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09 300 missing some mid range power


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anyone have jetting or setup tips to get better mid range out for a 09 300 xcw?

it has good low range but when half or wide open throttle it seems slow. took out my buds 250 xcw on the same loop and i had to let off the throttle in areas i had to hold mine wide open.

i just went to a 152 main from a 158, shop said it was too rich up top. this helped things but is still missing something. i would think holding a 300 wide open would want to throw you right of the back, the 250 seemed to hit the powerband with more power.

when i bought it new it seemed to have plenty of power. now not so much. even lifting the front end in rocky technical areas seems lagging now.

stock gearing, 50r 14(?)fr.

AS is 1.25 out (i tried 2 out and 1.5 out)

mj is 152

p is 35

3rd clip

yellow pv spring(liked red but it just made it hit harder down low)

fmf tc 2 muffler, stock up front.

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If it ran good at one time, and now you're experiencing a loss of power, you need to figure out what is different. Has the weather changed and your jetting needs to change with it? Is your compression down?

Try playing with the needle and pilot jet. Try putting a 51 or 52 tooth rear sprocket on. Try playing with the power valve. Is your ignition map on the "hot" setting?

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i did notice the 250 had a 51 and im running 50. would the one tooth make that big a diff?

the weather is about the same, same time of year as when i picked it up last year. temps are around 50 also.

i was thinking of bringing it in for compression check also, is there an at home method or tool out there? i know with cars they have a guage you thread in and turn over the engine. is there one specific for motos?

ignition is on aggressive, or connected. PV is clean. i did put in the red but it didnt seem to help alot in the mid range. definately hit harder in the low range.

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post this here in the rocky mtn regional area

https://thumpertalk.com/forum/forumdisplay.php?f=59

and ask locals what their jetting is on that bike in colorado at your altitude. seems like the pilot jet is small ( most 09 300's go with 38 ) but i dont know about the elevation. use the optional N2ZW needle too for more low to mid hit.

Joe

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ktm300,

intersting you say this. i replaced the gear with a new welded one. i marked it as recommended and put it back the same way. im checking this next, maybe i didnt get it back together right.

i checked compression and it came in at 135 psi (5600 elev) which equates to 167 (msl). anyone know if this is within range? low or high?

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checked power valve - good

checked carb - good

checked plug - good

checked piston - bad

cylinder - good

the compression tester didnt lie. the piston was scored on the front left and a half mil thick of carbon etc. on top of the piston. does this mean it ran rich?????

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what needle are you running? try a 1370 (similar to the stock 99' CR250 needle, but 1/2 a clip leaner).

this is what i'm running

FMF fatty pipe

162 main

38 pilot

1370 needle on the 2nd clip

yellow spring

this is at around 500-1200 feet and 50-80 degree's, with this setup the midrange and low are amazing, and rev's out better then any other needle that i've used, it's very very smooth in the transition from low-mid, where as almost every other needle a tried has a much more agressive hit.

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To my knowledge the 250 and 300 have different ignition's , so you will never get the 300 to respond like the 250 does... My 09 300 has always had that lag between the low end pull and the rip of the top end... I've played with the different PV springs but I'm almost thinking of changing out the blackbox . Anyone else try that or better yet the 250 SX ignition??

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got her all back together.

power valve looked clean and working properly. pin still in place.

cylinder looked good per shop. a little bit of piston skirt stuck to wall but very minor. experienced moto heads said it was a cold sieze, due to not being warmed up properly. they said you never notice due to it happens so fast and fires right back up.

went with the teflon coated skirt ktm piston. a bit more $$ but seemed like the right thing to do.

went with thinner base gasket and i could feel the diff in compression already. will run compression test tonight.

hoping to get a test ride either tonight or tomorrow to find out if new top end gave me back the power i remember. if not then i will move onto the jetting changes. most ktm owners locally have said my jetting looks good, maybe some minor changes but nothing major should be needed.

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To my knowledge the 250 and 300 have different ignition's , so you will never get the 300 to respond like the 250 does... My 09 300 has always had that lag between the low end pull and the rip of the top end... I've played with the different PV springs but I'm almost thinking of changing out the blackbox . Anyone else try that or better yet the 250 SX ignition??

the 300 piston just weights more, and its not going to ever move as fast as the smaller 250 piston, I have a 250SX black box on my 300, along with the SXS head, SST pipe, and Dicks racing oval bore carb, its a freaking rocket, BUT it wont rev as fast or as far as a 250, close but no, if you really want a fast reving 300, you need to start with a 250SX, they have a lighter crank, and add the 300SXS kit.

Mike

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