XR650 stalling when twisting the throttle

[blic]

The bike stalls when twisting the throttle fast from idle to 3/4 or full throttle. Gear in neutral or in any gear.
No matter if the bike is warm or cold.
And I haven´t touch the engine before this started, it just happened.
After it has stall in this way I can´t start it up in first kick, that it usually takes. In second kick it will fire up.
The old sparkplug was black and sooty. I have inspected it before the problem started and then it was gold/brown as it should be.

What I have done:
Put in a new sparkplug.
Cleaned the carb. with air pressure.
Raised the needle jet one step, no difference so I put it back as it was before.
Tested without air filter in it (just for some seconds), to see if it was clogged.
Raised the idle, didn´t helped.
Played with air screw, didn´t helped.

So still the problem is there.

Jetting: 175 main, 65 pilot, needle in 3th(from up). Air screw 1 3/4 out.

Please help me out!

 

[blic]

I have also drained the fuel tank and put in gas from another source, but there´s no difference.
I´m stuck with this problem!

 

[Grady]

An XR aint a high-revving 2-smoke. They all do it. It shouldn't be a problem, though?? There shouldn't be a need to do that, so don't, and it won't happen.

 

[mag]

Check your jetting!

 

[blic]

Made a valve adjustment today, no difference.

Jetting? Do I have to change the jetting from morning to evening? Cos that was the time between the bike running good and bad.

Thanks all

 

[Rannoch]

Its an XR thang. I believe the only way to fix it is a completely new carb. Just dont wack the throttle like that, and it wont die :)

My XR200 does it, the CRF230 does it (its really an XR at heart ;) ) my XR400 does it, the XR250 Ive ridden does it, and now you say the 650 does it.

Dont worry, its normal.

 

[flynbryan]

When you get a bog like that when quickly going from idle to 3/4-full throttle its usually an indication that your pilot jet is lean. If adjusting the fuel screw(its a FUEL screw not an AIR screw, so theres a difference in adjustment) didn't help go to the next richer pilot jet. With a four-stroke you will have a fuel screw which you turn in to LEAN the mixture, and turn out to RICHEN the circuit. Also check your float bowl level. If it is too low your carb will not have enough fuel in it for those quick stabs at the throttle. This shouldn't be a "trait" of any bike if it is adjusted properly, and has no air leaks. :silly: Take your time and eliminate all your variables, and your should be able to solve your problems.

 

[TexKDX]

no accelerator pump = no wackin the throttle open and the bike running. Doing so creates an instant loss in velocity, hence the stall. Accelerator pumps make this better. So do CV carbs - the slide rises as velocity increases thru the carb until the desired throttle opening is acheived.

What practical purpose does wacking the throttle to 3/4 or WFO serve anyway?

 

[blic]

Hi guys.
Thanks for the help (thanks for the fuel screw description too:).

The bike hasn´t had this problem before (as I described in my first post), if I twist the throttle from idle to 1/2 throttle it will also bog, but not really stall.
I have problems when I take off (don´t know the correct word for it), from 0 mph and accelerate. I have to be careful with the throttle and clutch so it won´t bog or stall.
And it´s running bad on idle, idle goes up and down.
I can also say that it seems like the problem is getting worser the more I ride it, the bike is not that fast anymore when accelerating. It hasn´t got that power it had before.
So I can tell you that this is a problem, I know what you mean with XR thing but this is far away from that, and the bike has been running good (with the exactly same jetting etc.)

 

[TexKDX]

Sounds like a clogged pilot jet. Air alone may not do it. Some nylon bristles pushed into the jet from both sides may dislodge some varnish that has formed.

I blew out a plugged pilot the other day and it opened up a little bit, but I had to do some scraping in the dished area to get all the crud out of it.

 

[motometal]

the best tool for that is a torch tip cleaner kit.  It comes with very fine stiff wires of various sizes, great for cleaning out jets.  Careful, you don't want to make it bigger (then again maybe you do).

 

[blic]

Checked the float level today, the level is right where the float bowl is attached to the carb ("main part"). Or at the float bowl gasket.
Isn´t that where it should be?

