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Jet slow 45 or 48 wich is best?

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Hi could someone tell me where between the 45 jet slow and the 48 jet slow is best and why.I heard the jetslow 48 produce less popping in deceleration but other than that is what it can improve something else?If someone has changed the 45 jetslow for a 48 what difference have you seen?

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You did not give any info,Pipe/air cleaner/ Mods/Elevation.150 or 230?????????????

Crf 230f stock pipe with baffle out,air restric out with uni filter,120 main jet 45 jet slow sea elevation 350-450 feet.

 

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Ok we have guys here same Elev as you,45p jet.We run bigger main jets.Only because,on long hi speed/super hot days.We also run on the beach,45p seems good.

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I have a 2008 230f and went with the power up needle, 32 main, and 45 slow with the intake restriction pulled and baffled drilled out similar to the Rick Ramsey mod. I still felt it took too long to warm up and now run a 48 which helped at sea level.

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Start with a 45 pilot.  After engine is fully warmed up adjust idle mixture screw for fastest idle.

If you end up at <0.5 turns you need a 42 pilot

If you end up at >2.5 turns you need a 48 pilot

 

Most CRF230s are fine with a 45 pilot at sea level.  Some, like mine, must have a 48 pilot.  Mike Coe found the same.

 

A 45 pilot works fine in my bike in the summer but is too lean in the winter.

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To be honest with you, change the 132 main for a 120 main. A lot of us have tried the 132 and it is way rich. Dyno test showed the 120 to be about perfect. Warms up quicker and builds better power. With my stock pipe the 45 pilot jet was good. When I installed pro circuit pipe I had to go up to the 48 cause I had to give it more than two turns out on the mixture screw with the 45.

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Start with a 45 pilot.  After engine is fully warmed up adjust idle mixture screw for fastest idle.

If you end up at <0.5 turns you need a 42 pilot

If you end up at >2.5 turns you need a 48 pilot

 

Most CRF230s are fine with a 45 pilot at sea level.  Some, like mine, must have a 48 pilot.  Mike Coe found the same.

 

A 45 pilot works fine in my bike in the summer but is too lean in the winter.

Hi VortecCPI my mods on my bike was 120 main 45 pilot needle clip 4 position 760 feets and fuel screw 3/4 turn out.And my problem is the bike  poping in acceleraton when i past  mid range????

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Hi VortecCPI my mods on my bike was 120 main 45 pilot needle clip 4 position 760 feets and fuel screw 3/4 turn out.And my problem is the bike  poping in acceleraton when i past  mid range and not easy to start when the engine is cold even with the choke.

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Hi VortecCPI my mods on my bike was 120 main 45 pilot needle clip 4 position 760 feets and fuel screw 3/4 turn out.And my problem is the bike  poping in acceleraton when i past  mid range????

 

First thing to do is to check/set/verify float level.  Float level trumps all metering.  If it is too low the carb will meter lean on all circuits.  If it is too high the carb will meter rich on all circuits.  3/4 turn out seems like too little to me.  Did you set it for fastest idle speed?

 

Misfiring/Popping on acceleration is due to a rich condition.  Popping on deceleration is due to a lean condition.

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First thing to do is to check/set/verify float level.  Float level trumps all metering.  If it is too low the carb will meter lean on all circuits.  If it is too high the carb will meter rich on all circuits.  3/4 turn out seems like too little to me.  Did you set it for fastest idle speed?

 

Misfiring/Popping on acceleration is due to a rich condition.  Popping on deceleration is due to a lean condition.

Hi VortecCPI tanks for the answer i turn out 3/4 because the bike run too lean,but i'm gone check the float level today maybe is't the problem with my bike.The bad thing i can ride my bike outside today because it snow and forecast 40 cm of white shi.....lol

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Hi VortecCPI tanks for the answer i turn out 3/4 because the bike run too lean,but i'm gone check the float level today maybe is't the problem with my bike.The bad thing i can ride my bike outside today because it snow and forecast 40 cm of white shi.....lol

 

I am originally from Buffalo, NY so I know a bit about the white stuff.

 

My guess is you will need to turn that idle mixture screw out a lot if it is that cold.

 

With a 48 pilot I am at ~1/2 turn out in the summer and 1-1/2+ turns out in the winter.

 

For every 5C colder you need to add 1% to your jetting.

Edited by VortecCPI

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I am originally from Buffalo, NY so I know a bit about the white stuff.

