Jump to content
Sign in to follow this  

help me out jetting this 07 crf250

Recommended Posts

shimming my valves so i thought id check my jetting

main 178

pilot 48

leak jet 70

slow jet 68

not sure on the needle yet didnt check that.

only mods are powerbomb header and white brothers pipe

the bike runs good but does bog down low if i dont keep the rpms up and just hammer it it will die. hot starts can be a pain sometimes

elevation is 900 ft

what are the stock jet sizes? temps right now are in the 80s and 70s

Share this post


Link to post
Share on other sites

Should be a 42 pilot, 172 main and a 45 leak jet to get rid of the bog. The plug should be close to black when you pull it out the way the jetting is set up. In NE Ohio, I set them all up like this unless the head is ported, then I'll run a 38 or 40 pilot jet. Start with this jetting benchmark. I'm sure it will run a lot better.

Share this post


Link to post
Share on other sites

While we're on the subject, I pulled apart my newly acquired 06 CRF250 to check the jetting too.

Pilot 42

Main 175

Leak 70

Didn't check anything else. I'm running stock piston/ HC stage 2, and dual Yosh exhaust. Mine is kind of a pain to hot start too. I'm just south of Cincinnati a bit. I plan on ordering a new leak jet, but should I get a 172 main, or will it make much difference?

Share this post


Link to post
Share on other sites
ok thanks alot ill get those jets ordered and on the way. are you still running the stock needle?

Yes the stock needle in the 4th position. I've had better luck getting leak jets from a Yamaha dealership.

Share this post


Link to post
Share on other sites
While we're on the subject, I pulled apart my newly acquired 06 CRF250 to check the jetting too.

Pilot 42

Main 175

Leak 70

Didn't check anything else. I'm running stock piston/ HC stage 2, and dual Yosh exhaust. Mine is kind of a pain to hot start too. I'm just south of Cincinnati a bit. I plan on ordering a new leak jet, but should I get a 172 main, or will it make much difference?

The way the weather is right now, the 172 may help a little. I'm in Lexington right now and it's pretty hot.

Share this post


Link to post
Share on other sites

Thanks, I'll try a 172. It is pretty hot today. What kind of jets do you guys run during the winter?

Share this post


Link to post
Share on other sites
Thanks, I'll try a 172. It is pretty hot today. What kind of jets do you guys run during the winter?

Usually bump the pilot to a 45 and move the needle clip down 1 notch. Unless it's below 45 degrees, you can leave the main jet alone. 175 any colder than that. Of course, adjust the air/fuel mixture screw before changing the jetting around.

Share this post


Link to post
Share on other sites

installed a 172 main 42 pilot and moved the needle to the fourth position from the top. still waiting on the 45 leak so im still running the 70. now the bike bogs BAD twisting the throttle. it will almost die every time. and the fuel screw has no effect at all on it. any ideas?

Share this post


Link to post
Share on other sites

Try a 45 pilot jet. I use a 45 pilot and a 172 main in my 09. Head is ported. I tried a 42 pilot in mine and could not get it to start. Runs great with the 45. Im also running a 70 leak. Haven't had a chance to try a smaller leak jet. Mine doesnt seem to bog. Also running an NCYS needle with the clip 3 down from the top.

Share this post


Link to post
Share on other sites

my 08 likes the 45 pilot 1 turn summer, 1 1/2 in winter, 172 main, stock needle and clip, 45 leak ( this does wonders for the bog), mine will also stutter with a 42 pilot, lots of starting issues with the 42 pilot

  • Like 1

Share this post


Link to post
Share on other sites

Have you checked your acc. pump diaphram? It could be in bad shape, and not drawing in enough fuel when you crack the throttle quickly.

  • Like 1

Share this post


Link to post
Share on other sites

im having trouble with the accel pump leaking fuel now. could it be bad? with the 42 pilot in the bike it starts wonderfully, just bogs. until i get the 45 leak its hard to say what its actually doing. i should also note the bike has a high comp CP piston

Share this post


Link to post
Share on other sites
Try a 45 pilot jet. I use a 45 pilot and a 172 main in my 09. Head is ported. I tried a 42 pilot in mine and could not get it to start. Runs great with the 45. Im also running a 70 leak. Haven't had a chance to try a smaller leak jet. Mine doesnt seem to bog. Also running an NCYS needle with the clip 3 down from the top.

