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CB750 engine speeding up

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neat street:
Rubbers are correct, only changed due to old ones being a little hard. seems strange as to the running as she runs well and picks up as she should, just the annoying speed `pick up`? checked cables and all seems to be in tolerance.
thanks again for your reply`s

K2-K6:
Just thinking this one through,  has it always been like this or has it changed to this status?

Reality check for me,  you can only set the main tickover screw to idle at correct rpm when this engine is warm. It has no throttle lift when cold starting and taking it off choke will need you to keep it running by operation of the throttle until it reaches normal temperature. 

If you adjust the main tickover screw with choke off and motor not warmed you will create the described symptoms.  It's just very manual on this era of bikes.

neat street:
Hi, thanks again for your reply
 it has been like this since the rebuild, if you set the speed when hot, (after a 10-15min ride) at 1500rpm, when you then try to start up from cold, it will not run (with choke on/or off), increase idle screw so it will tick over, but then when nice and warm (15mins) it then increases revs? not sure if it could be a jet issue??? plugs good colour though. don't know how it ran before rebuild, as was not running too good then

K2-K6:
See what others on here think if an F1 owner would look in and give opinion.

It sounds normal to me,  the error is being included when you adjust the idle speed without it being warm to operating temperature.

It really has no compensation for cold running,  you just have to modulate it yourself with the throttle / twistgrip until it'll tickover without interference. It will just stop otherwise.

Just set it as you want for rpm when it's warmed up and leave the adjustment alone,  that's how they work.

Some of the earlier twistgrip (K series) have a friction screw underside of handlebar,  you could tighten this so throttle would stay where you put it, could be used for warm up.  Don't know if it's fitted to your model.

Spitfire:
My F1 is fine, standard set up, jets, filter etc. To start, full choke, start up, set off, take choke off immediately and that's it, but it will not tick over cold though, you have to rev it.

Cheers

Dennis

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