Well my little buell blast finally hit 25,000miles and I'm thinking it may need a little work to hit 50000. I just took it on a 600mile ride through the gold country and while the bike performed pretty well it used quite a bit of oil(1.5qts). When I come to a standstill the bike pours out white oil smoke worse than a 2 stroke. The bike has always burned quite a bit of oil from when I got it with 6000miles and I think it either wasn't broken in correctly and is losing oil through the piston rings or the bike has a leaky valve guide seal. There is also the possibility it has something to do with a clogged pcv valve but I doubt you'd burn a full quart of oil, but I don't know much about bikes either.
I was just curious what is the best way to tell where the oil is entering the cylinder?
After the 600mile ride the bikes muffler is in 2 pieces and the tire is worn to the threads so it needs a bit of work. I'm ordering a new muffler tonight and just going to drive around town on the bald tire for a couple weeks until I decide whether to put a new tire on it and fix it or just sell it with future maintanence woes. Good little bike but I'm kind of getting sick of constantly dicking with it.
Any help would be appreciated,
Thank you!
Well, 1.5 qts in 600 miles is excessive. You might have a broken ring or something. A top end job on that bike won't cost much but your time. A few hundred on the outside. That much oil is not likely to be valve seals, but rings. I dunno about blasts, but Evo Sportsters can go a lot longer than that between top ends, unless it was really abused.
A compression test would be a good place to start.
I tend to go along with Dr. Hess on this one.
Valves guides are not impossible, but rather unlikely. But since the heads have to come off for a tear down, check them.
Rings are much more likely. Bad break in or improperly installed oil rings. This would be my suspicion.
A plugged pvc system would be suspect if you had oil squirting out of the engine from crankcase pressure. But you don't describe that being the problem. It's an easy enough check and fix in any case.
A pluged crank breather will push oil in to the cyl by way of ring float. Start there and then go with rings if its not any better.
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Oh yeah! I picked up a 10hp snow blower for almost free because it was blowing oil bad. The guy jammed a bolt into the crankcase vent tube, thought it was a vacuum line.
I ran it for 14 years.....
Plugged crankcase vent and rings are both viable reasons. Best thing to do before teardown: borrow a leakdown tester, hook it up and put the pressure to it. If it shows no leakdown, then remove the oil fill cap. If you now have leakdown and hear a hiss, the rings are toast. If removing the cap makes no change, investigate the crankcase vent system carefully.
Weird oil smoke problem I had several years ago: the bike was a Yamaha TT250G. It would for no apparent reason (at least at first) huff oil into the airbox which would make it smoke like crazy. I finally figured it out; the crankcase vent system was at the very rear of the engine cases and had a baffle system cast into the cases. I like wheelies 
and when the front wheel was in the air for a long time, oil would fill the baffle system and then be blown into the airbox.
(recalling my days in the H-D parts business)
Harley rocker boxes on the Evo and I believe TC88 engines were somehow vented ~somewhere~ (being dry-sump for no reason at all) by means of a one-way diaphragm called the "umbrella valve". I'm not kidding. Remember, H-D trademarked "the distinctive potato-potato exhaust note"...
Anyway, a top end rebuild or reseal, which at any given time several technicians were engaged in included this "umbrella valve" and I may recall that failure of same resulted in blow-by/high/consumption/plug fouling/lots of cursing at the write up desk...
I'd start with compression and leakdown checks then pop the head off. On a Be-Last it's no worse than post-race tech inspection on a Briggs and Stratton flathead.
The vent and umbrella is in the rocker boxes on a "head breather" Evo. I dunno about a Blast. Our Sportster vents at the bottom, as does my Big Twin Evo. The head breathers vent through the bolt that holds the air cleaner to the cyinder head. The umbrella valve is supposed to keep the oil in and just vent gasses. A failure will cause oily blow by, and if it vents into the air cleaner, that could cause the smoke. But, I dunno how much of all that a Blast has.
Cool thanks for all the information folks. I know the bike has a hacked emissions system which removed the charcoal canister so there may be an issue with the crank vent system which I will check first. I have seen oil before in the airbox if that means anything.
Other than the oil consumption and a worn clutch the bike runs pretty well. Would it be possible for a bike that has a worn piston ring to still drive fine? I've ridden the bike up to 85mph recently which is pretty close to the top end and I'd think if the compression isn't in the engine that wouldn't be possible but I'm no expert.
