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Old 12-04-2012, 02:47 PM
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Johnny 5 Johnny 5 is offline
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Join Date: Dec 2010
Location: so cal
Posts: 325
Default 183cc big bore alive with A12 cam

I am now very happy with the 62mm bore 3mm crank 183cc motor now.
The A12 cam does have some big lift , made sure there was no coil bind.
Also opened up the combustion chamber a bit to take the sharp edges off.
I also put back the stock valves after I noticed the ones I ordered were way heavy and not under cut at the stem. The main reason for replacing the valves was to put new springs on the fresh rebuild.

I think the last trip with the heavy valves it was causing float at 7500rpm.
And the 39t rear sprocket was keeping the engine at max rpm all the time.

I am puting a new stock 31t sprocket on to keep the rpms down so I dont bang a valve. I might still put ncy valve springs on, but am not sure about having too much spring presure and killing the valve and seat.

Now with the A12 cam the buggy takes off hard and pulls all the way down my short street. Before it would lay down about half way and felt really gutless. I checked the compression and is now at 145psi from 155psi with the stock cam and smaller combustion chamber. I am happy with the lower compression because the heat is a problem in the desert.

The next trip we are going on is at the end of december.