220 bogging off idle

[mechanos]

Recently did mods to my 05' KDX 220, added Pro Circuit pipe and 607 reeds.
With stock jetting (45 and 145) and clip at #3 position, bike bogged badly anywhere below 3/4 throttle. I raised the clip to #2 position and adjusted the air screw out to 2 1/2 turns which helped, but still had some bog.
I dropped the pilot to a 40 and that helped a bit more, also able to get idle air screw in to 1 3/4 turns but still had a bog when snapping the throttle from idle. I jumped up 150 main jet, and the bog was completely gone. Although I had only ridden with the 150 main in tight single track. This weekend I rode at a moto-x track and was hooking up like crazy, only to find that I had lost my top end power. Not liking that much I swapped my main back down to a 145. The power was back but so was the bog. The bog isn't terrible it just seems to come at the wrong time (creek or log crossing etc...) I will say that its better after the bike is good and warm.

Any suggestions on what to try next?

 

[sr5bidder]

there are a few sizes between the 150 and 145 sound like a 148 is the next step and maybe a 42 pilot??

 

[liven07]

Performance reeds require a down size in jetting not up and the pipe, most of the time stays the same. If you look at the package the performance parts come in it should tell you on the back what jetting you should use.

 

[KDXdog]

I'd call JD and order his jetting kit. The kit has needles in addition to jets. Sounds like you have done the jetting swaps, maybe a new needle in in order.

I put one in my 04, stock motor with FMF Gnarly woods & ISDT silencer. Bike runs clean down low, and RIPS up top!

I was amazed at the difference a jet and needle made!

 

[julien_d]

oops... double posted?

 

[julien_d]

Hmmm... Where were we when I discussed this with you before? TT maybe?

Anyway, you leaned out the low/mid to get rid of a lean bog, and then made up for it by going way to rich on the main.

Like I said over there, take the time to jet it correctly. If you want to keep guessing, then throw a 48 pilot in with the 145 main, run the needle in the in the stock #3 location. If you still have some bog, lower the clip one notch RAISING the needle.

All things in good repair bog should = lean, sputter = rich. Do NOT lean out the air/fuel mix to try and correct a bog. Scary.......

This is all the same stuff I told you already. You can keep asking on different forums until you are blue in the face. The ONLY correct answer is to correctly jet your bike.

 

[sr5bidder]

:cool: you tell him JD....can you guess who I am on TT?

 

[mechanos]

In my defense

I'n my defense... I did ask the question on another forum, and after a few days of no reponse (and my post getting buried on the second page) I asked here.

Sorry to put you out.

 

[mechanos]

The reason I posted in the first place was that lowering the needle, and installing a smaller pilot helped with the bog and also went along with Boyesens recommendation to lean my jetting, but was contrary to standard philosophy (lean bog theory).

If I had never read anything about carburation, my next step would have been to go even leaner.

Wouldn't it make sense that if I put the jets back to stock (larger) and the needle higher, my bog would get worse?

What part of this should I not be confused about?

The temp has dropped 40 F here, so I'll see if my bog is worse or better on this weeks ride.

 

[julien_d]

It's ok, I'm not put out. I'm really just trying to help you. The bog being partially better after you leaned it out could have been a placebo effect, or a side effect of your riding conditions that day. The most important thing to note is that when you went to quite a larger main, the bog was eliminated but you lost some over-rev.

The JD kit will help make your jetting experience much easier, for sure. Sorry If I sounded rude, I was a couple beers in last night.

Yeah SR, I've figured out once before who you were on TT. It's too early right now though... Give me a few, lol.


J.

 

[mechanos]

Thanks for your help, I'll ignore my own observations and jet a bit richer...I'll let you know how it goes.

 

[julien_d]

check it over really well for air leaks too, especially around the reed cage. That can throw your jetting WAYY off.