A massive vacuum leak could also cause similar problems, I guess. Maybe some hose or boot has a hole that only opens up when compressed maybe...?

It's a weird problem. Hopefully you get the old girl running right

 

Gronkfries, Tentacleslap and others - I've just solved that goddamn bump/misfire/power loss problem and it's a cracker.....I remember the previous owner had installed a datatool alarm and then had problems with it and took it off again over 25 years ago. After some of you (especially tentacleslap) insisted it must be an electrical problem I went through the electrical system thoroughly to check it. I saw some rather odd looking white insulating tape wrapped around the loom in the vicinity of the ignition control unit. I untaped it and found a screw down connector used for wiring houses (we call them dominoes in UK) holding 2 wires together and when I tugged lightly at it it fell apart. It was where the previous owner had taken out the alarm and bodged the repair to the wire which kept coming apart each time a bump jolted it. Properly soldered, it works a treat and now I can drive over as many bloody bumps/holes as I like without cutting out or misfiring. Can't be too many examples like that one???? Or can there? I'll update another thread I contributed to with this news for anyone who has subscribed to that one just to demonstrate that this forum's expertise really does help. Thanks so much for insisting it must be electrical 'cos I was almost ready to risk stripping the threads on the carb screws again!

 

Well done!

 

Yes, way to be persistent! Glad you got it solved. You can mail tentacleslap his ten bucks now...

 

Right on!

Let me just say, brightly colored electrical tape is awesome stuff. If I'm forced to hack something, I always wrap bright red tape over the splice. That way, I know where to start when it stops working

 

Only $10? Labour rates over that side of the pond really are cheap! I've just been looking at some of tentacleslaps' vids on youtube... It makes you realise what experience some of the folks on these forums (fora) have. Unfortunately, I'm thinking my own "problem" described in this thread is not yet fully at an end since I've now noticed some "rough running at low revs/idle" that was probably hidden by the other (now resolved) issue, but before posting for more help (yet again) I'll gather some running "experience" to help me better describe the symptoms. Until my next posting for help............thanks for the great advice so far!

 

Folks,

since my last post I've fitted a fuel filter as I had to disassemble the carbs again due to another idle jet related problem. The filter seems to be working well (at least for the 5 miles I've driven so far). Getting the bike (temporarily) back on the road has made me discover what appears to be a "new" problem - sighs. If I open up the throttle and release it again and then immediately pull the clutch, the revs increase as if the throttle is still held open. This can last a few seconds. The same happens when changing gear. It's as if something holds the throttle open for a few seconds before it then re-closes itself. And it seems to get worse as the engine warms up. I've checked the lie of the throttle cable runs for any snags and I'm pretty sure that's not the problem. I did notice when cleaning the carbs (again) that one of the sliders was a bit "sticky" when rising and falling and now wonder whether that could be the problem. I did try gently cleaning the slider and carb body where the slider runs up/down but didn't want to go at it too hard in case of damaging something. Could it be a sticky slider or something else causing the symptoms? If I'm forced to remove the carbs a third time to tackle it, does anyone have a suggestion how best to remove the stickiness from the slider without wrecking the plastic of the slider or damaging the bore of the carb in the process? I'm thinking of setting a new world record time.......... for removing CBR1000F carbs.....

 

 

Rhondasoulsoothinghonda Please excuse the new depths to which my ignorance is plummeting but, "crc"? Is that some kind of Aussie thing?