[dirtbear]

Please help I can't even ride my new bike. one minute it is at a nice rpm speed then it jumps up 6-700 rpms. It is to the point when you let off the throttle she is still moving thru the woods. Not a feeling I like. I am in my 40's and am shocked at how thumpers run today. The first weekend wasn't as bad but I still noticed it. This weekend has been shoot. Tried cleaning jets with no difference. Checked filter and all clamps. Couldn't adjust the mixture screw as it has a blocker in front of it and I was dumb and didn't rip the entire bike apart to take the carb out. I just want to ride with my son, he moved up to my 150f and I really wish I had just gone with the air cooled 230. Any suggestions?????

[JimDirt]

Welcome to the site !!

All of this depends on the year of the X (you did not mention the year , you just said New , but i don't know if that means New to You , or Brand New , did you buy it New or Used ??) , and elevation your riding , and if any mods are done to the bike

It sounds like it could be a couple things , it's possible it could be a worn Needle and/or a worn Needle Jet , the Needle jet is the main brass tube that the Needle runs thru and the Main Jet screws into , when the engine idles , and the Needle and/or Needle Jet are worn , it will give symptoms your describing as the Needle Jet is softer than the Needle so it ovals out from the vibration of the needle , its not noticeable to the eye , but you will usually find wear marks thru the Anodizing on the needle as a indication , or if you lower the needle (making the mixture leaner , but also shoving the needle taper farther into the needle jet allow it to move less , which should reduce the issue , though this should be only done for testing , as you do not want to lean the mixture any farther than it is from the factory , you will want it richer), as a result the Needle bounces around in the worn Needle Jet and you will get a rich/lean condition at idle and lower RPM's , , the other possibility is that the mixture is too lean for the location/elevation your riding at , where adjusting the Fuel Screw is needed , as well as a likely Pilot and/or Main Jet replacement to a larger size , the size of the jets , is determined by elevation , and temperature changes , and what your fuel screw is set at , your best bet is to remove the carb , so you can drill out the blocking cover for the fuel screw , so you can adjust it , and better yet , replace the awkward screw with a R&D Flex Jet

Another possible cause could be the Floating Valve Seal , which is the removable flat plate that attaches to the carb slide , if that seal becomes damaged or worn , it can give those symptoms as well

If you need more detailed info , go to the Jetting part of the forum and ask leardriver , he is the resident jetting expert here , and might be able to guide you better than i can ...........Hope that helps some

Floating Valve Seal:
https://www.crfsonly.com/catalog/produc ... ts_id/3687

R&D Flex Jet:
https://www.crfsonly.com/catalog/produc ... ts_id/2792

Needle Jet and Needle:(Part # 27 and #38)
http://fiche.worldofpowersports.com/yel ... CARBURETOR

[dirtbear]

New 2016 left over, ride at sea level, zero mods. Sounds like instead of riding I will start taking it apart. I knew that I would be heading back to the carb. Just sucks to have to screw with a new bike after spending that much. Thanks for the import, always appreciated.

[JimDirt]

If its that new , then i would think it had old gas in it , if it did , then the carb will have a green coating inside the float bowl , if it does , you can thank Ethanol , as it causes more carb issues then i helps the environment , remember water does not burn and 70% of Ethanol is WATER , that's why your car drips water out the tailpipe , i would check for blockages and make it so you can adjust the Fuel Screw , as its most likely heavily lean from the factory , also go with 1 size larger Pilot jet , and depending on your elevation 1-3 sizes up on main jet (what is your elevation ?)

I would not worry about the Floating Valve Seal just yet , its more than likely a clogged jet and a lean mixture screw , so go with the Flex Jet (make sure you remove the O-Ring and washer and spring if its stuck up inside , make sure the O-Ring does not get damaged or distorted , and install it on the Flex Jet , in order *spring first , then Washer and last O-Ring* , if the Flex Jet comes with new parts , then use them and save your old one for a backup) , and replace the jets (pilot and Main) with the correct one's for your elevation

[dirtbear]

Done screwing with it tonight! Seems not a bit different.

[JimDirt]

What did you try ??


If your not coming up with anything , PM leardriver , if its fuel related , he can figure it out