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Twitchy Throttle

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I took my new-to-me CRF230F out last night for a first ride in the trails. I have done the powerup mod (only because I was fixing the carb so I did it while I was in there), snorkle only with stock exhaust. My throttle is too twitchy for trail riding.

My friend has a 230f which is all stock, and I can roll on the throttle ever-so-slightly and roll away.. my bike "brapps" away. It's fun, and it revs happily and freely, but often I *need* just slight throttle.

I'm not sure my throttle tube is stock, perhaps it has a quick turn. Can someone post a pic of their factory tube diameter where the cables go?

Otherwise, does anyone have advice. The two bikes feel night and day different. Is it just the jetting?

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What does your so called "Power up" mod include. (In the interest of helping you to find a solution to the "twitchy throttle" problem .

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3 minutes ago, adnohguy said:

What does your so called "Power up" mod include. (In the interest of helping you to find a solution to the "twitchy throttle" problem .

The absolutely tried and true airbox uncork and rejet. 120 main and 45 pilot with 1 5/8 turns, 2004 needle on the fourth clip. 

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I don't know what to say .....

I'm sure adnohguy will be of help... He always is...

But this is kind of puzzling to me to hear of an uncorked 230 as being too abrupt in power delivery...  I can't imagine the situation where that would be the case...

What is your experience level, and where are you riding it??

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The absolutely tried and true airbox uncork and rejet. 120 main and 45 pilot with 1 5/8 turns, 2004 needle on the fourth clip. 

 That's great to hear, it's NOT a power up kit then, it was done properly.

So that means that you need to look elsewhere for your "Super" "RARE" problem

 

But if it was in my shop, personally, I would cover ALL THE BASICS first.

 

Some of them:

 

Properly adjusted engine valves.

Cylinder leak down test. Maximum of 10%

3-4% would be ideal

PROPERLY SET FLOAT LEVEL

Properly gapped NGK spark plug

Thourghly clean carb including every internal component and passage way.

Camshaft timing been checked?

 There is not such thing as a # of turns out on your idle mixture screw. Only a # of turns out reference is a STARTING POINT.

Set the idle mixture screw for the highest idle speed then set your final idle speed where you like it best. All bikes are different. Elevation and outside air temperature changes it also.

Clean and properly oiled air filter

 

You have a genuine Factory OEM Honda shop manual, correct?

 

 

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Awesome, I'll answer these questions below:

 

Properly adjusted engine valves. - about 20 hours on the bike. Do I still need to do this? Do I need a gasket kit?

Cylinder leak down test. Maximum of 10% - See above.

3-4% would be ideal

PROPERLY SET FLOAT LEVEL - Done, dead on the gasket height using the clear tube method.

Properly gapped NGK spark plug - New, gapped.

Thourghly clean carb including every internal component and passage way - Done. Had a blocked airport to the main nozzle earlier. Ports going to the diaphragm thingy are clear, and it was in perfect shape too.

Camshaft timing. - Do I need a gasket?

 There is not such thing as a # of turns out on your idle mixture screw. Only a # of turns out reference is a STARTING POINT.

Set the idle mixture screw for the highest idle speed then set your final idle speed where you like it best. All bikes are different. Elevation and outside air temperature changes it also. - I started at 1 5/8 (as the baseline), going less slows the idle and stalls at 1 turn. Going 1/4 more than 1 5/8 starts to slow the idle too, so as per the manual 1 5/8 is correct.

Clean and properly oiled air filter - yep

 

You have a genuine Factory OEM Honda shop manual, correct? - yep and the one from amazon in pdf.

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3 hours ago, mixxer said:

I don't know what to say .....

I'm sure adnohguy will be of help... He always is...

But this is kind of puzzling to me to hear of an uncorked 230 as being too abrupt in power delivery...  I can't imagine the situation where that would be the case...

What is your experience level, and where are you riding it??

Experienced rider, experienced motor work, riding in very very slow trails. I'm able to compare directly to another stock 230f that is relatively new and it does not experience this twitchy throttle.

I should add this: when the bike is warmed, it idles perfectly. If you introduce *ANY* throttle, even the tiniest amount, the revs will slowly climb to around 3K. I cannot keep the revs at anything just above idle. The other CRF230F I have access to does not do this.

