96 FXDWG 100000 klms My dyna has been sitting for the last 3 years because it doesn't run rite any more.....for you guys that want to read..allow me to give you the history on this bike
I am the original owner.
It has stage one done to it thats all.. and i raised the bars.
Three years ago it started to misfire and backfire severely out of the top muffler...i mean there was orange flame.
I decide to get $10 dollar maintenance manual off internet...that was probably a mistake...I have now ordered a real harley maintenance manual for 96 FXDWG..that was 3 weeks ago and I still dont have it.
I decide to drain the tank..take tank off..and lower the rear engine mount so as take off the rear head assembly.
I decide to give it a new ring job and have the heads redone at a harley shop and i re-install every thing...I also had a look at valve lifters...they look brand new.
I also get new harley battery, spark plugs, plug wires and a new coil..all stock stuff straight from harley.
It will start but misses on rear cylinder on initial start up and then clears up...but here is what it does.
It appears to run with choke fully on for several minutes ..fair amount of black smoke..but as i slowly push choke in it runs but gradually seems to choke itself....and then there is blue smoke coming out that top muffler after engine has warmed up significantly.
Would anyone with lots of EVO engine experience have any ideas as to what i may have done wrong.....thanks...my name is Arend

 

Blue smoke out the pipe means oil is burning in that cylinder head's combustion chamber. Oil can enter the cylinder head's combustion chamber one of two ways: either leaking valve guides and/or seals in the head or the piston rings are not sealing, especially the oil ring (bottom ring on the piston). The oil ring's job is to scrape the excess oil from the cylinder wall as the piston moves up and down. If the oil gets pass the oil ring, the top two rings will pass the excess oil up to the cylinder head's combustion chamber and generate blue smoke.


Do a compression test on both cylinders. If the cylinder that is blowing blue smoke is 10 psi or more lower than the one that is not, you have a piston ring problem, a valve seat problem (valves are not sealing at the valve seat), or a leaking head gasket. If the compression is close on both cylinders, you have a leaking valve guide and/or seal in the smoking cylinder's head.


You can usually diagnose a leaking head gasket by moving a lit cigar around the area where the headgasket is while the engine is running (be careful to stay clear of gas or gas vapors! Safety first!) to see if the cigar smoke is disrupted or by spraying WD40 around the headgasket area while the engine is running (safer) to see of the engine changes idle RPM or if the engine runs more smoothly (temporarily). If so, the headgasket is leaking. This will not be the source of the blue smoke, however.



A machine shop can test the heads for proper valve seat seal using a vacuum tester and also measure the difference in diameter (gap) between the valve stem and the valve guide to see if it is in or out of spec. They should also be able to tell if a valve seal is leaking. They can also check the trueness of the cylinder bores using a torque plate, bore gauges, and a micrometer.

If you find that you need to rework the heads or need re-boring or re-honing of the cylinders and new piston rings, find a top machine shop to do that work, not the local "Harley shop". Headquarters is located in Canada and are a top machine shop/engine builder. They will get it right.

The misfiring/backfiring could be a number of things, some of which can be related to your problem with burning oil. Find the source of the oil entering the smoking cylinder first and get that fixed and then worry about diagnosing/fixing the misfiring if it still persists. If so, it is probably due to a carb problem (carb should be rebuild and tuned).

 

OK really appreciate your input....but I shud have some degree of confidence in a Harley shop doin the heads and the sleeves......one thing I forgot to mention is happened to see the oil filler cap move....like there was excess pressure in oil tank or crankcase and all this happens after its been running for 10 minutes and then I see the blue smoke....thx Arend

 

First off, everything dynawg1 suggested is right on. With your comment about the oil tank cap, it sounds like you have crankcase pressure building. This, along with the blue smoke, could mean you have one or both compression rings installed upside down on the rear cylinder. A compression test, as dyna suggested will help point the direction to go looking, and after that a leakdown test can be very informative. With excessive leakdown you can pull the oil tank filler plug and listen: if you hear air rushing out there you know you have crankcase pressure leaking out of the cylinder and onto the crankcase. If you hear air in the intake, your intake valve isn't seating; air in the exhaust means the exhaust valve isn't seating. You may have more than one issue.

I also agree that you may have better luck with a reputable indy shop than the dealer. This isn't always the case, but dealership techs are often young, inexperienced, and they generally work flat rate,which means they're in a hurry to get the job done in order to make time. Like I said, there are exceptions, not all dealership techs are boneheads. But not very many dealerships have their own machine shop in house, let alone a competent machinist.