from a 160 stock main to a 158 to a 155 to a 152 main jet and from a 48 pilot to a 45. The stock jetting with the PC pipe made the bike loose power everywhere. If you're not sure what to do, talk to a shop or someone you ride with. Jetting should be as much a part of maintenance as changing plugs or oil.