The International CBX Owners Association

Having just rebuilt my 1979 CBX 1000z replacing or renovating existing bits over last 5 years time came to start it.
Started at press of the button to my delight, let it tick over for a minute shut the choke and it sat and idled nice at 1000 rpm. Tried to rev it gently and it stopped, started it up again immediate on the button, tried to rev it again it stopped.
Checked all obvious things removed vac tap to make sure fuel wasn't getting starved put some clear fuel pipe on to see flow
It will sit and tick over, can increase with idle screw to 2500 rpm any more & it stops.
Carbs been rebuilt engine all fresh by a trusted engine mans help and sounds perfect when idling.
Please can anyone help me where to look or what to check to allow the bike to work normally
I have had the bike 6 X years but it hadn't run for 20 before that, only done 7000 original miles by 1 X owner so a worth renovation back to how it came from Honda
Many thanks to any answers I get

Will it rev if you put the choke on? If so, you have carb problems likely. If not, then check the timing, both static and at advance. If that's OK, might be worth a look at the cam timing again. You did install the cams correctly?

Dave

Yes cam timing correct, ignition timing correct, tried advance & retatd while running plus set it with strobe so m happy all that correct
Spray break cleaner across back of carbs & it revs
So stripped carbs again, changed float heights from 15.5 to 15 to allow bit more fuel, checked accelerator pump new seal Spring fitted, slightly better but still will not Rev. Wish I'd got a spare set of carbs as I'm sure it's this area

Also will the engine Rev with no airbox as cv carbs tempremental or would it make no difference

Thanks again

No surprise it's likely the carbs. You need to make sure that your vacuum pistons are perfectly free to rise and fall in the domes. These can become very sticky. Also make sure your carb bowls are filling and that your bowls are properly vented. I've seen a couple of sets of carbs that the PO installed solid hose pieces between ALL of the bowl vent nipples. There's something there to be found.

Dave

Yes everything free on top all are spotless and free.
Hoses are all new and vent is clear, also new accelerator pump fitted even though old one looked fine, still will not run as soon as throttle opens.
With engine off and operate throttle I can see fuel been injected by all 6 jets at back of carbs
Really cannot work this out it makes no sence

Millscbx wrote:Also will the engine Rev with no airbox as cv carbs tempremental or would it make no difference

Thanks again

I am not sure if I understand your question right, but if you do not have the airbox connected to the carbs, your engine will not run right. It will be "temperamental". The CV carbs need the proper intake vacuum for the slides to rise.

You have probably cured this problem by now but I had the exact same problem with my CBX550. I disconnected the airbox and away it went, the best it had ever run. I bought the bike as a non runner. The plugs were black before and after running. I had set the float heights at the max, i will bring them to the min and see what happens. haven't looked at it in a couple of months.

Good luck

Lindsay