This is the main symptom; think about this happening when I'm riding. I can't keep the revs down until I close the throttle where it abruptly engine brakes and slows down rapidly. It's nearly impossible to go slow in first.

Edited by everlast

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Throttle cable so tight there is no free play in the throttle tube? That can cause the sensation you have described.

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4 hours ago, everlast said:

The absolutely tried and true airbox uncork and rejet. 120 main and 45 pilot with 1 5/8 turns, 2004 needle on the fourth clip. 

The late model bike has a different needle.  Could that be what you're liking?  First, I would richen the fuel screw and see if that helps because that's easy.  Also, is the 45 jet .45mm inside diameter?  Venting?

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Did you ride it before uncorking it?

If we were good before the uncorking, we can narrow it down to some element of  the uncorking...

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Go to a 48 pilot and readjust idle mixture again. Try that....
You need a little slack in the throttle cable. Lube the cable with a lube tool and lube the throttle tube with a light misting of silicone spray after the tube and handle bars are cleaned well with brake cleaner
If you have never adjusted the valves with a dead cold engine, do it.... basics have to be done first.
Never assume no matter what or how old the bike is.
This is not a normal problem....
But it can be repaired.....

IMG_0007.jpg

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Experienced rider, experienced motor work, riding in very very slow trails. I'm able to compare directly to another stock 230f that is relatively new and it does not experience this twitchy throttle.
I should add this: when the bike is warmed, it idles perfectly. If you introduce *ANY* throttle, even the tiniest amount, the revs will slowly climb to around 3K. I cannot keep the revs at anything just above idle. The other CRF230F I have access to does not do this.
This is the main symptom; think about this happening when I'm riding. I can't keep the revs down until I close the throttle where it abruptly engine brakes and slows down rapidly. It's nearly impossible to go slow in first.


Maybe a vacuum leak?

With a dead cold engine on cold engine first start up. Use can spray carb cleaner and use short quick shots of spray around carb attachment and where intake manifold bolts to head. Idle pick up?
If so, vacuum leaks (do not spray exhaust pipe and do not hold down spray nozzle more than 1/2 second at a time.) pause between squirts.

To confirm: spray bottle of regular water adjust nozzle or set to sharp stream spray.

(Hot engine ok) if you have a vacuum leak the water will make the engine idle speed slow down or kill the engine if it's a large vacuum leak.

A handheld propane torch (no don't light it) with raw propane (vapor) around intake manifold when starting a dead cold engine sometimes works better than spray carb cleaner for checking vacuum leaks..... does idle speed increase?

BE CAREFUL, to much raw propane is bad.
Do it out side, away from EVERYTHING.
Get a known good/working fire extinguisher handy.

Hey , thinking outside the box, trying to help, weird problems are hard to diagnose when the bike is not in front of me....
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All of the basics are well covered: air leaks, throttle cable / lube, etc. I'm going to swap back to new stock sized jets tonight and see if it improves. Also going to try to replace the o-ring with a piece of rubber in the air cut valve area. It's intention is to make the bike run richer (reducing air) which if it malfunctions might cause a slight rich condition at idle. Once I introduce a little air with the throttle, the would rev up quickly.

Edit: also, completely stock bike otherwise including two cables, etc.

Edited by everlast

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Solved!!

Once again, an air port was clogged. The port that goes from the main inlet area to the air cut diaphragm circuit was partially blocked. It was the port that goes to the hole at the bottom of the air cut area. I cleaned out the port earlier and air could pass, but I really reamed it out and got more gunk out of it. 

Hopefully if some else ever has this problem, this will help them troubleshoot!

Cheers guys!

Edited by everlast
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On 8/29/2017 at 6:02 AM, everlast said:

I took my new-to-me CRF230F out last night for a first ride in the trails. I have done the powerup mod (only because I was fixing the carb so I did it while I was in there), snorkle only with stock exhaust. My throttle is too twitchy for trail riding.

My friend has a 230f which is all stock, and I can roll on the throttle ever-so-slightly and roll away.. my bike "brapps" away. It's fun, and it revs happily and freely, but often I *need* just slight throttle.

I'm not sure my throttle tube is stock, perhaps it has a quick turn. Can someone post a pic of their factory tube diameter where the cables go?

Otherwise, does anyone have advice. The two bikes feel night and day different. Is it just the jetting?

