Topic: Cold Start

[simo]

Hi

My CB750 k2 is a pig to start when cold, fitted new plugs,points,condensers, balanced the carbs, set float heights, and re-set timing, once running it runs great and starts a first touch of the button once warm even after it's been stood a couple of hours, but if left a few days it takes a while to get it started.

Any ideas

Simo

[SteveD CB500F]

Is the choke operating properly?  It should close the butterfly valves.

Also, when it eventually starts do all 4 chime in together or just one or two (or three). My 500 does this after standing for a while. I think it has to do with one of the carbs leaking.

[stevej]

I would definatly check that your choke is connected,when I bought my K3 550 it too was a pig to get started from cold,soon found the cable had popped out of its carb. bracket.If I leave petrol in my carb. for a period of time say 3months my bike seems to run roughly when started again , I figured it was stale fuel or deposits,so I always turn the fuel tap off a mile from home this gets my bike home and empties the carbs Bike starts/runs fine even months later.

[cadler]

What octane gas are you running?
I was using  94 in my bike and it had a terrible time starting under 40F.
I used a hair dryer and a kerosene heater in my garage to get the thing up to a reasonable temp.
When I went to 89oct. the thing starts in 3 tries with low temps.

What octane gas does eveyone else use?

[Bob Wessner]

That would be one of the symptoms of using too high an octane fuel. Use regular, 87 octane.

[GeoffT]

I think I have a choice of Unleaded or ......   unleaded

[simo]

That would be one of the symptoms of using too high an octane fuel. Use regular, 87 octane.
[/quote

Thanks for the reply, I use standard unleaded, I've been told to retard the timming slightly and may be drop the needles one notch, any thoughts?

Simo

[Lumbee]

...simo this def. sounds like a choke problem/setting.  I was having the same problem with a set of carbs and the problem was the choke idle setting.  This was on a set of 78 carbs, so I'm not sure how its done on the older carbs.  Someone chime in here...is there a way to set the choke idle on the older carbs?

[eldar]

I am not sure if the earlier bikes even had a choke. I get the idea from some here, that there was no choke on 76 and earlier. but i am not sure.

[Gordon]

I am not sure if the earlier bikes even had a choke. I get the idea from some here, that there was no choke on 76 and earlier. but i am not sure.

All the models have a choke, it's the choke fast idle actuator that the earlier ones don't have.  You either have to hold the throttle open manually or turn the idle adjusting screw in for the first few minutes.

[eldar]

OK thats what it was. Icould not remember for sure.

[dusterdude]

pull the choke,start the bike and set the throttle where you want it and then use the knob on the grip to lock it in place

[SteveD CB500F]

then use the knob on the grip to lock it in place

Interesting.

Not the first time I've heard someone mention this?

I don't have a "knob on the grip" - is this supposed to fix the throttle at a certain position?  What models was it fitted on?

[dusterdude]

steve,my 750 has it,i thought all bikes after about 1970 had em.

[TwoTired]

My 72 CB500 has the friction knob under the throttle grip.  So does my 74 CB550.  These do NOT appear on the 75-78 CB550K or F models.
Mine are US model bikes.

Cheers,

[SteveD CB500F]

Well... I've just got home from work and checked my 500.

I've got one too!  Bloody great knurled knob under the throttle housing.  Howcome I missed it all these years... 

[ProTeal55]

Us in the American V-Twin world call that knob " POOR MAN'S CRUISE CONTROL" 

As for starting my bike , I have noticed that it was harder to start when i was running higher
octane fuel in it, rather than the 87 I now run. I always open the choke, get the bike started ,
and raise the idle so it can get good and warm. As the bike warms I lower the idel back to
normal and go from there...

Gotta love these cold-blodded bikes.......

[apormarkos]

Of course I buy the model which does NOT have this useful gizmo 

[TwoTired]

Of course I buy the model which does NOT have this useful gizmo 

As I said my 74 CB550 has the friction adjust.  I got this bike wrecked in 75.  The PO removed the throttle return spring so the friction lock behave as a "cruise control".  He told me this while hobbling around the garage with his cane after a lengthy hospital stay and negotiating a sale price of the bike.  The "story" was that he fell asleep while cruising up the freeway in the mountains towards Lake Tahoe.  The lack of directional input allowed the bike to stray from the highway.  The bike hit a large boulder whereupon the front wheel pitched up sharply causing the instruments to engage the faceshield and knock him off the bike.   When the rear wheel hit the boulder, the entire bike launched some unknown but impressive distance skyward.  The bike's decent was likely arrested by the rear wheel, as the rim was bent sharply inward to within 1/2 inch of the brake hub.  Then it fell backwards mashing the rear fender, seat, tank, gauges, bars, etc., finally coming to rest on the side smashing pipes, turn sigs, and various levers.  He had engine guards, which were badly scraped and bent, but the engine (1500 miles) was completely unscathed.
Anyway, he said that his back and leg wouldn't be bike worthy for many months, and we struck a bargain.
I repaired the bike to road worthy and bought a spring at the hardware store for the throttle return.  
At $0.75, I think it was the cheapest part I bought for the bike.  And, I very rarely use that throttle friction knob... and only while parked.

[Bob Wessner]

Hmm, a lot of detail there for an event that probably had a total elapsed time of 2 sec.  Hence the quotes around story I presume.

[TwoTired]

Well, I can only attest to all the impact damage I fixed on the bike.  It's amazing how compact a "ball" the bike can be bashed into.
The PO was supposedly unconscious thoughout the whole ordeal.  The accident report from the officer had the crash details, which the PO related to me.  Maybe he was going for a sympathy bonus in the negotiated price?  He was not in good shape and may have still been on pain killers.  But, seeing him and the bike side by side, left an indelible impression.

He was still bragging about his "cruise control" modification, though.  There are some aspects of history I strive not to repeat.  Cruise controls on bikes give me sympathy pains.

[dusterdude]

tt,i gotta say man,you`re looking much better these days

[TwoTired]

Well you did say you wanted more color in the cheeks.

[cbjunkie]

is that the same dude? he does look familiar, and better...where did he come from?

[TwoTired]

is that the same dude? he does look familiar, and better...where did he come from?

Yep same one,  Barbosa.