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05 WR 450 lean AF

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      I realize this is somewhat redundant, but I have not found an answer to my problem.  Just bought an 05 WR 450.  Has all the mods done except the AIS removal.  First couple rides bike ran great but had a hesitation off idle.  Opened up the carb to check out jetting after doing some research here.  Had a 170 main and a 45 pilot.  Riding between 1000-3000 ft ASL.  Bumped up the pilot to a 48 and changed leak jet from a 50 to a 40.  Bike seems to have better response off idle and pulls hard through the top end.  A little bit of popping on decel, but from what I have read could be due to the AIS still being on the bike.  Since changing the pilot and leak jets the bike runs extremely hot, to the point of losing coolant out of the overflow tank.  I have an adjustable fuel screw at 2 1/4 turns out.  Bike starts right up hot or cold, kick start or electric.  It also has the issue of the idle hanging up on occasion.  It will do it consistently for 15-20 minutes, then it won't do it for the next 30 minutes.  I put in a new plug and headed up to some higher elevation today. 5000-7000 ft ASL.  Bike still ran the same.  It fired right up hot or cold.  Pulled hard throughout the rpm range.  But kept overheating.  I pulled the plug and it was whiter than when I put it in.   Decided to call it a day and try to resolve the issue.

        I tried spraying carb cleaner around the intake boots, around the hot start nut, and by the header.  No change in idle.  Could the new pilot jet have debris in it?  Bought it from the local Yamaha shop.  But maybe something was in it from manufacturing?  Hot start nut threads look maybe a little suspect.  It snugged down nice and tight though.  Really just at a loss here.

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I'd just remove the ais. Also you could try an aftermarket metal hot start nut.

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Ais has no effect on AF. It just burns off unburnt fuel in the exahust

Until the carb is fully re-tuned for non-restricted use, it will have a flat spot

You must also CLEAR THE PASSAGE above the pilot jet, as it has a very tight bend that collects debris. Every old carb I have inspected has this issue.

The debris comes from the vent hoses, each time you shut the motor on or off. Re route them under the tank and filter them

The 48 pilot is not the solution, as it will add other problems. 

Go 45, NCVS 3rd, 165+ main (depending on pipe), disable/block the ACV valve, change to 100 pilot air jet, leak less than 55, change the apump system to the 2008 honda specs and change the linkage spring to 2008 specs,  a new slide plate seal, and a real brass fuel screw, like the R&D. 

Obviously, all intake and exahust restrictions must be removed.

 

 http://tokyomods.com...arburetion.html

  http://www.crfsonly....roducts_id/3932

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2 hours ago, Summit said:

I'd just remove the ais. Also you could try an aftermarket metal hot start nut.

I was going to remove the AIS, but have heard of people getting fined for that in CA.  Ordered the metal hot start nut from zip ty last night.

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1 hour ago, THE KRAN said:

Ais has no effect on AF. It just burns off unburnt fuel in the exahust

Until the carb is fully re-tuned for non-restricted use, it will have a flat spot

You must also CLEAR THE PASSAGE above the pilot jet, as it has a very tight bend that collects debris. Every old carb I have inspected has this issue.

The debris comes from the vent hoses, each time you shut the motor on or off. Re route them under the tank and filter them

The 48 pilot is not the solution, as it will add other problems. 

Go 45, NCVS 3rd, 165+ main (depending on pipe), disable/block the ACV valve, change to 100 pilot air jet, leak less than 55, change the apump system to the 2008 honda specs and change the linkage spring to 2008 specs,  a new slide plate seal, and a real brass fuel screw, like the R&D. 

Obviously, all intake and exahust restrictions must be removed.

 

 http://tokyomods.com...arburetion.html

  http://www.crfsonly....roducts_id/3932

It had a 45 pilot when I bought it.  The only things I changed were going to a 48, based off of the WR jetting guide on here and put in a 40 leak.  Somewhere in making those changes the bike started running super lean and overheating.  

It has all of the restrictions removed, grey wire cut, throttle stop changed.

As far as the vent hoses, rather than route them down through the swing arm just route them up under the tank?

I'm going to pull the carb and thoroughly clean it.  Any suggestions on clearing the passage above the pilot?  Don't have any experience with this carb. Yet.

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Quote

but have heard of people getting fined for that in CA.

Move

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18 hours ago, THE KRAN said:

Yes use carb vent filters. Several brands.

Use copper wire and strong solvent, carefully

Got carb pulled apart last night.  Pretty clean inside.  There where 2 o rings on fuel screw.  One on fuel screw, then a second stuck in the carb.  Probably not good, but would that lean it out so severely?  Also, no adjustable needle.  Going to buy a needle this morning as well as the seal on the slide.  Thing looks pretty rough.  Outside of that everything looked good.

Curious what issues the 48 pilot can cause.  Obviously run rich.  On the TT jetting guide most people are running 48 pilot and 168-170 main.  Mix of 40-50 leak.  Was going off of that info.  

Thanks for info.  Starting to think I should have spent the extra money and bought a FI bike.  Not that I mind working on bikes.  Just can't figure out why it's running so lean.

