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2006 Honda CRF 450r Jetting

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I ride a 2006 Honda CRF 450r

Mods:

Bills Full Exhaust

Modified air box

AP Mod

Twin Air Power Flow Air Filter

My elevation is 1000-3000ft

Temperature is 50-75F

My question is what should be my main,slow,clip position,fuel screw and leak jet be? I do technical trail riding/dunes

My Current Carb Setup

Main # 180

Slow Jet# 42

Leak Jet #55

Clip position 4th from the top

Fuel Screw 2 turns out

Honda oem jets/needle

Please and Thank you

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Main jet looks way big, I whould think you'd be running nothing larger than a 170. However, you need to let u know what running issues you are having. There is no one 'Do this and forget it' setting. Ride the bike, and any running issues, identify them and the EXACT throttle position and type of riding (whoops, uphill, down hill, fire road ripping) you are doing. Then we can offer suggestions.

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The only issue that I'm aware of right now, haven't had a chance to ride it yet since I installed the 180 is when I wack the throttle off idle i get a light puff of black smoke. Ill take it out today and test the throttle ranges out in a flat field. Correct me if I'm wrong but to tell if I'm running a to big or to small main jet I would run the bike at full throttle stop and pull out the plug and see what the color is ?

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The only issue that I'm aware of right now, haven't had a chance to ride it yet since I installed the 180 is when I wack the throttle off idle i get a light puff of black smoke. Ill take it out today and test the throttle ranges out in a flat field. Correct me if I'm wrong but to tell if I'm running a to big or to small main jet I would run the bike at full throttle stop and pull out the plug and see what the color is ?

You can't really read a plug using pump gas.

The black smoke is from the accelerator pump squirt. It's probably too long or too early. Pull up the sub-frame and watch it squirt. Should squirt all the way into the head, about.8-1.2 sec long. Adjust the linkage so the squirt just misses the slide.

180 main is pretty common on the R's, at 0-2000ft elevation.

45 or 48 pilot is more typical, but your fuel screw adjustment will tell you what's up with that.

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I don't quite understand what you mean pull up the sub frame and watch it squirt since the nozzle is on the intake side of the carb. If you could explain in more detail would be much appreciated. As for my slow jet it takes 1 turn to level out the idle anymore turns after 1 the idle doesn't change. I would understand that being the slow jet is to big. Correct me if I'm wrong. I also noted I did the AP mod how would I adjust my linkage ect to correct the black puff of smoke problem?

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Puff of black smoke when nailing the throttle is normal.

Look at this way, your jetting for steady state running is right or very close. When you nail the throttle, a lot of fuel is squirted in, and this is that black smoke. Visually trying to fine adjust the AP timing will only get it to be off and it does nothing regarding the volume of the squirt. To reduce it, you install a diaphragm with a longer rivet and possibly use a larger leak jet.

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.

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Thank you for the procedure. I did take it out on a test ride down a dirt road wide open and it seemed to really scream. Definite improvement from running a 168 to 180. I stopped and bounced it off the rev limiter and I didn't see any black smoke. I'm thinking my main jet size is pretty dam close. The overall performance of the bike with the ap mod and the bigger main jet made the power noticeable stronger. Ill pull my plug tonight and see what she has to say 👍

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Best tan looking plug I have seen. I think I got her dialed boys. Thanks for the tips and information much appreciated !!

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Best tan looking plug I have seen. I think I got her dialed boys. Thanks for the tips and information much appreciated !!

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