96 KLX 250R Starting/Sputtering issues. (My First POST!)

[_RaStA_RoCkEt_]

Hello Mighty Thumper Talk / T.T.,

Been a long-time password-less lurker, and now, as I'm onto my 6th Motorcycle, I figured It'd be a good time to utilize the resource that I've used to so much to-date to its fullest potential!

Thanks for having me!

BACKGROUND:

So, I've got a Classic KLX250R. I bought it for about 500$ here in Santa Cruz about 2 years ago, from a VERY large Chinese man who abused the mess out of it. I'm 150lbs, and this thing was already pretty bottomed out on a very stiff suspension set up.

However, as I've come to learn, it has been 'Strokerized', meaning that it's got a Non CA needle in the carb (perhaps re-jetted) , a hot-start, a removed airbox lid, a case-breather, and of course, a seat-cover saying so.

It took me ALL summer 2 years ago to get it running. I replaced things like the float bowl needle valve, air filter element, etc, and Carb was FUNKY and the Valves were (as i found out very late) were out of adjustment. I got them into the 'happy range' and rode it for about 10-13 rides out here in the Summer/Winter. . Awesome stuff. I did all the maintainance I could, and kept it pristine... except for the air-filter, which brings me here.

On my last outing, the bike became REALLY hard to start. (From a usual 1-3 kick start procedure)

I assumed, 'ok the air-filter's clogged' and cleaned it on the spot with some gasoline. It worked (albeit with ALOT of inaugural kicking) that day, but when I returned home, I knew the valves were locking up.

I promptly replaced the spark-plug (slightly carbon fouled), Oiled the air-filter, and pulled the carb to clean it (solely with Carb Cleaner spray into the intake ports, the float bowl, and the jet holes) and then pulled the valve cover.

As suspected, the Intake valves were near BOLTED shut.

I promptly re-shimmed them to their 'happy range' (.157mm) according to the FSM, and they took 2.40mm and 2.50mm shims, respectively L/R. The Exhaust remained in spec, at about .18mm clearance.

Now, Its STILL really hard to start. And when it does start, it will run fine for a few moments, and then, as if possessed, will sputter and die. If i can get it running, (10+ kicks) it will occasionally run great, but upon idling, will sputter to death. Any gas given will barely keep it running, and the opening of the hot-start hose will only increase idle speed slightly, but often will still not prevent shut off.

I diagnose this as:

1) Intake Valves re-seated into a higher position. I assume after I re-shimmed them, and the hard-starting is due to this now a WIDE open intake valve positioning, and they need to be re-shimmed yet again to a bigger shim.

2) Carb Float Needle Valve is gummy, or the Idle Jet is Gummy. This makes the Idle nearly impossible.

3) Insert other theory here. (Pitted Valves? Non-Operational Valve? Unknown Honda Gremlin inside my Kawasaki?)

What suggestions have you? I'm going to pick it apart tomorrow, but I assume that I'll only RE-Clean the carb and check valve clearance with the time I have.

Advice appreciated!

[_RaStA_RoCkEt_]

UPDATE X1:

I've been working on all things BESIDES motorcycles today. The KLX has been sitting on the stand all day, waiting for a tear-down... but that'll likely have to happen tomorrow.

[_RaStA_RoCkEt_]

Alright!

So, yesterday, I finally began the tear-down of the KLX.

Priority 1 was Re-Check the Valves, and the Priority 2 was to Clean/Re-Clean/Check the carb.

SO, Alá the www.planetklx.com website's take-down recommendations (which I love, and have followed before, thanks to whomever made those!) Here we go!

STEP 1 Remove Plastics/Tank/Seat.

STEP 2 Take of Timing Cover and use 17mm socket to rotate engine to 'TOP DEAD CENTER' mark.

STEP 3 Remove Valve Cover (x3 10mm bolts) Use FINGERS to pry off, a chisel-like flathead could mar your cover, and wreck your seal!

STEP 4 (OPTIONAL) Pull Spark plug before the valve cover comes off, and check it's condition. Not too white nor too black.

