Thanks for the info, guys. The snorkel is completely gone, that's for sure, and since the PO did not provide it to me I guess it's gone forever. What I may do, however, is plug up the two extra holes he drilled into the airbox cover.

I hate dealing with this many variables. I guess the best way to proceed is to reinstall the stock exhaust and jetting, take it up to altitude for a long run and then keep an eye on the plug to see how it's running.

Brieninsac, sure, I'll be happy to sell the Powerbomb header when I make the change to OEM. Know anybody who needs a Q4? If you are ever up this way give me a buzz at 530-621-0396. My name is Mike. I don't know how familiar you are with our El Dorado County backroads and fire roads but I've been on a lot of them and will be happy to show you what I know. My wife will be happy to know I'm riding with someone, because she thinks if I fall off and get injured up there with no cell phone service I'll be bear bait.

She is, of course, correct. If I start doing a lot of trail riding I'll probably have to get a SPOT or some other tracking device.

 

I can relate to what you are going through. I bought my 2006 in 2009, used with 1150 miles. I didn't do a test ride it when I bought it, just listened to it and checked it out in the guy's driveway to ensure it was mechanically sound. I assumed the transmission was OK because of the low miles (it was).

During the ride home I found that it ran like crap. It idled OK and seemed to run OK at very high rpms. It was awful everywhere else.

When I delved into it here's what I found:

Anti-backfire screen removed.
Slide was drilled to 7/64".
Main main jet: 125 (stock 118)
Pilot jet: 40 (stock 35)
Needle: N1TC
Mixture screw: 2 turns
Crankcase breather hole enlarged to about 1/2"

Snorkel:
KDX snorkel installed (larger).
OEM - Lower portion cut out and installed in addition to KDX snorkel.

Spark plug: CR7E - wrong heat range.
Unifilter installed dry. No cage support. (He had given me the K&N he had just replaced).

So, in order to get a baseline before I made any changes I returned everything to stock. What a difference it made in drive-ability and overall performance. I found it was a pretty nice little engine, other than the lack of power to be expected from 250cc.

Later when I asked him about it he said he hadn't done these mods himself. He wanted more power (he was a pretty big guy). So he had the dealership that he bought it from do them. It was going to "wake up" the bike.

Ron

 

Sounds good Mike. Right now we're in the process of selling a house and buying another. Once we get settle later this spring/summer that would be great. You'll have no problem selling the Q4 on here. I can probably trade you my stock header plus cash for yours when ready.

 

Welcome to the forums. Glad to have you aboard, and its nice to finally have someone older than me on here. LOL I was born 6 months after the Kennedy Assassination.

 

Now you're making me feel bad. I was a freshman walking across the campus of Ohio U. when I heard about the Kennedy assassination. By the time I graduated four years later Uncle Sam had an invitation to join his little adventure in Vietnam waiting for me. I guess he didn't want me to be one of those unemployed recent graduates.

Update on the bike: yesterday afternoon I put the entire OEM exhaust system back on and changed the main jet and needle back to stock. As far as I can tell from the OEM parts in the Dynojet kit that was all that was changed in the carb. I also adjusted the mixture screw to 1 1/2 turns -- it was at three. Started her up and seemed to run fine, and certainly a lot quieter. Now after some typical running I'll check the spark plug to see if it's running lean because of the extra holes in the airbox. If not I'll leave it be.

No bike (or car) is fun to work on IMHO, but this one is easier than most because of the mostly open architecture.

OK, Brieninsac, let me know when you are ready for a ride.

 

With today's fuels, reading a spark plug is difficult. It may not be a good indicator of lean. While you're riding, be on the lookout for lean surge at different throttle positions/rpms/speeds.

 

Izzat so? I didn't know that about plug readings. You can tell I'm definitely from antediluvian era of 2-stroke plug chops for tuning.

Next you are going to tell me that you can't find the optimum position of the air screw by listening to rpms. Then I WILL be lost.