Need Help 2008 DRR 50

[asadad00]

Hello, I just found this forum as I was searching the net for advice, after reading some threads I think this is the place to be . I purchased a 2008 DRR 50cc water-cooled for my son , but it does not run correct, it is used but very nice and well kept. At wide-open it sorta looses power , it is faster at half throttle. Changed the main jetting and that did not make a difference, changed to fresh gas, changed spark plug, no better. It sounds rich and the plug looks a little rich , not much though. I even swapped the carb off another friends 50 to ours but didn'thelp.
Any suggestions will be appreciated.

[selbygirl]

my boys bike did the same thing the plug was a little black check the orange wire and black wire that go to the coil and comes off the cdi box its a white fitting un plug it and clean the dirt out out of it. i cut mine and hard wired it i seen it happen to two other bikes at the track check your ground wires higher rpms the bike vibrates more just a easy check good luck tommy

[jerkyboy]

Is the carb the 21mm oko rr the smaller sunworld?
Had the sam problem with the 21mm oko.

[asadad00]

Thank you for replies. small sunworld carb, cleaned and checked coil wires and ground connections, but no better yet,

[EthansDad]

we run the same bike. on the sunworld 16mm, we've had good luck with the 110 or 115 main jet. if you are in SD and its cold, might have to up a bit more like 120 (with a uni air filter).

Also, are you sure it better at half than full, or better at 7/8 over full? sometimes, the slide in the carb will come up to high. you can take the air filter off and see how high it comes up on full and adj throttle thumb stop if it comes up too far.

something else to test, does it run the same with the wheels off the ground? if not, it could actually be a CVT/clutch issue.

[asadad00]

I put the atv on a stand and it still has the same problem , maybe not as bad but close. main jet is 115, I have been up to 125 and down to 105, not much change either way. Fires right up and idles good , revs up good until you go full throttle. Air filter is stock as is the whole atv. I will continue searching , thanks for the ideas.

[Nichols Atvs]

lean out your needle jet

[Andyman17dad]

make sure the choke is shutting off all the way. I have had the cable get hung up under the boot where you cant see it, also check the nut on the choke knob, making sure it hasn't back out some holding the the choke on just a little.

[Hetrick Racing]

Take the filter off and run it on the stand.
Very few run well on the big end with the stock air filter.

[nastynotchback1]

i had this same problem after installing a new plug.i rejetted and rejetted.last thing i did was change the new plug out for another new one and it fixed it.

[EthansDad]

Hey ASAdad,

all good advice here from everyone. We've run into each of these problems at one point they've described. Just keep us posted on testing/feedback and we'll get you running.

I think taking the airfilter off for testing would be a good starting point, and checking that choke cable. That's bit me more than once. If the needle is off, it will sometimes seem like the main won't come on. Tell us where the needle clip is, that will help.

[swamp]

i had the same problem changed the stator and the cdi no problems after that

oh yea sell it and buy a honda no more probs

[hotquads1]

Alot of good diagnostic advise here but from your description , your issue is most likely ignition (electronic) related , first by pass the factory tether switch by unplugging at the harness and plugging the 2 harness wires to each other, if bike runs good this way then get an aftermarket tether . Second remove coil and and sand the powdercoating off the coil mount surface and clean mounting surface of coil so there will be good grounding and reinstall coil . Both of these items were common on your quad and will take about 15 minutes to perform . Next I would check stator and cdi as mentioned earlier. Good luck and hang in there , you will get it going .

[asadad00]

Thats it , Drr is running perfect. Thanks to everyone for the help. I tried everything yesterday with no luck , but this morning I did the tether switch by pass per hotquads1 and now it revs to the moon crisp and clear, I will order a new switch today .Thanks again .

[coffing918]

same exact thing happen to me in 08

[kfx450]

bike ran perfect went on vacation for a week came back and the bike wouldn't run. took off off kill switch ran perfect. bike was about 4 months old.