 

My guess is you will need to turn that idle mixture screw out a lot if it is that cold.

 

With a 48 pilot I am at ~1/2 turn out in the summer and 1-1/2+ turns out in the winter.

 

For every 5C colder you need to add 1% to your jetting.

I d'ont run when i'ts too cold outside.So i live in Montreal,Canada and the sea level 760 feet i think ,1 to 11/4 out it's enough.

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I d'ont run when i'ts too cold outside.So i live in Montreal,Canada and the sea level 760 feet i think ,1 to 11/4 out it's enough.

 

You can safely go to 2-1/2 turns.  Any more and the idle screw can work itself out.

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i've rolled with a 135 main and 45 jet with 2 turns out and i'ts very too lean my spark plug was white.

 

With unleaded gas your plug will not color very much.  It will be off-white and only have color deep down inside the electrode.  This is why we have to chop plugs with unleaded gas.  You can NOT check plugs the way we used to back when we had leaded gas.

 

http://www.automotiveu.com/tuningunleaded.htm

 

Attached is a picture of my plug with jetting Frank Nye dialed in on a dyno.  He uses a 110 main with either his PoweRing or Outlaw system, both of which I have used and both of which are spot on with a 110 main jet.  You can see the electrode is white at the top and has just a little bit of color as you go down.

 

To size your main jet uses this:  http://www.mikuni.com/tg_main_jet_size.html

IMG_1331.JPG

Edited by VortecCPI

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With unleaded gas your plug will not color very much.  It will be off-white and only have color deep down inside the electrode.  This is why we have to chop plugs with unleaded gas.  You can NOT check plugs the way we used to back when we had leaded gas.

 

http://www.automotiveu.com/tuningunleaded.htm

 

Attached is a picture of my plug with jetting Frank Nye dialed in on a dyno.  He uses a 110 main with either his PoweRing or Outlaw system, both of which I have used and both of which are spot on with a 110 main jet.  You can see the electrode is white at the top and has just a little bit of color as you go down.

 

To size your main jet uses this:  

 

With unleaded gas your plug will not color very much.  It will be off-white and only have color deep down inside the electrode.  This is why we have to chop plugs with unleaded gas.  You can NOT check plugs the way we used to back when we had leaded gas.

 

http://www.automotiveu.com/tuningunleaded.htm

 

Attached is a picture of my plug with jetting Frank Nye dialed in on a dyno.  He uses a 110 main with either his PoweRing or Outlaw system, both of which I have used and both of which are spot on with a 110 main jet.  You can see the electrode is white at the top and has just a little bit of color as you go down.

 

To size your main jet uses this:  http://www.mikuni.com/tg_main_jet_size.html

 

With unleaded gas your plug will not color very much.  It will be off-white and only have color deep down inside the electrode.  This is why we have to chop plugs with unleaded gas.  You can NOT check plugs the way we used to back when we had leaded gas.

 

http://www.automotiveu.com/tuningunleaded.htm

 

Attached is a picture of my plug with jetting Frank Nye dialed in on a dyno.  He uses a 110 main with either his PoweRing or Outlaw system, both of which I have used and both of which are spot on with a 110 main jet.  You can see the electrode is white at the top and has just a little bit of color as you go down.

 

To size your main jet uses this:  http://www.mikuni.com/tg_main_jet_size.html

Ok if have restarts from the beginning first thing,check the float level do you know a link to guide me for adjusting a float level??after that turn more out fuel screw .Check the engine when it's hot check up the air screw.By the way i change my fuel screw the for a 2005 fuel screw because the head is not a D bit and it's more easy to screw what you think it can make a difference for mixing air/fuel?the carburator it's the same for all years since the 230 was came on the market.

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Ok if have restarts from the beginning first thing,check the float level do you know a link to guide me for adjusting a float level??after that turn more out fuel screw .Check the engine when it's hot check up the air screw.By the way i change my fuel screw the for a 2005 fuel screw because the head is not a D bit and it's more easy to screw what you think it can make a difference for mixing air/fuel?the carburator it's the same for all years since the 230 was came on the market.

 

All the fuel screws have the same taper so you are okay.  Float level is 12.5 mm / 1/2 in.  You will need a Honda Service Manual.

 

In the mean time see here:  https://thumpertalk.com/topic/883116-xr-250-r-carb-issues/?p=9300461

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