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#3 fires when it wants

4given

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Yes I have read on this forum
Yes I have googled other forums as well
Yes I have found similar topics

Ok
I have a 75 cb750 motor(told it belonged to John Soliday)
Dyna electric ignition, Accel coils/wires, Nkg plugs, 7A carbs,

So what's going on is
#3 doesn't always fire and never at idle
I've gone through my carbs even put on a freshly rebuilt loaner set, I am getting fuel
With no change
Have swapped plugs and wires,
Even re wired coils so as to fire 1/4 off 2/3 and vise versa, I am getting spark
No change
Compression is 155-165 across all 4

At idle #3 only warms up if i go ride it it well sometimes fire in 2nd gear rpms aournd 6k rpm
And ALMOST always in 3rd & 4th gear 5-6k rpm

I'd say carbs but even after cleaning mine it didn't help so I put on a set my friend just rebuilt with no luck either
I adjusted valve .002/.003 had some noise so buddy that I got it from said it's got a preformance cam and to set it .003/.004
I did no change

Driving me nuts

If any buddy thanks the can help I'll even give you my cell# so we can talk

Thanks fellas
 
Is the plug wet? If its wet the no spark or mechanical issue. If its dry no fuel and still could have a mechanical issue if you have a wiped out lobe...intake not opening letting in fuel air mixture...or exhaust not opening causing similar issue. If it was a new cam put in with old rocker arms it can easily and very likely destroyed a cam lobe.
 
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