2015 commando 961...Oil in airbox

Sticky tyres718

Sticky tyres718

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Jun 25, 2022
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I realise this topic has been chewed over before but actually finding a definite remedy is very difficult.
Anyone able to tell me a solution to the problem of oil in the airbox?
Is it a combination of the longer dipstick and breather rocker cover fix from Norton is has some clever dick found a way round having to fit an ugly plastic part to my beautiful bike.
I currently have the original "short dipstick" and I'm running a catch bottle... Getting roughly 300ml of oil every ride with a oil level at the top mark when I start off.
 
Welcome @Sticky tyres718

some good reading here:

www.accessnorton.com

Unraveling the 961 part two (oil in the air box)

There are two shortcomings with the 961 that have annoyed me the most. One is the idle which I've been investigating HERE The other is oil in places it shouldn't be! Neither unfortunately can be fixed with a cable tie! So this thread is going to deal with understanding the oil in the airbox...
www.accessnorton.com www.accessnorton.com

cheers,

cliffa.
 
Sticky tyres718 said:
I realise this topic has been chewed over before but actually finding a definite remedy is very difficult.
Anyone able to tell me a solution to the problem of oil in the airbox?
Is it a combination of the longer dipstick and breather rocker cover fix from Norton is has some clever dick found a way round having to fit an ugly plastic part to my beautiful bike.
I currently have the original "short dipstick" and I'm running a catch bottle... Getting roughly 300ml of oil every ride with a oil level at the top mark when I start off.
Click to expand...
Your introduction leaves little wiggle room. I would fit the AOS black box and position it (if you have a Commando) in the late high and back spot where it is least visible. Getting the parts might be difficult however right now. If you can't find one try ordering one from the Yam R6 of appropriate year (PM Stu Bodycote). Are you prepared to replace pistons/rings/barrels ? (If you can find them) . Get the long late model dipstick , it should help reduce your discharge rate. Are you breathing off the rocker cover or crankcase ? Ollie Thiel had the oil dipstick in stock . Also , based upon your introduction I would assume that you won't try any of the other solutions brought forth either like the additional air/oil/water separator ? If you have a Domi this can be positioned like iwilson did . I will attach a photo of my 961 Commando for reference . My bike was discharging oil equal to yours in the beginning , but now is well sorted.

 
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Like Tony and Gene said plus I can add that we have worked on numerous 961's that don't have the black box and we have been able to sort out the oil issue with different things on almost every bike. The first and foremost is the oil level. Some you can run a higher oil level some you get 10cc over and you get airbox oil. Others it was a matter of oil blow-by in the cylinders that was solved with rehone and rings. Some blocking off the cylinder head air vents and others opening up the air vents. All have benefited from the transmission vent.

We also found that if you have the inline filter removing it helps even though its controversial, but if you don't make sure the screen stays totally clean as any interruption in oil flow causes a back feed issue which raises the oil level in the tank because more oil is going in than going out.
 
Thanks for that
City Garage said:
Like Tony and Gene said plus I can add that we have worked on numerous 961's that don't have the black box and we have been able to sort out the oil issue with different things on almost every bike. The first and foremost is the oil level. Some you can run a higher oil level some you get 10cc over and you get airbox oil. Others it was a matter of oil blow-by in the cylinders that was solved with rehone and rings. Some blocking off the cylinder head air vents and others opening up the air vents. All have benefited from the transmission vent.

We also found that if you have the inline filter removing it helps even though its controversial, but if you don't make sure the screen stays totally clean as any interruption in oil flow causes a back feed issue which raises the oil level in the tank because more oil is going in than going out.
Click to expand...
 
Thanks

Thanks for the good information, I have only just purchased my Norton Commando 961 2015 and it's practically brand new 300km so am still in the running in process.
Pretty sure I'm not getting blowby but I will definitely change to the longer dipstick, I can handle a little bit of oil in the airbox but wasn't comfortable with the 300ml.
Hopefully as the bike gets more Kms on the clock things should improve.
 
