brown oily substance from exhaust

[md1028]

just did a new piston, rings, gasket andhoned cylinder. broke in piston
a little over an hour above idol. checked bikes operations couple times since,
ran great. took out to start today and got lots of smoke and brown watery,slight oily residue. please help

 

[blasterdemon7]

The smoke sounds like the crank seal. When was the last time you changed trans fluid ?

 

[Blaaster]

A few questions.

What oil and ratio?

What colour is the smoke and does it stink?

Have you overfilled the transmission?

Is the crancase breather blocked?

What was the reason for rebuild?

Have you done a leak test to see if the crancase is airtight?

Is the header pipe correctly correctly fitted to the cylinder and leak free?

It is normal for spooge to issue from a fresh build owing to the excess of oil used during assembly.

 

[md1028]

thanks for response guys, white kind of rich smell, just put new tranny fluid in, rebuilt top end cuz air leak on bottom gasket and found scratches on piston and sleave. ran great before work and after. bogs down and will stall if i dont keep on throttle. crankcase oil seems clear and i may have over filled crankcase by 1/4 qt

 

[md1028]

how do i check and change crankseal

 

[89blaster89]

how do i check and change crankseal

do a leak test and see if its leaking air i think?

 

[md1028]

i just drained crankcase and used 3/4 qt spectro sx. what should oil look like after breaking in piston. slight dark grey with slight medal pieces at bottom. could that be from old wear and new piston and rings. also was over 1/4 qt. blew out crank case bleeder port and hose. checked plug ok may be little lean and just above average smoke.

 

[Blaaster]

i just drained crankcase and used 3/4 qt spectro sx. what should oil look like after breaking in piston. slight dark grey with slight medal pieces at bottom. could that be from old wear and new piston and rings. also was over 1/4 qt. blew out crank case bleeder port and hose. checked plug ok may be little lean and just above average smoke.

Oil blowing from the breather tells me that you need to leak test now.

There is no connection of the crancase to the transmission, so the metal pieces will have been from the transmission, not the piston and rings.

The plug will look lean if you are drawing excessive air, and you will be if the crank seal is leaking.

You must leak test before you put your foot on the kicker again, otherwise BOOM.

 

[md1028]

thanks is there a link to leak testing and how to replace crankcase bearing

 

[Blaaster]

 

[md1028]

thanks for the tutorials blaaster. ill def get that done. Also after I drained tranny blew out crank case breather port and hose. refilled tranny properly it def ran great again, just afraid to run it hard to not damage engine if there is a prob i cant figure out yet

 

[Blaaster]

When it passes the leak test, post your mods and someone will suggest some jets.