| Author | Message | ||
     Cerbero |
had a top end rebuild done on my 97 M2 about a month ago: had new thunderstorm heads and pistons installed. the mechanic told me they started with 5 over pistons/rings, but that there was some scoring on the cylinders that required that they remachine it to 10 over. i rode it gently for 400 miles, then started riding "normally" (flogging it)... everything seemed fine until i went out for a long ride with friends today... apparently, i'm blowing smoke on acceleration. i noticed oily residue on the swingarm, so it must be pretty bad. i've got over 20K miles on the bike and this is the first oil it has ever burned! i'm wondering if i didn't break it in long enough, or if there's a chance the mechanic screwed up... i would assume it was my fault, except that i found a loose front spark plug (it was about 4 turns loose) and the top lateral joint (above the carb) wasn't tightened down at all! with that kind of sloppy work, is it possible he made a mistake that would cause this? | ||
| Aaomy |
do you still have your breathers routed into the carb??? | ||
| Tramp |
it's possible, BUT, it could just be that your rings are lining up. don't sweat it, yet. keep an eye on your level and change the oil and plugs frequently. | ||
| Cerbero |
aaomy: the breather is routed to a vent under the tail... it's been like that since i bought the bike... i did check to see if it was obstructed, but it looks fine. tramp: this was the first real flogging i've given it since the work was done, so maybe it was just the rings adjusting themselves... ...still, i'd hate to have to pull the cylinders and do all that work again! | ||
| Smitty808 |
I have built a few performance car engines in the past, and some of the high performance rings take a LONG time to break in, and quit smoking. I had a 302 I built for my Pinto(man what a ride!), that took almost 2000 miles to quit smoking. I think Tramp is on the right track...run it, and just keep an eye on things. If it starts getting really bad, then start worrying. | ||
| Bruce_bueller |
I found after my top end rebuild I had the same issues. I thought at first it might be valve stem seals or rings seating. Just because parts are new off the shelf doesn't make them good. Run the bike. Mine took almost 2000 mi to stop smoking. I noticed if I rode like a human it didn't smoke but, if I was (flogging it) then parked it the bike would smoke bad at start up. | ||
| Cerbero |
everyone: thanks for the info... i'll be patient and see if the "problem" corrects itself. | ||
| Djkaplan |
Say, what kind of oil did you use for the break in after the top end rebuild? Did you use a synthetic? | ||
| Bluelightning |
It is recommended to use a conventional oil for break in. Take a look at Amsoil and Red Line oils, both say right on the bottle "not recommended for use during break in of an engine." Don't know why, just always said "yes sir" and did as I was told. I'm such a good boy...lol | ||
| Cerbero |
i used the oil the mechanic put in the bike... i assume it was harley dino juice. (are dealers allowed to use anything else?) | ||
| Chasespeed |
Synthetic will slow the seating of rings, bue to its inherantly slick nature compared to dino oil. I prefer to rev it up, under load, gradually increasing in throttle..30%, 60%, etc, until I am at full rev in a higher gear....I have a way I do this, and everyone does it a little different. Though I will always prefer to break an engine in on a dyno, though wiht a bike engine...I dunno, I think the street woudl be the best way.... MY OPINION, and experience....nothing more.... Chase | ||
| Tomd |
Hi, Sorry to hear of your troubles. Few questions for you. When you say "apparently, i'm blowing smoke on acceleration.", is it one puff when you open the throttle or is it a blue trail that follows you? When you had the new heads setup, what did you use for seals? Are the guides bronze? Are they knurled for oiling? If it just puffs once, I would look to the guides. Since one of the mods you did were the heads, don't forget the importance of oil control in them. The new type valve seals are causing customer complaints of high oil consumption at the Harley dealers, Maybe your wrench used these. Also, valve guides in most high performance heads are setup a little looser than stock specs, the added clearance lets a little more oil slip by and keeps everything lubed. Knurled guides will also use a bit more oil. One other thought, you might want to ask around to make sure the oil drain holes in the new heads are at least the same size and location as the stockers, if the rocker boxes are filling up with more oil than stock, that could be a cause too. Unless it's smoking like a train, I wouldn't worry about it at this point. Change your oil, keep an eye on things. At the 1K mark, if your inclined to, change to a good synthetic like Amsoil. All my bikes run better and use less oil on Amsoil than any other oil I have tried. Tom | ||
| Denfromphilly |
If you put in total seal rings they create a very good seal and can suck oil through the valve guides until they break in. As a rule of thumb, a puff of oil at accelleration like a school bus is valve guide/seals and steady smoke is rings. I would let it break in a while, 1000 to 2000 miles and don't baby it and see how it goes. I get oily residue on my swing arm but the oil level does not go down. There is a trail of oil from the oil tank, either I was sloppy filling it or some leaks, the exhaust pipe is clean. Good Luck! | ||
| Cerbero |
tomd: i only said "apparently" because i've never actually seen it happen... i've had more than one person tell me it is blowing a bit of smoke on acceleration, and i see oily residue on my swingarm, but i can't make it happen when the bike is at rest... i assume it needs to be under load. the new heads and pistons are stock buell "thunderstorm" parts. i had the work done at a local dealership... i didn't ask them for anything custom, so i presume they used nothing but official buell parts. the thing that got me was that this bike has never burned oil... until now. thanks for all the suggestions/comments/opinions... i'm gonna talk to the dealer, watch the oil level, and keep riding it like it's on fire! | ||
| Blake |
Did they compression bore/hone your cylinders, meaining did they simulate the clamping load applied via cyl head and studs when boring and honing? Scoring that went more than 0.005" into the cylinder wall? If it were me, I'd be asking for a compresson and leakdown test. Suggest you verify where the oil is coming from that is accumulating on your swingarm. I'd be surprised if it is from the exhaust. More likely a leaky breather/fitting/line/gasket/seal somewhere. |
