What happened to all my gas!?

7 replies to this topic
  • mehowmix

Posted August 16, 2007 - 08:37 PM


I have a 97 XR650L that I bought used. I did the usual mods and tried to jet it but recently I've been getting about 10 mpg, and first I thought it was due to a fuel line leak, but now i have a new tank setup and nothing leaks. Still getting the same insanely crappy mileage.

Am I running too rich? is it even possible to be that rich? This is waaay below what I should be getting!!

My question for you guys is what should I look at? Where do i start diagnosing the problem? can there be some kind of leak, this is alot of gas being lost. I don't think my speedo is broken either.

Is it possible that this is a carb problem? Could it be an adjustment issue?
Or will I have to dig deeper and go down into my top end? or deeper?

Its a bit confusing to me because the bike almost seems lean to me and heats up a lot and doesn't hold well at a low throttle.

Could someone help me out and send me down the right path to fix this issue?

  • eastreich

Posted August 16, 2007 - 09:13 PM


I am no carb expert, but the thing that comes to mind for me is to check the float level. Possibly your float level is too high, and when you are riding you are losing fuel out the overflow hoses on your carb.

  • HeadTrauma

Posted August 16, 2007 - 09:30 PM


Pull the dipstick and smell it. If it smells like gasoline, you know where at least some of that gas went. You will also know the oil needs changing. If the carb is THAT rich, the bike would noticeably smoke black. Also have a look at the spark plug.

  • NavyNuke

Posted August 16, 2007 - 10:38 PM


another check is to put a bottle on the drain houses from your carb, ride a bit, stop and see if its full of gas.

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  • needsprayer

Posted August 17, 2007 - 07:08 AM


I am no carb expert, but the thing that comes to mind for me is to check the float level. Possibly your float level is too high, and when you are riding you are losing fuel out the overflow hoses on your carb.

Agree, sounds like an intermittent problem. If it was a constant leak you would see gas where you park.

  • mehowmix

Posted August 17, 2007 - 05:11 PM


I've taken apart the carb and I can't figure out what I use to adjust the float height. Its a 97 xr650l, with the stock keihin carb. I've tried searching around, but I honestly cannot find any detailed info about checking/ adjusting the float height. Is there some sort of method for doing this?

When people say float tang and talk about a metal piece to bend are they talking about the small flange around the float valve? Also there is some discussion about the little pin on the top of the float valve, and what thats supposed to be doing when the float is in its up position.

Could you guys please point me in the right direction here?
Thank so much for your help, you're all incredibly helpful!:worthy:

  • exaresix

Posted August 17, 2007 - 05:34 PM


By now I'm sure you're frustrated and your hands smell like gasoline, you have spent some time worrying about dropping a float bowl screw into your crankcase vent, skinned your knuckles, and cursed the fact that there are not Allen bolts to secure the float bowl! Yes, the float tang is the little tab of metal near the hinge. The float valve has a bucket handle that loops over this tab. First remove the float valve (little plunger with a conical rubber tip) and spray some carb cleaner up into the hole it was in. This will clean out any specs of dirt or rubber that have lodged in there (and they do lodge in there!). Reinstall the float properly with the flat side down. Every float has a different millimeter measurement as to what it the correct height, but if you can establish that the gas shuts off when the bottom of the float is absolutely horizontal (or parallel with the carb base) then it is probably within spec. If the float has to be pushed up higher than horizontal to shut off the gas, then you will spill gas out of the overflow vent. Likewise, if there is dirt in the float valve seat, you will spill gas. I can not imagine any carb burning 10 mpg, so you are spilling gas somewhere.

  • HeadTrauma

Posted August 17, 2007 - 09:28 PM


It's for a 600R, but here is a thread I posted pics in about adjusting the float in a PD carb.


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