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2005 crf250x Jetting Questions
Posted May 01, 2011 - 08:24 PM
NCYU Needle-clip 2nd from top
Leak Jet 65
Main jet 125
48 starter jet
68 slow jet.
This is a stock CA bike. With zero mods.
Bike starts easy
I would like to jet for approx. 5000ft elevation.
It currently has the off idle bog when throttle snapped open. I am thinking the bog is created by the AP Circuit too lean or rich.
Thanks for your help
Posted May 02, 2011 - 07:59 AM
Posted May 13, 2011 - 08:08 PM
Needle 3rd clip
Pilot jet 45
Starter Jet 68
Fuel screw 1 turn
no mods to bike.
I have rejetted and the bike runs pretty good, I still have a bog when throttle snapped from just off idle, I think the 55 leak jet will cure that. Only other concern, bike will start without pulling choke, when engine is warm.
I am thinking if I should use a 42 Pilot Jet.
Edited by CO_Ridge_Runner, May 13, 2011 - 08:24 PM.
Posted May 14, 2011 - 03:24 AM
Fuel Screw/Pilot Jet
Fuel screw settings in the 'book' are recommended starting points. Every bike is different, as is the temp and altitude. Set the screw according to this method. Do it with the bike fully heated up.
Gently turn the screw all the way in. Now back it out two turns. Start the bike and fully warm it up, go for a 10 minute ride. Set the idle to speed to 1,500~1,800 RPM as best you can (I know, without a tach this is tough, just set it to were it idles relatively smoothly). Once warmed, slow the idle to the lowest possible speed.
*** When turning the fuel screw, keep an accurate 'count' of the amount you are turning it and record it in case you have to reset it for some reason. Makes life easier when you can just set it from notes Vs. going through the procedure again.***
Turn the screw in until the idle becomes rough or the bike stalls.
if it stalled, open the screw about 1/4 more turn. Restart it and slowly screw it in till you can just perceive a change.
If the screw can be turned all the way in and the bike still idles perfectly and does not stall, then you need to go down a size in pilot jet.
Now very slowly, open the fuel screw till the idle is smooth. Blip the throttle, let the bike return to an idle, wait say ten seconds. Confirm it is the same smooth idle.
If the screw has to be opened more than 3 turns to get a smooth idle, you need to go up a size in pilot jet.
If you find it does not stall with the larger jet but has to be open more than three turns with the smaller pilot jet, put the larger one in and set the fuel screw at 1/2 turn.
If the idle speed increased, adjust the idle speed knob to return the bike to a real slow idle speed. You must then re-visit the fuel screw. Keep doing this till the fuel screw is opened just enough to provide a nice steady idle at the lowest possible RPM. Once this is done, increase the idle speed to the normal one for your bike, typically about 1,800 rpm, but go by the spec in your manual.
Posted May 15, 2011 - 06:13 AM
Posted May 15, 2011 - 10:46 AM