AussieSteve
Active Member
Yep, I think the extra vibration 'is' detonation. I tried a mix with no octane booster today, 91 octane (or lower) and it felt almost like a bent crankshaft, with the hi-comp head. Shook heaps. Back at 98-99 it's smoother and runs better. Love the smell of the octane booster, too, reminds me of go-karts.
Not sure where you buy your engines, but ZBox 66cc have an 0.79mm stock. That's their newest 'Series 3' as Warren calls them. Yours sounds like the same jetting and not 0.7 like many sellers. I think that the earlier carb had an 0.7mm main jet and non-coated, brass/bronze slide. The later carbs all have a coated slide. Not sure where the version with a fuel tap on the carb fits in to the scheme of things. I haven't seen one yet.
Didn't get a ride today, (a layabout mate dropped in and 'made' me drink beer all afternoon), but tonight I swapped back to an 0.76 jet, from 0.72 and lean at WOT.
Adjusted chains, too, etc, for tomorrow.
Who knows, I might end up over 0.8mm too.
Tomorrow, I'm hiding the beer from visitors, they leave sooner.
I want a couple of decent rides.
One quick point - you said you didn't bother trying the next size down. Although it seems pretty good, it might get better. Best is to go, in very small steps now, until you feel that you've gone 1 size too far, then back off one.
I know these aren't competition engines, but the nearer the better. You might even get a surprise. I'm beginning to get a feeling that with reasonably good breathing, the stock 0.79 or an 0.8 might go pretty close. (Assuming our engines 'are' the same.)
Let's see where we both end up.
I've got 2 new plugs waiting to do mid-range and WOT plug chops, when I get a chance, tomorrow I hope. I'll go from there.
... Steve
Not sure where you buy your engines, but ZBox 66cc have an 0.79mm stock. That's their newest 'Series 3' as Warren calls them. Yours sounds like the same jetting and not 0.7 like many sellers. I think that the earlier carb had an 0.7mm main jet and non-coated, brass/bronze slide. The later carbs all have a coated slide. Not sure where the version with a fuel tap on the carb fits in to the scheme of things. I haven't seen one yet.
Didn't get a ride today, (a layabout mate dropped in and 'made' me drink beer all afternoon), but tonight I swapped back to an 0.76 jet, from 0.72 and lean at WOT.
Adjusted chains, too, etc, for tomorrow.
Who knows, I might end up over 0.8mm too.
Tomorrow, I'm hiding the beer from visitors, they leave sooner.
I want a couple of decent rides.
One quick point - you said you didn't bother trying the next size down. Although it seems pretty good, it might get better. Best is to go, in very small steps now, until you feel that you've gone 1 size too far, then back off one.
I know these aren't competition engines, but the nearer the better. You might even get a surprise. I'm beginning to get a feeling that with reasonably good breathing, the stock 0.79 or an 0.8 might go pretty close. (Assuming our engines 'are' the same.)
Let's see where we both end up.
I've got 2 new plugs waiting to do mid-range and WOT plug chops, when I get a chance, tomorrow I hope. I'll go from there.
... Steve
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