A10 smoking

[ttrand]

1951 plunger Golden flash. I Recently got this bike to run and am very happy with it.

So far due to registration challenges, I’ve only been for a couple of ‘bad-boy’ rides around the block, but it runs/shifts great. Once it gets up to running temperature, the left side starts to smoke out of the exhaust. It’s a white/grey colour. If I leave it idling, the whole motor appears to be smoking. It’s very hard to see where the smoke is coming from, but it seems like there is oil in the combustion chamber on the LH side. Oil begins to leak from the muffler/exhaust pipe union, ane eventually the end of the pipe gets damp. Plugs are wet/ oily.

Took head off, I don’t see anything obviously wrong. I plan on taking cylinders off next and measuring inspecting pistons/ rings and measuring tolerances. The bores look clean/smooth.

This bike was rebuilt over ten years ago apparently. But hadn’t run. I guess I can’t assume anything at this juncture.

Looking for suggestions! I don’t want to miss anything while it’s apart….BTW yes, it wet sumps around a 1,1/2 cups every 2-3 weeks.

Thanks all!

[muskrat]

G'day tt.
Did you take the head apart? It could be a bad exhaust valve guide.
Cheers

[Swarfcut]

 With the head off, check that the oilway from the exhaust valve pocket down thro' the barrel to the crankcase is clear. If oil can pool around the valve spring it can work its way down the valve guide. Worn guides, head gasket problems, bore and rings, all need a looky look. But yes, good oil and a thrash will help diagnosis. It will also smoke if the sump is not adequately scavenged. Sump plate off, there should be little oil in there after a run. Sump gauze and Ball valve need to be clean and the ball free to rise and fall.

 Getting it good and hot will clear out any old oil from a previous  life mishap which is lurking in that silencer, could be the problem is in the exhaust system, not the motor. Running without the muffler worth a try for comparison as to the source.

 Swarfy.

[Slymo]

I had a similar experience with my SR. The motor had been rather nicely overhauled many years before and never properly reassembled. The rings simply wouldn't bed in and after just shy of 1000 miles I gave up ran a fine hone through the bores and put Gandini rings in. Doesn't burn any oil at all now.

[RDfella]

Sounds like an ideal vehicle to ride in front of some of today's militant cyclists ........

[Greybeard]

Sounds like an ideal vehicle to ride in front of some of today's militant cyclists ........

Or car drivers who cut up cyclists 🤫

Greybeard, cut up cyclist

[Slymo]

Yep I'm with the cyclists, its the bloody king cab utes and FWD's that ignore both motor and man powered two wheeled bretheren. They seem permantly angry and obviously need a little two wheeled time to return that joire de vive that they are so clearly missing. :)

[TimK]

I had a similar experience with my SR. The motor had been rather nicely overhauled many years before and never properly reassembled. The rings simply wouldn't bed in and after just shy of 1000 miles I gave up ran a fine hone through the bores and put Gandini rings in. Doesn't burn any oil at all now.

I'll second the reccomendation for Gandini rings (if you can get them). My story was very similar, >500 very smoky miles, fitted Gandini rings - instant success!

Tim

[berger]

ever since i was supplied rings from a famous company that spat neat oil out {long story but covered on the forum somewhere } i have sworn on the excellence of Gandini rings.

[RDfella]

Or car drivers who cut up cyclists 🤫

That's a tiny minority compared with the growing percentage of militant, 'entitled' cyclists. The ones who ride close to the white line to deliberately prevent you from overtaking, and then hurl abuse at you should you manage to get past. When I used to drive wide / slow loads I kept an eye on the build-up of traffic behind and periodically pulled into a layby or whatever to let them pass. Not today's cyclists. They don't care if there's a string of 20 vehicles that's been following them at 15mph for the last 2 or 3 miles. And when you finally get past, they'll undertake you at the traffic lights and it starts all over .... The rules of the road don't apply to them and many are uninsured - like the asswipe who hit my van by riding down a no entry. He dented the bonnet, smashed the windscreen and dented the roof as he went over the top. Thought he was dead, but he picked himself up and ran away. Cost me over £400 in repairs.

Please keep on topic
 

[Greybeard]

I've opened a new thread;  'Flippin cyclists'. Admin, would you like to move the off topic posts over?

[ttrand]

With the head off, check that the oilway from the exhaust valve pocket down thro' the barrel to the crankcase is clear. If oil can pool around the valve spring it can work its way down the valve guide. Worn guides, head gasket problems, bore and rings, all need a looky look. But yes, good oil and a thrash will help diagnosis. It will also smoke if the sump is not adequately scavenged. Sump plate off, there should be little oil in there after a run. Sump gauze and Ball valve need to be clean and the ball free to rise and fall.

 Getting it good and hot will clear out any old oil from a previous  life mishap which is lurking in that silencer, could be the problem is in the exhaust system, not the motor. Running without the muffler worth a try for comparison as to the source.

 Swarfy.

Took head and barrels off. Rings are all free and clear. End gaps on rings are around 40 thou.. possible that I need a rebore? I’ll take out valves soon and check guides. The oil ways are all clear.

[groily]

Best measure bores then to find out? And check for lip at top etc. Could just need rings for now  - depends how worn, oval, scored the cylinders and pistons are.
One man's worn out is another's nicely run in . . .

[ttrand]

G'day tt.
Did you take the head apart? It could be a bad exhaust valve guide.
Cheers

Will it be obvious to me that the guides are bad? How will I know? Cheers

[ttrand]

Best measure bores then to find out? And check for lip at top etc. Could just need rings for now  - depends how worn, oval, scored the cylinders and pistons are.
One man's worn out is another's nicely run in . . .

My bore gauge is in the mail. I had another look and there is a definite ridge at the top of the bore, with signs of blow-by. My suspicion is that it’s rebore-time. Stock pistons installed at this time.

However…. Bike came with another disassembled motor including a freshly rebored cylinder, complete with OS pistons (#11787, + 030”) and rings. These pistons are 8.5:1 with the crowned piston tops. (Currently I have flat top pistons. Does anyone see a problem with installing this set-up? Compression ratio, Valve clearance etc. OK?