Freshly rebuilt 750 burning oil

So, had my motor rebuilt by a local brit bike shop, i've now put maybe 200 miles or so on it, and it's burning oil from both tail pipes. At first i thought it was only on startup (caused by wetsumping) now i seem to notice it more and more. For instance i rode about 20 minutes yesterday, stopped for gas (bike was off maybe 5 minutes tops) then when i started it again big ol' puff of smoke. I mentioned it to the shop that rebuilt the motor and they said "the rings have to have a chance to seat, etc etc." like i said, after about 200 miles it's still there. I rode the bike today for around a half hour, and when i got home shot this little video, and took this photo of the spark plug...

http://www.youtube.com/watch?v=EmnA3tDU7qs




I want to talk to the shop about this again, and just wanted to arm myself with as much info as i can before doing so. I'm no expert, which is why i had someone else do the work. It seems to me like between the plug color and the smoke, it's certainly burning oil. Is there any little checks and test anyone can suggest to narrow down where the problem lies, and also any validity to the idea of the rings still seating after a few hundred miles of use?

Rings DO have to seat for maximum compression, but the oil control rings usually do so right away. Did he explain a ring seating PROCEDURE to you?

concours said:

Rings DO have to seat for maximum compression, but the oil control rings usually do so right away. Did he explain a ring seating PROCEDURE to you?

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negative. His terms were, because he wasn't building the whole bike, once i had the motor in and ready to run i had to bring it to him to start for the first time so he could confirm oil was pumping and everything was OK before he would warranty the motor. which i did. Took him the bike, he started it for the first time and gave the bike back to me with no further instructions aside from what oil he recommended.

Aw that don't look like smoke enough to be a serious valve guide leak, looks more like ring blow by yet. I'd put in straight 50 grade oil and then go out and run the living snot out of it WOT after engine rev'd up no to lug it and not to redline but dang near it then throttle snap shuts in cycles short of getting dangerous or arrested. Have more plugs on hand if current ones foul out in the process. Do not forget to re-torque head, barrel and cradle bolts after each cool down the next 1000 miles or so. It don't take much bore imperfections to let oil flim make smoke. Its could take 100's more miles but so what if not leaving clouds behind just hints of a real motorcycle going by with purpose. Could try the Bom Ami trick to speed up process, then chase with lots of water sprayed in while blipping to decoke the remains of the carbonized oil. Grey gook will spit out the mufflers till mostly white steam after a pint or more. You can't hurt engine like this as just stalls if too much sprayed in no hydro lock, just restart and give more throttle or a bit less water is all. Peek in at jug before and after, plugs too.

Define "motor rebuilt" to us. Crank bearings? Rod bearings? New rings? Bored oversize with new pistons and rings? Head bebuilt? New valves? Guides? Seals? Seats? Would you please scan your receipt (block the shop name if anonymity is a concern) and post it?

concours said:

Define "motor rebuilt" to us. Crank bearings? Rod bearings? New rings? Bored oversize with new pistons and rings? Head bebuilt? New valves? Guides? Seals? Seats? Would you please scan your receipt (block the shop name if anonymity is a concern) and post it?

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bored 30 over, new pistons and rings, new megacycle cam, new valves, springs, guides, bearings, i don't think there was much that wasn't replaced. Here are two shots of the receipt showing the parts/work done. At first the bike had 20W50 in it, just changed over yesterday to VR1 SAE50

Any reputable shop should have given you a break in schedule, not just insist on starting it the first time. IMO. Non detergent oil is good for first 50 miles to help rings seat, then use whatever you want. Rpm's should be limited to 4,000 for first 500 miles, then 4,500 max till you reach 1,000 miles. Hope it clears up.

About six months ago I rebuilt my T150 Trident engine including a plus 0.020" rebore and a set of the new Hepolite pistons & rings. These are I belive, made in China for Wassels. Before installing them I checked them for size and they all measured to within 0.0002". (two tenths of a thou) of each other. Then I weighed them. They were all the same . The machining was first rate as you would expect from modern CNC finished items. The rings also, were accurately made & didn't require gapping.
So far so good. Then I fired it up. It smoked like a forty year old Diesel lorry engine & didn't get any better over fifty miles.
I called on a couple of Triple experts for help who both told me it was the rings. I pulled the top end off , fitted a set of rings from Norman Hyde & hey presto no more smoke.
This maybe the problem you are having. I would try a set of rings from an American, British or Italian manufacturer.

Regards,

Martyn.

Maybe over oiled the bores when putting the barrels on and the rings aren't bedding in, which will course the bores to glaze up ???

This sounds spookily familiar. Just rebuilt my 750 Fastback with the "Genuine" Hepolite pistons from China. I've done about 250 miles and I've got a bit of smoke from one side when pulling away. The rings were properly gapped. I'll give it another 500 miles and then make a decision on the way ahead. The powder coating on the barrels does not seem to be coping with the heat too well so I might have to get that blasted off at the same time. Any suggestions for cylinder paint?

gripper said:

This sounds spookily familiar. Just rebuilt my 750 Fastback with the "Genuine" Hepolite pistons from China. I've done about 250 miles and I've got a bit of smoke from one side when pulling away. The rings were properly gapped. I'll give it another 500 miles and then make a decision on the way ahead. The powder coating on the barrels does not seem to be coping with the heat too well so I might have to get that blasted off at the same time. Any suggestions for cylinder paint?