(Nearly New CR8E plug with only 10-5mins of riding on it... so it was ok hahaha)

Here's the KLX250R FSM page on the plug. Gap is at 0.07-0.08mm, and the plug should be somewhere in the 'brownish hue'

SOMEWHERE IN HERE... I made a guide to the Valve Adjustment procedure that would include the 'in-spec' range, the clearances I observed, and the Shims going out/in. I HIGHLY RECOMMEND THIS FOR SIMPLICITY AT THE NEXT VALVE ADJUSTMENT!

STEP 5 Use Feeler Gauges to check the spacing on the valves. Slip bellow cam lobes and make sure the INTAKE is within 0.10-0.19mm and the EXHAUST is within 0.15-0.25mm

STEP 7 EITHER find that your valves are in-spec and you don't need to change anything (as I did) OR go to http://www.planetklx...ips/valves.html and use the remainder of this tutorial to find the How To. Here's what you do when you're done with either. SCRAPE SCRAPE SCRAPE all that old gasket material off the Head, the Valve Cover, and the Gasket. Then re-apply some NON RTV Silicone gasket maker. (I like Hondabond 4, some prefer Yamabond).

NOTE: it took me the better part of 3 hours to really clean that head to my personal happiness / satisfaction. I lamented the difficulty of doing this, when Honda and even Kawasaki (with their KLR 250) have made a MUCH simpler valve adjustment process by using small, gasket'ed socket-wrench-removable adjustment holes in the valve cover... but that was mostly my time working on a XR-L that was taunting me.

...Now, here's where things get interesting....

It seems that my Carb, a stock KLX250R Carb, is what is giving me the trouble.

I have been using this page (http://www.planetklx...b-cleaning.html) as my barometer for what to do and not to do... but after following this procedure today, I discovered a few things.

Here's a diagram: http://www.gadgetjq....keihin_carb.jpg

1) I have a STOCK CVK32 Carburetor, with a 115 Main Jet and 35 Pilot Jet. Further, I have a N1SA needle.

2) The Diaphragm on the top of the carb was really funky when I removed it. The outer surface was coming apart and the actual rubber was kinked pretty badly. I feel as though the seal may have been compromised, but I got it back together.

3) My PILOT JET was loose, about 1 full turn. I don't recall if this was because of a foolish decision I made when I was assembling it last year/2 years ago, but it was loose. I tightened it down.

4) I Dialed the FRONT PILOT MIXTURE SCREW BACK 1/2 turn. (more on this later)

So, after finding out all this, I figured a good douche with some Carb Cleaner would get this thing running at last... so I bolted nearly 100% of everything back onto this machine and went to kick start it.

Nothing. Engine turned and turned and turned. Choke on/off, Hot Start open/closed... didn't matter.

I assumed that perhaps, with a friend's suggestion guiding me, that the Pilot screw might be in too tightly. So, I turned it back another 1/2 turn.

The Bike fired, and ran, 3rd kick. Hooray... I promptly (after warm up) took it around the yard.

It Sputters and Chokes on anything more than 1/3 throttle.

WHYYYYYY?!!!!!!

So, Again, I'm at a loss... However, it must be carburetor related! So, I'm getting closer, and DONT have to scrape the gasket material off the valve gasket again!

Any suggestions?

Also, in other news, I realized that my rear wheel bearings are going. got a lil' too much free play in there... we'll do that later!

THANKS FOR READING!

[Oldmxer]

That looks like a CV type carb. most likely the diagram has a hole in it. IE it can pull the slide up.

[_RaStA_RoCkEt_]

. most likely the diagram has a hole in it.

Good Eye! a CV(K) 32 it is!

This was a feeling I'd had, since it was running so sporadically before... but when I pulled it last it, whist it was so dirty, it seemed 'non-porous' to me. I'm thinking i'll take another peek really soon, but i just started school today, so time will come, well, when it comes.

Other than this, I'm assuming perhaps a fuel/air mixture problem. I'm envisioning in my mind's eye just gobs of gas being dumped in... but, what could cause this... I don't know. Jetting? (seems dubious, as it was running fine)

Diaphragm is nearly 110$ but, we'll diagnose and go from there.

