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Norton Dominator 99 problems

Norton Models (not Commando or P11)

Norton Dominator 99 problems

Postby KuusistoNorton » Wed Jul 26, 2017 8:51 am

Hello!

I am very new guy here and i need little bit help.

About two weeks ago i bought my first Norton and i've been riding it almost 900km(560miles) and im in love with it and i think its working pretty good.

The thing is that since i am not so familiar with Nortons or other british motorcycles, i been scavenging through the internet to get information and such things to get known with the bike.

The "problem" is the engine breather hose. Where it should go? Should 99 Dommie have almost same oil lines than commando has?

In commando it looks like the breather hose should go back to oil tank.. but in my bike the breather hose is attached to the oil return line with a T-coupling. T-coupling is fitted between rocker feed banjo and junction block.

The thing that makes me wonder is that i have understood that the return line is reduces little bit after the rocker feed banjo, making the oil go easier to rockers. And i am not sure if the breather hose has any valves in it or not, but i am afraid that because of the reduction in return line, scavenge pump would also pump oil wrong way to breather hose back to engine.

If that is correct and should be like that, then its ok and i dont think i will make any changes to it,but it got me wondering..

Greetings from Finland!
Last edited by KuusistoNorton on Thu Aug 10, 2017 8:08 am, edited 1 time in total.

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Re: Norton Dominator 99 problem?

Postby KuusistoNorton » Wed Jul 26, 2017 9:04 am

Here is couple pictures of it.

Image
T-coupling


Image
T-coupling


Image
Engine breather hose.

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Re: Norton Dominator 99 problem?

Postby kernel65 » Wed Jul 26, 2017 9:13 am

That's a method of returning oil that has collected in the crank case (wet sump for example) to the oil tank due to lack of a return line made into the earlier oil tanks. I believe this line original should have gone to a small tube on the front of the chain guard that allows this line to otherwise vent to atmosphere and lube the chain.

As for your question on reducing flow to the head I do not know and not a fan of the Factory set up on the low pressure side to begin with. In a recent discussion with Comnoz on a similar concern about back flow to the engine it would be my understanding of low probability given that the breather is going to be slightly pressurized. I would shoot him a pm to further discuss scavenge pressure vs breather pressure of various set ups.

Scott
Last edited by kernel65 on Wed Jul 26, 2017 9:23 am, edited 1 time in total.
1959 Norton Dominator 99
1965 Norton Atlas
1970 Norton 750 S
1972 Norton 750 Combat
2014 Triumph Tiger 800XC
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Re: Norton Dominator 99 problem?

Postby KuusistoNorton » Wed Jul 26, 2017 9:21 am

kernel65 wrote:That's a method of returning oil that has collected in the crank case (wet sump) to the oil tank due to lack of a return line made into the earlier oil tanks. I believe this line original should have gone to a small tube on the front of the chain guard that allows this line to otherwise vent to atmosphere and lube the chain.

Scott


Hello,

Thank you for answering.

So what do you think about that method, will it work just fine or should i change it?

I've heard about the wet sumping and i've been using two brake cable pliers to avoid wet sumping. When i finish driving and get back home i attach those two pliers to feed and return line. I have taught myself to use right side fuel tap as primary fuel tap so every time i'll go for a ride i'll see those pliers sticking out when im opening fuel tap.

Will it occur some problems with that method being used, like could scavenge pump push oil back to engine through that breather hose instead of pumping it to the rockers?

-Kuusisto

KuusistoNorton
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Re: Norton Dominator 99 problem?

Postby kernel65 » Wed Jul 26, 2017 9:29 am

See the above edit. If Jim doesn't chime in I would send him pm, he's a good resource on explaining some of these venting differences between models and your options.
1959 Norton Dominator 99
1965 Norton Atlas
1970 Norton 750 S
1972 Norton 750 Combat
2014 Triumph Tiger 800XC
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kernel65
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Location: Natural Bridge, NY USA

Re: Norton Dominator 99 problem?

Postby KuusistoNorton » Wed Jul 26, 2017 9:48 am

Hello,

Lets wait and see if Jim would chime in, if not then i'll maybe try contacting him via pm.

I think i'll need to redo the rocker feed anyway at some point, previous owners has made new upper pipe to it and solderings doesnt seem that good in my opinion, and i dont know if the 5mm outer dia copper pipe is enough anway.. I've seen some braided steel kits etc for sale maybe ill buy one of those at some point.

Also need to adjust valves again since i did it wrong last time.

Somehow i tought that it would be done same as my Moto Guzzis valve adjustment but it was not. I adjusted both intake and exhaust valves at the same time in compression stroke TDC, but afterwards i red about it and its wrong way to do it. Asking now just to be sure to do it right.

Left side intake valve is adjusted when right side intake valve is fully open? (Compressed) Same with left exhaust valve when righr ex valve is fully open(compressed) and vice versa to right side adjusment.

Before adjusting valves first time the bike was spitting and coughing through the carb when engine was warm. After adjusting clearances little bigger it stopped. Here in Finland we use metric system and i tought that 0,10mm for intake and 0,15mm for exhaust would be enough?(about .004" and .006").

