oil leak

Joined
Sep 18, 2005
Messages
2
my 70 commando leaks oil from the back of the airbox-just behind the air filter. is this common? is there a fix or part i need? any help appreciated. ed.
 
Joined
May 22, 2004
Messages
522
edcommando

I think you may be able to find considerable feedback related to this issue in previous discussions but ~

My 850 does the same thing.. I believe mine does it because the "full" mark on the dip stick is way too high, thus the oil level is too high .

If I fill mine to the full mark, the bike will discharge the oil thru the breather to the air filter. (And no ~ ideally it is NOT meant to do this!)

If I put crank up a consistent 4,000 plus rpm, this serves to increase the scenario ~

I have worked out that my "full" mark is half way between the 'add' and 'full' marks.
 
Joined
Sep 18, 2005
Messages
4
oil leaks

I do not believe this is a serious problem as it is just the excess from the breather pipe but oil breathing problems seem to be a major concern for Nortons these days.I previously owned a 850 commando & had very little problems with it but I always ran the bike on straight 50 oil.Having just returned to Nortons about a year ago with a 750 fastback I started running the bike on multigrade oil. The bike started to blow oil from the breather at an increased rate. I checked all Norton sites for advice which all proclaimed to have the answer of fitting PC valves repositioning the breather to 850 positions inducing suction via the inlet rocker cover & other exotic solutions. Prior to resorting to this extreme I obtained some straight 50 & change the oil. Lo & behold oil breather problem cured.All this goes to show that
1/ as multigrades more viscous at lower temperature thaty are more likely to cause wet sumping via the oil pump.
2/ the bikes never needed all these optional extras before multigrades were around & the engine was designed around the oil of the time.
Multigrades are fine for wet sump engines but not drysump.This may be why Les Emery of Norvil will not warrant his bikes if run on multigrade.
 
Joined
May 22, 2004
Messages
522
David
I tend to agree in as much as it is not a major biggy ~ but an issue to be aware of.

As for oil/s: in a one on one conversation with Les Emery some time back, he explained to me that Penrite oils were developed in association with the Norvil shop and their race bikes. He was adamant that the Penrite oils were ideal for the Commando.

When I first ran the Commando I went along with him and used HPR 50 ~ BUT that was in an extreme Australian average temperature ~ <35 deg C >

I actually tried another product .. multigrade.. but I now run Penrite 40 in a less average temperature 25- 30 deg C .

This is very noticeable in that the engine far less prone to wet sumping ~

As for ventilation valves.. I fitted a PCV from a GM (Holden) motor vehicle.
This made a dramatic difference to the oil misting that forms around the crankcases of my Commando ~ Previously the engine 'could' use a 'wash down' after any 'reasonable ride'.
Now it is only needs a degrease / wash every now and again!
 
Joined
Aug 20, 2005
Messages
116
Why not route breather outlet from oil tank to just over rear chain, oil mist makes a great automatic luber!
 
Joined
Sep 18, 2005
Messages
4
oil leaks

Stuart SS
Thanks Stuart I'm not saying any answer to this question is right or wrong as each case may be different but the multigrade I used was Penrite HPR40 . I live in Toowoomba & I found it also seemed to be collecting water overnight I rang Penrite but they had no solution so I thought I may as well give the straight 50 a try as oil changes are relatively cheap compared to some other solutions. I also haven't had crankcase misting problems so like I said every case is different. The only thing I did apart from the oil change was I previosly ran the breather pipe to the magnato coverplate before returning to the oil tank simmilar to the 850 setup but allowing a larger volume for the oil & gas to separate than in the top of the tank. The best part about this setup was even if it didn't work the only part that needed replacement was the cover plate.No holes in cases or major re engneering etc. Don't like the breather to chain idea as oils not that good for chain lube and is messy as it drips from under the chaincase making it look like it is leaking.
 
Joined
Aug 28, 2005
Messages
33
Yep - Penrite HPR40 is the way to go. Had my 850 rebuilt by Bob at Classic Cycles here in Wellington last year. After many years of experience, this is the best oil for a Commando in NZ's climate in his opinion. Also, the comment about the dipstick levels is correct - not sure how it's measured, but I had new "low" and "high" marks labelled on mine and they're a fair bit lower.

Cheers, Nick
 
Joined
May 22, 2004
Messages
522
Nick

(How's that great NZ weather ~ last I heard we rotate our (local) weather with the North Island over here in Far north QLD)

I will add one point in reference to the use of HPR 40. I feel as it is a heavier oil, I like to warm up over say 20 KMs before giving the beastie any degree of styck !

Another 'innovation' I have incorporated is the use of a Fleetguard filter #3460.

This required the fitting of an adaptor which was made up for me by a mate in Melbourne. (He is a diesel fitter and made extensive research into this issue and came up with this filter combination~ )

The adaptor is a merely a thread adaptor which screws onto the filter base and accommodates the 'new' filter.

I have actually seen a similar adaptor on Ebay.
 
Joined
Aug 28, 2005
Messages
33
Stuart,
QLD weather in Welly, mmm, maybe Northland is closer :D
Been some great weather recently for going up and over the Rimutakas and grinding the pegs!
Saw an Aussie Commando at Classic Cycles whilst mine was being rebuilt - the only Commando I've ever seen with an oil cooler! I think it may have been a Queensland bike....?
Interesting filter mod. Was this just to get a better quality filter on there for hotter conditions? I've read on some European forums that there are some cheap filters about that fit the COmmando that should be avoided. I think the Citroen 2CV filter fits, but there are some crappy "no name" versions about.
Cheers
Nick
 
Joined
May 22, 2004
Messages
522
Nick

It seems a mate of mine who lives near Tauranga ~ a classic racing buff claims that as soon as we get the fine weather ~ he gets the snotty stuff ~ :lol:

Definitely the objective was to fit a superior filter! "Tiger" being a diesel fitter and service agent wanted to go for optimum performance and I feel the "standard filter" is too expensive, by today's standards and ~my - our question ~ WAS ~ IS it the best deal after all the standard filter was designed around the same time as the Commando.. (Perhaps it has been upgraded too .. but still ~)

I think Classic MC and spares in Wellington, have a nice glossy picture of my bike too as I bought 90% of my spares from them and I sent them a shot of the finished product, which "Tim" announced they had added to their feature wall ~

I have toyed with the idea of an oil cooler myself ~ but I do not like the look of the Hyde cooler as it looks more like a refugee form the back of a wrecked refrigerator :lol: !