Thanks for the input Ol'MX'r, you're the first one to help me out! ?

[_RaStA_RoCkEt_]

OF NOTE:

On my next carb disassembly, I'll be sure to not be a lazy POS and take pictures so ya'll can see the innards! (and perhaps, we can figure out what's up wit' her!)

[Oldmxer]

You can probably fix it better by getting rid of the cv and swapping to a real dirt carb. Search. I am sure it has been done many times before. A DR 350 or 400 carb should be able to fit. Probably have to change cable too. But it should run better too

[js1012]

I have a 1990 Klr 250 which was acting same way and it turned out it was gas cap try running without it

[_RaStA_RoCkEt_]

...1990 Klr 250 acting same way.... Turned out it was gas cap....

Hello JS, thanks for joining in the fray.

I'm thinking this is a simple test, and I'll certainly try it before I pull the carb again. I really appreciate your input! Thanks so much!

... swapping to a real dirt carb.

You know, M.X.'r, it seems that people do the FCR carb mod on these bike, alá www.planetklx.com, and it looks pretty effective at making the little bike run fast. However, I'm really on a tight budget here (both with money, and alas, time as well) since I'm in the first weeks of a schooling program that lasts a year and increases in intensity as time goes on...

I'm thinking your initial suggestion, swapping the Diaphragm out, might be a simple route to go. I'll try JS's suggestion too, before I pull the carb yet again, just to be sure.

Until then, I'm looking for either a low-cost KLX250R to cannibalize, or I'll get the gumption to spend 100$ on the diaphragm after really giving it another good once over. 'Til then, she sits, Carb Drained / Tank Drained, next to her Red, Blue, and Green cousins in the stable.

[_RaStA_RoCkEt_]

Alright!

July 25th being my last day writing about this, I'm glad to say I'm back on the ball and getting the bike torn into!

 

I again, for reminder and diagnostic clarity, I started the ol' KLX yesterday before mounting it up on the Stand for a teardown.

Events as follows:

-Took 10-15 Kicks to get it to start (Choke/Hotstart open/closed/open/etc)

-When it did start, any 'smack' on the throttle would just make it bog. 'Bueghhhhhhh', then release the gas, and it'd Idle again.

-SLOW roll on the throttle = ALMOST normal engine speed increase to full revs... but still with a few hiccups. (sputter,miss,etc)

 

So, I'm going back into the carb. Pics to follow today.

I'm looking for:

1) Torn/messed-up diaphragm. (had someone theorize this could be a cause, and want to prove/disprove)

 

Other than that, I'm at a loss for what could be causing this 'throttle-smack' bog. It seems like it's just a fuel-air ratio issue now, considering MORE gas = LESS go... but, I could be wrong.

 

Theories appreciated!  Pics to come to show ya'll what I find!

Thanks!

[Oldmxer]

The damaged diaphragm is the most likely cause. The way a cv carb works... the cable is not attached to the slide. The cable opens a butterfly valve on the front of the carb. This lets in more air. The venturi effect (air rushing in) causes the diaphragm to lift (suck up) the slide. A Torn diaphragm does not raise the slide. IE then you have too much air since the butterfly opened but the slide did not come up to let in more gas.

FYI: the delay (hesitation) of the diaphragm raising the slide instead of a direct connection with the slide being raised by the cable, is why the folks change to a different carb. The bike is more responsive.

The slide can also bounce in rough terrain in a CV carb due to no cable holding it up.

All that said, the diaphragm is probably just weather cracked and has to be replaced one way or the other.

[_RaStA_RoCkEt_]

Oh Joy... 

Back again, to this lovely issue, that seems to plague me.

 

But first, pictures and procedure of Today's joyous time wrenching!

 

1) I've got the Carb out and back on the bench, here we go...

 

 

 

2) Got the top cap off, and again, the actual Diaphragm seems good. At least at first inspection, the seal was solid, and the spring pushed up properly... nothing looked 'aged', 'frayed' or the like... so onward.

