• Required reading for all forum users!!!

    Welcome!
    Register to access the full functionality of the GSResources forum. Until you register and activate your account you will not have full forum access, nor will you be able to post or reply to messages.

    A note to new registrants...
    All new forum registrations must be activated via email before you have full access to the forum.

    A Special Note about Email accounts!
    DO NOT SIGN UP USING hotmail, outlook, gmx, sbcglobal, att, bellsouth or email.com. They delete our forum signup emails.

    A note to old forum members...
    I receive numerous requests from people who can no longer log in because their accounts were deleted. As mentioned in the forum FAQ, user accounts are deleted if you haven't logged in for the past 6 months. If you can't log in, then create a new forum account. If you don't get an error message, then check your email account for an activation message. If you get a message stating that the email address is already in use, then your account still exists so follow the instructions in the forum FAQ for resetting your password.

    Have you forgotten your password or have a new email address? Then read the forum FAQ for details on how to reset it.

    Any email requests for "can't log in anymore" problems or "lost my password" problems will be deleted. Read the forum FAQ and follow the instructions there - that's what we have one for...

  • Returning Visitors

    If you are a returning visitor who never received your confirmation email, then odds are your email provider is blockinig emails from our server. The only thing that can be done to get around this is you will have to try creating another forum account using an email address from another domain.

    If you are a returning visitor to the forum and can't log in using your old forum name and password but used to be able to then chances are your account is deleted. Purges of the databases are done regularly. You will have to create a new forum account and you should be all set.

White Smoke

  • Thread starter Thread starter PAULJAC47
  • Start date Start date
P

PAULJAC47

Guest
Hi Guys,any advice on this before i tear the motor down.
850 gs with slide Mikuni Carbs
Rebuilt last year with new pistons,rings,bored oversize with honed bore.
Carbs, all new jets properly set up and balanced.
Was run in on mineral oil to specs.
All bores show 140-150 psi cold with throttle blocked open.
Replacement head less than 1000 miles on new valve stem seals.
Bike shows white smoke on acceleration and deceleration,plugs showing sooty,now using oil,but pulls like a train and starts easy....Any input appreciated......
progress.gif
 
Yeah I was scratching my head about that - figured he knows something I don't...

Is it possible you're not using the right motor oil? Is the jetting right could you be running lean? plugs of the right temperature? Is timing advanced?

Are you burning oil?
 
Could you define what mineral oil to spec means.

Because when I hear mineral oil, I think of cosmetics or something household usage not high film strength engine applications.

What did you set the ring end gap and did you stager the openings 120 degrees apart not using the 12 and 6 'o clock thrust areas?

hanging/folding a oil control micro ring will do this too - if they are the three piece type. I mean the piston will go in and the top rings seal but the oil is getting thru - might have a score in there too...

look in the exhaust pipe for the excessive soot and burnt oil 1 cyl or all 4?
 
I think by mineral oil he means non synthetic.
Sounds to me like everything was done correctly, busted ring on installation?
Really easily done.:(
 
By mineral oil i do mean standard non synthetic as originally used in these old bikes ,always been told by engine rebuilders in uk to run engine in using this type of oil,thanks for other input here, have gapped rings,rings are in right way up,carbs have correct jets and are balanced,carbs have been,cleaned and all airways are clear,plugs of correct grade and timing spot on,using Dyna s set up ,new air filter,shims all done and valve timing correct,all four plugs are sooting still though some slightly more than others,you can actually see the motor burning rich just off idle,using a Gunson colourtune which lets you see into the combustion chamber,guess the next thing to try is to get a set of proven carbs and give them a try!!!
One thing i have noticed is some smoke apparent when you take the oil filler cap off after a run,possible crankcase pressurisation???
Any more input appreciated.....
 
tatu said:
I think by mineral oil he means non synthetic.
Sounds to me like everything was done correctly, busted ring on installation?
Really easily done.:(
Click to expand...

ah semantics...

Well if you're burning oil it has to get in there somehow... +1 to this or the scored wall being the likely culprit.


Man that Gunson colortune is the bees knees! I want one now.

http://www.youtube.com/watch?v=6hFUvQ4gaPc
 
Last edited:
trippivot said:
Could you define what mineral oil to spec means.

Because when I hear mineral oil, I think of cosmetics or something household usage not high film strength engine applications.

What did you set the ring end gap and did you stager the openings 120 degrees apart not using the 12 and 6 'o clock thrust areas?

hanging/folding a oil control micro ring will do this too - if they are the three piece type. I mean the piston will go in and the top rings seal but the oil is getting thru - might have a score in there too...

look in the exhaust pipe for the excessive soot and burnt oil 1 cyl or all 4?
Click to expand...

I folded over the corner on an oil ring once, put a nice sized score in a freshly bored wall. Ended up having to resleeve it....
 
You won't get white smoke caused by your carbs being set up too rich - you'll get black smoke. Plus when you are running just off idle you will get a yellow flame when see through a Colourtune. If you pull, say, 2 plug leads (so that the engine revs won't scream up) and hold the throttle fixed at around 1/4 throttle you will see the blue flame come back - you have to hold it steady for a time though - not a 'blip'.

White smoke is oil smoke. You're going to have to pull the top end to see what's what I'm afraid.
 
hampshirehog said:
You won't get white smoke caused by your carbs being set up too rich - you'll get black smoke. Plus when you are running just off idle you will get a yellow flame when see through a Colourtune. If you pull, say, 2 plug leads (so that the engine revs won't scream up) and hold the throttle fixed at around 1/4 throttle you will see the blue flame come back - you have to hold it steady for a time though - not a 'blip'.

White smoke is oil smoke. You're going to have to pull the top end to see what's what I'm afraid.
Click to expand...

Thanks for that Hog,why do you get the Blue flame back when running on two?and yellow just off idle.According to the colourtune bumf,you should get blue right through the range with a gradual throttle increase,and initially blue then yellow,then blue if you snap throttle open:confused:
 
You must log in or register to reply here.
Back
Top