I have non of the tool that you mention. But I have blew out the jet and I can´t see any dirt in it, it´s clean.

thanks

 

[TexKDX]

Float level and float travel effect the bike when it is under a load and going over terrain, not sitting still under no load.

The float travel does need to be reduced on this bike as does the float level lowered if you are to ever ride it over whoops and jumps by the way.

There is a small tab on one side the effects to float travel. Set the level first, lower it to below horizontal. Then reduce the total float travel to 17 mm or so with the float travel tab.

 

[magneto]

I like to use a piece of multi-stranded copper wire (like automotive wire) instead of a steel torch tip cleaner to clean out carb orifices. IMHO the copper strands aren't hard enough to distort the precision holes in the jets and passageways. (use multiple strand within the wire to clean the larger holes.)

Get a gallon of strong carburetor cleaner (the stuff with sodium hydroxide and a chlorinated solvent that comes with a dip basket) to thoroughly clean your carb. The spray cleaner is like water compared to this stuff. Completely disassemble the carb and remove ALL rubber and plastic parts before dipping since these parts will dissolve in the liquid. WEAR GLOVES AND GOGGLES WHEN USING THIS STUFF! Check for proper float level when reassembling carb.

 

[blic]

TexKdx:
Could you please decsribe more detailed what the difference betwenn float level and -travel is. I didn´t really understand your last post.

 

[TexKDX]

level - if you take the bowl off and turn the carb upside down, where the float sits is the float LEVEL.

If you now turn it right side up, the distance the float travels until it stops DOWN is float TRAVEL - the distance the float travels from highest point to lowest point.

On one side of the float near where the pin that holds it on goes there is a little brass tab. Bend this tab to reduce float travel. The float rests on the tab when the carb is right side up.

Make sense?

 

[motometal]

I wouldn't think under normal circumstances the float would need to reach the bottom of it's travel, unless the bowl is empty.  I could see where whoops could cause the float to bounce, which could cause a problem (not sure specifically what would happen).  Float travel is something I never thought much about, I learned something new today...thank you.

My XR hates whoops and needs all the help it can get!  Jumps, no problem!  Whoops, not good!

The torch tip cleaners shouldn't do any damage to jets as long as you are careful.  The tips are rounded.  I wouldn't recommend sawing back and forth with it. 

 

[TexKDX]

Yup, lower the float level and decrease the float travel is SOP on the XRs, 650 included. A bud with a 650R had to lower the float way down and greatly limit the travel in order to get the bike to work in whoops. You might want to talk to the guys at Baja Designs for more info as they have done alot of 650Rs. My bud's will actually starve for fuel on long WFO runs in 5th gear - draining the float bowl. BUT, it does work in Whoops. My 280 I keep playing with. It is so-so now but still needs more tweaking.

 

[blic]

I have set the float level to 1 mm under the horizontal or the split between the float bowl and carb (don´t know the name).
But I think the bike ran worser after that, it would easily stall now when letting off the gas.

I haven´t set the float travel cos I don´t know exactly where I should measure it??

I have also been to a mechanic at my dealer. He lissened to the bike and he thought it was something with the carb, some dirt that was still stucked in it.
Can I clean the carb with diesel? I don´t know where to get any special carb cleaning stuff here. The mechanic did know one product, but that costed 100$ for on litre. :(

 

[flynbryan]

Originally posted by blic
The mechanic did know one product, but that costed 100$ for on litre. :(

:| Anything to make a buck right? :flame: Go to Walmart, Napa, Autozone, which ever. Any of these stores will have carb cleaner for around $3 in an aerosol can. If that bum of a mechanic couldn't even have the courtesy to tell you that, Id be scared to see what he'd try to charge you to repair the bike. :scream:

 

[Rawdy Rider]

I got a similar Prob with my 08, 650l.Starts sputtering at higher throttle settings.Done a bunch of stuff cant place a finger on the goddam problem!If there’s a vacuum prob it will affect operation of the accelerator pump right??.