smoking from new pistons.rings.jugs

I am sure that I made careful note of the 'top' designation on the rings when installing....... it does seem to be settling in......

thanks for your commentary. I think that I was babying it too much...... the last two rides , which were maybe 25 miles each, I've been giving it a lot more throttle coming out of the corners..... as I said. it does seem to be settling in. At 500+/- miles I'll do a compression check,look for nasty bits in the oil sump and report back.

If we EVER get another sunny day here on the east coast of the US I might be able to get a ride in: right now she's hiding in the shed until the rain passes again.


kfh

When you get that sunny day take your Norton out and wring it's neck. Six K thru the gears. If it isn't already glazed, the rings should seat. If not, pull the cylinder and find out why. I had a smoky jug once. Found out I'd over-lapped the ends of the oil scrapper ring.

Give it some welly = wring its neck = lots of throttle and revs :shock:

Short bouts of large throttle openings followed by closed throttle will keep the temps down.

Rebuilt a B44 last year, smoked a bit at first after the ticking over for setting timing etc but 400 miles later is smoke free.

I'll give it some welly and report back!

Should I switch oils to a non detergent, single grade (say 30w) while I give it said welly or keep the Castrol in and hold off changing it until 500 miles?

kfh

Now you really want to get tricky, a break in and oil in the same thread! Why not throw tires in?
I'd use cheap 30 and change it soon myself. i'd only add expensive oil to a well broken in engine if the factory did not call for it like my BMW.

thanks......

and speaking of tires........ (just kidding)

kfh

update on smoke issue:

As per recommendations of this learned group, I did as you suggested: I changed to a cheep non detergent 30 weight and stopped being so 'nice' to it in the break-in period..hammering out of the corners, running right through the rpm range etc....... smoking is all but gone. when motoring around at back road speeds (up to about 50 mph) there is little to no perceptible smoke. When it is good and hot AND at highway speeds (55-60.... which is the most I wanted to push it... and only for a short time, maybe 10 minutes at a whack) there is quite a bit of smoke still... but that's with the inexpensive stuff and high summer heat.

I'm heading to Ireland for a much needed vacation next week (Galway) but when I get back I'm going to retorque the heads, give it a once over, switch back to the castrol gtx 20-50 and re-assess and report back.

The problem I think arose from a rookie mistake: I got brand new jugs from British Cycle supply in Nova Scotia.... They appearred to be pre-honed... so I assembled it with only a light , home-grown hone job. I should have given the jugs to the machine shop that did the heads....... I think that's the culprit but all that thrashing about with the cheep oil seems to be bedding the rings nicely.

The smoking at highway speeds seems a bit baffling to me: I didn't alter the crankcase venting at all. could higher speeds and stock venting (71) cause oil to be pressure-feeding into the cylinders?

as I said , I'll re-evaluate after head torquing, tuning, etc. and report back. I think Strunzo is just about ready for his first 100+miler when I get back from Galway 8)

wort case scenario, He'll get disassembled this winter and professionally honed and new rings.

thanks for your help (and any feedback about the highway smoking issue) as always:

Karl

Do a compression check. Should be about 150psi by now and pretty even as long as the valves are correctly seating. Is oil level going down? Black smoke or blue? Plugs oily wet or just black? Any chance somebody put two cycle mix in the tank?
A few dumb questions but somebody's gota ask em. :wink:

Re-Torque your head bolts, I found this the reason mine smoked after reasembly, also be sure to check the valve clearances after re-torq.

Do a compression check. Should be about 150psi by now and pretty even as long as the valves are correctly seating. Is oil level going down? Black smoke or blue? Plugs oily wet or just black? Any chance somebody put two cycle mix in the tank?
A few dumb questions but somebody's gota ask em. :wink:

Click to expand...

Seriously, thanks for asking: I'm a guitar builder and teacher, not a professional mechanic so there's certainly the chance that there's something else I missed. I did all the work on this bike except for getting the heads professionally machined and reassembled.

I don't have a compression tester (yet) but when back from vacation I'll do that: A Month (300 mi) ago the plugs were oily but now look in the 'normal' range if you look in the repair manual : it's still burning some oil but mind you, it's the cheepo 30 weight........and smoking is clearly more when the oil is up to full operating temperature. exhaust pipes are of equal warmth you shut it down .

Strunzo is in his stable until August 10th: then I'm going through it, changing to the 'good' 20-50 weight, retorquing everything, checking timing and tappet clearance and then will write a full report: my gut is telling me that things are seating well. It sure pulls strongly in all 4 gears and as stated earlier, I'm grinning like a Cheshire cat

thanks for your excellent suggestions.

