I have a 2002 sportster 883 thats been converted to a 1200 with a cam upgrade awhile back. Recently started making a knocking noise after about a 20min or so ride. When you crank it up it sounds great. Riding it before the 20 mins or so it sounds and runs great. After the 20 min or so it starts making a knocking sound that you hear when idling and especially once you get to going down the road. There even seems to be a lose of power when taking off. Sounds seem like it comes from the top end of the motor. I took the front cylinder rocker covers off just to look at everything. My first thought was that there wasnt much at all residual oil in the rocker boxes. Even has almost a dry feel with my fingers. Looking at the rocker arms the front one has side to side movement and is at the upper limit for tolerance per the HD manual for this bike.

My question is, is there a way to determine if there is proper oil circulating thru the motor during operation. Are my lifters functioning properly as they were replaced when the cam was upgraded about 6 months or so. But the noise seems to really get load once the motor gets up to temperature and actually the rocker boxes seem to be really hot. Didn't put a temp gun on it to see how hot.

I am at a lose on what could be. Any thoughts?

 

Sumping?

 

Sumping? Define sumping. Oil pump issues? Or just sumping wrong with the bike!

 

Sumping is when oil isn't scavenged from the crankcase. Did these symptoms start right after the conversion?

 

Nope! Pretty recent actually. Did a little reading up on sumping. I have noticed my oil level changing on how full the oil reservoir is. Also with the heat as I live in Georgia. Once it started getting in the mid to upper 90's F for where Im at is really when it started.

I figured maybe a good oil change and replace the check valve and spring and see how she goes then. Ill keep you posted on result of that.

 

You could remove the oil tank cover while the bike is running, and see if there's an indication of oil movement.

 

Bad lifter?

John

 

Get a two ear Mechanic's stethoscope and isolate it. Is it in head under valve cover, over tappet covers or other side at base of cylinder.

How many miles? Proper Harley open micron filter and 50W conventional oil? Modern synthetic works great when all clearances are right.

Can cause a piston slap if clearance are even .002 over. Sounds just like lifters. With a stethoscope, it will point it out to you.