I'm getting a LOT of smoke now when I start it up. It gets a little better once it's warmed up, but still smokes. I't burning oil, and now I have to keep adding a little whenever I use it (1/4-1/2 quart).

I think this is from my piece of junk stock filter letting in so much dirt in (and some mud). I moved the filter too late.

Any ideas how I can check diagnose this problem to see what is 'actually' at fault. It has been Idling quite erraticly, hovering around 2k rpm. Not sure if this is related.

Oh, well. Maybe I can rebuild it better/stronger/faster/sexier/meaner...

Hi, id make sure the crank case breather is not clogged up and your not sucking oil vapors into the intake. Two do a compression test,you will need a screw in compression gauge. Remove all the plugs do a check on each cylinder,hopefully their all close. I don't know what the compression is suppose to be on a 800. Maybe somebody on B.G. knows. When is the last time you did a valve adjustment.Ghost

They should be all above 150psi at three complete cranks. These carbs are very touchy gotta keep them clean. Also couldn't hurt to check your head bolt torques. Sounds to me like valve guides or rings

Thanks, i will try fo find/buy a compression tester. last time I had this thing in the shop he adjusted (I think) just one valve or both valves on one cylinder...

Is checking/adjusting the valves something I can do in the garage, fairly easily.

it could also be the valve stem seals letting oil by when it sits, oil will get into the cylinder and it will smoke when first started

Hi all.

I went out today and got a compression guage. (AutoZone rents them - for free). here's what I have

#1 150psi 6-8 cranks
#2 150psi 8-10 cranks
#3 160psi 5-6 cranks

Did the test cold.
Also, when I pulled the plugs all 3 were covered in oil.
OK... Now I have this new info, what does it tell me?

Thanks

Hi vepr308, compression looks good,have you checked the crankcase vent,is it attached to the intake system anywhere,if so disconnect it,plug the inlet try running with out it. Could be valve stem seals.Worse case sern. you will have to pull the head to change them,then you could see what the cylinder bores look like. Hope you don't have to pull the head,but that might be the only fix.One other thought,what weight oil are you running,how long between changes. Whats Motos specs on viscosity req. Ghost

Ghost,
The crankcase vent is connected to my intake. It used to just plug into the end of the OEM/POS filter, when I relocated filter I used an air tool nipple to hook the line up to the new ABS.
I wouldn't mind pulling the head (too much) as long as I can get a new head gasket (the RIGHT one).
The oil I use is... Castrol Syntec 10-40. The first change was real soon after I got it (break in), to get the junk OEM oil out. Then again at 600 miles, I'm at about 900 now.
I will check to see if BMS has stem seals (and how much). Other than the smoke, this thing has been running pretty darn good.

Hi, is there excess oil in your new air cleaner,is your air cleaner a cotton K&N type,i have seen were these have been over oiled,causing oil burning. Your engine pretty new to have bad valve stem oil seals,but its possible.Ghost

Disconnect the breather. Place a filter over the oil breather. One of those little ones from Autozone will do. See if that fixes it. Let's try as much as we can before taking off the head. I found that if you leavew the gas tank valve in the on position it will drain into the crank case. That will cause it to run idle bad to say the least. If the oil smells a lot like gas, change it. I would try running some fuel cleaner through it. If it were valves or rings your compression would mostlikely be lower.