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Jetting for totally stock CRF230F at 5000 ft

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Hi all, I recently purchased a very lightly used 2006 CRF230F.  Carb was partially disassembled when I got it, so I took the whole thing apart, soaked everything in carb cleaner and blew the passages out with compressed air.  It has the 102 main jet and 42 slow jet in it.  It runs pretty well now but chokes if you open the throttle very quickly - gotta slowly roll it on and then all is well.  It sounds like it's a little lean to me.  What jets are people using on totally stock setups?  I only trail ride and would rather have a quiet, stock bike than a little more power by removing the snorkel or spark arrestor.  I searched the forums a little and it seems like people are using the following setup.  Do you think this will be too rich with a stock setup? 

120 Main jet

45 pilot jet

needle- Part # 16012-KPS-901 (stamped 39A) with the clip at 4th slot from the top. Came stock on '03-'05 230F's.

Thanks!

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All good except use a 118 main

Any higher elevation will require the needle clip in the middle.

 

You MUST make sure the float level is correct !!!IMG_1527.JPG.b57a3257641bae27902063cf189ea923.JPG

 

 

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Yep checked that also, the level is just slightly below the bowl gasket, say 1/8". Is is supposed to be even with the bowl? 

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20 hours ago, adnohguy said:

All good except use a 118 main

Any higher elevation will require the needle clip in the middle.

 

You MUST make sure the float level is correct !!!IMG_1527.JPG.b57a3257641bae27902063cf189ea923.JPG

 

 

 

19 hours ago, VortecCPI said:

Multiplier for 5,000 feet is 0.958 so 115 main with proper float level.

3rd clip for 70F and below and 4th clip for 80F and above.

Did you guys read the original post?  

OP said 5,000 feet with the snorkel restricting intake and stock baffle highly restricting exhaust (quiet).

I'm thinking a new oem 42 and stock 102 or 105 main jet, leave the needle at sea level setting.  Existing 42 is probably varnished and fuel screw passage may be restricted (very lightly used).

Adjust fuel screw for changes in elev.

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Just now, Baja Rambler said:

 

Did you guys read the original post?  

OP said 5,000 feet with the snorkel restricting intake and stock baffle highly restricting exhaust (quiet).

 

Multiplier is still the same so 0.958 x 102 = 98 main.

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Right now it has a 102 main and a 42 slow jet. If I leave the choke partially on, snapping the throttle open works perfectly. With no choke, it dies. That makes me think it's running lean somehow and I have already done a pretty thorough cleaning of all the jets and passages in the carb and the float level is pretty close to the diagram adnohguy showed. I did buy a carb kit which came with new stock jets but I figured the keihin jets that came from the factory were probably better than the aftermarket ones in the kit.

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2 minutes ago, Germanium said:

Right now it has a 102 main and a 42 slow jet. If I leave the choke partially on, snapping the throttle open works perfectly. With no choke, it dies. That makes me think it's running lean somehow and I have already done a pretty thorough cleaning of all the jets and passages in the carb and the float level is pretty close to the diagram adnohguy showed. I did buy a carb kit which came with new stock jets but I figured the keihin jets that came from the factory were probably better than the aftermarket ones in the kit.

Are you doing this while riding or while sitting still in neutral?  If in neutral it means nothing.

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4 minutes ago, VortecCPI said:

Are you doing this while riding or while sitting still in neutral?  If in neutral it means nothing.

Oh.... yes that was in neutral although snapping the throttle open while riding also has the same effect of making it die. I just didn't try it with the choke partially on while riding. Does having a load on it make a significant difference?

Edited by Germanium

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24 minutes ago, Germanium said:

Oh.... yes that was in neutral although snapping the throttle open while riding also has the same effect of making it die. I just didn't try it with the choke partially on while riding. Does having a load on it make a significant difference?

Testing like that has no value as almost any non-AP carb will result is such behavior.  I can kill mine the same way yet it will take WOT in third gear at a very slow pace.

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So you think it's operating normally and there's nothing to be gained by increasing the jet size? I expected a little better throttle response than that...

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The fuel screw has a passage from the bowl that feeds it.  When you adjust the fuel screw with bike fully warm, how many turns out is the highest idle?  If it makes no difference, fuel is not getting to venturi.

Do you plan to ride at any other elevations?

Pilot circuit needs to be dialed in exact before you mess with other jetting. 

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Richening the needle one notch can help throttle response but not until you confirm your pilot circuit.

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Did you guys read the original post?  
OP said 5,000 feet with the snorkel restricting intake and stock baffle highly restricting exhaust (quiet).
I'm thinking a new oem 42 and stock 102 or 105 main jet, leave the needle at sea level setting.  Existing 42 is probably varnished and fuel screw passage may be restricted (very lightly used).
Adjust fuel screw for changes in elev.


Must be afraid of it running it ""un-corked" ?

Way to much power I suppose....

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Thanks for the advice on the pilot circuit, I'm not sure how far out it is now, I'll do that procedure and check. Adjusting the fuel screw does affect the engine's idle as expected.

5 hours ago, adnohguy said:

Must be afraid of it running it ""un-corked" ?

Way to much power I suppose....

 

My reasoning behind that is I only plan to trail ride and would rarely need full power anyway, so why sacrifice the quieter exhaust for a few extra hp that you'll likely never need? This was never intended to be a racing bike...

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I got a factory service manual and set the float level as described in there and also replaced the slow jet with the new one from the carb kit I bought. Bike runs pretty nice now, I'm about 2.5 turns out on the fuel screw. Might try going up one size on the slow jet still but it's running pretty nice for now.  Thanks for the advice! 

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15 minutes ago, Germanium said:

I got a factory service manual and set the float level as described in there and also replaced the slow jet with the new one from the carb kit I bought. Bike runs pretty nice now, I'm about 2.5 turns out on the fuel screw. Might try going up one size on the slow jet still but it's running pretty nice for now.  Thanks for the advice! 

Is 2.5 turns the highest idle?  If so, that sounds great.

If you go higher in elevation, say above 8,000', you can just turn the screw in one turn or so. 

If you go up one size, that would be for if you are going to ride down to sea level and you would have the screw at one turn out at 5,000' then turn it out at the lower elevation.  Get it?  That is why I asked if you were going to ride at other elevations.

 

Edited by Baja Rambler

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Thanks for the advice on the pilot circuit, I'm not sure how far out it is now, I'll do that procedure and check. Adjusting the fuel screw does affect the engine's idle as expected. My reasoning behind that is I only plan to trail ride and would rarely need full power anyway, so why sacrifice the quieter exhaust for a few extra hp that you'll likely never need? This was never intended to be a racing bike...  

 

 While Removing the intake silencer and properly jetting certainly adds performance only because it allows the engine to run properly. Doing so does not make it a "Racing Bike" .I'm not sure how anyone could actually believe that a 230f could instantly turn it into a "Racing Bike" buy Removing the "Restrictor" from the air filter box, installing a 45pilot jet, a 120 main jet, or raising the needle one notch he higher than stock?

 

Maybe you should also refrain from checking and setting the "Float level" properly?

Maybe if the float level was not adjusted properly and you were able to correct that common problem, it would allow your bike to run more efficiently with out removing or replacing anything?

 

And: changing the exhaust system in any way is not required for the engine to run more effectively.

 

Since your more than satisfied with the way it runs bone stock, may I suggest that your correct the suspension inadequacies and replace the stock tires with tires that actually provide enough traction and side bite around turns and off cambers to keep you from hurting yourself at any speed over and above that in which third gear will provide.

Enjoy and be safe.

 

 

 

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