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is 32:1 too rich??

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Well like it says I was wondering if the 32:1 I'm running a little too rich. My bike smokes a lot and never seems to run too well at lower rasmps and builds up sometimes in slower trails. I have tried justabout ever jetting combo to clean this building up prob leaning out richeniing up etc to clean it up and the current jetting I have seems to be working the best but still builds up. Slightly etc. I just repacked the silencer too to see if that was it. I have a 04 cr250 with a gnarly pipe shorty silencer vforce3 410 main 32.5 pilot needle 2nd air screw 1.5-1.75 out. I have gone down on the pilot to 30 and it runs on.unless the air screw is in to 1 or less. Lowered the needle and it will not start or even idle, needle up one and it will never clean out. The last thing I can think of is. The 32:1 is too rich? The bike runs good at higher rpms but when I'm in lower rpms it will build up slightly if I go to take off again or need a quick burst for a hillclimb or something. What premixes r y'all using?

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Your problem is NOT THE PREMIX....it's the STOCK NEEDLE. Replace the stock one (2.65mm dia) with a leaner needle (2.66or 2.67mm dia). OR get the JD jetting kit. Those needles are sized like so.

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That was going to be my next move just didn't know if it was necessary to spend 80 bucks. I just knew that some people run leaner premix so I didn't know if there was a different or better option than 32:1

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Read up on this thread.

http://www.thumpertalk.com/forum/showthread.php?t=1030096&highlight=

Using Maxima SuperM here at 32:1. Low smoke. Low load up. Tight trails only. Try Honda's jetting chart as shown in 02-03 manual (page 4-5 or whatever page in your 04 manual). Bike revs out freely for quick bursts. No spooge either. Stock exhaust on fully rebuilt motor.

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jd kit the biggest waste of money this century. call sudco and get 5 needle for 25 bucks. or 2 needles and a crap load of jets. if you know precisly what needle you need then buy just one.

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jd kit the biggest waste of money this century. call sudco and get 5 needle for 25 bucks. or 2 needles and a crap load of jets. if you know precisly what needle you need then buy just one.

On my already jetted YZ250F the JD kit made it way worse. More bog using his identified settings. :bonk:

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There enlies the problem.I got no idea where to begin when looking into needles I have not done much research into needles to know much about em. I have read a lot that the 250's are better running at 40:1 is that true?

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I have read a lot that the 250's are better running at 40:1 is that true?

There are a lot of factors involved such as the particular oil and the max/rpm duration the engine sees for your particular riding. 32:1 is the no-brainer ratio that is safe under most conditions.

That being said, your problem with smoke, spooge and loading up is most likely carburetion. A light oil like Lucas will help reduce smoke/spooge somewhat, but if you are trail riding an '04 CR250, you would probably benefit most from a carb swap to a Keihin PWK.

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i ran 50:1 for years in CR500's, and never-ever had one single lubrication related issue. i say definitely try 40:1. you will need to lean your current jetting though.

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i ran 50:1 for years in CR500's, and never-ever had one single lubrication related issue. i say definitely try 40:1. you will need to lean your current jetting though.

A more lean fuel mixture would also mean leaner jetting? I figured it'd be opposite which is why I recommended the leaner mix.

And jedclampette the stock needle in my bike is 2.820 mm would a leaner needle used be like a 2.830 or 2.840? (Those r the options in the manual it suggests)

Edited by Paczowski123

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lean oil will make the bike run richer.

get a PWK airstriker and have all tour problems dissapeir. get it from JD and itll come almost perfectly tuned to your door.

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A more lean fuel mixture would also mean leaner jetting? I figured it'd be opposite which is why I recommended the leaner mix.

And jedclampette the stock needle in my bike is 2.820 mm would a leaner needle used be like a 2.830 or 2.840? (Those r the options in the manual it suggests)

those values apply to the straight section diameter only, which in turn only really does work at closed to 1/16 throttle or so. buying those needles IMO, would be a waste of money. realistically, moving the needle clip around shouldnt cause the bike to not start or not idle, those are pilot circuit issues. when you move the clip you esentially move when the taper comes on, the straight section remains the same.

the thicker the straight section, the leaner the needle.