 

 

3) Took the Diaphragm out of the carb body after this picture, and really caressed it. Made sure all the edges were smooth and nothing brittle or crusty. It passed both mine and my ASE-certified Room-mate's inspections (he's working on a FJ60 carb right now too!) So, it seemed like it might be something else...

 

 

4) Maybe the NEEDLE. It's an N1SA stock KLX250R needle, clipped at the center position. I Stacked the Washer ON TOP of the needle, and inserted it into the spring holder's UNDERSIDE, and then buttoned the top back up... (I believe this is the proper order,see next pic to confirm)

 

 

5) Seems like the FSM says NEEDLE --> SPRING HOLDER ---> Circle-Clip ---> Spacer. But this seems VERY Wrong to me... did I booger this here? Either way, I put it back together as shown in picture 4.

 

 

6) Perhaps something on the bottom, the Jets (115 main, and 35 pilot, OEM stock) both still good, and BOTH tightly seated. (ok!)... Figured I'd check float bowl height whist i was in there...

 

 

7) Needle Valve looks good... I KNOW i replaced this 2 years ago, and see no pitting or anything on it... onward to float-level checking.

 

 

8) The level was SLIGHTLY off. 17mm before the little-springed Rod insight the Needle Valve moves at all is what the FSM calls for, and so I adjusted it back out a smidgen. It needed, seriously, like .001mm movement, if that.

 

 

9) So, it's all reconnected. Back to the way it was.... and time to put it back in the bike... 

 

NOTABLE ADJUSTMENTS: 

- Needle assembly order

- Adjusted Float Bowl height.

 

Nothing else seemed like it needed doing, and so I didn't touch anything else.

Re-connected the carb, got the Gas tank on, and put the seat on so I could roll it out into the yard and try it out.

 

Made sure to let ample fuel drain into the carb BEFORE trying to start it. (Checked this with the drain screw)

 

Here's what happened:

 

1) Took 10-15 kicks to start. CHOKE ON, HOT START CLOSED.

2) When it did start, and I shifted the bike from a leaning-on-kick-stand position to 'sitting' position, the idle dropped a noticeable amount.

3) Any attempt to rev or put the bike in gear Killed the Engine.

 

So, I'm honestly worse off now then I was this morning. At least this morning, there was no 'shift weight and bike dies' condition... super lame...

 

I'm at a loss. What am I not doing? Should i have cleaned the carb with cleaner (again) before reassembly?! It's SO perfectly clean in there already, and all the jets are right, and tight... 

Diaphragm seems PERFECTLY FINE. 

I have no idea what to do now.

 

In my mind, I had a Fine running machine at the end of summer, which needed a valve adjustment because I forgot to clean the air filter, and a very simple procedure turned my bike into a 350lb paperweight.

Further, what could i have messed up that did this to my fine-working-reving-running bike? What's THIS sensitive in the carb?

I'm nearly 100% convinced it's the carb, and I really want to get THIS carb working, not FCR or Flat-Slide it... 

 

Suggestions? Helps? Criticism?

 

I'm going to PM some KLX elders I've been seeing in other threads here, who were active in the mid 2000's, and hopefully one of them responds... this is ridiculous!

[_RaStA_RoCkEt_]

The damaged diaphragm is the most likely cause....

...the diaphragm is probably just weather cracked and has to be replaced one way or the other.

 

MX'r, thanks for this advice so far... I'm just not ready to shell out 100$ for a new diaphragm yet since I feel like it could be something else. I'm going to wait for some other O.G.'s to come in a comment here, and now I'm going to pull the carb back off, back the bike into a corner so it can think about it's sorry self, and leave this issue for today.

 

Too much sadness already. 

[brewster]

On the carb parts breakdown photo is #5, the Needle Jet/Bleed Pipe.  Above it is the Needle Jet (not numbered).............is it still in there and installed correctly?  The combination of the Needle Jet and needle control fuel flow as the diaphragm moves the slide up and down.

 

When you install the needle, the parts must be put into position to hold the needle in place in the top of the slide.  Also make sure that none of the "feet" on the white plastic cage block the hole in the top of the slide. 