There are two types of oil rings:

1) 3 piece with scrapper on top and bottom with a funny looking spring in middle. -GOOD

2) Two piece. Large taller scrapper with normal looking spring that goes inside of it. -BAD

I once had the rings (2) on a new rebore and could not figure out the smoke. I purchased rings (1) and it fixed the issue. I might not be making sense here as is 2 AM in th emorning. If you need me to take a photo of the 2 types of rings and post here let me know,

Cheers

Jerry Doe said:

There are two types of oil rings:

1) 3 piece with scrapper on top and bottom with a funny looking spring in middle. -GOOD

2) Two piece. Large taller scrapper with normal looking spring that goes inside of it. -BAD

Click to expand...

I'd have to say there were (at least) three types of oil scraper ring, as the last set of AE/Federal Mogul rings I bought for my T140V were one-piece with no spring.
(the one shown top right)


There's never been the slightest trace of smoke since I fitted these rings, but of course they must be fitted the right way up

I installed the three piece rings and am sure I fitted them with the 'top' mark correctly installed..... I really think that it had to do with incorrect honing... but it's settling in: I'll report in a couple of weeks....

thanks for all the great feedback... I'm off to Galway Ireland for a LONG overdue holiday in about 3 hours 8)

Karl

Have fun!!

Cheers

so after 500+/- miles I changed to the 20-50 oil, retorqued the heads, adjusted valved etc and happily set off for a few rides: at low RPM's not too bad except at a light, when Idling in hot(ish) weather (80 degrees F) I get a slight blast of smoke when taking off from the light......

I was out on the highway running around 50--55 MPH and looked back.... steady light blue blue smoke...... There was a State Cop behind me for a while who looked disapprovingly at me but didn't pull me over.

so.......

it's back in the shed and the next rainy day I'm ripping it apart. I'm taking the jugs to the machine shop where I got the heads done for a proper professional hone, and putting new rings in it, taking special care about installation.... As I told you way back when , I did a cursory hone job because I (mistakenly) thought that they came pre-honed from the factory....live and learn.

I Have to get this right because everything else about the bike is great: usually a first kick starter, never left me on the side of the road, plenty of power and it's dead sexy!

It's actually good timing to do this because on my last ride (August on Cape Cod.. touristas galore) I was almost picked off three times in 50 miles by inconsiderate drivers. It would be staying in the shed until WELL after Labor Day anyhow!

thanks for your continued support and advice. I'll report back when it's back together!

I had a 3 week vacation in Marthas Vineyard in the 70s which is near you. my auntie married a yank.
may i respectfully suggest you ship your engine to mr rambow at cnw for a winter rebuild and you will be very happy ever after, as a owner of one of his machines i can speak confidently , what ever he charges you it's more than worth it .
In fact as a norton fan , a visit to his works would be like a pilgrimage as bracebride street was pulled down years ago.
and norvil is nothing to write home about ( i know i've been ) and his bikes lack the quality ride and finish of matts .

Richard Barks

In my opinion, there are a couple of members who post here that I'd trust to build an engine for me. On the commercial side, Leo Goff, of Memphis Motorwerks, takes a back seat to no one. CNW is certainly top shelf. The key is experience and knowledge of upgrades. Many of the stock parts can be improved upon for essentially the same cost as stock.

thanks for the feedback:

Martha's Vinyard can be a zoo in the summer. they rent mopeds and there are alarming numbers of accidents there.

respectfully, I think I want to tackle this myself. I have a local engine machinist/rebuilder whom I will have the cylinders honed..... then I'll put it back together. I rebuilt a few engines (VW's ) back a ways with great results, so I trust my skills pretty well.... I'm almost sure that the lack of a good hone is the culprit, since the heads were rebuilt by the selfsame gentleman. Also... $3,000 +/- for a CNW rebuild is I'm sure worth every penny but it's out of my price range right now.

I'll report back once the tourists leave and I'm back on the road... smoke free I'm sure 8)

kfh

I think the key to doing a good job yourself is perserverance. If things don't turn out well research and do it again.
I've lost track of how many engines I rebuilt but to me the key is a good machinest. If possible take the piston in for him to look at before honing.

Respectfully, I agree with Cookie. When it is time, do it yourself as you've already got the worst behind you. I bet you'll pick up on the problem right away. On the honing, what many over-look is a good scrubbing with soap and hot water to remove the remnants of the honing stone from the cylinder walls. After scrubbing, soak the cylinder bores with WD-40 immediately. The three piece rings can be tricky, also, as the lower "wiper" tend to want to jump out (and fold over) when the rings are leaving the ring compress and going past the corner break starting into the bores. I hose the cylinder, piston/rings with WD-40 only on assembly. Memphis Motorwerks & CNW are stand-up outfits but they won't be on the side of the road with you if you have mechanical/electrical problems. Your only looking at a few gaskets and rings....and labor. The only time you need to hone one is if it has been bored.

Z