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Re: Norton Dominator 99 problem?

Postby Triton Thrasher » Wed Jul 26, 2017 10:03 am

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Re: Norton Dominator 99 problem?

Postby KuusistoNorton » Wed Jul 26, 2017 10:51 am



Hello, thank you for that manual, i tried to search manual but didint success in it.

-Kuusisto

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Re: Norton Dominator 99 problem?

Postby bad_friday » Thu Jul 27, 2017 12:44 am

KuusistoNorton wrote:… and i tought that 0,10mm for intake and 0,15mm for exhaust would be enough?(about .004" and .006").

It should be 15/100 on inlet and 20/100 on exhaust.

Fritz
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Re: Norton Dominator 99 problem?

Postby KuusistoNorton » Thu Jul 27, 2017 1:01 am

bad_friday wrote:
KuusistoNorton wrote:… and i tought that 0,10mm for intake and 0,15mm for exhaust would be enough?(about .004" and .006").

It should be 15/100 on inlet and 20/100 on exhaust.

Fritz


Hello,

Thanks, i need to check what they are with the "right" method.

Since when it was on compression stroke and TDC (rockers were free) the 0,10mm gauge did not fit inlet and 0,15 did not fit exhaust either. The ones that fitted were inlet 0,07-0,08mm(.002"-.003") and exhaust 0,12-0,13mm(.004"-.005") and i think they were too tight!

So i adjusted inlet 0,15mm(.006") and exhaust 0,20mm(.008") and also the way gauge was little bit stiffier to move than normally and its now giving small tapped noise even warm engine. Thats why i thought that maybe 0,10mm inlet and 0,15mm exhaust could be good? I have gauges range of 0,01mm (.0004") so if 0,10 and 0,15 is too small maybe i could cut it half and put inlet 0,12-0,13 and exhaust 0,17-0,18.

-Kuusisto

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Re: Norton Dominator 99 problem?

Postby Bernhard » Thu Jul 27, 2017 7:52 am

Re; “The thing that makes me wonder is that i have understood that the return line is reduces little bit after the rocker feed banjo, making the oil go easier to rockers. And i am not sure if the breather hose has any valves in it or not, but i am afraid that because of the reduction in return line, scavenge pump would also pump oil wrong way to breather hose back to engine.”
The later Atlas has a timed breather at the end of the camshaft, which is useless info for you here, this went into the tower on the top of the oil tank, so have you got the earlier oil tank without the tower on the top of it :?:

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Re: Norton Dominator 99 problem?

Postby KuusistoNorton » Thu Jul 27, 2017 8:26 am

Bernhard wrote:Re; “The thing that makes me wonder is that i have understood that the return line is reduces little bit after the rocker feed banjo, making the oil go easier to rockers. And i am not sure if the breather hose has any valves in it or not, but i am afraid that because of the reduction in return line, scavenge pump would also pump oil wrong way to breather hose back to engine.”
The later Atlas has a timed breather at the end of the camshaft, which is useless info for you here, this went into the tower on the top of the oil tank, so have you got the earlier oil tank without the tower on the top of it :?:


I dont know if the tank is original or not, i didnt get anything with the bike when i bought it.

And since i bought it only two weeks ago, i havent actually done anything crusal to it.

I'll add pictures from the oil tank.

Should 99 dommie have timed breather? If it should is there possibility check it out without dissassemblying the engine? Like if i try to blow through the breather should there be only one or few spots that let air go through?(blowing in to the hose and rotating engine by alternator nut, without spark plugs).
This because i dont know if its removed.


Image
Oil tank front side

Image
Oil tank top

Image
Oil tank backside

By the way, what is that big bolt/nut with square stub? Since bottom right bolt is drain bolt and in the bottom left you can see what i think is oil tank breather?

-Kuusisto

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Re: Norton Dominator 99 problem?

Postby Bernhard » Sat Jul 29, 2017 3:14 am

Re “Should 99 dommie have timed breather?” – No, this only came with the 750 engine.
You have earlier oil tank without tower.
The problem you have is the engine breather pipe is connected directly to the oil engine oil return pipe- which has gears twice the whit of the feed gears. Your engine breather is not doing anything, but being fed via the oil return pipe. I suggest you remove the pipe from the back of the crankcase and direct it to a bottle to see if much comes out other than an oil mist. At the oil tank have one pipe on the return side. ( and one for the feed side.)
Re; “By the way, what is that big bolt/nut with square stub?” not seen this before, it looks like a homemade mod GOK

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Re: Norton Dominator 99 problem?

Postby chris plant » Sat Jul 29, 2017 3:43 am

the 99 dommie should have a timed breather chris
the older i get the faster i was

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Re: Norton Dominator 99 problem?

Postby Triton Thrasher » Sat Jul 29, 2017 4:03 am

You're up against it when a previous owner makes modifications as daft as plumbing the breather into the rocker feed.

The crankcase must have been breathing into the oil tank, via the scavenge line. The oil tank would need a fairly big outlet somewhere, to let the pressure and fumes out. I can't see one.

It would contaminate the oil quicker than normal too, quite possibly restrict the scavenge sometimes and make oil frothing in the tank worse.
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