06 300 de powerband issues

[risk74]

If you haven't cleaned the powervalves, do so. Mine had a lot of hours on it running/racing single track, felt a bit flat on top. When I took the main valve out there was so much carbon build-up it could not open up all the way.

[Powerhouse]

Powervalve was checked and was fairly clean . It is opening all the way. I'm convinced at this point it's all in the jetting. Plan is to tune it best I can for now and ride all summer. Will get new topend and head mods over the winter. I need to get the suspension set up for my weight (220# with gear) before any engine mods. Lots of roots and rock gardens where I ride and this thing is like a jackhammer right now.

[Powerhouse]

Just an updated. I have tried a few different needle and main jet combinations and have settled on 42 pilot with airscrew around 2 turns out,DEL needle on middle clip and a 178 main. This was the best all around setup. The ddk was good down low but to rich in the middle and up top and the cck was to lean everywhere. I do have a n3eg needle on the way and will try that when it arrives. I did change out my springs for .46 front and a .56 rear and it is much better in the rough stuff. This bike is turning me on to 2 stroke enduros again. Been on my ktm 450exc in the woods for years and love the grunt it has but the weight does take it's toll on you after a while. And while the 300 doesn't seem to have as much power , low or high, it's plenty enough to get the job done and the lighter weight takes less energy and is far better thru the corners.

[Powerhouse]

After playing with jetting and getting the bike to run much better I still wasn't happy with the power...or should I say lack of power so decided to pull down the top end for new rings and head mods. Piston still looked and measured good so I applied a moly based skirt coating and cut 1.25mm off of the head to get the squish to 1mm. Only took a few CC's out of the chamber to keep compression high ( I always run 50/50 race and pump gas) hopefully this will give me the power the bike seems to be lacking.

[Powerhouse]

Bike is back together and running. Did a compression test before starting it. Compression now cold is 185# vs. the 125# cold before. While the piston still measured in spec. The ring gaps were in the 1.25 mm range. No signs of leakage past the top ring but clearly worn and out of spec. The bike was assembled before with a .5mm base gasket and squish measured in the 2-2.25mm range. I assembled with 2 gaskets measuring .8 mm . This aligned the top of the piston with bottom of the ex. Port. I removed approx. 1.25 mm from the head. This resulted in a squish area of 1 mm at the area near the cylinder wall and 1.25 mm at the inner edge of the squish band. Bike started right up and seems much more responsive. Ran for about 5 minutes to heat cycle. I will let cool and retorque head and base fasteners. Will take the bike out for a ride later with current jetting ( 42 pilot,n3eg middle clip,178 main, air screw around 2 turns) and reassess and make changes as needed.

[motopsycho87]

I use the KTM spec as my ring gap, which I believe is about 0.3-0.5mm, worth noting

[Powerhouse]

Gap with new rings was right at .5 mm

[Powerhouse]

Got out for a quick ride and definitely found the power it was missing. A little rich down low and getting a little pinging at mid rpms but clears up as it hits the powerband. The bike pulls real hard now mid to top end. Plan is to go to a 40 pilot and retard timing just a touch and reassess. Very happy with the results so far.

[(F5)]

So chamber looks nice but you should machine head squish to match piston as wedge shape, we'll was on mine. I had to take quite a bit out to reduce compression once that was done.

Compression gauge will lie to you. Throw it away and use a burette to measure actual volume available online.