Hard to Cold Start (2011)

Having real trouble cold starting my bike. Hot starting is one kick, cold starting is 20-40

'73 Mk2 850
Single Mikuni
Trispark ignition
Dyna twin outlet coil
NGK suppressed leads
Iridium plugs
K&N filter

Carb is brand new, supplied for the bike by reputable company. Everything else listed is new also.
Petrol tank cleaned and coated, fuel taps and lines also.
Wiring checked, earths cleaned, connections replaced or cleaned up.
Timing set 28 with strobe
Fuel flow good.
Runs fine when warm, as said starts first kick when warm.
Tappets checket and set- they were pretty close anyway.

Very hard to kick over, requires my full weight on the kickstarter with the bike on the sidestand and some times it just stops even when I am leaping up and fully putting everything into it. Weather is warm and sunny, not even cold.
Compression when cold is 60psi, left cylinder has slightly more than right, when warm it is 100psi maybe more but I can't easily kick it fast enough to get a decent result but both sides are even.
Enigne has reciepts for full rebuild and only has 400 odd miles but was rebuilt 4 years ago and not used since.
Why could it be so hard to kick over? The kickstarter is sometimes slipping because of the extreme force needed to turn it over

I'm only 76kg but a friend with a Combat has tried it and found it really hard as well.
When the bike is running you can feel decent compression comming out of the exhausts from about 3 metres behind it.

I really need some help on this please, it's killing my body

I should also add that I have read all the Mikuni, Trispark stuff on here using the search function.

Your not alone on this one Dodgy. My bike has a fresh top end & I haven't done a commpresion test but It's up there i'm sure. It starts on the first kick when warm and will cold to IF I have the leg power to give a good kick. The only thing I can think of for you is the battery may be low. I have a Boyer and what they say is true, if the battery is a little low like 10. Volts mine will kick back and if my head light is on it won't start. Full battery it starts first kick but that still doesn't answer the question as to why it's hard to kick. I just assumed my old bones don't have the youthfull mojo no more!

That bike should fire at 2 to 3 kicks max of even on the 1st kick cold or hot. People who hammer and hammer on that kicker (swooshdave) are really wasting their time and effort. If there is no sign of life after a few or so kicks and after proper priming, then stop and check for fuel and spark. Troubleshoot the obvious. Do not continue to persistantly drive that poor pawl into that poor first gear lay.

I agree with the battery concern from GTsun. Get in a dark location and look at the spark of the plugs carefully. It may not be a huge spark but it should be more then likely a thin clean blue spark. That battery has to be 12v +.

I'll be curious on others thoughts on this too - my bike is more troublesome in the cold, but by cold i'm talking in the 40's and it's usually 8-10 kicks (usually) - it also has a mikuni. I have found that typically the bike has wet sumped some (making it hard to kick start) - most confusing thing is my BSA A10 will start first kick in the 30's ever time - not sure if it has anything to do with it but i always suspected the amal on the BSA when primed dumps plenty of gas into the cylinders, but since the mikuni operates with a choke lever and no real priming type thing it has a harder time atomizing the fuel w/ condensation or lower temps or other such chemical-physical-voodoo properties

then again it could just be its a temperamental bitch at times (pun intended)

m

VM34 Mikuni? Check that it has a 40 Pilot jet and that the choke lever depresses the plunger. Without those functioning it will be a pain to start cold.

Mick

Check your primary chain tension, just for fun.

How does it kick over with the plugs out. That is to say, is it a compression thing or is something binding?
How cold is it? Isn't it summer down there?
With the Mikuni, I validate choke position, turn full throttle and push it through a couple times BEFORE turning on the key and then giving it a go.

My 750 will stop me solid too....if it is not willing to start. And I'm 185 lbs. When it wants to start, only the first compression is hard, and then with firing the rest goes on through almost like it's helping. Not everyone has the leg muscles to push it through all the compressions. I always had to get my weight all the way up, stand left leg on the left peg, get it just over compression and then give it the old 1-2 following through with a straight leg and my weight. I have seen fellows that have the strength to sit on the seat and use their leg muscle just to push it through. Not me.

It may be you are not getting enough fuel in it like my Amal's do, they really flood the carbs and that's what it takes cold.

You will get the routine down sooner or later.

Dave
69S

Hi Dodge

The Norton's are a high performance motor and that is why they had twin carbies, restrick it to just a single carb, is just taken the performance away, with cold starts they need that extra fuel, I have the twin Amals without chokes and it aways start first kick weather its hot or cold, but then I do run a Joe Hunt Maggie that throws out a big spark evey time, so make sure your battery is fully charged under load and it should start first or secon kick...