All of the above posts, and it really depends on the terrain and speed you are riding; slow technical in 1st gear is probably the worst. I rejected buying 2 YZ250F for that reason when riding open trails in other than 1st gear. They were bad.

I have a CRF250X that use to be that way, and sometimes my XRs have, but none as bad as the 2 YZ250F.

My X is probably the closest to a 230 because of the dual cables and adjusting out cable slack really helped mine, just be careful not to adjust so tight that friction increases. The CRF250X also has cable routing issues that can cause binding. I also use a progressive throttle tube but both cable need to be adjusted so there is little to no slack at idle and no binding at full.  I can now ride gnarly slow ST that I had previously reserved for my light weight XR and Trials bike. This is a pic on my XR throttle but same mod on my X.

59ab89d41f1bb_ThrottleModded.jpg.075641fa9ab58d946f06fc42ca17e398.jpg

The other mod that helped both bikes was a slight uncorking of the muffler, both bikes have the same muffler and insert.  I replaced the insert with an aluminum doughnut shaped  disc that really smoothed out throttle response at slow speeds.

59ab8aa338ba3_CRF250XPowerRingInsert.jpg.4b5cc5354131ddc503157a3abe92bd6a.jpg

So the fix is a lot of small changes. I had one XR that was pretty bad and it was a worn needle jet making the off idle mixture too rich.
Sometimes just increasing idle speed a bit will help at very slow speeds. And lastly cover the clutch as a bit of clutch slip can soften sudden throttle response. That is what I do on my X in 1st gear, and in 2nd gear on my XR in the really gnarly ST.

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11 hours ago, Chuck. said:

All of the above posts, and it <snip for readability> the really gnarly ST.

All great advice.. I really like that throttle tube modification; I'm going to try that! The bike is now fixed thanks to finding a blocked air port, but even more control would be better!

I actually removed the jetting and went back to stock for now, with the air snorkle installed. I don't need any more power yet; maybe as I get better and start to outgrow the bike. We had a blast yesterday playing in an area where the trials bikes play, doing wheelies over big rocks and hopping logs, etc. Excellent practice for the gnarly trails!

Edited by everlast
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All great advice.. I really like that throttle tube modification; I'm going to try that! The bike is now fixed thanks to finding a blocked air port, but even more control would be better!
I actually removed the jetting and went back to stock for now, with the air snorkle installed. I don't need any more power yet; maybe as I get better and start to outgrow the bike. We had a blast yesterday playing in an area where the trials bikes play, doing wheelies over big rocks and hopping logs, etc. Excellent practice for the gnarly trails!


Proud of you, you did it yourself and now it's time to smile and laugh under your helmet and enjoy the fruits of your labor and frustrations.

Good job!
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The bike is now fixed thanks to finding a blocked air port, but even more control would be better!

 

 

 

And lastly cover the clutch as a bit of clutch slip can soften sudden throttle response. That is what I do on my X in 1st gear, and in 2nd gear on my XR in the really gnarly ST.

 

This.

 

Even an XR 100 can have jumpy throttle response. Dirt bike control can really be improved by learning to intuitively feed the clutch during acceleration. You'll notice almost every image of a motocross rider shows their finger on the clutch. This really smooths the drive of any bike and gives the rider much more control. It's a great habit to develop. Don't worry about the clutch. I've ridden my 230 this way for years and the clutch works great.

 

One finger. Two if you must. Keep the others loosley wrapped around the grip for control.

 

Congratulations on your successful trouble shooting. It's good to hear you're enjoying your 230. These are really fun bikes.

 

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7 minutes ago, motrock93b said:

This.

Even an XR 100 can have jumpy throttle response. Dirt bike control can really be improved by learning to intuitively feed the clutch during acceleration. You'll notice almost every image of a motocross rider shows their finger on the clutch. This really smooths the drive of any bike and gives the rider much more control. It's a great habit to develop. Don't worry about the clutch. I've ridden my 230 this way for years and the clutch works great.

Congratulations on your successful trouble shooting. It's good to hear you're enjoying your 230. These are really fun bikes.

 

 

 

 

 

Sometimes when I'm really hooning around the trails, I just keep the revs up and use clutch to move the bike, basically slipping the clutch for minutes at a time; they're made to do it. I do get more clutch particles in the oil when I change it but nothing terrible.

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