Other Bringing back a Crf230l

PSJBrock

PSJBrock

not sure if this was posted yet or not. A quick way to see if your hanging idle is caused by an air leak is to start the bike and then spray WD40 or carb cleaner between the carb and the motor. If the idle rises you have an air leak somewhere. Also those CV carbs are a pain in my opinion. (which is what it looks like you have). IF you have an air leak you will never be able to tune the carb and make the bike run right.

If this has already been mentioned disregard this post and carry on.
 
J

johnrunner

PSJBrock:
not sure if this was posted yet or not. A quick way to see if your hanging idle is caused by an air leak is to start the bike and then spray WD40 or carb cleaner between the carb and the motor. If the idle rises you have an air leak somewhere. Also those CV carbs are a pain in my opinion. (which is what it looks like you have). IF you have an air leak you will never be able to tune the carb and make the bike run right.

If this has already been mentioned disregard this post and carry on.
Click to expand...

Thanks for the suggestion. I inspected the air boot already and it seemed like new still. Will do the carb cleaner trick though just in case. The idle doesn't seem so much hang as it does alter in speed. Which I know could be the air boot or just the excess amount of air being let in due to the removal of the air lid. Either way the jet kit should help out :thumb:

And if I did have an air leak, like I once did on my Yz, I just replace the air boot assembly right?
 
PSJBrock

PSJBrock

johnrunner:
Thanks for the suggestion. I inspected the air boot already and it seemed like new still. Will do the carb cleaner trick though just in case. The idle doesn't seem so much hang as it does alter in speed. Which I know could be the air boot or just the excess amount of air being let in due to the removal of the air lid. Either way the jet kit should help out :thumb:

And if I did have an air leak, like I once did on my Yz, I just replace the air boot assembly right?
Click to expand...

Well it depends. Sometimes you can get away with tightening the clamps or replacing just the clamps.
 
J

johnrunner

James or BK, shut this bad boy down...today the scooter was

Moto-Morini-sold.jpg
 
J

johnrunner

I figured I was just going to keep dumping money into the project bike to turn it into something it will never be, just for the bike to sit in my garage and never get used. If the bike was going to be used as I originally wanted it to, for my gf and or buddy bike, then it would of been okay. But to see the money spent collecting dust in a garage does sit right.
 
G

grnd0

SRAD97750:
What you describe is a "hanging idle." Typically caused by a cracked airboot downstream of the carburetor, which makes it impossible to fix by adjusting the carburetor. But since yours is nice and clean, I am fairly positive the airbox modification is the culprit.

OK. Since we're "going there," I'll whip it out all over you...

There are multiple 'circuits' (passages) in the carburetor that are metered by jets. Each circuit reacts differently at different throttle positions. Each circuit is adjustable, some in multiple ways.
For this instance,
With the throttle closed, the idle circuit (sometimes called slow jet) provides fuel through a jet and downstream of the slide. Typically much smaller than the other jets, and has a screw adjustment on the side/bottom of the carb. This is called the idle mixture screw. It can be adjusted 'on the fly.' The jet is also interchangable and sizes come in tiny increments. Typically $3-$6 each.

So, first and most importantly, you need to get the bike completely warmed up. So that you can't touch the cylinder with your hand. If it's not warmed up completely, you are wasting your time.
Second, let it come to idle. Turn the idle speed screw so the rpms increase to a high idle. The following is performed at a high idle.
Next, turn the idle mixture screw slowly counter-clockwise until the engine speed slows. (Richening)
Now, Turn it clockwise until the idle speed peaks. (Leaning) Stop there, and back it out 1/8 of a turn. (Should be slightly rich for cooling)
Lastly, set your idle speed screw back down to a realistic idle speed.

This should solve your hanging idle cause by an airbox mod. This means you will also increase the power potential of the carburetor as a whole!
To read more about this subject I strongly suggest this website. It is an excellent source on carburetor theory.
http://www.iwt.com.au/mikunicarb.htm
DISCLAIMER: 2 stroke carburetors typically have idle mixture screws that control air intake. 4 stroke carburetors use a screw that controls fuel.


Now, on to your needle adjustment, which I recommend over changing the main jet.
Take a photo of your needle and slide separated, i'll explain how to adjust it. It's not like a regular carburetor slide.

:wiggle:-BIG DAN
Click to expand...


First post. Still have one of these dinosaurs and I have the above symptoms. I just tried to
adjust the idle mixture screw and as soon as I start inserting tool the rpms go up. Put my
finger over the opening and it picks up dramatically. Just had carb completely apart, cleaned,
everything looked good. I think there was a small o-ring on the mixture screw, think that might
be the problem????? Thanks

Larry
 
SRAD97750

SRAD97750

Moderator
Staff member
grnd0:
First post. Still have one of these dinosaurs and I have the above symptoms. I just tried to
adjust the idle mixture screw and as soon as I start inserting tool the rpms go up. Put my
finger over the opening and it picks up dramatically. Just had carb completely apart, cleaned,
everything looked good. I think there was a small o-ring on the mixture screw, think that might
be the problem????? Thanks

Larry
Click to expand...
Yes, if you get a change from putting your finger over the screw, then the o-ring is most likely damaged or missing. -BIG DAN:thumb:
 
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