1987 KLR250 carb install

[vtraudt]

Had the carb cleaned and setup.
Installed.
Kicked while on the stand and ran for a minute. Finished putting the rest of the bike together. Since then, can get a single fire!

New NGK plug gapped to 0.8mm is in. Have spark.

Choke, no coke. No throttle, little throttle, wide open. Kicking and pushing.

No nothing.

Can it be that I hooked the fuel line to the wrong elbow?
I connected it to the bottom one (the top to the overflow hose).
Wrong?

If not wrong, what else could prevent it from firing even a single time?
Particularly, since it was running for a minute or so, and has spark!

[vtraudt]

Could it be that the choke cable/slider did not get seated properly?

[hodgie]

i am in no way shape or form, an expert. but if your choke cable isnt right, you will have a vaccume leak, and i dont believe it will run like that. you have your fuel line correct.
when you cleaned it out, did you blow out all the oriffices orthe carb? no disrespect meant at all, just want to be sure. i just did mine, i actually out mine in a ultrsonic tank for a couple of hours. and i bought new jets. i bought an array of jets at my local shop for 2.50 each i believe. my pilot jet was beyond repair.
just a bit of noob insight, LOL

[hodgie]

and BTW, the top elbow is a vent.

[vtraudt]

Originally Posted by hodgie

i am in no way shape or form, an expert. but if your choke cable isnt right, you will have a vaccume leak, and i dont believe it will run like that. you have your fuel line correct.
when you cleaned it out, did you blow out all the oriffices orthe carb? no disrespect meant at all, just want to be sure. i just did mine, i actually out mine in a ultrsonic tank for a couple of hours. and i bought new jets. i bought an array of jets at my local shop for 2.50 each i believe. my pilot jet was beyond repair.
just a bit of noob insight, LOL

Thanks for the response.
I took the carb to a local motorcycle repair shop. He soaked it in a special both for 24 hours (no varnish left, looked like new).
Out of the bath, he washed it to get rid of the solvent.
Blew it out.
Then he disassembled completely and put back together. Checked the main and pilot jet (read the numbers off it). Drilled out a tiny bit of the pilot jet (said they run and start better with a little larger size).
Checked the float height (but only visually, explained that the 'arm' should be parallel, which it was, to the carb mounting surface.

Then assembled, checked the parts, blew out a bit more.

I installed, and HATE how it is impossible to get the rubber air box to rear of carb piece on!

But it seem obvious that the carb does NOT get any fuel.

Before taking it out: will try to attache the clear tube to the drain, and tape it to the side of the carb, see how high the fuel level goes when opening the drain screw.
If obviously low: no other option than take the carb out again and play with that darn tiny flimsy 'tang' and see if I can increase the fuel heigth.

Is that a possible cause and troubleshooting approach?

Any other things that could prevent fuel from getting into the carb?

[KLR250STL]

Drain the carb bowl first if its not full of gas then your theory is half proved. make a 'beer bong' gas tank and then you can leave the bowl open to see if gas trickles out, then close the drain screw and note how much the bowl fills.

[vtraudt]

Originally Posted by KLR250STL

Drain the carb bowl first if its not full of gas then your theory is half proved. make a 'beer bong' gas tank and then you can leave the bowl open to see if gas trickles out, then close the drain screw and note how much the bowl fills.

Yeah. Second time, I had air bubbles in the clear hose. Even so I bent the tank, the level did not seem to change.

Yesterday at the shop who cleaned and setup the carb, he checked the height again. This time it was a bit high (maybe 3mm above the edge).

He played with the idle, mix, etc. but could NOT get the idle to hold (either 3k, after a while on next time to blip the throttle, it goes down to 1k or dies). Adjusted throttle cable (good play), no change.

He wants to look at it again today.

[KLR250STL]

they idle jet is clogged or the needle is dirty or thelittle ribber dick on the end is mishapen. Can you start it with arb cleaner sprayed into the air box.

[KLR250STL]

Im on my phone so pardon grammer. Is your key ON and your kill swith ON ?

[TownsendsFJR1300]

The float level should be 17mm from the base of the carb body to the edge of the float as it rests upside down...

The actual fuel level (checking with a clear hose on the drain from the bowl) should be 1.5mm-.5mm from the bottom edge of the carb body.

Make sure your plastic nut for the choke cable isn't cracked, if it is, you'll get a vacuum leak.

Also, try cranking the bike with the fuel cap partially open should you have clogged vent causing a vapor lock...

Below is a a good link on the basic's of the carb:

http://myural.com/keihin_32cvk_disassembly.htm


If the choke nut is cracked, this company makes a metal replacement:

http://www.steadengineering.com/main.sc

[vtraudt]

I think the main cause was 'erratic' spark/non-spark cause by loose connection.
With professional cleaned carbs, she was still not idling well.

Brought her back to the shop who did the carb cleaning (off the bike).

He drilled open one of the jets (idle too lean?).

Started GREAT (better than EVER since I own the bike). Maybe a bit rich (no choke EVER).

But: idle wasn't holding steady.

Brought here back. Idled fine.... for a few days.

