Sir dan im definite the smell is coming from the exaust, doesnt smell like fresh gasoline.  Im just not sure if its burnt oil or gas.   
I may need to install a catalytic converter on my mini, but im worried that it will slow down my already slow mini.   

Smoke from exhaust pipe:
The exhaust from a car engine should be clear and colourless. If the engine and exhaust are cold, you may see a mall amount of water vapour (steam) - water is a big by-product of combustion. In cold weather, the steam will take longer to dissipate in air.
If the engine and exhaust are warmed up, but you still see a pale whitish exhaust, suspect that water is getting into the combustion chamber.
If you see a greyish, grey-brown or black smoke, suspect a rich mixture or other reason for incomplete combustion. Check also for the scent of unburnt fuel in the exhaust smoke.
Bluish smoke indicates oil is getting into the combustion chamber but is not being burnt up. Check for an oily film on the back of the car.

There are many possibilities.
First, you need to confirm what kind of fumes - exhaust (products of combustion), smoke from the wrong things burning (oil, additives, something touching something hot, brakes etc.) or raw gas either coming out the exhaust pipe or leaking out of the fuel tank, anywhere along the fuel line, or even at the carb or the fuel bowl overflow.
One reason you experience the problem around 40mph is aerodynamics. Mini car bodies are not anywhere close to airtight - the have many openings. When you drive forward, the boxy shape of the Mini creates low pressure areas at the sides of the car, especially at the sides of the windscreen. If your door seals leak, or your door windows are open, these low pressure areas suck air out of the car. This means replacement air gets pulled in through the holes.. through the firewall, through the floors and sills (via the companion boxes), from the boot through the rear bulkhead, and through the back of the car.
As you drive along, there is a big low pressure area behind any car, easily seen on a dusty road by the dust cloud behind the car. The Mini, being boxy, creates a good low pressure area for its size. This happens to be where the end off the exhaust pipe is, so above 40mph, you are making more exhaust AND the low pressure cells that collect exhaust and suck it forward through the car. Centre exhaust pipes and incorrectly-sized exhaust systems make it worse.
From previous posts we know you have experimented with the intake system leading to your carb. When you made changes, you affected how the carb functions, making the main jet needle less than ideal for your car. Since you need choke at certain times indicates it runs lean at those times. However, at other engine speeds it may be running rich, lean or something in between. Just changing an air filter brand can affect the carb, Changes to the exhaust system can also actually affect intake and combustion.

Start by determining what fumes you get and where the come from. Eliminate the obvious things like a leaky gas tank. You should not drive the car unless the tank is safe enough to fill right up to the lip of the filler neck without leaking or fumes in the boot. Then check your exhaust system for leaks or restrictions. Too much back pressure forces exhaust out the joints. Too little back pressure affects the engine performance. Make sure your crankcase vent hoses are connected to your intake system so those fumes get burnt and aren't leaking through the firewall.

Sir Dan,,, question:  i have been smelling fumes inside my mini, especially at 30-40mph  , my mini doesn't smoke. my question is am i smelling burnt gas because it's rich? or is it burnt oil? how do you distinguish the two smell if it's oil or gas? considering the fact that my mini doesn't smoke and the compression on all chambers were around 165psi.

ps: when i accelerate from stop, the car struggles a bit but when i pull the choke a bit while stepping on the gas the car pulls strong.

What i hate about rebuilding a car is that, yes i will take all the parts out of the car, then scrape the body to metal, patch the holes,repair the rusty panels, bondo the uneven surfaces , take the engine out, repair all the leaking parts, pistons ,valves etc. you spend thousands, maybe 3k on repair and hundreds of hours in labor and the cost of the car is maybe 8K so total of 11K....THEN you go to craigslist or ebay or mm mini for sale  only to see that there are mini for sale for $5 or $8K  fully restored...i'l be like,,really???? that's why what i did on my mini was just to patch the holes, weld sheets of metals over it, i did not really make it look nice, anyway the floor is hidden underneath the carpet,what's the use of making it nice, as long as it's rigid and intact, im ok with it.
But yah, some people would say fixing the car is fun and  "priceless"...  well hmm i agree

