My 1978 CBX 1000 Running cold on 1 and 6 Cylinders

[PAUL N]

Hi All
My CBX has just had an engine rebuild after a hydraluic lock issue.
The carbs have being balanced and all ecectrical components checked.
However the bike is running cold by about 40% on 1 and 6 cylinders when its warmed up and not running well.
Would appreciate some advice or feedback for my Mechanic who is puzzeled.?
Thank you
Paul Nicholson
Ireland

[banjobill08]

Hi Paul,
Welcome, sorry to hear about your issue, on the rebuild I assume the engine did not have a rebore or new rings fitted, valve clearances checked and compression is ok?
My next thing to check would be the coil as that fires on 1 and 6, then just by switching over the supply connections to another coil and see if the problem has moved to either 2 and 5 or 3 and 4?
Then may be the ignition pick ups and then coil igniters, all getting old and less reliable as they once were?
See how you get on.

Good luck.

[Jeff Bennetts]

what banjo said!

[PAUL N]

Hi Banjo
Many thanks for your reply I will pass this on to my mechanic and see what he says hopefully we can get to the bottom of it.
I will be back to you soon with an update if thats ok?
Also thank you Jeff.
Paul Nicholson Ireland

[512tr]

Agree what the others saying about the ignition, here is the ignition wiring showing the 3 separate units that giving spark to the 6 cylinders. Most likely it is the coil #1, but could also be the spark unit #1 or the 1-6 pulse generator....or just a wiring problem.

ign 1-6.png

[daves79x]

It is far more likely to be the spark unit. These are failing at a pretty good rate as they age. Easy to see if you have a known good one - just plug it in and try it - no need to ground/mount it.

Dave

[swarrans]

Paul, I had a long term poor running issue that I feared was carbs (cos I'm terrified of having to work on them!). It turned out to be a poor electrical connection in the ignition circuit. Might be worth checking and cleaning if you haven't already

Simon

[PAUL N]

Thanks Dave,Simon and 512tr
I will let you know how my Mechanic gets on.
Paul Nicholson
Ireland

[CBX-tras]

Ignitech eliminates the need for the spark units.

See my other post.