Jump to content
Sign in to follow this  

CV 36mm Blip of the throttle kills the motor. ?

Recommended Posts

Hi.  Sorry, it's another jetting/set up question.  I've searched and read everything but haven't been able to find the answer.

 

I live in Phoenix, AZ.

2003 Green DRZ, 1500 miles.

Mikuni CV 36mm

Full FMF Factory 4 pipe.

Stock Foam filter - Just cleaned and re-oiled

Fresh Gas

3x3 mod

JD Kit installed

155 main

25 pilot

1.5 turns out (I think)

Blue #3

 

I had the same issue before the jet kit and now after.  From Idle a quick twist of the throttle will kill the engine.  It happens hot or cold, before acceleration and after deceleration.  It's kind of annoying.  I try to feather the throttle up off of idle, but if I go to quickly, it kill the engine.  As in this happens when I'm riding in traffic around town.  I currently use my bike to commute.  I've killed it at a light, halfway through a turn and rolling down the road.  It only happens off of idle or near idle.  For example, I pulled in the clutch to coast up to a stop light, down shifted, then the light changes.  So I blip the throttle to match rpms with my speed so I can release the clutch.  The bike dies.  I even tried today to be very conscious about how much and how fast I was giving it throttle.  I barely gave it a turn and it died.  Thankfully, this is an electric start.  But I would really suck if I had to get out of the way of something and the bike dies.  As of now, it really just an annoyance.

 

So how do I fix it?

 

I should probably get this sorted first as my other woes might be included.  I bought the bike with the pipe but no 3x3 or Jet kit.  I just did both of those.  Due to it being lean, I didn't ride it until I jetted it.  Just a quick 1 mile run down the freeway.  So I don't have much comparison.  That said, the bike is good in the mid range but seems to really fall off in the top end.  My pre-jet run pulled 92 mph.  My post-jet and mod, I can just squeak up to 97 mph.  Is this all it has?  I would have thought the top end would have seen more improvement.

 

Appreciate any thoughts, input or suggestions.

Share this post


Link to post
Share on other sites

Try 2.5 to 3 turns on the fuel screw.  Your top speed sounds fine.  You can try a 160 main jet but I doubt you will see more speed.  97 is pretty good for a KLX400SR.  Idle speed should be 1500 to 1800 RPM

  • Like 2

Share this post


Link to post
Share on other sites

Try 2.5 to 3 turns on the fuel screw.  Your top speed sounds fine.  You can try a 160 main jet but I doubt you will see more speed.  97 is pretty good for a KLX400SR.  Idle speed should be 1500 to 1800 RPM

Okay.  I think we originally set it for 2 turns out.  Turning it 1.5 didn't seem to make a difference.  But I will try turning it out.

 

I knew that Kientech screw would be worth it!!

 

Not that I'm trying to go over a 100 mph.  It's just that I commute on the freeway about 24 miles in a week.  I changed to a 41T sprocket for a little more top end.  But if that's all it's got, so be it.

Edited by GavMac78

Share this post


Link to post
Share on other sites

Not idles, if your in natural and blip the throttle does it die? If it does then also and while in gear Noble is right on target.

Yes, off idle, in neutral or in gear with the clutch in.  I don't think it's ever died from a throttle blip while driving.  I might have to try that tomorrow.  But I don't think so.

Share this post


Link to post
Share on other sites

How do I go about setting the idle to 1500 rpms?  It's stock, so no rpm gauge.

Share this post


Link to post
Share on other sites

Set your fuel screw via this procedure....http://www.thumperta...ad.php?t=327405

an  Extended Fuel Mixture Screw will make tuning easier

With an open pipe use Blue needle , clip 4 and 160 main jet..

Use 22.5 pilot jet with ext fuel screw

around 2.5 to 2.75 turns is where you should end up...

You want 1800 ~1900 rpm as a good idle speed....If you don't have a tach you just have to set it by ear..Set it so it feels solid and doesn't sound like it could cut out easy...

A TTO Tach/hour meter is a fairly cheap option if you want to be more precise..http://www.ebay.com.au/itm/Trail-Tech-TTO-Tach-Hour-Meter-Silver-/131268329293?pt=AU_Motorcycle_Parts_Accessories&hash=item1e9033bf4d&_uhb=1

Edited by Craig-o
  • Like 1

Share this post


Link to post
Share on other sites

Set your fuel screw via this procedure....http://www.thumperta...ad.php?t=327405

an  Extended Fuel Mixture Screw will make tuning easier

With an open pipe use Blue needle , clip 4 and 160 main jet..

Use 22.5 pilot jet with ext fuel screw

around 2.5 to 2.75 turns is where you should end up...

You want 1800 ~1900 rpm as a good idle speed....If you don't have a tach you just have to set it by ear..Set it so it feels solid and doesn't sound like it could cut out easy...

A TTO Tach/hour meter is a fairly cheap option if you want to be more precise..http://www.ebay.com.au/itm/Trail-Tech-TTO-Tach-Hour-Meter-Silver-/131268329293?pt=AU_Motorcycle_Parts_Accessories&hash=item1e9033bf4d&_uhb=1

 

Thanks Craig-o.

 

I tried sending you a message yesterday but it said you can't receive any more messages.

 

Sorry, my earlier post was misleading.  I did purchase and install the Extended Fuel Mix Screw.  The pipe is open, nothing inside, no spark arrestor.

 

Current jetting was the recommendation of JD Jetting.  I knew I should have asked here first!

 

Basically, it sounds like I have to redo the jetting.  Crap, I was hoping to avoid that!  I didn't realize the pilot was still the 22.5 with the extend screw.  I'm very busy with school.  It might take me a bit to change out the jets.  I'll try the screw and raising the idle tomorrow.

