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SLJ

New Used 650R and confused?

7 posts in this topic

Hi Everyone,

I just bought a used 2000 XR 650R today and already have a slight problem. The guys at the shop didn't know what exactly has been done to it so I took it as is without knowing anything about the motor, jetting, suspension, or anything I couldn't see from the outside. It ran fine at the shop. When I got home I tried to start it and it wouldn't even begin to fire. I pulled the plug out and it was very black and wet. So I replaced the plug and did the flood drill to start it. It took about three or four kicks and it started right up. After probably 30 seconds or so I wicked the throttle and it died right away after a slight pop from the motor. I decided to check the jetting to see what the last owner had in it. It has a 65 pilot, 175 main, and the clip is 4th position from the top. It has a white brothers R4 muffler and some aftermarket headers (not sure what they are), and a K&N filter with a slightly drilled out airbox cover. I live at 5000 feet and it's about 60 degrees in my garage where I tried starting it. This jetting seems very rich to me for this altitude.

I also have a stock 2003 650R with standard uncorking and 65 pilot, 168 main, and 3rd position on the clip which seems to be great jetting for it.

Would the pipe make that big of a difference for the jetting? How can I tell if maybe it has a different cam and higher compression piston to warrant the rich jetting?

Thanks,

Shane

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I would first start with dropping the main down to a 168 or 172 and the clip to the 3rd position. Check the airfilter for cleanliness and go from there. Jets are cheap buy a ton of em'(right from honda ) :) Also remember when it's colder out you want to be a lil richer than in the summertime.

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Alright, so I went out and bought a bunch of jets. I put in a 170 main since they didn't have a 168 to start with. I moved the needle clip to the middle (3rd from the top) and left the stock pilot (65). It started right up with a fresh plug. But then it wouldn't run with the choke even in the middle position or off. Ok, so it's probably too lean. So I put the clip back to the 4th position and it would then run with the choke off but was really lean on the top end when giving it throttle. So I put in a 172 main and was still too lean on the top. So I put in a 175 (the same one it had to begin with) and it still cracks like it's lean even a bit on the bottom at idle. I then turned the fuel screw out 3/4 of a turn and that changed it a little for the better but still seems lean. Maybe this is just the sound of the pipe. I have never heard one so I don't really know. This seems really rich to me for this altitude. Can a pipe, headers, K&N filter and drilled airbox alone change the jetting that dramatically from a stock uncorked bike? I still haven't been able to ride it so I don't know if it maybe has a diffent cam, piston, etc... It definitely sounds different than my other one.

Thanks,

Shane

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Hi. Do this: at 5000', run a 165-170main (depending on your pipe), clip in 4th position (or 3rd position if you have the competition needle). Stock pilot jet. And make Damn Sure the airbox baffle plate is removed, and the intake manifold boot is the 40mm unit.

The bike should run well set up that way. I can't give much advice on the aftermarket pipes you have, as far as how much they could affect your jetting requirements, but in general, the more open the pipe, the richer it needs to be.

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First thing I would do is toss that K&N filter and put a foam one in. Then, rather than spending all kinds of $$$ on guestamate parts, just swap the one in question between the two bikes you have. Still, if I was a betting man I would say it is that K&N.

It is my EXPERIENCE that an overly rich big bore four stroke acts as though it is running lean. :)

It doesn't act like a two stroke, which will run overly rich.

Best of luck.

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