Author Topic: Smoking on start up.  (Read 1747 times)

Offline Dean

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Smoking on start up.
« on: 09.05. 2016 10:17 »
My engine has decided to smoke on start up, and I mean smoke. It clears after about 100 metres of riding and doesn't return.
I have just rebuilt the bottom end with regound crank etc.
It did not smoke before then.

I will leave it to sit for a while and check wet sumping (which I doubt)  but in the meantime I would be grateful for any other suggestions (other than start it after dark)

While waiting for you clever guys to get back to me I am going to try and locate the source of an embarrasing engine whistle!

(BTW I used to get an occasional whine from the rear of the bike but it seems to have cleared since polishing the pillion seat with silicon)

cheers
Dean
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Re: Smoking on start up.
« Reply #1 on: 09.05. 2016 10:25 »
(BTW I used to get an occasional whine from the rear of the bike but it seems to have cleared since polishing the pillion seat with silicon)

Love it! *lol*

Offline muskrat

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Re: Smoking on start up.
« Reply #2 on: 09.05. 2016 11:52 »
G'day Dean.
I've got money on wet sumping. Did you renew the ball & spring?
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Muskys Plunger A7

Offline Dean

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Re: Smoking on start up.
« Reply #3 on: 09.05. 2016 13:59 »
You may well be right Muskrat. Indeed I hope so as its the easiest to live with.
No I did not replace the ball and spring as it was not wet sumping previously and bitter experience has taught me to leave well alone. I also have a new SRM oil pump fitted. Hence my wondering about other causes.
Never tell people your troubles. Half of them are not interested and the other half are glad you're getting what's coming to you.

Offline stu.andrews

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Re: Smoking on start up.
« Reply #4 on: 09.05. 2016 14:45 »
Muskrat is right but sometimes a little oil will run down the inlet valve guides to cause this, although the amount would be very small.
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Offline edboy

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Re: Smoking on start up.
« Reply #5 on: 09.05. 2016 16:33 »
well,  if the problem has started since you changed the oil pump i know where i would start looking.

Offline Dean

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Re: Smoking on start up.
« Reply #6 on: 09.05. 2016 17:29 »
No, I had the new oil pump before rebuilding the bottom end *conf*

It did not do it the first couple of runs after the rebuild. It has done it since I used the trick of sticking my finger over the return pipe in the oil tank to get a load of oil up to the rockers. But I guess at worst that would result in a load of oil up there that might find its way into the barrels but that would have cleared by now. I can't think why that would cause it to smoke on restarting after having cleared during the previous ride.

PS. I did search the forum for an answer before bothering you all.
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Offline muskrat

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Re: Smoking on start up.
« Reply #7 on: 09.05. 2016 19:41 »
Do you have a sump plate with a drain plug? After a run and she sits for a while (cools down) there should be about 1 cup (250ml) of oil left in the sump. This amount won't cause smoke on start up. After a few days parked drain the sump to see how much is in there. Now go through your normal start/ride procedure and note if it's any better or the same.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Muskys Plunger A7

Offline Steve.Carter

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Re: Smoking on start up.
« Reply #8 on: 09.05. 2016 20:55 »
It's been ages since I've posted on this forum so I must apologise for that but I think I might be able to help with this problem.
My poor Huntmaster had serious smoke problems on start up straight  after fitting a new barrel and pistons. I did every thing I was supposed to do. I gave it an Italian break in on running in oil and after 1000 miles it still smoked, worse if anything.
It was all down to the rings. The Ariel club have had pistons made by IMD that fit the Huntmaster so I got hold of a couple of plus 20 thou and just put them in, didn't even check anything or even hone the bores. Just chucked them in. Result. No smoke. Fixed.
When the old pistons were in I could kick the bike over and watch the oil pouring down the barrels onto the top of the pistons As soon as the new pistons were in no oil was visible anymore.
The first picture below shows the old pistons with the oil pouring down the bores.
The other is the new pistons fitted.

The other one was me at a rally earlier this year, the talk was getting around I'd bought a two stroke!


Steve

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Re: Smoking on start up.
« Reply #9 on: 09.05. 2016 21:08 »
Hi,
Quote
It has done it since I used the trick of sticking my finger over the return pipe in the oil tank to get a load of oil up to the rockers

Have you checked that the correct oil feed bolts are fitted?
The bolts for the A10 have different size restricting holes than the "same" size bolts used on the single cylinder BSA's
Maybe when you blocked the return you dislodged something in the plumbing that has increased the flow to the valve gear ??????

John
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Offline Dean

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Re: Smoking on start up.
« Reply #10 on: 09.05. 2016 21:47 »
Do you have a sump plate with a drain plug? After a run and she sits for a while (cools down) there should be about 1 cup (250ml) of oil left in the sump. This amount won't cause smoke on start up. After a few days parked drain the sump to see how much is in there. Now go through your normal start/ride procedure and note if it's any better or the same.
Cheers

Exactly what I plan to do....a bit frustrating as I'll have to go without riding her for a couple of days.

Thanks Steve and John for your suggestions. I'll look into them if wet sumping is eliminated
Never tell people your troubles. Half of them are not interested and the other half are glad you're getting what's coming to you.

Offline muskrat

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Re: Smoking on start up.
« Reply #11 on: 10.05. 2016 03:31 »
To save being off the road, drain the sump till you get less than a drop every 30 seconds. Then place an empty container under her and check how much oil is there in the morning. Don't forget to put the plug back in  ;).
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline Dean

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Re: Smoking on start up.
« Reply #12 on: 10.05. 2016 14:38 »
Good tip Muskrat. I'll give it a try.

Mind you it has helpfully started pissing down here today and is forecast to keep it up for a couple more.
Never tell people your troubles. Half of them are not interested and the other half are glad you're getting what's coming to you.

Offline Gavin

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Re: Smoking on start up.
« Reply #13 on: 10.05. 2016 14:38 »
My Bike responded very well to a thicker cork on the breather. I am sure I had a pressurized sump which loved to smoke up, like your 2 stroke ( *smile*)  It's a quick easy and inexpensive cure if it works, and saves lots of work too. Could be worth a try.

Offline Dean

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Re: Smoking on start up.
« Reply #14 on: 10.05. 2016 14:57 »
Hi Gavin.
I'll give it a try. If nothing else it will use up one of the loads of corks that have been left overs from gasket sets over the years ;)
I'll have to get brain rond how it might only affect start up smoking though.
Never tell people your troubles. Half of them are not interested and the other half are glad you're getting what's coming to you.