Thank you for your information.
I'm no mechanic but am wondering if a compression test would reveal a blowby issue? Even though I doubt it to be an issue as bike is brand new 300km.
It has a breather hose of the transmission but I'm confused as to how this might remedy oil in the airbox as transmission oil is separate to the engine oil on the 961 commando... unless I am missing something?
Norton are not much help and trying to find parts etc in New Zealand is like searching for "rocking horse shit"
Any photos or videos would be most welcome.☺️
Sticky tyres718 said:
Thanks for that
Click to expand...
 
Sticky tyres718 said:
Thank you for your information.
I'm no mechanic but am wondering if a compression test would reveal a blowby issue? Even though I doubt it to be an issue as bike is brand new 300km.
It has a breather hose of the transmission but I'm confused as to how this might remedy oil in the airbox as transmission oil is separate to the engine oil on the 961 commando... unless I am missing something?
Norton are not much help and trying to find parts etc in New Zealand is like searching for "rocking horse shit"
Any photos or videos would be most welcome.☺️
Click to expand...
I think that City Garage was adding the trans vent because while you are there take care of this . My last compression test showed about 180 psi , both were very close . Get some more break in miles on your engine , that should help you. Look up compression test for the exact numbers from my bike.
Look here : https://www.accessnorton.com/NortonCommando/norton-961-compression-test.34275/
 
TonyA said:
I think that City Garage was adding the trans vent because while you are there take care of this .
Click to expand...
yes exactly. Also just in case someone ran the line into the airbox as we have seen before.
TonyA said:
My last compression test showed about 180 psi , both were very close . Get some more break in miles on your engine , that should help you. Look up compression test for the exact numbers from my bike.
Click to expand...
Tony is right on with his numbers though we have seen lower and later found some serious ring issues. You should be getting close numbers on each cylinder. Make sure the intake is wide open and be sure to keep the spark plugs in the caps
 
Sticky tyres718 said:
I realise this topic has been chewed over before but actually finding a definite remedy is very difficult.
Anyone able to tell me a solution to the problem of oil in the airbox?
Is it a combination of the longer dipstick and breather rocker cover fix from Norton is has some clever dick found a way round having to fit an ugly plastic part to my beautiful bike.
I currently have the original "short dipstick" and I'm running a catch bottle... Getting roughly 300ml of oil every ride with a oil level at the top mark when I start off.
Click to expand...
Hi and welcome, TonyA and others have helped me over time with exactly this issue, I even had guidance for Max one of the original Engineers at SG Norton.

My take is there are 2/3 actual issues not one alone, blow-by, wetsumping etc etc, Ive come to the conclusion that my Bikes Bi-polar, just when I think ive worked her out she does the total oposite.

On reading a couple of recent oil/airbox threads and having a few months away from the issue I had one of those "Eureka" moments and I think I have the answer now, Ill pm you to discuss.
 
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Bluey72e said:
Hi and welcome, TonyA and others have helped me other time with exactly this issue, I even had guidance for Max one of the original Engineers at SG Norton. My take is there are 2/3 actual issues not one alone, blow-by, wetsumping etc etc, Ive come to the conclusion that my Bikes Bi-polar, just when I think ive worked her out she does the total oposite. On reading a couple of recent oil/airbox threads and having a few months away from the issue I had one of those "Eureka" moments and I think I have the answer now, Ill pm you to discuss.
Click to expand...
 
Sticky tyres718 said:
Thanks mate... I've been trying to hook up for a private chat but am new to this forum business and are stumbling around.
I'll try again but failing that maybe email me? iratepirate666@gmail.com
Thanks.
Click to expand...
To P.M. somebody click or touch the persons icon and choose “start conversation” Or go to the mail icon on the top right and start a new conversation.

IfI were you I would remove that email address from your post, as you could get spammed as a result of having it on a public forum.
 
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Bluey72e said:
Hi and welcome, TonyA and others have helped me other time with exactly this issue, I even had guidance for Max one of the original Engineers at SG Norton.

My take is there are 2/3 actual issues not one alone, blow-by, wetsumping etc etc, Ive come to the conclusion that my Bikes Bi-polar, just when I think ive worked her out she does the total oposite.

On reading a couple of recent oil/airbox threads and having a few months away from the issue I had one of those "Eureka" moments and I think I have the answer now, Ill pm you to discuss.
Click to expand...
You are right on Bluey ! How quickly I forget ...
 

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