Compression? How much?

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Neufcruz

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i found my compression gauge. What should I be looking at for my set up?
66cc, high compression head.


Mike
 
I like to see somewhere between 90 and 100 PSI in an unmodified engine.
 
open throttle, cold motor, I usually get between 120 & 150 on a standard, good running motor - below 120, they usually run a bit slow & climb hills poorly - built up motor can be at 165 (my GF has one) and goes really fast

a non-starter standard motor above 175 is full of oil
 
So with my 66cc and high compression head. Don't think it matters but reed valve, windowed piston, expansion pipe. What should I expect so I know it's right? Anyway to text the intake valve make sure there is no leak. I want to make sure everything is perfect before any give tuning.
Thanks
Mike
 
So I did a test with engine cold, throttle open and a full kick/ revelation of peddles and registered 175.
With this being said, I would assume 8 should run the highest octane I can get (93) here in Miami.
Would adjusting the jaguar CDI to a higher setting help as well?
Mike
 
I would defer to others but I still highly recommend a premium iridium or platinum spark plug at the temperature you require for your area. The reason why is that the material allows the tip of the plug to be extremely tiny and thus causes less strain on your motor to generate the spark. Since you are running a high compression head and with that high psi, I would think that the easy spark from the iridium/platinum spark plugs will be the next most beneficial upgrade. I know when I put mine in; my motor went from semi-bogging to a roaring monster.
 
I would defer to others but I still highly recommend a premium iridium or platinum spark plug at the temperature you require for your area. The reason why is that the material allows the tip of the plug to be extremely tiny and thus causes less strain on your motor to generate the spark. Since you are running a high compression head and with that high psi, I would think that the easy spark from the iridium/platinum spark plugs will be the next most beneficial upgrade. I know when I put mine in; my motor went from semi-bogging to a roaring monster.


I will try this today! It's not too hot yet. 80 no humidity but getting warmer in the next month and then Summer.
What number plug? Any specific brand or go with ngk?Is a higher plug number cooler? I have a 7 in now and seems good.
Gapped at .30
Mike
 
Yeh, I would stick with 7 then. I have a 7. NGK and Champion have good reputations.
 
for gas & timing, I'd say listen for pinging before deciding - if it pings, then better gas - if it still pings, then retard timing
 
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