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Blowing white smoke

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wayne-o
Posts: 18
Joined: Sat Jun 26, 2010 7:48 pm
Bikes: 1964 pan, 1970 honda 100cc, yamaha wr 250f
Location: New Mexico

Blowing white smoke

#1

Post by wayne-o » Sat Jun 26, 2010 10:13 pm

I just had my 64 pan overhauled and now have about 500 miles on it and it has started to blow white smoke out the front cylinder and the pipe is soaked in gas I hope someone can help



steve_wood
Posts: 947
Joined: Tue Jan 08, 2008 12:32 am
Bikes: 56 FLH, 2007 FLHRCI
Location: Belleville, Ontario, Canada

Re: Blowing white smoke

#2

Post by steve_wood » Sat Jun 26, 2010 11:36 pm

Can you run a compression test? And a leak down test? That will tell tell you a whole lot more.

wayne-o
Posts: 18
Joined: Sat Jun 26, 2010 7:48 pm
Bikes: 1964 pan, 1970 honda 100cc, yamaha wr 250f
Location: New Mexico

Re: Blowing white smoke

#3

Post by wayne-o » Sat Jun 26, 2010 11:42 pm

I can do compression test. Can you explain a leak down test for me?

steve_wood
Posts: 947
Joined: Tue Jan 08, 2008 12:32 am
Bikes: 56 FLH, 2007 FLHRCI
Location: Belleville, Ontario, Canada

Re: Blowing white smoke

#4

Post by steve_wood » Sat Jun 26, 2010 11:52 pm

Leak down test:

- You need to purchase or manufacture an air fitting that screws into the spark plug hole. I made one by knocking out the electrode of a sparkplug and then glueing a air fitting in place with epoxy. Pretty ugly, and it will only work with low air pressure, but it works.
- screw the fitting into the spark plug hole and attach low pressure compressed air.
- with a stethescope, or your ear, listen for leaks. You'll need to rotate the crankshaft to the point where both valves are closed.
(1) If you hear air hiss in the exhaust pipe, your exhaust valve is leaking
(2) Remove one of push rods and stick your stethescope up into the rocker cover. If you hear hiss, your valve guides are leaking (or you have a cracked head).
(3) If you hear hiss in the carburetor, your intake valve is leaking
(4) Find the crankcase vent (you may have to disconnect a hose) and listen. If you hear hiss, your rings are leaking.
(5) Listen around the exterior of the head and cylinder; especially the head gasket area.

That's the jist of it; I'm sure you can find much better instructions on the net somewhere.

john HD
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Re: Blowing white smoke

#5

Post by john HD » Sun Jun 27, 2010 12:38 am

assuming it is running rough, any chance you just have a fouled plug? what do they look like? front exhaust pipe cold?

they will run on one cylinder!

john

wayne-o
Posts: 18
Joined: Sat Jun 26, 2010 7:48 pm
Bikes: 1964 pan, 1970 honda 100cc, yamaha wr 250f
Location: New Mexico

Re: Blowing white smoke

#6

Post by wayne-o » Sun Jun 27, 2010 1:24 am

Thank for the info Steve

john HD wrote:assuming it is running rough, any chance you just have a fouled plug? what do they look like? front exhaust pipe cold?

they will run on one cylinder!

john

The bike is running pretty good, except it has a hard time idiling after its hot, Both plug look good and the same front and rear cylinders. since it started to smoke I have changed plugs and checked them during a ride and after. could it be and intake leak that is causing this?

john HD
Moderator
Posts: 3674
Joined: Sat Aug 20, 2005 7:24 pm
Bikes: '42 WLA X 2, '55FL, '93 Ultra Classic, '91 Fatboy, '97 883, '71 Suzuki Duster 125, '83 GPz 750.

Re: Blowing white smoke

#7

Post by john HD » Sun Jun 27, 2010 2:39 am

without a doubt!

john

wayne-o
Posts: 18
Joined: Sat Jun 26, 2010 7:48 pm
Bikes: 1964 pan, 1970 honda 100cc, yamaha wr 250f
Location: New Mexico

Re: Blowing white smoke

#8

Post by wayne-o » Sun Jun 27, 2010 3:22 am

Thanks i will check it, another question do you think i did any damage to the head or rings if it had been washing the cylinders down. this happened during the breakin period of this fresh rebuild. If so what should i check and how shoud i go about it

steve_wood
Posts: 947
Joined: Tue Jan 08, 2008 12:32 am
Bikes: 56 FLH, 2007 FLHRCI
Location: Belleville, Ontario, Canada

Re: Blowing white smoke

#9

Post by steve_wood » Sun Jun 27, 2010 11:25 am

Do you have one of those small LED flashlights with the head on a flexible gooseneck? Remove the sparkplug, put the flashlight in the cylinder and peek through the sparkplug hole. It takes a bit of manuoevering, but you can see quite a bit of the cylinder wall surface. This will tell you a lot about the condition of your piston and rings.
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wayne-o
Posts: 18
Joined: Sat Jun 26, 2010 7:48 pm
Bikes: 1964 pan, 1970 honda 100cc, yamaha wr 250f
Location: New Mexico

Re: Blowing white smoke

#10

Post by wayne-o » Sun Jun 27, 2010 5:14 pm

I check that thanks, Would it be worth doing the compression test or leak test, Or I guess it would burn oil if there was any damage done right. sorry for all the questions Im just learning and my mechanic is no help at all he just want the bike in his shop, but after a 11 month rebuild that aint happen again Im not an idiot just a rookie

socalrider
Posts: 322
Joined: Sat Jun 14, 2008 5:22 am

Re: Blowing white smoke

#11

Post by socalrider » Mon Jun 28, 2010 2:34 am

the exact same thing happened to me on a shovel rebuild. turned out the head bolts were not torqued down

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