Keith,

I can't believe you're running that big of a pilot. My kids 08 has a serious porting job and I was running a 38 in the summer when it was 80+ and a 40 when it was under 80. Winter was a 42 for unheated indoor tracks and it was on the verge of running a little flat. Air/fuel screw almost all the way in. With a ported head, the jetting should go down. (Should) With the 45, it may make it easier to start, but it can't possibly run nearly as strong on the bottom with that big of a pilot. Of course, there are many varibles that may dictate that type of jetting, but it's strange going that big with a ported head.

Share this post


Link to post
Share on other sites
Keith,

I can't believe you're running that big of a pilot. My kids 08 has a serious porting job and I was running a 38 in the summer when it was 80+ and a 40 when it was under 80. Winter was a 42 for unheated indoor tracks and it was on the verge of running a little flat. Air/fuel screw almost all the way in. With a ported head, the jetting should go down. (Should) With the 45, it may make it easier to start, but it can't possibly run nearly as strong on the bottom with that big of a pilot. Of course, there are many varibles that may dictate that type of jetting, but it's strange going that big with a ported head.

I think I may need to take what I said back. I rode last night and the bike was bogging a little and just seemed sluggish. I tried my 42 earlier in the spring and it didnt want to start or run worth a crap. Seemed way too lean. Its starting to get hotter here. I turned the fuel screw in to about 1.25 open and it got a little better but not that good. will try the 42 again next time out and play with the fuel screw. Hopefully it will relieve the sluggishness. It was driving me crazy. Couldnt ride worth a damn. Im also going to try a 45 leak.

Share this post


Link to post
Share on other sites
I think I may need to take what I said back. I rode last night and the bike was bogging a little and just seemed sluggish. I tried my 42 earlier in the spring and it didnt want to start or run worth a crap. Seemed way too lean. Its starting to get hotter here. I turned the fuel screw in to about 1.25 open and it got a little better but not that good. will try the 42 again next time out and play with the fuel screw. Hopefully it will relieve the sluggishness. It was driving me crazy. Couldnt ride worth a damn. Im also going to try a 45 leak.

The 45 leak jet does wonders. I think you'll be happy with it. If it still boggs, something is wrong. Are you dealing with a hard landing bog also?

Share this post


Link to post
Share on other sites
The 45 leak jet does wonders. I think you'll be happy with it. If it still boggs, something is wrong. Are you dealing with a hard landing bog also?

I've got a 50 leak jet ordered. Hope that will be close enough. Cant really say about the hard landing bog. I don't ride aggressive enough at this point to really experience rough landings. If I do I probably wont be riding away from it anyways. lol My other problem is the previous owner took the plate out of the carb bowl that covers the leak jet. Do you think this is going to be a problem?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

  • Similar Content

    • By Kadensmith44
      I’m wanting to powder coat my bike but it’s all new to me. I’ve got a powder coater picked out that I’ve heard is good for what I’m doing. I’m not 100% what kind of sand blaster I need and what kind of media. I have also heard you can’t cook in the oven after you’ve baked your parts is that true?
    • By luke8500
      Hi all, 
      I have a 2004 honda crf250r and it wont start hot at all. The motor was just rebuilt with a new cylinder and piston. The valves were just adjusted. It will start cold in 1 or 2 kicks with choke but as soon as it gets hot it wont start. If you bump start it the motor will just turn over without starting.  sometimes it will start. It runs great until you shut it off.  im thinking its either a fuel issue or an electrical issue. Any help would be greatly appreciated. 
    • By SandSoldier
      Hello! This listing is for my 2007 Honda CRF250R dirt bike. Last winter I spun the rod bearing and just recently finished rebuilding it. Selling to fund new bike. I am currently the second owner.

      Current registration valid until 2020, pink slip in hand.

      Fresh parts:
      -top end kit: Wiseco; forged, moly skirt coated, 12.9:1 comp ratio (new wrist pin, gaskets, etc)
      -cylinder: new OEM
      -bottom end kit: Wiseco; (new bearings, seals, etc)
      -oil pump: new OEM
      -head studs & nuts: new OEM

      -fresh oil and filter
      -all tolerances checked in top end
      -valves adjusted
      -carb adjusted

      Note:
      *rebuild was done by my dad (master tech at CAT) and I (4th year mechanical engineering student)
      *has maybe 15 minutes on new parts, IT HAS NOT BEEN PROPERLY BROKEN IN YET
      *I have email receipts, pics of rebuild, and old parts as proof of rebuild, just ask and I'll show em off

      Other parts:
      -90% tread on front and rear tires
      -excell takasago front wheel
      -custom aluminum skid plate
      -wrap around hand guards
      -spark arrestor
      -kickstand

      Feel free to ask for any more specifics or pictures!

