Topic: Won't cold start w/o extreme idle adjustment.

[D-Ral]

Turned the air screws in a 1/4 turn, works much better now. Was able to idle sans throttle super quick.

[Clasico]

There are two types of choke/throttle arrangements that Honda bikes employed on various models.  Most of the early models had a choke that was not connected to the throttle, and its application simply restricted the air intake.  The second/later type of design also advanced the throttle slightly as more of the choke was applied.

In the first design, with a cold engine the choke is applied and the throttle opened about 1/8 to 1/4 turn and HELD (not twisted or pumped) while the starter is engaged or the kick starter applied.  Holding the throttle steady at this setting, the choke can slowly be disengaged in stages while the engine warms up.  When the choke is disengaged a bit, the engine speed will likely increase and some of the initial throttle setting can be relaxed.  Also as the engine warms up, some gentle blipping of the throttle can be performed to see if the motor is ready for less choke.  If really cold, after starting the throttle can be raised while running to promote a higher idle and faster warm-up.  Eventually the motor should warm up sufficiently to have the choke and throttle completely off, a smooth idle speed present, and an even response to gentle blipping of the throttle up to 1/2 open.  Experienced riders can speed the warm-up process by riding off with the choke still on, carefully riding the throttle while minding the choke, and thereby loading-up the motor.

The second/later design of choke advances the throttle with its application.  How much advancement and when it is fully released are usually parameters that can be tuned or adjusted at set-up.  When starting with this design of choke, the throttle does NOT need to be touched (or held open) when starting.  If it does, then it is either very cold or more likely the throttle advancement mechanism needs adjusting.  With a cold motor, once started and running with full choke, the choke can be relaxed in stages and the engine speed should decrease.  A sign that the choke is ready to be released some is when the engine speed climbs to a higher level (e.g. 4,000rpm).  Again, the warm-up period can be reduced if gentle riding is performed while some of the choke is still on.

Either design works properly only when everything is correctly adjusted - e.g. idle speed, mixture, timing.  Using the choke for starting-up is usually needed for a cold engine, but sometimes also briefly needed when still warm.  Get to know your motor, how it responds, and what it needs to start.

Sorry to open up and oldish thread but i just want to make sure which choke type a 500 k1 has. I guess is the first type you mentioned and therefore the best thing on cold starting is to hold the throtle open 1/8 and closing the choke when pushing the starter, right?

[HondanutRider]

There are two types of choke/throttle arrangements that Honda bikes employed on various models.  Most of the early models had a choke that was not connected to the throttle, and its application simply restricted the air intake.  The second/later type of design also advanced the throttle slightly as more of the choke was applied.

In the first design, with a cold engine the choke is applied and the throttle opened about 1/8 to 1/4 turn and HELD (not twisted or pumped) while the starter is engaged or the kick starter applied.  Holding the throttle steady at this setting, the choke can slowly be disengaged in stages while the engine warms up.  When the choke is disengaged a bit, the engine speed will likely increase and some of the initial throttle setting can be relaxed.  Also as the engine warms up, some gentle blipping of the throttle can be performed to see if the motor is ready for less choke.  If really cold, after starting the throttle can be raised while running to promote a higher idle and faster warm-up.  Eventually the motor should warm up sufficiently to have the choke and throttle completely off, a smooth idle speed present, and an even response to gentle blipping of the throttle up to 1/2 open.  Experienced riders can speed the warm-up process by riding off with the choke still on, carefully riding the throttle while minding the choke, and thereby loading-up the motor.

The second/later design of choke advances the throttle with its application.  How much advancement and when it is fully released are usually parameters that can be tuned or adjusted at set-up.  When starting with this design of choke, the throttle does NOT need to be touched (or held open) when starting.  If it does, then it is either very cold or more likely the throttle advancement mechanism needs adjusting.  With a cold motor, once started and running with full choke, the choke can be relaxed in stages and the engine speed should decrease.  A sign that the choke is ready to be released some is when the engine speed climbs to a higher level (e.g. 4,000rpm).  Again, the warm-up period can be reduced if gentle riding is performed while some of the choke is still on.

Either design works properly only when everything is correctly adjusted - e.g. idle speed, mixture, timing.  Using the choke for starting-up is usually needed for a cold engine, but sometimes also briefly needed when still warm.  Get to know your motor, how it responds, and what it needs to start.

Sorry to open up and oldish thread but i just want to make sure which choke type a 500 k1 has. I guess is the first type you mentioned and therefore the best thing on cold starting is to hold the throtle open 1/8 and closing the choke when pushing the starter, right?

Check your manual.  I'm not familiar with the 500 Four, so maybe someone else who is can chime in, but on my 1974 350 Four it has a linked choke/throttle arrangement.

[Clasico]

I went for the second ride on the bike today.
This time everything has worked fine. It started first time, got reasonable warm after a couple of minutes holding the dialed 1400 rpm thereafter. Still the gears are a bit hard to engage but i've been able to engage neutral when desired!.

Maybe the first time i didnt do the start procedure quite right and the rpm were to high later on, hence the difficulty in selecting neutral.

I'm sticking to
-open gas tab
- close air
- 1/8 of gas on starting
- open air as it starts
- then keep around 2k rpm with the throtle till it warms (it also helps to reduce cam/primary noise)
- then drive cautiously (max 4k) till it gets fully warmed

[TwoTired]

A dragging clutch will cause gear selection issues.  And, I urge you to address that hastily.  The extra pressure required for gear change is hard on the shifter components and fork sliders and causes accelerated wear.  It's an engine out and split lower cases to repair/ replace those components.  The clutch and it's actuator can be mended while the engine sits in the frame.

There are many posts about correcting dodgy CB500 clutch and shifter ills.  One discussion includes the shifter rod breakage, which I feel is mandatory to inspect on every CB500 with unknown history.


The choke can be modulated during start and warm up to select just what is needed so no stationary run time is needed to drive about.  The extra power needed to move bike and rider actually reduces warm up time.  Just don't ask for max power until the engine and oil have warmed up.  Driving off with some choke on is routine, and reaching down to nudge the choke lever closer to off is very easy to do for the few block it is needed.
The CB500 does not have a fast idle linkage connected to the choke mechanism.  Fast idle during warm up is the responsibility of the rider on the twist grip.  This is another reason why a stationary warm up is unnecessary.

The advice here assume a bike with stock induction and exhaust components.  Changes to these can severely alter starting and run operation requirements.  The stock bike was pretty operator friendly.  Modifications and wear defects can easily change that.

[Mo]

So quick question. If you keep the revs up with the throttle, doesn't this interfere with your clutch operation? I've always learned you are supposed to roll on the throttle as you ease of the clutch.

[TwoTired]

So quick question. If you keep the revs up with the throttle, doesn't this interfere with your clutch operation? I've always learned you are supposed to roll on the throttle as you ease of the clutch.

I'm not sure I understand your question.  But, revs don't have any effect on clutch operation/actuation.  You can feather the clutch at any RPM.  In fact, watch a drag racer abuse the clutch at the starting line.  High Revs (in the max power band) and feather the clutch to couple max power to the rear wheel without breaking rear wheel traction.  Is it hard on the clutch?  Yes.  Drag racing is hard on the whole machine.  But, you are allowed to rebuild the machine every 1/4 miles. 

[Bankerdanny]

If the clutch is properly adjusted the higher revs won't matter. It is dragging a bit though then the higher rev's will have an impact on shifting since the extra force exerted by the engine will be transfered to the transmission components.

[Mo]

Ahh I see. I guess I was just referring to how you're supposed to throttle as releasing the clutch. The question made more sense in my head. Forget it :p