CR125 Carburetor Problems

Todd Kageals · Joined: 15 Jun 2012 Posts: 285

Guys,

I finally fired up my '99 CR125 rebuild tonight but I am having carb issues. Sad

All of this is on the stand. If I run it at less than full throttle, it sort of sputters but continues to run and the pink vent lines slowly fill with fuel (they are gathered and pulled up out of the way). At full throttle it revs up and dow...up and down but never very fast and it slowly draws the fuel out of the pink vent lines. It sure seems like the pump is overpowering the floats in the carb. This is a brand new straight out of the box PWK. The engine has just had a COMPLETE rebuild. The tank is vent to the atmosphere but there's no return line anyway on the Dellorto. I read some threads and thought this would be a simple way to go but I guess that's what I get. I do have a pump around I could put on it but I was hoping to avoid it. I have a video posted below so you can see the setup but the kart was not running as I can't do both with only 2 hands!

http://www.youtube.com/watch?v=ijqL5dzepDg

If you have any advice or see something wrong in the setup please let me know. The kart shop that sold me the pump insisted it should be fine for the CR125 as it limits pressure to 1 bar (or something like that).

Thanks in advance for the help. I am sooooooo close to getting it out on the track.

Todd

http://www.youtube.com/watch?v=ijqL5dzepDg

Matt Dixon · Posted: Mon Jan 14, 2013 5:10 pm Post subject:

http://youtu.be/JZJo7p8W8tQ

Turn the volume way up and listen closely... then don't listen to Steve Wink

, listen to Jimmy and call Jason...

We never have a problem!
_________________
Matt Dixon
94y Energy Corse/Swedetech

Todd Kageals · Joined: 15 Jun 2012 Posts: 285

Well...I appreciate the help but I could not hear much of anything on that video. Who is Jason?

joseph hollinger · Posted: Mon Jan 14, 2013 5:46 pm Post subject:

The usual: which jets (main and pilot) and which needle?
_________________
A lie gets halfway around the world before the truth has a chance to get its pants on. -- Winston Churchill.

Jeff DeMello · Posted: Mon Jan 14, 2013 5:51 pm Post subject:

adjust your float level
_________________
Jeff DeMello
Emmick F125 Pavesi

Todd Kageals · Joined: 15 Jun 2012 Posts: 285

Joseph,

Honestly I am not sure as it was brand new and I have not looked since I unboxed it several months ago. I can't see how this is the problem as fuel is being forced into the vent tubes. Doesn't it pretty much have to be that the fuel is being pressurized in the bowl for it get into the vent tubes? I COULD see it being the float level but it's still being forced past the valve. I'm certainly not an expert but I can't see how the jet size could be be the culprit. It's not just running rich, it's forcing fuel UP the vent tubes. The tubes are above the carb and there is enough pressure in the bowl to force the fuel up the lines. It's got to basically be spraying out around the needle and jets if it's got enough pressure to force the fuel upwards above the carb several inches. Doesn't it?

Chris Laird · Posted: Mon Jan 14, 2013 7:53 pm Post subject:

Page 6 shows some detailed pics that should work just fine for your setup. http://ekartingnews.com/viewtopic.php?t=117823&postdays=0&postorder=asc&start=75 if I remember right Sam messed with the float heights in the carb but its been a while.

Benn Herr · Joined: 18 Jul 2001 Posts: 1584

The DellOrto pumps usually work fine. If the float level is off, or the needle is dirty, or the float tab is crooked, it can cause problems like you describe. Try it with the two pink lines like you have them but but the black line (I assume it's the one from the overflow outlet on the bottom of the carb) pointed down hill and dumping onto a catch can. This should help your "surging".

It may be that the pump is just a little too "strong" for the stock seat. You can help this by mounting the pump lower. Just above frame works good. You'll have to check the line for oil every so often but it should knock down the pressure just enough for the stock needle/seat to work.

When everything is right, there will be no fuel in the vent lines (they'll be slightly damp) and the overflow line will put a couple of teaspoons of gas in your overflow bottle after a race.
_________________
Benn Herr
Come see our Superkart Build Off @
http://www.lostenduros.com/?page_id=1534
beherr3@cox.net
http://www.southwestkarters.com/
http://www.lostenduros.com/
Kart Design
Chandler, Az.

Chris Laird · Posted: Mon Jan 14, 2013 8:10 pm Post subject:

Oh yeah by the way Jason is from Swedetech and sells these to REALLY fix fuel delivery problems http://www.shopswedetech.com/mobile/default.aspx#P327

joseph hollinger · Posted: Mon Jan 14, 2013 8:26 pm Post subject:

Todd Kageals · Joined: 15 Jun 2012 Posts: 285

Point well taken.....however.....I THINK....I put a jet in it when I got it a couple of months ago. I'll check it out and possibly move the pump lower. Will report back.

Mike Goebel · Posted: Mon Jan 14, 2013 9:10 pm Post subject:

joseph hollinger · Posted: Mon Jan 14, 2013 9:24 pm Post subject:

Steve Buckner · Joined: 22 Apr 2003 Posts: 839

joseph hollinger · Posted: Mon Jan 14, 2013 10:41 pm Post subject:

So going to buy one of those.
_________________
A lie gets halfway around the world before the truth has a chance to get its pants on. -- Winston Churchill.