Post by: neat street on September 03, 2019, 10:08:09 AM
my F1 on standard setup has a small niggling start-up running problem which your thoughts would be appreciated on. when starting (with choke) starts and runs on first touch, take choke off and ride, after 15 mins or so, the engine speeds up from 1500, to 2500, reduce tick over adjustment screw, and all is great as normal, but when stored and restart, you have to readjust the tick over screw again to gain revs to 1500 and start the same process again?
any ideas please?
thanks
John
Post by: K2-K6 on September 03, 2019, 02:49:13 PM
Reason behind this is that uncontrolled air effectively bypasses your carburettors to which you respond by making adjustments.
Are you confident that the rubber and clamps are in good order? Worth a close inspection to spot anything obvious.
Also, if you spray a small amount of carb cleaner onto the rubber carb mounts (don't do this inside a garage) if it changes by sucking that in and burning it then it would confirm a leak.
Post by: neat street on September 03, 2019, 09:17:22 PM
thanks
John
Post by: K2-K6 on September 03, 2019, 09:26:40 PM
Minimum amount of slack available in "pull" throttle cable? The manual specifies this measured at the twistgrip.
Post by: neat street on September 03, 2019, 10:30:23 PM
Post by: neat street on September 04, 2019, 09:21:37 AM
thanks again for your reply`s
Post by: K2-K6 on September 04, 2019, 09:54:33 AM
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.
Post by: neat street on September 04, 2019, 10:50:23 AM
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
Post by: K2-K6 on September 04, 2019, 11:21:05 AM
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.
Post by: Spitfire on September 04, 2019, 11:25:43 AM
Cheers
Dennis
Post by: Moorey on September 04, 2019, 11:46:53 AM
Post by: neat street on September 05, 2019, 08:34:29 AM
I will continue with what I do at present, just thought here would be an easy fix. I do the same as Dennis.
thank you all again
john
Post by: K2-K6 on September 05, 2019, 08:43:05 AM
The very next model F2 K7 they put a choke cable on for ease of use, along with different carbs that have a throttle lifting facility on operation of the choke.
These do the opposite to yours as the manual spec for "on choke" rpm is 2750 +/- 750 which alarms people as it sits there with elevated revs when cold. ;D
Post by: hairygit on September 05, 2019, 08:46:11 AM
thanks for our reply`sThat's exactly how bikes were even brand new back in the day. No fast idle on choke, it is the rider that keeps control of the idle speed with the throttle until the motor is properly warm. Older bikes like these can seem very odd if you didn't ride them back in the day and have only ridden modern stuff. The brakes on these old Honda's were some of the best in their time, but younger riders used to modern brakes find them terrifying!
I will continue with what I do at present, just thought here would be an easy fix. I do the same as Dennis.
thank you all again
john
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Post by: neat street on September 06, 2019, 09:14:26 AM