New Top end blowing lots of blue smoke

[RvP]

I just had a set of barrels, pistons, rings and valves fitted by a reputable rebuilder. The parts were repro parts I purchased awhile ago and sent them to the rebuilder to make sure everything fits properly and fix what does not.

I installed the new top end and I am not happy. The symptom is the engine blows TONS of blue smoke when pulling away from a stop. The engine runs good, compression feels strong and it idles great. There is no blue smoke when idling or at cruise. However if I stop at a traffic stop and then pull away the blue smoke literally billows out the exhaust in a huge cloud, almost obscuring the front of the car behind me. While accelerating I will leave a cloud of blue smoke that dissipates when shifting into 2nd gear.

I only have 60 miles on the new top end and have been riding between 35mph and 45mph to break it in. Is this too early to call the rebuilder and complain? Can this be as simple as the rings not seated yet?

If I was a betting man I would say the intake valve guide(s) is over reamed or the intake valve stem too narrow and oil is leaking past the guide.

Any opinions accepted before I go ballistic on the rebuilder and have to tear it apart again.


Thanks.

[RvP]

Follow up: Am I getting the run aorund?

I called the “reputable” engine builder this morning and I am doubting his knowledge, my knowledge or he just did not want to deal with me. He asserted that blue smoke is not oil burning but an indication of a rich high speed carb setting. I always though blue smoke was oil, black smoke was rich. He corrected me that black smoke is oil and blue smoke is a rich carb setting.

Even though the engine accelerates smoothly he recommends I lean the high speed ˝ turn and the problem will go away. For the amount of blue smoke present I doubt that ˝ turn lean on the high speed will change it but it is easy to do.

I offered to take the 2 our drive and bring him the bike so he can diagnosis it and he said all he would do when I brought it there was lean the high speed by ˝ turn to solve the problem.

Am I getting the run around?

[duffeycycles]

He is full of crap,you are right

[larry]

I bet rings. What do the sparkplugs say?

[T. Cotten]

I can't remember Folks,...

Is it blue smoke is gas and black is oil, or is it the other way around?

....Cotten
(PS: I know white is 'steam'.)
PPS: One of my '65s ran great before I "put it away", and after a zillion miles, it didn't smoke excessively. However Folks would pull up from behind to tell us how bad it smelled.
It shall be fired again eventually. I probably won't be around for the autopsy, but whatever is found, its all my fault.

[gww]

hows bout give n up the (the “reputable” engine builder ) name. folks dont need that drama.

[Rubone]

There are plenty of scenarios as to the 'blue smoke". Some simple, some not so much. Rings incorrectly installed (there is a top and bottom), ring end gap incorrect, rings not staggered, excessive oil in crankcase, missing case baffles, rods installed in reverse, crankcase breather not functioning correctly, and so on. Without intimate knowledge of your engine who knows what could be the issue. But one thing is for sure, it isn't right. Guide clearance is more of an oil issue on OHV engines. Most sidevalves don't exhibit issues from excessive clearance as there is only mist in the valve area, no pressure feed...

[shelbyinparadise]

I agree with Robbie, it is hard to just guess. you said the parts were repro, did you mean the cylinders were new repro or used cylinders? I had one experience when I was pretty young, where a set of cylinders looked real good, I cross hatched the cylinders, put on new rings, double checked everything, base gaskets letting oil drain back, all looked good. But when it fired up it smoked like you describe. Tore it back down and rechecked everything especially the rings up right way and gaps spaced, same thing. remeasured the bore, everything was right down to the wear pattern on rings from only a few miles. Looked right. Desperation set in so I Bored the cylinders to next size, same brand rings and pistons. Problem gone. Then I spent a lot of money to buy AN-600 head for wet Sunnen honing machine. Using the Sunnen hone, it would show the used cylinders high and low spots, wear patterns and I could quickly tell if cylinder need boring or if it would clean up round with the hone. Not sure if this is your problem but trying to save a few bucks only honing cylinders with drill rig bit me only once.

Good luck, Shelby

[RvP]

First off not mentioning the name of the rebuilder is not drama. Everyone makes mistakes and I am not going to hurt his reputation since he is highly recommended and has a good track record from others in my area. I may be the once case in 1,000 where a problem occurred. I would not feel right hurting his business if I am the oddball or there are other problems not associated with his work.