      LOCAL PICK UP ONLY

      Thanks!
    • By Matt Ray
      Okay so the title is a little vague. 
      So it was having trouble idling and even starting when I first bought it about a month ago for $2k. 
      So I did a rough clean of carb, looked up on YouTube, Forums, Etc on how to do it. I only cleaned jets with carb cleaner and sprayed around the float bowl area and such, so not too extensive.
      Did that and I took it out to a park, It would start up right away mostly, few kicks sometimes, but when I got it started, I had to keep the choke on. Right when I was ready to go fast and go up to 3rd and 4th gear I'd switch it off and it would work fine and sound fine and everything, but when I slowed back down and coasted around 1st gear i'd pop it back out again because it sounded like it was going to do. I have some videos if people would like me to link to them.
       
      So after that I decided to take it apart and replace spark plug with OEM NGK R0409B-8, replace main jet from a old 170 to a new 170, replaced pilot jet from a old 40 to a new 42, and kept starter jet the same just made sure that wasn't clogged, ordered a new adjustable fuel screw and used that.
      and it was still having a little bit of problems! I just started up today and the day before today. It would run only with choke on, if i twisted throttle in neutral it sounded pretty good, no gun shot noises or anything, pretty smooth. 
      If I tried to take choke off it would die immediately. So I started it back up again, took around 6 kicks.. So again with choke on it sounded like it was starting to lose power and RPM's would drop so I'd twist throttle a few times and it would stay idling.. then after a small amount of time, start to sound like its about to die again... so I would rev it up again, and repeat..
       
      Fuel line isn't clogged, flows fine.
      I tried fuel screw everywhere between 1 and 2 turns out..
      I checked valve clearances, and I'm no expert but from the videos I watched the slipped underneath intake and exhaust with only minor force.
      So I'm lost.. 
      Maybe float bowl is messed up? Should I just do a COMPLETE carb rebuild from videos I've seen on youtube, like this one -> https://www.youtube.com/watch?v=3AXb9UprT30? Or what? 
       
      It's getting annoying taking it apart all the time, I jsut want it to start up quickly and run well!!
       
      Thank you!
       
      Austin, TX, Elevation 600ft, where I ride its around 900ft
       
       
    • By Bryan Bosch
      WASHINGTON, D.C. – August 16, 2018 – (Motor Sports Newswire) –

       
      Honda Recall Summary:
      Name of product: CRF250R Off-Road Motorcycles Hazard: The clutch outer can break, posing crash and injury hazards. Remedy: Repair Recall date: August 16, 2018 Units: About 3,200
      Consumer Contact: American Honda toll-free at 866-784-1870 from 8:30 a.m. to 4:30 p.m. PT Monday through Friday or online at http://powersports.honda.com/ and click on “Recall Information” at the bottom of the page for more information.
      Honda Recall Details:
      Description: This recall involves all 2018 Model Year CRF250R off-road motorcycles. The recalled motorcycles were sold in a red color. The names “HONDA” and “CRF250R” are printed on the sides of the motorcycle. The model name and model year are printed on a name plate label located at the front right top of the frame, near the steering head.
      Remedy: Consumers should immediately stop using the recalled off-road motorcycles and contact their local authorized Honda Powersports dealer to schedule an appointment for a free repair. Honda is contacting all known purchasers directly.
      Incidents/Injuries: American Honda has received 19 reports of clutch failure, including two that led to engine lock up. No crashes or injuries reported.
      Sold At: Authorized Honda Powersports dealers nationwide from November 2017 through July 2018 for about $8,000.
      Manufacturer(s): American Honda Motor Company Inc., of Torrance, Calif. Manufactured In: Japan Recall number: 18-759 This recall was conducted, voluntarily by the company, under CPSC’s Fast Track Recall process. Fast Track recalls are initiated by firms, who commit to work with CPSC to quickly announce the recall and remedy to protect consumers.
      The U.S. Consumer Product Safety Commission is charged with protecting the public from unreasonable risks of injury or death associated with the use of thousands of types of consumer products under the agency’s jurisdiction. Deaths, injuries, and property damage from consumer product incidents cost the nation more than $1 trillion annually. CPSC is committed to protecting consumers and families from products that pose a fire, electrical, chemical or mechanical hazard. CPSC’s work to help ensure the safety of consumer products – such as toys, cribs, power tools, cigarette lighters and household chemicals -– contributed to a decline in the rate of deaths and injuries associated with consumer products over the past 40 years.
      Federal law bars any person from selling products subject to a publicly-announced voluntary recall by a manufacturer or a mandatory recall ordered by the Commission.
      Source: Consumer Product Safety Commission

×