Thanks again for the advise, the only reason I don't want to pull the thing apart is I have to wait at least 1 week to get any parts for this bike, HD stocks nothing for a buell.
Thanks again I appreciate it.
Yeah, well, they stock nothing for a Harley either, so don't feel special. bikerbobsstore.com is a dealer in Chicago and has stuff at 20% off, but you have to wait about 2 weeks for anything.
The 'umbrella valve' setup sounds a lot like the Husaberg/Husqvarna system where oil was sent to the top end via crankcase compression. There was an oil passage to the top which had a series of one way reed valves. Actually worked pretty well.
In most cases, a 4 stroke anything with crappy rings will be hard to start when the engine is cold and will also be down on power. I had an old lawnmower with bad rings, the vacuum was so bad that to start it I had to soak the foam air filter in 90 weight, stick it back in then start it quick. Once running it actually ran pretty well.
The Evo top end, including the Sportsters and I believe the Twinkies too, have the top end fed by oil going up the hollow pushrods. Porsche designed the Evo top end in the 80's. Prior to that, there was a separate oil feed from the block up to the back head with a solid oil tube, then another short solid tube from the back head to the front head. The big twin Evo still has the hole in the block where the feed went up, but now there's a pressure sensor/idiot light sender there. I am not real up on the umbrella valves because my bikes are bottom breathers, but I think the main function is to flap and let gas through but not oil.
BB, on your bike you might try routing the breather out to atmosphere and see if you have a lot of oil mist coming out. That could be a bad umbrella valve or excessive blowby. I think it's going to have to come apart either way, and if you have the rocker box off, taking the head and cylinder off is only another half hour's work, or less.
I've posted this before, but here I am in '07 behind the hotel in Pierre, S.D.:
Dropped an exhaust valve guide. Lost about a day and a half.
Thanks for the info I'm pretty sure I've seen a site online where they modified the PCV system to vent to the atmosphere. I can check the PCV valve, compression, and leakdown at the same time because the tank needs to come off to get enough access to do a compression or leakdown test because there is only about 1inch of clearance between the gas tank and spark plug.
Thanks again for all the info and I'll keep y'all posted as to the outcome of my investigation.
My name is Daryn, I feel kind of strange with the handle "benzbaron" because it sounds kind of pretentious.
Taking the tank off of a Blast is as easy as taking out three small bolts and unplugging the gas tank lines. I can do it in 45 seconds now. Just remember to take off those rubber spacers that hold the front of the tank in place at the top.
And when you set the tank down, make sure you don't accidentally turn the fuel valve on. 
Good luck.
Thank you for the information Confuzion. I will be doing that job after I get a working exhaust; with just a straight pipe the bike is too loud to even ride. I am always hesitant to work with gasoline but I finally got 2 fire extinguishers to save the day so thanks for the tip on removing the tank.
sorry that I'm so late to this party, but I have $.02 that might be relevent. B-lasts are heavy breathers (I know, not nearly as heavy breathing as real H-Ds, but they still huff & puff pretty good), and if the crank case ventalation isn't right and your getting oil into the air box, start there. Also, if only the oil ring is failing, a compression test, and even a leak-down test might not reveale it, do the compression test any way, maybe it will puff some oil out while you are testing it. good luck
I'll be sure to check the easy stuff before tearing the bike apart. Thanks for the info Andy. It makes sense that the breather system might be messed up because the previous owner overfilled the bike with gasoline which either flooded the carb or filled up the charcoal canister with gas. When the bike was fired up apparently it blew the carb off. I wouldn't be surprised if the gnarley backfire might have damaged something in the breather system also.
I'm waiting on an exhaust so I'll get back in a week or so and give y'all a heads up. Thanks folks, I appreciate it.
benzbaron wrote:
When the bike was fired up apparently it blew the carb off.
Haha. We did that to my roommate's bike. I think we had the wrong spark plug in it and it wasn't running right. My brother was revving it a bit to keep it running and then BAM! It took us an hour to figure out why it wouldn't start anymore.
The only thing worse is the olde tyme 2 smokers with timing real close to TDC (old Yamahas and Bultacos in particular) which could start up and run BACKWARDS. 
Hard to tell it had happened until you dropped it in gear and dumped the clutch. 
