Modified Animal Timing

mike97760

mike97760

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I have an Animal thats been modified and its always been a little sluggish at low rpms. After it struggles on a start is good and strong. Animal with a 308 cam, stock rockers, flathead crank and a 28mm Mikuni flat slide. Bought a longer exhaust pipe hoping to pick up a little more bottom end. Maybe helped a little. Will hit 9500 on the dyno but runs out of steam at 8600 on track. I do not know what springs it has. Its always been this way, showing a lot of promise but the low end kills it. Thinking its maybe timing. Before you ask a lot of questions I have little knowledge about other engine details. My first thought is that it could be timing. Where should it be and what else would cause this? Spark plug looks like it burns clean, perhaps on the lean side if anything.
 
My experience with the 308 cam is the same as yours.
I think the shorter duration hurts the top end in actual on track situations. Might be able to advance cam to help low end.
Dyno sheet will show power in a sine waveform. Doesn't seem able to pull back up to the final high wave on track.

The 356 cam seems better able to make the rpms, although I try to stay under 9000.
 
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@8600, that cam is dead (for the most part.) It' son the downhill side of the curve, and fast.
To help bottom end, you can advance the cam timing, open up your lash slightly to remove some overlap, AND increase the jet size...especially since you already indicated that it may be lean. Lean carb settings kill you on starts and restarts.


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mike97760 said:
I have an Animal thats been modified and its always been a little sluggish at low rpms. After it struggles on a start is good and strong. Animal with a 308 cam, stock rockers, flathead crank and a 28mm Mikuni flat slide. Bought a longer exhaust pipe hoping to pick up a little more bottom end. Maybe helped a little. Will hit 9500 on the dyno but runs out of steam at 8600 on track. I do not know what springs it has. Its always been this way, showing a lot of promise but the low end kills it. Thinking its maybe timing. Before you ask a lot of questions I have little knowledge about other engine details. My first thought is that it could be timing. Where should it be and what else would cause this? Spark plug looks like it burns clean, perhaps on the lean side if anything.
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Mike my engine does same thing.8800 rpm is about all she will do on the rd.mine has arc crank 155 over piston 356 cam stock rockers and 32,28 valves..welch told me its setup for shorttrack but i put a 28mm slide on it.buy a keihin 26 mm and put a tick smaller jets in it than is in your mikuni and cut the right side float off the float assembly
 
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