Santa Claus will never grant your wish sir don, because he knows that the person who you refer to as troll is a humble , honest , simple down to earth Asian guy who is a legitimate owner of a 1977 Leyland  mini special  and who only wants to enjoy his mini and the mini community here in minimania... But if you prohibit asians to join this group THEN that is another issue.






https://youtu.be/4j9r96WJGw0

hi guys, as you all know, this thread has been made due to several reasons: mainly to  Criticize and /or Praise a member for his build, creation, upgrade and ingenuity ,originality all with regards to the mini. or just make a friendly comment about anything that pertains to mini and mini owner.

lately while i was browsing this forum, something really caught my attention, someone is actually in  the process of re-building his mini from the ground up, and i saw one picture that really interests me and actually got me impressed of the owners ingenuity and quick thinking. the owner did not put a caption but as i look at the picture Obviously what he was trying to imply is that If you are trying to pull the engine out of the mini and you don't have an engine hoist, what he did was to cut the front part of the mini so he can easily pull the engine out... I'm so impressed, very clever. i like the concept it's "priceless"

here i took a picture of it, in case someone else is in the same situation.

Priceless..................

this is the very reason why i DO NOT fill my gas tank past the sending unit. or even close to the sending unit, because if you notice the sending unit has some kind of an arm that sways back and forth to facilitate the up and down of the gas gauge,  the up and down motion can create a really tiny spark which is very dangerous. and also the static electricity is another source of spark.  the two wires that attaches to the back of the sending unit(outside the tank) is a positive and a negative wire which are the 2 main ingredients to produce a shortage. That is why every time i go out for a joyride i only put $2 worth of gas and just refill if need more.

Ok... I promise i'll try contain my comments in my thread.   But do not attempt to contradict my opinion here in my thread. ... Deal? 

Dan, for all the good you're doing here you might as well go outside, face into the wind and take a big p*ss.
We'll all see what you've done, but at least you'll get a warm feeling as your efforts are blown back onto you.

*IF* we can all try and ignore the sanctioned lunacy of this troubled individual, he might keep his brand of bullcrap to this thread alone - we know he won't go away but at least some threads may be saved...

Wrong again! Mur was not saying Malcolm was not savvy.

savvy: Shrewd and knowledgeable; having common sense and good judgement; well informed or experienced in a particular domain.

I think I've got his, Bill...

Wrong Again. BC (aka thewerewolf) is not just a dealer. He knows a lot about Minis (among many other vehicles) and as far as I know does his own mechanical work. he is also very knowledgeable about the intricacies of importing, exporting and legally registering vehicles.

To all newbies, like me...if you have issues with your classic minis there are a lot of good guys here who can really help you with your problem, big or small. You can rely on Dan,jemal,jeg,malsal, miniman and alex(of course i'll pick alex over bill anyday) and many others but pls avoid some who are only good in buying and selling minis and catalina mokes, that guy does not wrench at all., he doesn't even know what an allen wrench is ,lol... have you heard of the song a "wolf in a sheep's clothing" ????

Mur is calling sir Malcolm a "not so savvy folks"... I wonder what savvy meant. ... The word is too slang for asians  like me... 

oh, ok now i understand sir Paul, thanks... who am i to argue with a guy who has 45yrs mechanic experience, i always look up to you, and sir mal and sir dan, i'm here to learn. i am just a lowly "fabricator" i maybe not be a government certified fabricator or any certification giving body, much less have sold close a billion in auction asset as jrscott pointed out in his post. but sure enough i know my stuff. Maybe jrscott hasn't seen my old post, and he hasn't realized that replying to my post is just a waste of time, but i wanna thank jrscott for spending time to write 2 long paragraph alotted only for me.

Sir jrscott, pls give my regards to Wayne Carini

Maybe ... just MAYBE... you should actually read the original post. Note the year and model. Not a Classic Mini at all, so it will have lots of control arms in the rear suspension.

If it "holds" that suggests that it does not allow it to Move at all? If it "controls" that suggests movement in a controlled manner. suspension arms hold the hubs, "control" arms keep them in the correct location. Got it now?

Sir paul, my answer is suspension arm.

an arm that holds,,not an arm that controls..

So in your world what stops the rear suspension from moving side to side or back and forth?.........................