Everyone has one: Jetting 300ex + some other Qs

[asleepz]

Alright, FMF Powercore 4 full system.. Worth it? Better than just a HMF slip on?

I'll be modding the airbox, adding a uni filter, and a exhaust system. The powercore system asks for a 130 main jet and no other adjustments.

With doing all the other things, what would you suggest? New Orleans, LA anywhere from 12' above and below sea level.

[bwamos]

Yes the full system vs. a slip-on will make a significant improvement. The stock header is tiny in comparison.

With a well ventilated airbox, aftermarket filter, and aftermarket pipe on a stock motor, you should be running a 132-135 Keihin Main Jet at my elevation.

At your elevation I'd say 135-138. You'll most likley need to raise the needle up one position (clip down) also.

[asleepz]

So if you were to pick one jet, which would you pick to try first?

Anyone have any experience with the powercore 4 system?

Oh, and pilot jet? Should it be ok?

[asleepz]

alright I got a line on a 138 jet from a guy at the honda place, hooked me up (99 cents woo!) I'll probably hold off on the 135 till I give it a try. All I need to know now is if I should up the pilot at the same time too. Or I could wait and ride to see if the 135 is needed and just check if the pilot is ok then.

[bwamos]

Leave the pilot. If it backfires on decel. Adjust the fuel screw. If that doesn't fix the backfire get a 140 pilot.

[asleepz]

Originally posted by bwamos
Leave the pilot. If it backfires on decel. Adjust the fuel screw. If that doesn't fix the backfire get a 140 pilot.

lol I hope you mean a 40 pilot but. Alright gotcha, I'll keep ya posted

[asleepz]

Changed it around a bit and decided to get a HMF slip on for now..

Going to have my UNI filter, no airbox lid and the hmf. Trying a 132 main. Sounds good? I'll be doing the white bros header soon after probably around the end of may.

[MTDman11]

get a white brother e series head pipe to go with that hmf, its wat i got, large improvement. c&d racing can probably hook you up

[asleepz]

I plan on it, just can't afford it at the moment and I'll probably ride quite a few times before I get it, so I guess I'll be jetting twice. No biggie. So does the 132 main sound right? I got a 128, 132, and a 135 just in case.

[bwamos]

Originally posted by asleepz
lol I hope you mean a 40 pilot but. Alright gotcha, I'll keep ya posted

Yes I meant a 40 pilot.. lol.

Thanks. ;)

132 keihin main should be a good starting point.

[asleepz]

Stuff should come in at the end of this week or beginning of next. My pipe is coming from OH, so if they can hurry up and get it shipped I'll have it for this weekend :)

[asleepz]

Installed my new HMF slip on, pro armor swing arm guard and rejetted in an hour and a half.. Not bad for the first time. I used the 132 jet. I'm going riding this weekend to find out how it'll work. I also have a 128 and a 135 like I said before but I think if anything it'll be spot on or a little rich (better than lean for now). The fuel adjustment screw is the one to the right of the idle screw correct? Mine won't budge... :( But the idle still seemed good.

First crank was great until I saw black smoke... Then I realized that I had left the choke on putting the carb back in place :scary: but for everything else it went really well..

It's loud as hell.. Honestly it doesn't sound much quieter under load than with no exhaust at all, just took the raspyness out. Anyone know if the quiet core really does a good enough job of "quieting"? Personally I want my ears to ring after I ride.. But when riding at the spillway the ranger's don't share my same enthusiasm.

[bwamos]

fuel/air screw is the brass slotted screw located on the very bottom of the carb. Center front. Directly between the large 17mm bowl main jet access plug and the enging manifold just past the front edge of the float bowl. If that makes any sense.

Quiet core usually (depending on the quad) makes a fairly significant difference in sound level.

[gixir]

I have the quiet core for my hmf as well. I just haven't had a chance to put it in to hear the diff. I'll do it tonight. HMF will convert your slip on to a full system. Think that will be a good thing for me to do this winter. My 300 is louder than all of my friends 450r's running a HMF full system. I wonder if that is due to the smaller head pipe???


Do you want to adjust the fuel screw in or out to correct back fire on decel?

[gixir]

I have the quiet core for my hmf as well. I just haven't had a chance to put it in to hear the diff. I'll do it tonight. HMF will convert your slip on to a full system. Think that will be a good thing for me to do this winter. My 300 is louder than all of my friends 450r's running a HMF full system. I wonder if that is due to the smaller head pipe???


Do you want to adjust the fuel screw in or out to correct back fire on decel?

[MTDman11]

lol cmompared to whate i used to have (dg rcm) my hmf is quiet. even not compared to it i dont think its that loud.

[asleepz]

Well I went and rode for about 7 hours today and damn was it good. 132 jet was spot on, but the mid range was a little lean since I hadn't messed with the needle yet. I'll do it the next time it isn't raining. It was backfiring while deceleration but I'm not going to get another pilot until I get the needle right.

Everything was great and I'm really impressed with it.