opinion needed on jetting 02 XR650R

My friend just purchased this bike and took it up to the coast range elevation 500-3000' temp around 70. He said that the idle didnt always return quickly and also it ran bad. So I took the carb apart to check things out. It is clean but has a 190main jet witha 70 pilot and needle in the 5th position from the top. This bike is stock except for a big gun silencer and aftermarket header. It has the stock cam and airbox also.

From what I have read so far. This should have around a 175 main with 68S pilot and middle position on the needle. The plug was black. I know that going too lean can damage a motor so I just wanted some opinions before I do this. Not sure if this is the reason for a hanging idle though. Cable was adjusted properly and I can here the slide bottom out when I let off the throttle even when bars are turned so I know its not a cable issue. Thanks,

Jeff

Also I wanted to ad that on the needle jet is adjustable since there is a jam nut on it so you can adjust the height. The jam nut is currently in the middle. Anyone know if this is right. Thanks again,

Jeff

Also I wanted to ad that on the needle jet is adjustable since there is a jam nut on it so you can adjust the height. The jam nut is currently in the middle. Anyone know if this is right. Thanks again,

Jeff

I was gonna advise adjustment of the fuel jet to correct the hanging idle and leaner main and pilot until I saw this. Now I'm totally lost. Is this the stock Kehin? :banghead:

I was gonna advise adjustment of the fuel jet to correct the hanging idle and leaner main and pilot until I saw this. Now I'm totally lost. Is this the stock Kehin? :banghead:

Yes it is the stock carb.

It's more of a c-clip than a jam nut, i hope. For sea level up to 3000' feet a 172 main, 68s pilot, Honda comp. B-53 needle(in 3rd clip, 4th clip for stock needle) with the fuel screw 1 1/2 to 1 3/4 turns out. Airbox snorkel and plastic clip removed along with a uni air filter. This is what I run on my bike after lots of trial and error and I'd say it's about optimal for my location which is relative to yours.

It's more of a c-clip than a jam nut, i hope. For sea level up to 3000' feet a 172 main, 68s pilot, Honda comp. B-53 needle(in 3rd clip, 4th clip for stock needle) with the fuel screw 1 1/2 to 1 3/4 turns out. Airbox snorkel and plastic clip removed along with a uni air filter. This is what I run on my bike after lots of trial and error and I'd say it's about optimal for my location which is relative to yours.

So whoever was in this carb really fattened it up too much. So the only question I have now is the needle jet. It does have a jam nut on it and has probably 1/4" of adjustment. The needle jet is the piece that the main jet screws into and the needle rides in it to controls 1/4-3/4 throttle.

Jeff

The needle is accesed via the top of the "stock" carb. Adjustments to that are made via moving the needle clip up or down a slot. I've never messed with the jam nut you speak of. Although I now know the one you're talking about. Don't mess with it. Someone hopefully didn't touch that. I don't think it has much effect anyhow. Someone totally fattened that sucker up WAY too much.

Someone has been in there so I dont trust to just leave it alone. The adjustment of the jam nut would do the same as needle clip position. Someone has to know.

I get the hanging idle too. Anyone know what that is all about? I only tend to get it when the engine is really hot. This happened when I was doing alot of lower speed tight trail riding where the engine couldn't cool very well.

Typically that would be called a "run on". These usually result from a lean pilot circuit. My 650 did that before I rejetted.

I OWN A 650R AND I WENT THROUGH ALOT OF TROUBLE AND TIME GETTING THE JETTING AND NEDDLE JUST RIGHT. I USE A 175 MAIN AND A 65 PILOT WITH A HRC NEEDLE (CLIP IN THE MIDDLE RANGE) FMF PIPE, K&N AIR FILTER AND IT IS RIGHTON THE MONEY FOR THOSE ELAVATIONS AND THE HIGHER I GO IN ELEVATION THE BETTER IT LIKES IT :banghead:

That is the needle jet holder. With the needle/needle jet in place screw it in until it lightly seats. Then tighten the locknut. If that is the B53D then the clip should be on the 4th slot. If its the B53E then the clip will be on the 3rd slot.

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