I oiled and installed a new K&N on my son's Sunl 50 and it's running a bit sluggish since. The engine bogs a bit when you first hit the gas and overall it's not as powerful.

We had the older style filter and it was a total joke. Oily dust was visible in the carb inlet. The filter was a lose peice of foam, maybe 3/8" thick held losely in a circle. Inbelievable.

 

Did you adjust the air screw? It may be sluggish now because the carb works on vacuum. Some of these smaller engines dont work well with aftermarket filters because it will lose vacuum. If you can find a way to modify the intake portion of the filter by making it longer this will help. A longer tube hooked to the carb then the filter attached will help or put some duct tape over part of the filter so it will cause more vacuum. Yes the stock filters are a joke and will ruin the motor in time.

 

I took my K&N off the Yamoto,a nd went with a UNI. With all the dust in Arizona, I was getting too much into the carb. About 2 hours into the ride, the K&N was clogged and letting dirt in. The UNI seems to have more tolerance for dust.

 

Are you using a pre filter on your K&N? We run 3 K&N bikes in the sand and don't have a clogging problem all weekend!!!

 

Yes, I have the pre-filter. Sand is larger than the dust we have out here. Hasn't rained for 96 days now, so that makes it worse. At the place we go, you can see the cloud of dust for 3 miles down the road.

 

I tried turning the airscrew to the right and left but it didn't seem to help any. I may need to move the needle up or down.