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[CB-750] Re: Spark Advance? craigburlette Tue Oct 30 18:04:28 2007

Thanks for the reply, the bike is new to me so I can't comment on when
it started. I removed and re-built the carbs because one of them was
constantly leaking fuel through the overflow tube. One of the needle
valves had slipped out of the float holder, or possibly never been in
there in the first place??? Anyway I changed all of the gaskets,
needle valves and jets with new units from a rebuild kit. This stopped
the fuel overflow problem, but has had no affect on the "popping".
It's still about the same as before the rebuild.

Next on the agenda was a check of the ignition timing, which was
retarded to between the F and T marks. I reset the timing to between
the index marks and throttle response seems to be much better than
before. But the "popping" is still there. Next I checked the advance
and found that the timing is fully advanced by 2k rpm, not 6k as
indicated by my Clymer manual. All of the car's that I've worked on in
the past the timing advance was a smooth progression the full rpm
range, I expect that this is how it should be on the Honda as well.

The popping seams to be coming from the tail pipe, and I do not think
there is any power loss when it occurs.

I am in the market for an advance unit in good working order, I just
as well change that while I'm working on the bike.

Also I am looking for a good front brake master cylinder, any
suggestions other than ebay?


> Hiya,
>   Little pops are a tough one. At first glance I'd say
> your mixture is too lean, that would cover
> the,"doesn't pop all the time" part but if you have
> not messed with any carb settings I would tend to look
> for something else. Can you tell if the pop is comming
> from the carb or tail pipe? Any power loss when
> popping?
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