06 300 de powerband issues

[Powerhouse]

Hi everyone, first post here.I recently picked up a rough running 06 300. After reading thru threads here I got her running much better. The bike had real good bottom end and slightly into the midrange and then it would just flatten out and not rev. What I found was an almost completely clogged turbine core assembly in the silencer. Also found a 45 pilot,ddk needle on middle clip and a 158 main jet in it. After disassembling and cleaning the silencer I installed a 42 pilot,cck needle in top clip and a 175 main. The problem I'm having now is getting it into the powerband. It has strong low and mid power but again flattens out past the midrange. If I hold it wide open when it's doing this after 5 seconds or so it will slowly hit powerband and rev out or if I stab the clutch as soon as it starts to flatten it hits the powerband much harder and revs out. I'm thinking I have a jetting issue but wanted to get some insight from anyone that has had this issue and fixed it. Thanks Andy

[dANbOT]

Maybe someone who is familiar with the needles you have will chime in, I'm no help there. Have you have tried your needle clip in a richer position? The way you describe it being flat sounds lean to me.
Pretty easy job to pop an exhaust valve cover, and rev the bike in neutral just to be sure the exhaust valve is operating.

[Cox76y]

Sounds rich to me. Try a smaller main..

[motopsycho87]

Check -

Spark plug (use iridium, i only get 3 rides out of a standard)

Power valve adjustment

Float height

Then try the jetting in my Sig, or close to. The needle jet (not needle) has a tendency to wear over time so leaner needles are required.

Silencer (standard ones break down) (not applicable to you)

Make sure you have a resistor type spark plug cap, non resistors kill cdis QUICK on these

If it's still there. HT Coil, stator coil, cdi. Check all earth points and contacts before changing things.

[Powerhouse]

If I drop the needle it looses it's crispness down low. Powervalve was checked and is opening .

[Powerhouse]

Plug is a new iridium - br9 eix ,float height is good. This bike has definitely seen a lot of time, it was raced, but was maintained. I am thinking it might be a worn needle jet based on the fact that I need to run the top clip. I also don't think it's idling solely on the pilot curcuit as the idle screw is almost all the way in and the air screw has no noticeable effect anywhere from a half turn out to 3 turns out. I have a new carb on the way and will have it this week. I will set that up with my current jetting and then reassess. Thanks for the replies

[Powerhouse]

Got a chance to try a new needle Tonite. It's out of my old Suzuki rmx 250.... 1472 ... equivalent to a dgn. According to the keihin chart it's leaner than the cck at 1/8-1/4 throttle and richer from 1/4-3/4. I installed it on the middle position. After warming the bike up I gave it a quick ride down the street. It definitely smoothed out the power down low but still had plenty and was good til wot. Then It just flattened out, definitely lean. I then swapped out the 175 main for a 185. This worked wonders. Smooth power all the way. No sign of a powerband hit just smooth revs to redline. I'm gonna pick up a 180 main and play with the clip position to try and lean it out a little so it's not so 4 stroke feeling but definitely made steps in the right direction.

[motopsycho87]

That's surprising, mine rips your arms clean off!

[julianorettore]

Originally Posted by Powerhouse

Got a chance to try a new needle Tonite. It's out of my old Suzuki rmx 250.... 1472 ... equivalent to a dgn. According to the keihin chart it's leaner than the cck at 1/8-1/4 throttle and richer from 1/4-3/4. I installed it on the middle position. After warming the bike up I gave it a quick ride down the street. It definitely smoothed out the power down low but still had plenty and was good til wot. Then It just flattened out, definitely lean. I then swapped out the 175 main for a 185. This worked wonders. Smooth power all the way. No sign of a powerband hit just smooth revs to redline. I'm gonna pick up a 180 main and play with the clip position to try and lean it out a little so it's not so 4 stroke feeling but definitely made steps in the right direction.

Did you check the ignition timming to see if it is correct? It may be that the ignition is with the delayed point and this inflates directly in the acceleration of the motorcycle (translate by google :-))

[Powerhouse]

Originally Posted by motopsycho87

That's surprising, mine rips your arms clean off!

Im feeling it's a little too rich thru the mid and top right now which is softening the hit. I ordered a couple different needles in between the cck and the dgn plus a 180 and 182 main and will keep testing. This engine is all stock also so I'm sure it has a huge squish area and lower compression than yours which certainly doesn't help powerwise. It feels about equal in power to my 450 exc ktm but not even close to my CRF 450r