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first thing you will have to grasp before you ever understand jetting is that rich/lean refer to the air;fuel ratio. not the fuel;oil ratio. a jet will pass a measured amount of liquid. the higher the premix ratio, say 50:1 vs. 20:1, the more fuel that is in that amount of liquid that passes through the jet. and therefore 50:1 is a richer mixture than 20:1 because there is more fuel to mix with the air. grasp that concept, and you will be much better off when tuning. on a side note: dont be afraid to run high premix ratios! back in the day we used to do alot of riding in the winter. and, on the really cold days all my friends would go from 32:1, to 20:1 thinking that more oil would help the engine. when in fact all it did was lean out the mixture, and cause ALOT of seizures. where i would go from 40:1 to 50:1 to richen the air;fuel ratio a little bit, and my engines always lasted a long time. i tried to edjumacate them, but they wouldnt listen. they would always say "bullshit, more oil has to be better!". wrongooo.......

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I'm not a fan of altering premix ratios to correct jetting issues. I run 32:1 (Maxima Formula K2), find a baseline combination that works, then alter jetting for temp and altitude as needed. I'm also not a fan of thinner mix ratios than 32:1. I know many successfully run less oil, but the only upside (IMO) is saving a couple bucks on oil. The potential downside is increased wear or failure. YMMV

I didn't have any troubles getting my Mikuni to run crisp and idle well. But I highly recommend taking the $80 you were going to spend on a JD Jet kit, and put it towards a Keihin PWK A/S. It's a better unit for the 3rd gen CR's, jetting is more stable, and low-mid throttle response is noticably improved. It's the 2nd best mod I have spent money on for my CR, the 1st being suspension.

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And jedclampette the stock needle in my bike is 2.820 mm would a leaner needle used be like a 2.830 or 2.840? (Those r the options in the manual it suggests)

SO your '04 CR2 did not come w/ the new TMX carb w/ the TP sensor? Because if it did, the stock needle in there would have been a 2.65mm diameter. Just to verify, do you know what is the last 2 digits (right after the dash) of your Honda needle?

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the only reason i brought up changing the premix ratios to alter tuning, is because when you can have day to day temp fluctuations of 30degrees, its a pain in the ass to rejet every day. its true that it is not the preferred, or proper way to do it. but it does work. and i had 20years of success running 40-50:1 premix ratios. in that 20 years i had 2 seizures. one was before i understood jetting (it caused me to learn real quick! thank you Eric Gorr for the couple hour long phone conversations!), and i forgot to put coolant in a CR500 one time. other than that, not one single oil related failure.

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I'm not a fan of altering premix ratios to correct jetting issues. I run 32:1 (Maxima Formula K2), find a baseline combination that works, then alter jetting for temp and altitude as needed. I'm also not a fan of thinner mix ratios than 32:1. I know many successfully run less oil, but the only upside (IMO) is saving a couple bucks on oil. The potential downside is increased wear or failure. YMMV

I agree...you first must establish your baseline. THat is the holy grail. Once you know what that is, for your style of riding, and temp and altitude, then jetting for different seasons and riding in different parts of the world is but a few changes away. As for sticking to the old school 32:1 ratio, nothing wrong with that. But the old school ratio was based on old lubricants and old R&D metrics. With so much advances already been made in synthetic premix, you don't need to take the shotgun approach anymore. The synthetic premix is far more efficient at dropping out of suspension and it lubricates for longer periods and protects parts much longer too. With prolonged use of 32:1 when a 50:1 gets the job done, one negative I know that rears its ugly head is the powervalve gets gummed up and carbonizes too much.

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first thing you will have to grasp before you ever understand jetting is that rich/lean refer to the air;fuel ratio. not the fuel;oil ratio. a jet will pass a measured amount of liquid. the higher the premix ratio, say 50:1 vs. 20:1, the more fuel that is in that amount of liquid that passes through the jet. and therefore 50:1 is a richer mixture than 20:1 because there is more fuel to mix with the air. grasp that concept, and you will be much better off when tuning.

This part needs to repeated. Rich/lean only refers to whether the AFR is less or greater than 14.7:1 (with gasoline)

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