KDXRIDER.NET

Hey guys... Did a little work today. I went from all stock to:

1997 KDX220R
FMF Woods Pipe
Stock Silencer
Boyesen 607 Reeds
150MJ/Stock PJ (Not sure of size)
Needle 2nd Clip from Top
(Edited) 49T Rear Sprocket

Those are the upgrades. It wheelied really well off the bottom before, and now it seems more linear. Is this normal with this setup? Seems like it should have amplified things... Plug looks chocolate brown at idle, and with a wide open plug chop. I have not done a plug chop at ~50% throttle yet...

Any ideas? Suggestions?

Thanks!
James

if you still have the stock PJ your going to be very rich on the bottom. Get a 40 and a 42 to try and see how it feels.

Main sounds big for a 220 too.... still running the stock carb?

the 39t rear sproket really geared it up...unless you meant a 49t rear and then I'd say your jetting is off. try a 145mj,42pj, clip in middle position and go from there.

To clear up a few things....

#1 I do still have the stock pilot, and am not sure what size it is. I will check that out tomorrow.

#2 I am running the stock carb. Wide open plug chops in 3rd gear (after 5 seconds of wide open running at top speed in 3rd) show a great plug with the 150 MJ. I should add that I am in Boise, ID, at 2200'.

#3 I went from a (Edited) 47T to a 49T for a bit more low speed crawling with the kids. No way I can run a 145MJ. I tried a 148MJ and it was too white for my taste after the same style 3rd gear plug chop. I have not changed the PJ yet. I started with the clip in the middle position and it was not clean when revving. I moved the clip up, lowering the needle, and it seemed to rev out smoother.


***You know, it could just be my mistake on it. Off the bottom it does wheelie away, but I think I was getting on it at too high an RPM, excepting a lot more punch on top. That is probably the Woods Pipe keeping the top end away.....

James

Yep. Like I mentioned in your other post, the woods pipe really kills what little top end the 220 has to begin with. Put the stock pipe back on and see what you think.

LOL.... great....

Anyone wanna trade a perfect Rev pipe for this perfect Woods pipe?

:)

James

I bet someone eventually will, if you post it up in the FS section.

So.... with the Desert/Rev pipe, will I still get GREAT bottom end with wheelies no problem? (As you can see easy wheelies are an important aspect of my "fun" equation)

Any loss in bottom end at all?

James

I don't get it. You say you have a 39T sprocket. Stock is 47T, not 37. Pay attention to what jbowens is trying to tell you fer crine out loud. If you really do have a 39T and didn't shorten your chain, then there's your problem, the chain is wrapping around the kick stand or something and killing your power before you can even get to the bad gear ratio problem.

My apologies. The rear sprocket is now a 49T. For some reason my mind wasn't working properly. I have had a sinus infection all weekend and it is affecting my ability to think (sinus PRESSURE!)...

So.... to quell your suspicions, the gearing is fine, and is 2T shorter than stock.

James

FYI: Please read the post above.

I just pulled my PJ and it is a 42. I know the original owner of the bike and he never touched the carb. Perhaps the shop where he bought it swapped it out because we are at 2200'.... Regardless, I have a 42PJ.

I could try a 40PJ and see what happens. First I may try the air screw/PJ check:

"Turn the airscrew slowly in, and then out, until you find the point where the idle is fastest. Stop there. Now is the time to determine if you have the correct pilot installed in your carb. The airscrew position determines this for you, making it very simple. If your airscrew is less than 1 turn from closed, you need a larger pilot jet. If it is more than 2.5 turns from closed, you need a smaller pilot jet."

James

Okay, just did the test.

The mixture screw was in the exact correct position, at the beginning of the highest idle point.

With the 42PJ my mixture screw is EXACTLY 2 full turns out from closed (two turns counterclockwise from being all the way seated down).

This tells me my PJ is correct, and I know my MJ is correct from the plug chops I did in 3rd gear.

So... Looks like this is just the power characteristic this pipes is going to give me.

James

Even at 2200 ft...I think the main is rich. I ride between 1500 and 2000 and my jetting was on at 142mj, 40pj, and the stock needle in the 2nd position. After I got the rb'd carb, which is bored to a 36mm my jetting is 150mj, 40pj, and a cek needle in the middle position. Granted the temp is around 95 F right now. I think you may have an air leak somewhere...spray some carb cleaner around your carb boots and see if that affects your idle. You may be right on with the 150mj, but something seems a little off.

Okay, I will try that...

FYI it is about 85-90 degrees here right now. The 148MJ was really white on the insulator when I plug chopped it, so I went back to the 150.

I will check for any air leaks in the next couple days...

Thanks!
James

You don't leave the idle screw at the point of highest idle. That is simply to test for pilot jet size. You want to continue adjusting the airscrew out/in in 1/8 turn increments until you find the best off-idle throttle response.

Ah... okay. It didn't say that in the test I found while searching.....

I am happy to report there are no air leaks...

I dunno what to tell you. Each bike is different. I am running no airbox lid, and a brand new No-Toil dual stage air filter, along with the new set of reeds and the pipe has just a few hours on it.

I would take pictures of plug chops with different main jets, but I will have to give the neighbors a few days to forget about the noise...

James

I never do a plug chop for this reason...

I don't ride that way. I normally ride rough stuff at low R's and my jetting does not fair well by going by a plug chop.

I need grunt without all the extra gas in my cylinder when I am running in the woods.

This is why I run it the way it responds best for the conditions I ride in.

I'm going to read this very thoroughly to learn a bit more:

http://justkdx.dirtrider.net/printcarbtuning.html

Then buy a few plugs and cut them up at various jet sizes... I don't really have anything else to tinker with right now, so it will be fun tuning the bike to its max potential....

James