Question about my XR250R that is burning oil

[XR400RMan]

I posted a while back that my 1991 Honda XR250R was burning oil after a Complete Topend rebuild, It is still burning oil and I will tell you some of the story again because I got something bugging me, I got the bike and rode it for about a week and I was riding in my yard and the bike just quit and would not start back so my dad tore the top end down only to see the whole thing was tore to ****, So he took it to a guy and he called back and said that the oil pump was not working so we orded a whole new Top-End for it including a new Valve cover and Cylinder head since the head was so messed up, So I was going to go with a Wiseco piston so I had to order a new sleeve anyways so The dealer ordered the piston for us and then had to bore the new sleeve to fit the piston, So anyways we get to whole new topend put together and I get it home and it is smoking terrible and my dad said well the Rings may just have to seat so we waited and now it is still smoking so My dad talked to the guy that rebuilt the engine and he said maybe there is a Low-Spot in the cylinder wall alowing oil to get past the rings, So my dad is going to take it back apart when he gets a chance, Now for the part that is bugging me, I was talking to a guy on AOL Instant Messanger last night and he is about 16 years old like me and he has a 2000 XR250R, He got it and it was burning oil so he put a whole new top end in it, I told him the story on mine and he said that when you bore a cylinder to fit the piston that you cannot have a LOW SPOT, Is this true? He asked me how often I changed my oil after the rebuild and he said that he put oil in his and then when the engine got to operating Temp he changed the oil again, and then he rode it for about 5 hours and changed it again and he said if you don't do this on a new engine there are little pieces of metal that will score your cylinder walls and create Blow By, He said that if I went above Half throttle during break in I could have seriously damaged my engine, I didn't go above half throttle but my uncle did, I was just learning to ride my first motorcycle so I was scared to go half throttle, He said that it is probably my fault that the engine is burning oil and that since I have rode it for about 2 months with it burning oil that I will probably need atleast a new piston and rings and maybe a whole new cam and Rocker arms and everything else, I cannot afford to pay for another topend and if I didn't change the oil like he did could this be the problem, I have more questions but I have to go to work so I will ask you experts when I get home, Sorry for the long post but I am just so fustrated and confused and kind of depressed about the whole thing because I just spent over $1000 including labor on the topend so I can't do this again, I am still paying the bike off, Please help me out,Matt

 

[snaggleXR4]

Hey,
When breaking in a new engine, it is important to not got full throttle, and it is important to not hold constant RPM's for long periods of time. Other than that you should just ride easy like. Everybody has different opinions on proper break in procedures. Going past 1/2 throttle is not going to kill your motor. It is true that during break in, internal mating parts are wearing in to fit each other. Small metal particles are the result. Changing your oil for every hour or two of riding is absolutely necesary for proper break in. In general, your aircooled motor needs the oil changed very often anyway. Don't forget about cleaning your oil strainer screen, oil filter, and air filter!

There is a good chance that your valve guide seals are quite worn out, which, I believe could also cause your motor to burn oil. If the valvetrain on your motor is all original, this is very likely. Ask your dad, or a mechanic at your shop to do a compression test on your motor. If you have low compression, your rings did not seat properly during break in, or your cylinder wall is scored, or both. If the compression is good, but leaks, then you have worn valvetrain components such as valve seals, guides, seats etc... Your compression should be somewhere about 180-200 psi I believe if you rings are good..

I'm sorry to hear about your misfortune. I know you are sick about it. However, you have to remember, your bike is over 10years old. XR's are very dependable, but any bike will wear out over time. If it isn't your piston/rings/cylider it will be your valves, if not that then your transmission, bearings etc... At some point it is better to sell it, get what you can out of it and invest in a newer bike. Do research and search old posts about compression tests, leakdown tests etc... Then test your bike, it might not be your piston/rings afterall. Good luck.

 

[XR400RMan]

Thanks SnaggleXR4 for your reply, You are right I am sick about the whole thing, I mean you have valves,Piston and Piston Rings and so much other stuff in a 4-stroke engine that it is very hard to pin point what it could be exatly, Oh and one other thing I should note, When I got the bike there was black stuff like oil residue on the bottom of the rear fender but when i was riding it my dad didn't seem to notice any smoke so at SOMETIME IT HAD BEEN SMOKING BEFORE OR MIGHT HAVE BEEN THEN BUT JUST A TAD THAT YOU COULD NOT REALLY SEE, I will have to wait and see, Thanks again Matt