The engine was low on compression after 34,000 miles. I could kick it over compression without exerting any force and blowing smoke out the breather so I “assumed” it was time to have it bored and install oversize pistons and rings. Since I had a new top end sitting in a box I sent that out.

I am assuming the new barrels are repro since they were not advertised as NOS when I bought them. The barrels came with pistons, rings, valves and valve springs, supposedly all new.

I sent them to the rebuilder to make sure things fit properly since the origins of “new” parts was unknown they would be checked, measured and fitted or replaced where needed. The bore checked to fit the pistons, cross hatch pattern done on the smooth bore, ring gaps measured and fit, rings installed on the pistons, valve seats ground and valves lapped and push rod coves installed.

All I had to do was put the pistons on the rods, slip the barrels over the pistons using a ring compressor and bolt them down. I installed the rings with the top ring gap 180 degrees from the exhaust valve and the 2nd ring and the oil control ring gaps 90 degrees in opposite directions to the top ring gap. The crankcase baffles are not broken and the rods were never removed. There is no smoke coming out the breather, only clear air blowing out.

With regards to excess oil in the crankcase I am not sure. The oil tank gets hot when running so I assume oil is returning. How much I don’t know but I did have one time after installing a new oil return fitting to the oil tank the fitting was too long and restricted oil returning. This caused gobs of oil to come out the breather. I had to cut down the tip of the fitting to make sure it did not touch the far side of the tank fitting. This has worked for 30,000 miles.

I am not sure the ratio of oil pumped in versus oil pumped out. If the crankcase accumulated excess oil due to blow by would the return pump empty the excess or will I always shave excess in the crankcase? In other words does the return pump move more volume than the feed pump?

I am going to give it a decent break-in of at least 200 miles before I pull the top end off and replace the rings in the hopes that the rings have not properly seated yet.

One more thing, we had a tornado pass thru south ‘jersey last night so I have not had time to pull the plugs to read them or try leaning out the high speed by ˝ turn for sh*ts and grins.

[shelbyinparadise]

Good for you on your approach to working through this problem. Not knowing if your cylinders are the ones made in India or not that are on the market, I have heard of problems with some 45 and BT cylinders made there with porosity where at low speeds such as idling these pores hold some extra oil, that goes away with higher piston speeds. Material control in the casting process overseas can be iffy. Years ago Anders at Flathead Power in Sweden, made his cylinders of a much tougher iron and Rings had a problem of not seating. I was able to successfully sleeve the new cylinders with sleeves from LA Sleeve, and regular Hastings Rings worked perfectly. lot of extra work over 15 years ago but cylinders are still in service.

Oil return is more than necessary to quickly remove any leak down oil from pump check valve, and it is not pukeing oil out breather while running says the return pump is working, simple to check return flow which will just be short spurts not a constant flow except at higher speeds.

I am eagerly waiting on Enfield Racing to produce the new cylinders, I will have much more faith in Bruce's Products than the imported ones from India. Good luck chasing down your problem.

[tfburke3]

First off not mentioning the name of the rebuilder is not drama. Everyone makes mistakes and I am not going to hurt his reputation since he is highly recommended and has a good track record from others in my area. I may be the once case in 1,000 where a problem occurred. I would not feel right hurting his business if I am the oddball or there are other problems not associated with his work.

The engine was low on compression after 34,000 miles. I could kick it over compression without exerting any force and blowing smoke out the breather so I “assumed” it was time to have it bored and install oversize pistons and rings. Since I had a new top end sitting in a box I sent that out.

I am assuming the new barrels are repro since they were not advertised as NOS when I bought them. The barrels came with pistons, rings, valves and valve springs, supposedly all new.

I sent them to the rebuilder to make sure things fit properly since the origins of “new” parts was unknown they would be checked, measured and fitted or replaced where needed. The bore checked to fit the pistons, cross hatch pattern done on the smooth bore, ring gaps measured and fit, rings installed on the pistons, valve seats ground and valves lapped and push rod coves installed.

All I had to do was put the pistons on the rods, slip the barrels over the pistons using a ring compressor and bolt them down. I installed the rings with the top ring gap 180 degrees from the exhaust valve and the 2nd ring and the oil control ring gaps 90 degrees in opposite directions to the top ring gap. The crankcase baffles are not broken and the rods were never removed. There is no smoke coming out the breather, only clear air blowing out.