 

Ride on

Brewster

[_RaStA_RoCkEt_]

......is it still in there and installed correctly?  

 

Brewster!

 

Thank you SO much for stopping in and taking a look at this problem! I really appreciate it!

 

Regarding your question, currently the order of install is NEEDLE (clipped at center) with GOLDEN WASHER (Needle Jet?) on top of the Circle-Clip, then that whole assembly into the bottom of the white PLASTIC CAGE. Spring installed on top of that, and then Cap.

 

Is this correct? The FSM makes it seem like the needle has the Circlip/Golden washer ABOVE the cage, with the needle pushed through the center... but the top of the cage is too small in diameter to hold the circlip/washer firmly and the needle would jump all over the place.

 

I've got the Carb in my room, about 2 feet away now, and I'ma sleep next to it til' I solve this plaguing issue!

[brewster]

PLEASE confirm that the needle jet is installed. It is not the golden washer. It goes up into the same tube that the Bleeder tube (#5)goes into. The tip and tapered portion of the needle travels through it.

Ride on

Brewster

[KAWBOYBILL]

I am thinking you did not understand Brewster's reply. If I am understanding you properly you are still referring to putting the slide and needle assembly together and Brewster is referring to the assembly above the main jet. The main jet screws into the Needlejet bleed pipe which holds the needle holder in place. If it is not there the symptoms you describe will be there. If that is not the problem the picture of your plug looks to show a rich condition. Is the insulator a sooty black like the outer edge of the plug ?   

[x_JT_x]

I have a Pumper carb that came from a klx300. should be the same as the one used on the 250. I could possibly give it to you for free since i have the same thing but stroker on my klx300 anyway. The thing is the pumper plunger got stuck down so i have to get it out or else it most likely wont work. Let me know if you'd be interested in it!

[_RaStA_RoCkEt_]

I am thinking you did not understand Brewster's reply....

 

....If that is not the problem the picture of your plug looks to show a rich condition. Is the insulator a sooty black like the outer edge of the plug ?   

Bill! 

Thank you so much for showing up for me! Many wouldn't do the same, so again, thank you!

 

I WAS misreading Brewster's reply. I Do have the Golden Needle Jet, it is installed. Forgive me.

 

I'll pull the Plug today, and examine the insulator. I know it's running rich, since when I try to start it the air around me gets real 'gassy' smelling.  I'd assume the insulator is darker... but more on that to come.

 

 

Let me know if you'd be interested in it!

 

Joel! Thanks for the offer. I'm certainly interested, and I'd love to take it off you hands and pay the shipping, if need be to get it to me. This Little CVK has me down, but not quite out though... so, I'm going to slog though this a little further before I go for a pumper.. but I'd sure love the option!

Whereabouts are you located?

 

PLEASE confirm that the needle jet is installed. 

 

Brewster!

Thanks for the clarity. I was being foolish, and thought you were talking about the Needle itself, not the Needle Jet. Yes, it's there. Forgive me.

[x_JT_x]

Bill! 

Thank you so much for showing up for me! Many wouldn't do the same, so again, thank you!

 

I WAS misreading Brewster's reply. I Do have the Golden Needle Jet, it is installed. Forgive me.

 

I'll pull the Plug today, and examine the insulator. I know it's running rich, since when I try to start it the air around me gets real 'gassy' smelling.  I'd assume the insulator is darker... but more on that to come.

 

 

 

Joel! Thanks for the offer. I'm certainly interested, and I'd love to take it off you hands and pay the shipping, if need be to get it to me. This Little CVK has me down, but not quite out though... so, I'm going to slog though this a little further before I go for a pumper.. but I'd sure love the option!

Whereabouts are you located?

 

 

Brewster!

Thanks for the clarity. I was being foolish, and thought you were talking about the Needle itself, not the Needle Jet. Yes, it's there. Forgive me.

Located in Roseville CA. I will do my best to find and unjam it. just hoping it didn't get thrown out in my dad's latest shop cleaning haha. Sorry if I'm unable to find it, but I'll let you know if I find it or not in a day or so!