1999 650L before and after Mods

Just in case anyone is interested in the results from what typical mods do, here is my story.


1999 xr650l. White Bro's pipe (with disks), smog kit eliminated, jetted correctly, air box mods, good foam filter, street tires, supermoto fender.

best 1/4 mile time of 13.9 @ 89mph.


JE piston, 10.5:1.

Hot Cams Stage 2

Cleaned Intake/Exhaust Ports, combustion changer etc...

best time of 13.2 @ 95mph.

Weight with me on it is 495lbs as measured at track.

Jetting seems to be a little lean with the new combination, a carb is a definite mod for the future, as well as intake porting.

It feels great, although I think with the current carb and port combination, a stage 1 cam would have been a better compliment, as it wants to rev out, but kind of hits a "wall" on top.

I think the clutches started going out, as my first run of the night was my best, after which the shifts started feeling mushy, not solid engagement. It is the original clutch with a shit ton of hard miles on, i was quite surprised it has lasted this long to be honest.

Important to note, starts like shit, barely turns over without the compression release. If jumped it starts great though.

So there you have it, truly just "bolted in" the mods, and that is the difference. I would highly recommend the piston to anyone, and if you want a fun wheelie machine maybe the stage1 cam instead.

Stock carb I assume?

The starting thing is kinda got me worried about the hi comp piston for mine. I already have the stage 1 hotcam and want the piston.

Although if I keep hearing these starting issues, I dont know...

OEM battery?

Yes, stock carb with correct jetting to the "before" bike.

OEM battery that came with the bike. The bike just plain needs more juice to turn it over. If it is jumped it fires right up. Once hot, a 1/16 turn throttle and it fires right up, un-jumped. Needs throttle because it is now too lean on bottom.

Its a great mod, and I would recommend it. Honestly, the bike has always had a hard time turning over with the stock battery, even without piston and cam.

Slide drilled?


No. Should I?

Actually, anyone have a link to the FCR41 carb mod. I would really like to do this, but am bad at finding a good post on what carb to get, where to get it and what i need to do to make it work.

I run the slant FCR 41. Non choke. If you have a hi comp piston and starting is an issue, may want the MX choke version.

I just read a couple articles, the mikuni looks great for the price.

I dont ride the bike often, and when I do, it is for performance only.

Is this carb a good option?

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