Ashley

Hey dodgy,... Binding up when cold ? I wonder if the breather is o.k. Or if the bike has a breather mod, could be it needs a clean up or a good check over. Could be it sticks when left sitting for a while... The Mikuni will need to be right, I have always liked them set up so the choke will kill the engine when it's hot... After a few kicks, the plugs should be quite wet, if they're not I think you are too lean...It's all good fun... After you have finished....AC.

The Mikuni is an odball when it comes to cold starting. The choke lever opens up a separate circuit with it's own fuel supply. It is defeated if the slide is opened any above idle. I've found that on my bike if I open the 'choke' and leave the throttle alone it will fire up. I then need to back off the choke and raise the slide till I have a nice warm up idle. After a few minutes I can lower the slide to normal. If I raised the slide with the screw before getting it started or opening the throttle some then it wouldn't start.
Has your girlfriend got a sister?

Addendum:
If your crankcase is full of straight weight oil you might be fighting that.
I've found that with the kick lever where it is on my bike it's at about 11 o'clock in relation to the gearbox when it engages. If I let it slip with the clutch to around 9 or 10 o'clock then then it's much easier to kick it over.

mIki carbs with their tiny enricher starting carb, are harder to kick over cold because ya can't crack the throttle to lower air resistance like ya can a tickled Amal or two. Norton lore says that if not needing choke to start cold then its tuned too rich for warm running. Cold oil is definitely harder to kick over.
Alcohol spiked gas is leaner burning so adjust richer to suit if using with that.

Should have also mentioned the battery is brand new. Pulled the plugs and they were wet. Tried draining the sump, still a nightmare to kick over.
The bike came with the Mikuni, it was not my choice. Twin carbs do not phase me in the least as all my other bikes have them, 2 of which have the banned by health and safety double pumper Dellortos. If I could afford to buy 2 Amals and the inlet manifolds and air cleaner, believe me I would.
I will try a few things mentioned, but my knee needs a rest first. Timing marks might not be correct either- don't have a degree wheel to check them. When warm and riding the engine will pop back out of both exhausts at around 3,500 then nothing- like no spark until I back of to about 2,500 and then it picks back up again. Today the main fuse blew, in fact every time I have ridden it something has caused me to breakdown.
I'm at that stage where I got home today and shoved it in the back of the shed and put a cover over it so I don't have to see it...

Will try some of the suggestions, maybe on the weekend. Body needs a rest.

You have thickened up the plot to again imply a lean condition, float level to clogged jet to needle clip. Double pumpers eh, oh my oh my got ya some right now response with that juicer.

Timing light and following instructions will lead ya astray - if - ya ain't nailed down the degree indicator by degree wheel, and even then only for future reference, after you have bumped up advance till slight back fire on starts, then backed off till just ain't. Then is when ya go measure and mark and take notes.

That hard starting when cold sounded like carb problems. This part sounds like it's electrical. Maybe give Steve a call?
http://www.trispark.com.au/

Dodgy said:

I will try a few things mentioned, but my knee needs a rest first. Timing marks might not be correct either- don't have a degree wheel to check them. When warm and riding the engine will pop back out of both exhausts at around 3,500 then nothing- like no spark until I back of to about 2,500 and then it picks back up again. Today the main fuse blew, in fact every time I have ridden it something has caused me to breakdown.

Click to expand...

There is a troubleshooting guide under the Installation section on the Trispark website if you have any doubts about the spark.

hobot said:

You have thickened up the plot to again imply a lean condition, float level to clogged jet to needle clip. Double pumpers eh, oh my oh my got ya some right now response with that juicer.

Timing light and following instructions will lead ya astray - if - ya ain't nailed down the degree indicator by degree wheel, and even then only for future reference, after you have bumped up advance till slight back fire on starts, then backed off till just ain't. Then is when ya go measure and mark and take notes.

Click to expand...

I suppose you are saying that with an unknown motor you have to go to first principles. Find TDC , fit the degree wheel, set the timing statically and then .....it all sounds a bit feelly touchy...
They say you should only change one thing at a time....but in this case its finding a starting point and going from there. I've ridden it prior to the new ignition and carb, was ok for the the first 20 -30 minutes although it did not have the crispness of the 750 Combat. Then it was hard to start and it seemed like you were kicking it to a resistance rather than the sparking cylinder assisisting. Then I noticed the bogging at over 2500 rpm and to me it didn't seem carb like as it would not stop when throttle was reduced...... as they say in London " doing my bleedin' head it was"

Dodgy,

73 Mk2 850
Single Mikuni
Trispark ignition
Dyna twin outlet coil
NGK suppressed leads
Iridium plugs
K&N filter

Click to expand...

Have the plugs got an R in the number ? if so they'll be resistive and as you've got suppressed leads that'll give double the resistance to the spark, very bad for cold starting.

Cash