With regards to excess oil in the crankcase I am not sure. The oil tank gets hot when running so I assume oil is returning. How much I don’t know but I did have one time after installing a new oil return fitting to the oil tank the fitting was too long and restricted oil returning. This caused gobs of oil to come out the breather. I had to cut down the tip of the fitting to make sure it did not touch the far side of the tank fitting. This has worked for 30,000 miles.

I am not sure the ratio of oil pumped in versus oil pumped out. If the crankcase accumulated excess oil due to blow by would the return pump empty the excess or will I always shave excess in the crankcase? In other words does the return pump move more volume than the feed pump?

I am going to give it a decent break-in of at least 200 miles before I pull the top end off and replace the rings in the hopes that the rings have not properly seated yet.

One more thing, we had a tornado pass thru south ‘jersey last night so I have not had time to pull the plugs to read them or try leaning out the high speed by ˝ turn for sh*ts and grins.

To eliminate the issue of to much oil in crankcase drain the sump oil after running and check amount in case.Dry sump motors return pumps have way more capacity than the feed pump to keep the sump empty(almost)
Tom

[RvP]

Just an update.....the problem did not go away after 450 miles. It is the rear cylinder that is blowing smoke and compression is measuring 110 psi. There does not seem to be any oil puddling up in the crankcase when I drain it. I am not sure with compression that high in the rear cylinder if it is rings, maybe the oil ring or something else like over reamed valve guides.

It will idle all day without smoking and no blue smoke while cruising. The blue smoke only appears when pulling away from a stop, especailly if I apply liberal amounts of throttle. If I barely bring the throttle up and feather the clutch there is almost no trace of smoke. It is runing very heathly and I am going to live with it for now until I know the rememdy (new rings, valve guides, other?) and have a reason to pull the gas and oil tank.

Thanks for the advice.

[tfburke3]

Just an update.....the problem did not go away after 450 miles. It is the rear cylinder that is blowing smoke and compression is measuring 110 psi. There does not seem to be any oil puddling up in the crankcase when I drain it. I am not sure with compression that high in the rear cylinder if it is rings, maybe the oil ring or something else like over reamed valve guides.

It will idle all day without smoking and no blue smoke while cruising. The blue smoke only appears when pulling away from a stop, especailly if I apply liberal amounts of throttle. If I barely bring the throttle up and feather the clutch there is almost no trace of smoke. It is runing very heathly and I am going to live with it for now until I know the rememdy (new rings, valve guides, other?) and have a reason to pull the gas and oil tank.

Thanks for the advice.

Did you thoroughly wash all the parts in hot soapy water to remove all the machining grit?
BTW,I think you are the builder,using a reputable machine shop.
Any issues,wrong clearance etc,should be picked up by the rebuilder(in this case you).
Be curious to see what you find when it does come apart.
God luck
Tom

[RvP]

Tom, maybe something got lost. I am the "assembler". I sent a new set of barrels, pistons, rings, valves and valve springs to a rebuilder to do the fitting and any machine/parts replaced so I could just "assemble" the new top end. This is the 2nd top end I have put on in 35,000 miles. The first was stock stuff that was on the engine that I removed, checked tolerances and put back on to see if it would run. 10,000 miles later there was barely any compression, time for a change. Had a new set of all the above and I fit the rings and lapped the valves myself. No smoke and 24,000 miles later was tired. Since I had another new set I sent it to a recommended builder/machinist for proper fitting.

Never thought to wash the parts before assembling. Good advice for the future. No, I did not check the ring gaps and certainly should have.

[RvP]

I am thinking about a longshot half-baked idea regarding my 45. It is running great and I have around 600 miles on it and it still is smoking. Here is a review of the symptoms:

- Will idle all day with no visible blue smoke out the exhaust
- At cruise RPM no visible blue smoke
- Smoke is only visible when idling for a few minutes and increasing the RPM, such as when stopped at a traffic light and bringing up the RPM to slip the clutch to pull away
- It is the rear cylinder spark plug that gets packed with black oil, front spark plug is tan
- Rear cylinder compression is 110psi

My longshot half-baked idea is if the centrifugal valve in the oil feed pump is stuck in the closed position. Assuming it is that would pump oil to the crank pin instead of diverting it to the timing gear case. Given it is the rear cylinder oil fouling the excess oil on the crank pin is being slung into the rear cylinder.

Since it is really running great I hate to take it apart unless I know what to fix or look for other than a bad oil ring. Suggestions (and criticisms) welcome.

Thanks