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White smoke after installing FMF

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2007 CRF450X - I drained and replaced antifreeze with engine ice.  I also installed FMF Power Core 4 slip on last night.  Now there is a lot of popping when I let off the throttle.  There is a little white smoke while running warm but more when turn bike off.  The previous owner had the idle down really low and I tried to adjust but I am not sure if that made it worse.  Is there any factory recommendation on the idle screw?  Turn all the way (left or right) then turn out so many turns?  No other air box or modifications, factory jetting.  Any suggestions?  I found somewhere the smoke could be antifreeze?  Could have I over filled?  Running really hot and heating up really fast on idle.  Thanks.  

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1.  You can't upgrade the exhaust without upgrading the intake and the jetting. The bike is too lean already. Put the stock exhaust back on until you fix the airbox and jetting....

2.  You adjust the fuel screw first (1 turn out) then the idle (as low as it will go) then re-visit the fuel screw to raise the idle (about 1.5)

3.  If you have stock jetting with a modified exhaust you might have warped your head and you are leaking antifreeze into the cylinder. There is no other logical way antifreeze can get inside the motor...

4.  YOU NEED A SERVICE MANUAL

5.  YOU NEED TO READ ALL THE PINNED POSTS at the top of the forum.

 

165 main

45 pilot

NCVS needle 3rd clip

50 leak jet

4x4 opening on top of air box

R&D fuel screw to aid in fuel screw adjustment

Edited by Krannie

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I have not taken the bike out since putting the FMF on the bike, just let it warm up and road around the yard for less than a minute.  I will put the stock exhaust back on for now and see what happens.  Not looking for major performance improvements I just thought the exhaust would sound and look better.  I guess I should have left it alone.  I am coming off a CRF 450R and did not have these issues.  Thanks for the advice.  

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Thank you for the advice.  Put the stock muffler back on and running a lot better.  Still slight pop but nothing like it was with the FMF.  No smoke with stock.  Ordering a jet kit and will open up the air box before putting it back on.  I will try cleaning the jets for now.  Bought used and I think it might have been sitting awhile. 

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<< I found somewhere the smoke could be antifreeze?  Could have I over filled?  Running really hot and heating up really fast on idle.>>

 

 Besides running lean because of the pipe change, I think your going to find you have a head gasket leak.   White smoke is coolant being burned.

 

 You can't overfill the radiator.   It will blow off (assuming the cap is working correctly) as soon as it warms up.  Check where it is now and note. Then do what Krannie said and closely monitor the raditator level after that.   if it keeps dropping, you have a leak.

 

Jim.

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the smoke is likely from the new pipe. mine did the same thing and will go away shortly. its white smoke coming out the pipe after you shut it off almost like something is burning inside right?

you also need to rejet like others have said.

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I just received my FMF jet kit.  It has main jets 128-132-136-140-144.  The kit recommends 136 and 132(3000-6000 ft) and 128(above 6000 ft).  I am in MD so I am close to sea level.  It does not have anything close to a 165 main jet.  Am I missing something?  I ordered extra 45 pilot jets.  

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I just received my FMF jet kit.  It has main jets 128-132-136-140-144.  The kit recommends 136 and 132(3000-6000 ft) and 128(above 6000 ft).  I am in MD so I am close to sea level.  It does not have anything close to a 165 main jet.  Am I missing something?  I ordered extra 45 pilot jets.  

Yeah...about 10 years of advice on this forum. FMF jetting kits suck.

Do it yourself with Keihin brass or buy a JD kit.

Send that thing back while you still can...

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Thanks returning and will just get the jets from my local shop.  I have new needle from rebuild kit from my 450R.

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Thanks returning and will just get the jets from my local shop.  I have new needle from rebuild kit from my 450R.

 Excellent.

Best 450R needle is the NCVS 16233-men-671

3rd or 4th clip based on mods

Main jet 165 to 175 based on mods

 

Pilot jet 45 or 48 based on mods

 

Leak jet 50

 

fuel screw out 1 1/2 to 2 1/4 turns based on mods.

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I have the bike running again.  There is a pop if idling in neutral open throttle and let go.  It does not pop if riding around.  It is just because not air flowing when sitting still?  Any suggestions?

 

1.  FMF Power Core

2.  JD Red Needle Middle

3.  170 Main, 45 Pilot - Both new

4.  Fuel screw 1 1/2 replaced with MSR

5.  Air box mods - vents cut out on both sides and snorkel removed.  

6.  New UNI Red filter

 

Thanks for your help.  

Edited by wade234

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