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I used PJ1 fast black with no complaints. I think powder coating can only take up to like 400-500 degrees

I thought PJ1 was no longer available

gripper said:

I thought PJ1 was no longer available

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not that i know of? I just googled it and found at least 10 websites selling it. Also saw it on the shelf at a local motorcycle shop about two months ago.
http://www.google.com/#q=pj1+fast+black ... 80&bih=680

Could be that he put oil in the ring grooves in the pistons. Don't do that. The result is a 'wet' motor. It will smoke.
Maybe the honing angle is incorrect. Should be 45 degree honing angle at the grit specified by the ring maker. If not it will smoke.
Is the engine breather fitted correctly and unblocked ?
Did you do something to the carb's ? Could be too rich, check the needle position.
Is the air intake obstructed ?
Too much oil drained down into sump ?
Correct plug's ?
Correct timing ?
Correct ring's ?
Check the compression. A ring could have snapped on assembly.
Sometimes they need a while to brake in the ring's.
Go back to the guy and demand a fix. If no, slap the bastard !
Hope you resolve this soon.

Is the smoke a whitish colour (oil) or blackish (fuel). ? NEW spark plugs.

hobot said:

Could try the Bom Ami trick to speed up process, then chase with lots of water sprayed in while blipping to decoke the remains of the carbonized oil.

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BONAMI does work.1886 Original Formula is best.It worked here;results in 2 miles:http://www.triumphrat.net/classic-vintage-and-veteran/234962-smoking-3.html.Change the oil afterward,within about 20 minutes.
I think the water trick would only clean carbon off the pistons and head.You can just pour 1/2 glass slowly into each carb,when the engine is hot.Pour it too quickly,and the engine slows down too much.

If the honing is too fine,you can have trouble.Coarse hone is better;not finer than #220.#320 can work,if you try harder to get everything else right:
*ATF lubrication for cylinder walls,then wipe off as much as you can,before assembly.
*Dry rings and ring-grooves.
*30% bigger gap on the 2nd ring (compared to top ring) improves compression and reduces oil burning.
*One drop of oil smeared on the front and rear piston skirts.
*Low-detergent/dispersant oil in the tank helps,if you're not putting a high enough load on the engine.
*Don't let the engine idle when you first start up.Put it in gear and start loading the rings.
*Give it plenty of throttle or no throttle.Alternate on/off avoid to excessive rpm.A few seconds on,a few seconds off.

BONAMI can help,if you didn't quite get it right.

MotoMan gets good result with a a slightly different approach,but similar:http://www.mototuneusa.com/break_in_secrets.htm

Another source of oil-burning can be leakage between the guide and the head.It happens if the old guides are removed without blasting the carbon off first,and the head gets scored.It usually smokes more than a worn guide,from about a minute after start up.Any chamfer on the top of the new guide bore won't help either;it collects oil.

Pump up water sprayer is only way to go on side draft carbs and easy to meter water just fine. Bom Ami is put in a sock and bumped in front of carb keeping 2000 + rpm for cam protection. Commando's easy inhale this much water in heavy rain just fine. Its really good for engines now and then or ongoing. I'm thinking of dumping some Bon Ami Orginal into engine oil on initial start up to polish up and clean insides but who'd follow my shade tree ways eh.

Total Seal sells a Bon Ami type powder to install rings dry and say at most use wd40 which they well know is not a lube and flashes off on first ignition but eases the newbies minds. I asked theif tech department so can you.

Another place to get oil smoke from is gasket leaks in the tunnel area. Only takes missed re-torque in time of need to beat gasket down in that area then can't torque enough to seal till another gasket, though 200 miles may not be enough and nothing to loose trying but some alloy threads.

After re-ringing Trixie she was smokeless for few 100 miles then alternately smoked on either side a fog till a minute or so but recently after 1000 more miles she's didn't smoke hardly at all a few days ago and oil is topped off.

Your receipt doesn't list valve stem seals for the intake valves.
They are cheap so maybe just not listed and hard to imagine an experienced shop forgetting them, however if not installed you will get smoke like that.

I really suspect more miles won't make the smoke go away.
My new rings seated so fast I never saw any smoke. JCC pistons and rings from Taiwan and with extremely low oil consumption.





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rx7171 said:

Your receipt doesn't list valve stem seals for the intake valves.
They are cheap so maybe just not listed and hard to imagine an experienced shop forgetting them, however if not installed you will get smoke like that.

I really suspect more miles won't make the smoke go away.
My new rings seated so fast I never saw any smoke. JCC pistons and rings from Taiwan and with extremely low oil consumption.

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+1

Or possibly they weren't seated and have come off, bouncing with the stems. Hard to tell for sure from your video, but it seems to clean up when you blip the throttle at positive pressure and comes back at idle (and startup as you say) when there is low pressure, potentially allowing oil to creep down the valve stems into the combustion chamber.

If this is the case, it's a relatively easy fix - either pull the head or do a quick and dirty rope trick.

rx7171 said:

Your receipt doesn't list valve stem seals for the intake valves.
They are cheap so maybe just not listed and hard to imagine an experienced shop forgetting them, however if not installed you will get smoke like that.

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he gave me a box with all the old parts in it when he was done, here are the old valve seals, so i would GUESS new ones were installed.