new oil,smoky exhaust

[jack02]

Hello all.

I'm one of those who,for better or worse,change the oil and filter at ridiculously short intervals, ie no more than 1500 miles. I've never used anything fancy - whatever's available cheap at the supermarket - on the premise that such frequent changes will outweigh any adverse effects of less-than-premium oil. I just bung any ol' 10/40 in and have never had any problem. Last time around though I put 20/50 in and now I get the symptoms of shot valve guide seals - lots of smoke at start up for about half a minute. I'd like to know your thoughts on this. Could the new 20/50 oil have caused some damage to the seals?/ is it purely coincidental that they were on their way out and started to show it at the time I put the new weight oil in?/ or is the smoke a normal characteristic of using heavier oil,somehow? And would replacing the 20/50 with the regular 10/40 resume normal service? Approaching midsummer here in the UK and don't wanna be pulling my motor down right now....  Thanks for any thoughts/advice you may have.

[mz_rider]

Hello all.

I'm one of those who,for better or worse,change the oil and filter at ridiculously short intervals, ie no more than 1500 miles. I've never used anything fancy - whatever's available cheap at the supermarket - on the premise that such frequent changes will outweigh any adverse effects of less-than-premium oil. I just bung any ol' 10/40 in and have never had any problem. Last time around though I put 20/50 in and now I get the symptoms of shot valve guide seals - lots of smoke at start up for about half a minute. I'd like to know your thoughts on this. Could the new 20/50 oil have caused some damage to the seals?/ is it purely coincidental that they were on their way out and started to show it at the time I put the new weight oil in?/ or is the smoke a normal characteristic of using heavier oil,somehow? And would replacing the 20/50 with the regular 10/40 resume normal service? Approaching midsummer here in the UK and don't wanna be pulling my motor down right now....  Thanks for any thoughts/advice you may have.

Jack,

I can't see the change in grade causing smoking. My Yamaha Service manual gives 20W40 oil for use over 5C. The manual is 25 years old and the oil available changes. I use 10W40 semi-synthetic or 5W40 fully synthetic in my FJs. I wouldn't worry about burning a little oil - look on the plus side it will stop the exhaust rotting! "approaching midsummer here in the UK" isn't it approaching midsummer everywhere in the northern hemisphere? I know what you mean that our northern latitude gives plenty of daylight - if it would only stop raining here. 

Stuart (Glasgow, Scotland)

[jack02]

Stuart,thanks. Seemed like too much of a coincidence that the smoke started at exactly the same time as the oil change,after 22 years on this planet being a strict non-smoker (the bike,not me)! For my own peace of mind I think I'll go back to 10/40 asap and sort the seals out over winter. Hope it's not something more serious. Rain?  I'm only a few hundred miles from you (Yorkshire) and I can't remember the last time I saw a drop - tho' a little is forecast for tonight.

[mz_rider]

Jack,

Yes I keep hearing about a "drought" but we've have lots of showers recently and heavy rain today - typical West of Scotland. North Yorkshire is a favourite biking area of mine. I'm hoping to go camping in Masham next month and have a few pints of the "Old Peculier".

Stuart

[Rampant_ant]

Hey I've just had a similar problem. I changed the tar that was in my 85 1100 and put some 15w-40 in itnd now its smoking badly and missing a bit. All I had done was turn the idle screw a bit because it seemed like the butterflys were closed to much and it wasnt idling well.

Ita got me kinda confused because its blowing a lot of smoke. Filled my garage up pretty quick.

Oh also when I gave it a rev it was like the engine didnt wana slow down properly

Cheers.
Kev

[ribbert]

Did you change the filter as well?  A common problem is getting a wire pinched behind the filter housing and leaking oil onto the exhaust which gets hot enough to smoke very quickly.

[jack02]

Kev,makes you wonder if *certain oils* cause this kinda thing - though it would have to reach the cylinders somehow. I aint had time to ride my bike of late,let alone change the oil,but I'll be changing back  to 10/40 asap and hoping for the best. Smoke apart,it runs exactly the same as before - rippin'!