 

Just wanting to confirm.  I live in Arizona, it's hot and dry here.  Easily average 105F/40C.  And I'm at 1200'/365m ASL.  Does this change your recommendation?

  • Like 1

Share this post


Link to post
Share on other sites

just look at the fuel screw like its not set in stone on where it should be .. if its dying when you blip the throttle its lean so ease it out an 1/8th at a time until its not doing that and responding and starting good ..

  • Like 1

Share this post


Link to post
Share on other sites

Thanks Craig-o.

 

I tried sending you a message yesterday but it said you can't receive any more messages.

 

Sorry, my earlier post was misleading.  I did purchase and install the Extended Fuel Mix Screw.  The pipe is open, nothing inside, no spark arrestor.

 

Current jetting was the recommendation of JD Jetting.  I knew I should have asked here first!

 

Basically, it sounds like I have to redo the jetting.  Crap, I was hoping to avoid that!  I didn't realize the pilot was still the 22.5 with the extend screw.  I'm very busy with school.  It might take me a bit to change out the jets.  I'll try the screw and raising the idle tomorrow.

 

Just wanting to confirm.  I live in Arizona, it's hot and dry here.  Easily average 105F/40C.  And I'm at 1200'/365m ASL.  Does this change your recommendation?

 

Before you pull the carb to change jets, try tuning with the 25 pj via the procedure I listed....If you can get some reaction to fuel screw and set a smooth idle , leave the 25 installed

As your in a hot climate your current main and needle setting will be ok...it seems that it's running fairly good, just the bog that is the issue...?

Edited by Craig-o
  • Like 1

Share this post


Link to post
Share on other sites

Minor update.

 

I turned to FS out a bit and that seemed to help.  It didn't die as much.  I finally took the time today to do the recommended setting of the FS.  The bike got rough and then died about 1 turn out.  I cranked it out to 5 turns out with no change past 3 turns out.  Went back to all the way in and then came out to about 2.5 turns.  Tried blipping the throttle and it didn't die.  Tried a few times, still didn't die.  I went for a quick 3 min ride and tired to kill it, and it still didn't die.  Yay, for progress.

 

So while it didn't die, it had a noticeable pause hesitation.  Like it needed a minute to catch up.  Still better than dying but not great.  I also notice a tiny bit of what might be surging.  In gear trying to keep the same rpm's it seems like it might be surging.  I initially thought it was just the feedback from the road.  Paying closer attention to the sound of the engine, it sounds like surging.

 

JD Jetting originally told me if it was falling off in the mid range or surging, to go up to Blue #4.

 

Thoughts?

 

Side note - I still don't know what my idle rpms are. 

Share this post


Link to post
Share on other sites

150ron posted this on another thread.  He's running a TTO for rpms.  I'm going to try it soon and adjust my idle to something close to this.  It should at least get me into about the right rev range.

 

"Your idle is too low,   with the idle set to 1800 rpm's (where it should be) the bikeicon1.png does 7mph indicated by itself,  with no throttle needed in first gear."

Share this post


Link to post
Share on other sites

This exact issue occurs on my bone stock 2014 drz400sm. It only happen when I want to duplicate the issue, under normal operation it doesn't ever unintentionally stall, JD jet kit and 3x3 going in Saturday :)

Share this post


Link to post
Share on other sites

This exact issue occurs on my bone stock 2014 drz400sm. It only happen when I want to duplicate the issue, under normal operation it doesn't ever unintentionally stall, JD jet kit and 3x3 going in Saturday :)

 

Did you also get the Extended Fuel Screw?  My buddy gave me crap for spending $16 on something he thinks I won't mess with much.  And while I agree, you won't adjust it much.  I will say it's a Hell of a lot easier to tweak with it, than with out.  

 

I'm not exactly sure what changed besides a little tweak of the FS and a slight raise of the idle, but I haven't killed it in the last 48 hours.  Will see what happens after this weekend.

Share this post


Link to post
Share on other sites

Yeah I ordered the extended fuel screw. From what I gather on the forums I need the following setup:

 

22.5 stock pilot (when using extended fuel screw)

155 main jet (3x3 only, stock exhaust)

Blue needle, clip position 3

2.5-2.75 turns out from fully righty tightied

Share this post


Link to post
Share on other sites

GavMac, at your temp/elevation I'd be using the 22.5 stock pilot jet. I have DJ needle installed along with the 3x3/full pipe and use the stock 142.5 MJ. Bike responds very well to off-idle throttle and midrange is clean and crisp. Located in the mountains of BC, running from 1,300 asl to 7,000'

I'd love to have a day with the FCR, but its a little too tough for me to part with all those bucks to actually buy one

Edited by shuswap1

Share this post


Link to post
Share on other sites

extended fuel screw is absolutely usable with a 25 pilot jet, no reason to change back to 22.5.

in my experience extended screw is about 1 turn richer than stock

pilot 25 + stock screw at 2.5-3 turns =  pilot 25 + extended screw at 1.5-2

Share this post


Link to post
Share on other sites

extended fuel screw is absolutely usable with a 25 pilot jet, no reason to change back to 22.5.

in my experience extended screw is about 1 turn richer than stock

pilot 25 + stock screw at 2.5-3 turns =  pilot 25 + extended screw at 1.5-2

He did say:

"I live in Arizona, it's hot and dry here.  Easily average 105F/40C.  And I'm at 1200'/365m ASL."

That's a serious reduction in air density, to over 5,000'

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  

×
×
  • Create New...