cold starting system V50

Strange - utter strange…
After I fabricated new manifolds & moved my carburetors out (positioned now like at a Le Mans) I binned the lever & cabling of the Cold start system - just leaving the small bronze “pistons” together with their springs - carefully making the cable holes airtight!
Because some while ago, I started the motor in about 6 degrees Celsius, using the Cold start mechanism - and start it certainly did - but, instantly “running rich”!
That made me think.
Because I want the bike to be comparably “uncluttered” as much as possible - so why not try to un-install the system?
So, this morning, it was 3 degrees below the freezing point - really shivering Cold…
Would the starter motor turn the thing - would it start without “choker”?
Absolutely - it sprang in movement almost instantly - and just after a couple of minutes, it settled Down to a firm idle at 1100 revs!
As this motorcycle exclusively will be used in the summertime, I ask WHY on earth this cold start system were incorporated from the Factory in the first place??
My motor is surprisingly easy to start - and I simply cant imagine I ever will need it in the warmer months.
Has any of you V50 owners same experience - or some explanation?

PS. a fairly short drive, made me smile from ear to ear!
The motor is VERY responsive, and also much more powerfull than expected - very brisk acceleration, with no “weak spots” - just a seamless stream of power.
And - best of all, the peculiar “coupled braking system” Works a treat!
Good.lasse2014-01-13 16:39:17

well it gets cold in Mandello Del Lario it near the mountains
in other countries its essential
maybe your mixture is too rich ?

Firstly check that the neoprene insert at the bottom of the brass plungers is not chewed up and looks as if it is seating properly. Any leak here and the mixture will be rich.The needle jets in the carburettor body wear oval with the movement of the needle through them. This also gives a rich mixture.On my V50 I didn’t need the cold start system at all, until I replaced both needle (atomizer) jets.

What Brian said, the seals on the bottoms of the plungers cease working can be a common problem, then you get petrol leaking in from the starter jet(s) then it’s always rich. Generally if it’s working properly then yes bike is running rich almost as soon as it starts, this is why having a variable choke control rather than the ‘on-off switch’ type lever is better IMO. You may need to examine the plugs to check if your carburation is correct. (?) As Raphael suggests maybe it’s on the rich side? Appendix (edit) - note the starter jets include an atomizer tube to mix the fuel with air supplied via an external vent hole and passage, the tiny holes of the atomizer are easily blocked by gunk dropping out of modern fuel when it dries out (brown or green ‘varnish’ or ‘deposits’ aka, crap) it’s very important therefore that these are clear else starter system will be too rich making motor actually more difficult to start. This is in addition to same crap constricting jet hole sizes (I’ve mentioned this before) HTH
Mike H2014-01-14 12:33:52

Thank folks - fortunately the neopren “bungs” under the brass “pistons” are like new!
Also, the Cold starting jets and atomizers are very clean & unrestricted (ultrasonic cleaned)
The reason for the instant starting & good running, are deliberatly created by me…
Why, and how?
I am running almost completely open carbs, on short stub manifolds, in combination with a very “open” exhausts system - & that alone calls for a 10 to 15% richer mixture - at the same time, I am forced to use modern 95 octane fuel - burning hotter than the fuel used in 1979.
So also to protect the valves, I run the motor quite rich, as I am not aiming at a very good economy and mileage!
I use NGK Iridium plugs, with good results here, as on my other bikes.
The V50 were somewhat “restricted” from factory - and were marketed partly on its very good fuel economy - while the motor wasnt too powerfull compared to other 500cc competition.
So, I guess I found a couple of extra Bhp by doing what I did - at The same time “protecting” the motor & valves from beeing overly hot.
But, in the beginning of this “recreation” I have been extremely Lucky, because the bike just covered guaranteed 16.000 miles - and had stood redundant in more than 20 years in a protected garage.
Everything is virtually “as new” - and thats why I snapped it up, whwn it finally became available!

Sorry, I forgot to tell I had raised the needles one step, and are now using mainjets 12% larger than standard.

Oh well it’s probably too rich then. What is the spark plug colour. Should be pale grey (loose black soot is allowed that wipes off easily with a finger, but mustn’t be a hard deposit). You usually need a very very good reason to change the position of a needle from standard setting, as it is the NUMBER of the needle that is chosen to match a particular application.

Remember the unleaded does often leave different deposits to what we have all come to expect…

Hi Mike - yes the number…
But I am from those ancient times, where we used to grind the needles around the mid - to get over “blind-spots” (mostly on two-strokes) - and because I tend to use the throttle mostly in the fully open position, it makes sense to raise the needle one step…
Never be afraid to experiment!

My plugs were just grey-light-brownish, & dry - but the motor never really became throughly hot, because of the very Cold day.
So, we will see…

Yes I wonder if your jets have got constricted with crud, making the holes smaller. Guess how I know       I tend to find the factory settings are nominal. Them having worked it out first. Otherwise there's a possible prob...      Last year put bike back on the road after a long abstinence, initially kept popping and banging, even needed a bit of choke to keep it going smoothly. Changed main jets, mostly sorted that out but still not right. On a whim changed all the jets, ALL were affected, every hole had been made smaller by hardened deposits. Carb cleaner hadn't touched it. Trouble is of course you can't really tell without new jets to compare with, then the amount of constriction may be glaringly obvious.     I didn't start messing with the needles 'cause I knew it worked perfectly alright before, so must be something else. Just sayin'.    HTH 

Mike H2014-01-16 12:31:01

new main jets - the rest ultrasonic cleaned - carb. cleaner than from factory…

Oo I dunno { sucks through teeth } that stuff is pretty tenacious, I had to stuff copper wire up the jets to get it out. It literally had to be scraped out. That was just an experiment, I better trusted the new jets. EDIT: when I say new jets I had to change them all, new mains on their own wasn’t enough. EDIT #2: cos can’t type (combination of laptop keyboard and bifocals)

Mike H2014-01-16 16:57:57

Does there have to be problem here?
Maybe Lasse has got the bike set up OK
Have fun

If you have raised the needles by one notch, just make sure that the jets they run in are not physically worn, mine were clearly oval.

Mine clearly circular…
(and, Thank you Guzzibrat!)