Significant power decrease, no more hills, 3 weeks old

[nsxcorvette]

Hello,
I searched the forums for over an hour before posting, but could find any answers that I didn't already try. I'd greatly appreciate anyones help. I recently finished a 66cc build from kings. This is around my 10th build. I finished the bike about 3 weeks ago and have put around 300 miles on it. I've been very careful since it's the break in period. A couple days ago the bike started losing power, and is most noticable trying to go up this one hill by my house. When I first completed the bike, it pulled up with no problem, over the past couple days it has diminished to where I'm pretty much just pedaling like normal to get up it. I've switched the spark plug, changed the gas, checked all bolts and gaskets, and tried adjusting the carb. There seems to be an excessive amount of fuel coming out the tube on the right side of the carb. There's also no strange noises like what I've read about when the fuel isn't being distributed evenly and the piston is knocking.
Thanks!
CareyWb

 

[Bikeguy Joe]

Has the jet come loose in the carb maybe? Or....the fuel inlet jet gotten crapped up with something so it's flooding?

Just some things to check.

 

[nsxcorvette]

Update: If I turn the fuel valve off while I'm riding, it gains all its power back and rides perfect for about 20 seconds until it runs out of fuel. So that, along with all the gas coming out of the carb tube, would mean its either getting too much gas or not burning enough? How could I adjust that?

 

[JonnyR]

i think it needs a float adjustment or you lost the jet into the carb

 

[Bikeguy Joe]

That means it's flooding for some reason.
Like I said, crud in the float needle/seat, or maybe the jet came out.

The float's rarely if even "go out of adjustment". I may have sunk though.

Take the float chamber off and have a look, it takes 5 minutes.

 

[nsxcorvette]

Thanks for the replies! I took the float cover off this morning and it seems to be working fine. Difeinitely seems to be an issue in the carb though. I'm about to go outside and take the carb off and check the jet and the rest of it. Will let you know

 

[biknut]

Junk the junk CNS carb and buy a NT or Speed carb.

 

[nsxcorvette]

Thanks biknut, I actually went ahead and ordered the RT from thatsdax this morning after taking the factory carb apart and finding nothing. Hopefully that will solve the problem.

 

[JonnyR]

the RT is a nice carb from what i here but it usually needs jetting out of the box to match your engine but from what i here its the best on the market right now congrats i might buy one in the future but im happy with the NT for now

 

[Saddletramp1200]

Did you wash that carb, before you put it on? I bet a tiny sliver of metal is blocking the main jet.

 

[nsxcorvette]

I did not wash the carb before installing. never have. I have since taken it apart and thoroughly cleaned it with carb cleaning, making sure everything was clear and didn't see anything. Hopefully the new one will be here tomorrow and won't have to worry about it.
cwb

 

[nsxcorvette]

Well I got the RTcarb in today, installed it, and now the bike won't run at all. won't even fire. the spark plug is still sparking, so its gotta be a gas issue I would think. I reinstalled the old carb and it ran weak just like before, but it at least ran. reinstalled the new carb again and nothing. Anyone know of anything I need to do to the RT carb to make it work? I bought from thatsdax and couldn't reach him on the phone. when I ordered he said its ready to go out of the package with a 75 jet installed. float looks fine and fuel is in the float case. at a loss!

 

[nsxcorvette]

It's fixed! The choke on the dax was getting stuck. Works tons better than the old one. got old power back and then some.

 

[maniac57]

Anytime turning off the gas makes the engine run better, the float is stuck open and flooding the carb.Clean the needle and seat and use a fuel filter to stop this problem.

 

[goofyfoot2001]

I have had the DAX for about a month and it was great for a couple of rides. Then for no apparent reason I lost 20-30% power. Replaced the gas thinking maybe it had water in it. That didn't work. Replace the carb with the stock and same issue. It used to idle beautifully but now will only idle well if the choke is on. any ideas? This is with the DAX back on.

 

[Bikeguy Joe]

Air leak?
.

 

[goofyfoot2001]

I sealed everything with tons of goop. I guess there could be and it would seem to indicate that but if it is an air leak, it's on both carbs. I'll try the stray wd-40 thing on it tonight.

 

[biknut]

Most leaks are easy to find, because oil comes out of the leak, and makes a mess.

 

[goofyfoot2001]

NO oil except though kinda sorta some around the sparkplug. But that was happening before the power loss. i did buy a straight head cover to try in place of the slant head should I get that desperate.

 

[Bikeguy Joe]

I sealed everything with tons of goop. I guess there could be and it would seem to indicate that but if it is an air leak, it's on both carbs. I'll try the stray wd-40 thing on it tonight.

That would indicate that the air leak was around the crank seals or the intake to cylinder junction.