[WTFWFO]

Hi guys new to the board. Pretty good with carbs....usually. My buddy’s CRF150F 2007 wouldn’t idle off of choke so I brought it home took the carb apart and cleaned it as it needed a little love. Bought an All Balls racing rebuild kit and replaced all orings and jets with stock size (was already stock)

Put it back together and it idles extremely high. Will not start or run with choke ON only with choke off. Has stock needle with 2 positions clip is in lower position. Has a 40 pilot jet with a 95 main jet. The fuel screw had the “d” style and has been replaced with a slotted style and is 2 turns out. When idling high the idle screw is 2.5 turns out and if I back it out more the idle does not change however if I turn it in the idle speed climbs even more. I have moved the fuel screw from anywhere from 1.5 - 3 turns out and it has no affect on idle as I would think it shouldn’t due to stock jetting. Please tell me what I am missing?

I sprayed WD 40 as I didn’t have carb cleaner on the boot and vac lines will it was running to see if it changed anything and it didn’t. Appears no air leaks on either side of carb. The accelerator pump line routing is a little funky looking. Perhaps I have lines crossed up. As it was running I tried unhooking some to see if anything would change in idle speed and nothing. I have jetted and setup many carbs 2 stroke and 4 but am overlooking something obviously. Please tell me what I am missing. The needle jet holder is a little mushroomed on the end so I am going to Honda tomorrow to get one of those and a new idle screw set in case something is off with that as well.

Pleas help me out on what I might be missing. Does anyone have a routing diagram for the lines from the accelerator pump to the carb body? Appreciate any and all input here.

If I can get this idle problem solved I would love to uncork this thing with a bigger pilot, main, no baffle and open the air box but seeing as how it ran good stock before and now idles crazy high I just want to get it running stock again before tweaking anything else.


Thanks so much

[JimDirt]

Welcome to the site !!

Leardriver is the resident carb guru here , hopefully he chimes in soon ... I know the Owners Manual does not cover line routing , so the Service Manual is about the only way you are going to get the info you need .... What I would do is go to the local Honda Dealer , and ask their Service Dept. , to print you a copy of the pages with the info you need (line routing , etc.) , that would be the only way I can think of short of ordering a Service Manual ...

[Leardriver]

Welcome.

There have been so many changes made that you may have cured the original problem and gained a new one along the way.

The stock jets are a 40 pilot and a 95 main. While that is a jetting configured by the EPA and lawyers, not engineers, the bike should run decently with those. What altitude are you at?

Your carb is likely to be dirty in a passage somewhere. It is really hard to diagnose over the internet.

You could try the other needle clip setting, but that wouldn't affect idle. Maybe 2 orings on the fuel screw, or not one at all?

[WTFWFO]

Welcome.

There have been so many changes made that you may have cured the original problem and gained a new one along the way.

The stock jets are a 40 pilot and a 95 main. While that is a jetting configured by the EPA and lawyers, not engineers, the bike should run decently with those. What altitude are you at?

Your carb is likely to be dirty in a passage somewhere. It is really hard to diagnose over the internet.

You could try the other needle clip setting, but that wouldn't affect idle. Maybe 2 orings on the fuel screw, or not one at all?

Thanks for the insight. I cleaned the carb in an ultrasonic cleaner with simple green but will take apart and clean again. Took out the fuel screw and replaced it plus spring washer and o ring. Going to replace the idle screw as well.

[Leardriver]

Are you using plenty of compressed air when you clean the carb?

When the fuel screw and pilot jet are out, blast up in there and listen for air coming into the center of the carb.

What I meant by the two o rings is that when you take the fuel screw out, sometimes the old oring stays in there and causes havoc with the mixture. I've seen that 4 or 5 times. Even if you see the old o ring come out, perhaps there is another one left in there by the previous owner.

[WTFWFO]

Using plenty of compressed air but going to do it again.

I didn’t see a second o ring but going to check again just to be safe. Going to replace the idle screw as well.

The needle jet holder that the main jet screws into seems to be mushroomed at the bottom. Shouldn’t affect idle but am going to replace this as well.

I cannot find a downloadable manual does anyone have one they can scan me the carb section. I am wondering if the float level is a little low and causing that high idle as well but want the specs to measure it.

To answer your it earlier question about elevation . I am at sea level but ride I at 2-3k feet

[JimDirt]

Just do what I mentioned before and go to the local Honda dealer and check with the Service Dept. and ask if they will print you off the pages from their Service Manual , they should do it with no problem ... since online downloads are limited or non existent , this may be your only option short of ordering a Factory Service Manual , I do not have one , or I would gladly post what you need , I have most every other Honda service or owners manuals in PDF format and some hard copies , but not that one ... I have mainly big bike manuals (250/450)