[Rampant_ant]

Did you change the filter as well?  A common problem is getting a wire pinched behind the filter housing and leaking oil onto the exhaust which gets hot enough to smoke very quickly.

Nah I had just changed the oil but no filter. I'm planning on runnin it for a bit to help clear the old stuff out (which had been in there a while) then I will do another change with a filter.

Plus its got 4-1 exhaust so nothing on the left to drip oil on if that does happen. I'll definately keep it in mind when I change the filter thought 

[ribbert]

Did you change the filter as well?  A common problem is getting a wire pinched behind the filter housing and leaking oil onto the exhaust which gets hot enough to smoke very quickly.

Nah I had just changed the oil but no filter. I'm planning on runnin it for a bit to help clear the old stuff out (which had been in there a while) then I will do another change with a filter.

Plus its got 4-1 exhaust so nothing on the left to drip oil on if that does happen. I'll definately keep it in mind when I change the filter thought 

Did you move/dislodge/reconnect/kink the engine breather hose? It runs very close to the idle adjust screw.  I assume the smoke is coming out of the exhaust not from around the motor.

[Rampant_ant]

Did you change the filter as well?  A common problem is getting a wire pinched behind the filter housing and leaking oil onto the exhaust which gets hot enough to smoke very quickly.

Nah I had just changed the oil but no filter. I'm planning on runnin it for a bit to help clear the old stuff out (which had been in there a while) then I will do another change with a filter.

Plus its got 4-1 exhaust so nothing on the left to drip oil on if that does happen. I'll definately keep it in mind when I change the filter thought 

Did you move/dislodge/reconnect/kink the engine breather hose? It runs very close to the idle adjust screw.  I assume the smoke is coming out of the exhaust not from around the motor.

Yeah its definatly coming from the exhaust. When I shut the engine off it curls out from the exhaust for a few seconfs afterwards

[andyb]

Shot valveguide seals usually meant smoke on trailing throttle with high rpm use (seeing huge vacuum in the intake runners), I thought.  Smoke on startup or on accelleration I usually figure to be rings.  Compression check would tell you, though.

Meh, you change oil often, just change back and see what's what.

[mz_rider]

Shot valveguide seals usually meant smoke on trailing throttle with high rpm use (seeing huge vacuum in the intake runners), I thought.  Smoke on startup or on accelleration I usually figure to be rings.  Compression check would tell you, though.

Meh, you change oil often, just change back and see what's what.

Andy,

I'd say the exact opposite. My experience is that smoke on start up is valve guide seals. Oil leaks when the bike is sitting then burns when the engine is started. Many years ago I had a Honda CB250RS (4 valve single) that smoked on starting. I had to strip the bike to fix the gearbox and replaced the seals whilst it was apart and fixed the problem. Smoking when backing off could be caused by vacuum in the cylinder drawing in oil from the crankcase past worn rings.

Stuart

[Rampant_ant]

Shot valveguide seals usually meant smoke on trailing throttle with high rpm use (seeing huge vacuum in the intake runners), I thought.  Smoke on startup or on accelleration I usually figure to be rings.  Compression check would tell you, though.

Meh, you change oil often, just change back and see what's what.

The easiest way tell if it as valve seals or rings is by the amount of vacuum thats in the engine intake at the time. So your valves seals normally only leak when the vacuum is high ie at idle or when you roll off the throttle (purely because the butterflies are closed. Rings normally show up when theres,load on the engine.

I just thought it was really odd that it was fine before the change and now its not.

Kev

[JMR]

Shot valveguide seals usually meant smoke on trailing throttle with high rpm use (seeing huge vacuum in the intake runners), I thought. Smoke on startup or on accelleration I usually figure to be rings.  Compression check would tell you, though.

Meh, you change oil often, just change back and see what's what.

Bad exhaust seals/ guides will also cause this.

[srutherford]

hello all im back. its been a while so i will intro my self at the home page. my / is why 15/40 or 20/50 seems heavy to me mine is smoking a little in the a.m. and was low well from the window check. put one quart in it and back to spec. worn valve seals,piston rings? any way to take care of it asside from rebuild wieght brand half synthetic full ? thanx