Now back to inconsistent idle (either 3000 or dead); have to manually 'hold' her.

Since it WAS all good (stable idle at around 1300 or so) for a short time: what is causing it to become unstable again?

I don't like to go back to the guy (all he got out of me was $40 for the carb cleaning), but also don't want to shell out big $$$.

[TownsendsFJR1300]

Try opening the gas cap and running the engine. Its possible your gas cap vent is clogged, not venting the tank and pretty much not allowing fuel to the carb (literally running out of gas).

The electrics on the KLR are designed fairly well... The weakest point of the bike, especially if not ridden regularly is the carb.

***There is an idle/air adjustment screw which is underneath the carb, just before it attaches to the intake manifold. From the factory, the aluminum carb protrusion has a small (approx .25" across) cap pushed into the carb body blocking access to it. The float bowl itself is just behind the protrusion.

That screw, from the factory, is usually set pretty lean from the factory. It helps control idle up to about 3,000 RPM. Removing this plug (a small drill bit, sheet metal screw and a pliers) and gain access (if its still even there). Turning the screw outwards (as you look at it, richens the mixture).

As I recall, that screw is set around 1.5 turns out. On both my 1989 KLR 250 and last 2005 250, I opened up that screw about a half turn... Made all the difference in the world. Don't go overboard with turning it out.. Maybe 2.25 turns out at most..

Also, IMHO, I'd find a new jet for what he drilled out and replace it... He made a quick short cut that did not work. All that will do is add fuel, (likely too much), richen up the mixture too much and help carbon build up faster than normal...

I checked a part fisch for your bike and it doesn't appear to have a vacuum operated fuel valve. The 3 settings for the lever should be on (straight down) reserve and off. Disconnect the hose at the tank valve, hook up another hose and make sure you have fuel flow when in the "ON" position and and the "Reserve" postion. If you have little to no flow, there is a filter attached to that valve, inside the tank. Empty/pull the tank and then the valve and check for debris. It may very well be clogged allowing just a trickle of fuel to the carb, just enought to run, but run crappy..


If you have a small spare fuel tank (I use a very small spare mower gas tank), bypass the bikes tank/valve and hook it up directly to the carb.

BTW, it sounds as if your bike is running very lean at idle.

[vtraudt]

Originally Posted by TownsendsFJR1300

Try opening the gas cap and running the engine.

Done. No change. Bike runs good at WOT for hours. At some point, thought full tank vs. empty takes makes a difference with the idle. But could not substantiate the claim.

Note: only complaint is idle not reliable (too high or too low; mechanical stop no fix).

Originally Posted by TownsendsFJR1300

Also, IMHO, I'd find a new jet for what he drilled out and replace it... He made a quick short cut that did not work. All that will do is add fuel, (likely too much), richen up the mixture too much and help carbon build up faster than normal...

What is that jet called (there seem to be few in there) or part number to order.

Note: ran perfect for a week or so. Stable idle, best start ever (can kickstart the thing with my hand). Since the jet did not change, what else caused the change?

Originally Posted by TownsendsFJR1300

I checked a part fisch for your bike and it doesn't appear to have a vacuum operated fuel valve. The 3 settings for the lever should be on (straight down) reserve and off. ..

I drain the tank again. Valve and flow are fine.

[quote=TownsendsFJR1300;1144845BTW, it sounds as if your bike is running very lean at idle.[/QUOTE]

My guess is pig rich (at least to what I had before). In the past, she AlWAYS neede a bit of choke, even in 100 deg weather. Now NEVER choke (even if the she running at mid RPM, moving some choke in kills her.

Bike was running fine for a week or so after it came back. Holding idle, starting PERFECT.

No changes (aside from constant attempts to adjust idle with the mechanical stop on the right side).

Still starts and runs perfect. Just idle all over the place.

I assume some dirt go it?


Can the carb be blown out backwards?

[TownsendsFJR1300]

There's an idle jet and main jet. I don't know which one he drilled..

If you check your bikes parts fisch, you'll see the different jets available:

http://www.babbittsonline.com/home

The bike when cold (approx under say, 50 degree's F) should need some choke to start. If it doesn't, its likely too rich on the bottom end (having enough fuel to start as if the choke was on). Pull your spark plug and see how its burning (see below pic).

This link shows how the carb is designed and the jets:

http://myural.com/keihin_32cvk_disassembly.htm

As noted above, I would adjust out (if not done already) the idle air adjusment screw located underneath (see attached pic, also in the link showing the breakdown of the carb)

You may also want to check the rubber intake boot (bolted to the head) for any cracking. Just due to its age, rubber breaks down, allows air to enter and screws up your mixture big time. besides visual cracking, spraying some carb cleaner around the boot, while it running, listen for ANY RISE in the idle. Its a sure indicator.

Also, if the vent for the gas cap is plugged/partially plugged, its effects will be MORE PRONOUNCED with a full tank of fuel. It'll develope a lock and NOT allow fuel to flow.

IMHO, if feasable, pull the carb yourself and check it. Its really not hard to do, the link above is pretty informative for anyone who's never been inside a carb.