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On July 17, 2017 at 10:23 AM, THE KRAN said:

Hot start leak/corrosion

Fuel screw leak

Partially clogged pilot passage

....even a contaminated/ melted body seal, melted from using too much strong solvent....

My man!  You nailed it.  Pilot passage was completely clogged.  I have a small high powered light.  Could not see light through the hole at all.  Used a piece of welding wire.  Clear as day.  Surprised it started and ran as well as it did.  Thinking it may have been partially clogged before I installed the 48 pilot.  Going to put the 45 back in per your advice.  Waiting on adjustable needle and float bowl gasket that I ordered to arrive to put it back together.  If you're ever around Auburn hit me up.  I owe you a beer!

How do you like your YZ450FX?  If I had the money to buy a new bike I think that would be my choice.

And thanks Again!!!

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No sweat. It's an extremely common problem.

If you put in a fuel filter to the carb (not plastic, metal) and put gas treatment in every tank, and re-route the vents above the tank and filter them, you can eliminate the debris and corrosion that mess up the carb.

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8 hours ago, THE KRAN said:

and put gas treatment in every tank

This works! I've used non ethanol 91octane treated with Startron in my 05 since new. Always runs like brand new, never bothered to drain gas as is sits all winter. 

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On July 16, 2017 at 6:38 AM, THE KRAN said:

Go 45, NCVS 3rd,

Alright, one last question.  Appears to be needle from 04 YZ450?  Better option than 04 WR needle?  I ordered the WR one.  

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11 hours ago, Nomadic said:

Alright, one last question.  Appears to be needle from 04 YZ450?  Better option than 04 WR needle?  I ordered the WR one.  

Every year Yamaha YZ has at least (6) needle options. So, without knowing which one you have.....

The WR needle is too lean, you do not want that .

The NCVS is a Honda CRF450R needle that is richer across the board, with a nice taper. JD Red and Blue needles are other nice options.

The YZ needle are usually much leaner, but that carb has no ACV, a larger pilot air jet, and an ignition that is advanced 10 degrees from the start, and more as rpms go up, a head with HUGE amounts of flow, a larger header, etc etc. 

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On July 16, 2017 at 6:38 AM, THE KRAN said:

Go 45, NCVS 3rd, 165+ main (depending on pipe), disable/block the ACV valve, change to 100 pilot air jet, leak less than 55, change the apump system to the 2008 honda specs and change the linkage spring to 2008 specs,  a new slide plate seal, and a real brass fuel screw, like the R&D. 

Alright, I did all of these things with the exception of the AP setting.  The AP seems to be working fine.  Sprays just after the slide goes up and has a solid stream.

Went out and rode the bike today on a pretty open road so I could focus on throttle and bikes reactions.  It fires right up hot or cold.  First kick or with the button.

Fuel screw turned all the way in and bike still runs, indicating I need a smaller pilot jet.  I can turn it out nearly 3 turns before it effects the idle.  I set it at 1/2 turn out.  Bike revs from idle fine.  While riding you can roll on the throttle or twist it to the stop and it pulls with no hesitation to the upper rpm's.  However when I let off the throttle I get some popping.  Seems to get worse as I turn out/richen the fuel screw.  I'm thinking it's the AIS doing it's thing burning off extra fuel. Especially since I blocked the ACV  which is supposed to help with that.  

I was feeling like everything was good.  Then I pulled the plug.  It is still white like a new plug indicating a lean condition.  I am confused.  Based off of the fuel screw I need a smaller pilot.  Based off the plug and what I'm now thinking is a lean pop on decel I need to go richer???

I put in a new plug and dropped the clip one spot on the needle.  If anything the popping got worse and the bike did not seem to pull as hard through the rpm's.  Pulled the plug and it still looks like a new (white) plug.

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Yes, but if you blocked the  ACV, you need to change the pilot air jet from 70 to 100, as mentioned in my first reply.

That is why you are rich. Don't change the pilot, change the pilot air jet. 

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12 minutes ago, THE KRAN said:

change the pilot air jet from 70 to 100

I did that.  Bike runs strong with all of those suggestions done.  I know it's hard to say without being there, but do you think it's popping from lean condition or AIS burn off?   Seems like fuel burn off since it gets worse as I richen mixture, but white plug has me concerned.

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First off, adjust the fuel screw to kill the motor only works if you start with a correctly adjusted fuel screw and SLIDE height.

You can't adjust the fuel screw if the idle is normal or high. With a hot motor, turn the fuel screw to 1 out, and then drop the idle as low as it will go.

Now turn the fuel screw out to raise the idle.

Second, the AIS will always create popping, no matter what you do to the jetting, unless the the ACV is active.  Remove it.

Thirdly, you cannot read a plug from looking at the tip, you look at the base of the insulator. You need to cut off the threads or get a plug loop.......but don't bother, because you are running pump gas which will always give you meaningless readings, relatively.  A typical plug on pump gas it white with a black rim.  

Do not try and jet the bike for plug color. You would have to use race gas if you wanted to do that.

 

Edited by THE KRAN
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