When living and working in the Northern Territory, the oil cooler was a definite option.

There was a cooler on Ebay Aust last week and looked more like the Trident/ rocket style ~ it went for about $36 but I have hauled in my Ebay expenditures at the moment.


But I have to say the best option I took up of recent was to fit the NHL steering damper ~ it made a fantastic difference ~
 
Joined
Oct 4, 2003
Messages
11
hi every one ,i have the same problem Oil leaking from a breather
hole in my oil box [1969 norton750 commando] which would be in my air filter box {if i had one]. i have a single Mikuni conversion, this problem seems to get worse the longer i ride , like serious oil on tire. any sugg
jimd
 
Joined
May 22, 2004
Messages
522
jimd

As suggested earlier and in earlier subject strings on site, the correct oil level is of debate with the commando.

I find this leaking only really occurs when I top 4,000 rpm, and with all my British bikes this is the "bizness as usual " range.

As the oil level dropped from the top mark, to approx half way and stabilised, the seepage/ leak has decreased.

The first time it was suggested to me to redirect the breather to the rear chain I thought the poster was yanking my chain.

I have blocked off the chain oiler and I have no intentions of going that way either !

I bought a KN style air filter from Art Xander, (Xander bikes) and he suggested dropping the breather pipe into a contianer in the battery region, being that his Commando/s don't drop oil.

But I figure it would be no big deal to adapt a breather pipe to the back of this smaller compact filter.

At the ned of the day , I intend to monitor the 'new' marked full line and see how it goes..
 
Joined
Sep 18, 2005
Messages
4
oil leaks

Intrudin,
I think I'll have to be on my own here & reinstate that my problems of wet sumping & excess oil from breather disappeared when changing back to straight weight oil. As wet sumping occurs when the engine is stationary multigrade oils are at their thinnest at this time Therefore more prone to leak through the oil pump. As the single Mikuni limits petrol usage & power over the standard you will be increasing the amount of oil in your combustion which solves nothing burning excess oil instead of retaining it in the engine.Oil as chain lubricant no good for the same reason plus it doesn't stick to the chain like a proper chain lube so it is useless & messy. I wonder how often you have to remember to check your oil catch bottle ? do you pour it back into the oil tank? or does it stabilize?That would seem like a capacity problem. At 4000rpm the ratio of oil to gas should be greatly reduced unless you have a semifilled sump.
 
Joined
May 22, 2004
Messages
522
David wrote : " Oil as chain lubricant no good for the same reason plus it doesn't stick to the chain like a proper chain lube so it is useless & messy. "

I totally agree David.. the oiler was disconnected as a very early part of my restoration ~ I fitted a chain guard extension which reduced the mess even with chain lube ~

I genrally lube the chain manually ~

As for collecting the oil deposits.. was not conidered .. my priority was to elminate the problem and I feel the slightly lower dip stick setting is the way to go.. mine appears at this point to be quite stable at the lower setting which I have marked .. 8)
 
Joined
May 22, 2004
Messages
522
David wrote : " Oil as chain lubricant no good for the same reason plus it doesn't stick to the chain like a proper chain lube so it is useless & messy. "

I totally agree David.. the oil'er was disconnected as a very early stage of my restoration ~ I fitted a chain guard extension which reduced the mess even with chain lube ~

I generally lube the chain manually ~

As for collecting the oil deposits.. was not considered .. my priority was to eliminate the problem and I feel the slightly lower dip stick setting is the way to go.. mine appears at this point to be quite stable at the lower setting which I have marked .. 8)
 
Joined
May 22, 2004
Messages
522
David wrote : " Oil as chain lubricant no good for the same reason plus it doesn't stick to the chain like a proper chain lube so it is useless & messy. "

I totally agree David.. the oil'er was disconnected as a very early stage of my restoration ~ I fitted a chain guard extension which reduced the mess even with chain lube ~

I generally lube the chain manually ~

As for collecting the oil deposits.. was not considered .. my priority was to eliminate the problem and I feel the slightly lower dip stick setting is the way to go.. mine appears at this point to be quite stable at the lower setting which I have marked .. 8)
 
Joined
May 22, 2004
Messages
522
David wrote : " Oil as chain lubricant no good for the same reason plus it doesn't stick to the chain like a proper chain lube so it is useless & messy. "
I totally agree David.. the oil'er was disconnected as a very early stage of my restoration ~ I fitted a chain guard extension which reduced the mess even with chain lube ~

I generally lube the chain manually ~

As for collecting the oil deposits.. was not considered .. my priority was to eliminate the problem and I feel the slightly lower dip stick setting is the way to go.. mine appears at this point to be quite stable at the lower setting which I have marked .. 8)
 
Joined
Aug 20, 2005
Messages
116
One reason oil as chain luber if applied in a small steady quantity is that grit and road dort does not stick to it. My modern bike a triumph sprint has a scottoiler fitted which does just this and the chain is always coated with thin coat of oil & stays clean. I agree that pointing breather is not a proper way to do it & is unreliable and messy, but I am a total peasant so I do it anyway!
 
Top