Comments on plug color

Zingzing29

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Oct 26, 2021
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May have a 38 mm cylinder, with a high hole piston. When you torque it down, the clearance shortens, gaskets squish. You should always torque with the head off, to see where the piston sits, or do a solder squish test before pedaling it.
It's impossible anyways I ran the 40mm jug for months. All the way down no base gasket nothing. I couldn't even use a head gasket because the squish was like 1.2 same with the grubbee cylinder I had to cut my base gasket in half by .2-.3 to get it close to 1.0mm. and now neither cylinder has the clearance for the piston to come flush or below the deck in fact it stick out of the jug on both of these cylinders by 3mm. What i don't understand is how does that happen. The crank has to be bent or something?
 

Zingzing29

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Oct 26, 2021
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284
Looks like I can start rebuilding this from the case up. Like I originally intended. Wonder what I should build. Any recommendations for some good starter builds.
 

Zingzing29

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Oct 26, 2021
Messages
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Better to start fresh anyways than to keep piecing together a build I wasn't finished with. The 47mm piston have gapping oiler to the phantom having none. Here's even the same piston I was running won't work. What can you tell me about tthe burn pattern here I've look up some stuff. From what I know where the carbon and metal meet is supposed to be where the burn ends. Other than that idk
 

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Street Ryderz

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Oct 14, 2016
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It's impossible anyways I ran the 40mm jug for months. All the way down no base gasket nothing. I couldn't even use a head gasket because the squish was like 1.2 same with the grubbee cylinder I had to cut my base gasket in half by .2-.3 to get it close to 1.0mm. and now neither cylinder has the clearance for the piston to come flush or below the deck in fact it stick out of the jug on both of these cylinders by 3mm. What i don't understand is how does that happen. The crank has to be bent or something?
You're not making any sense, what do you mean by 40mm jug? The difference between a jug used for the 40mm stroke and the 38mm stroke is only around 1mm in height, as was mentioned above there are short and long rods in both strokes and high and low holed pistons and you can't just mix and match all willy nilly from one to another.
Generally short rods use low holed pistons and long use the high, not all ways but most commonly. If you put a low holed piston on a long rod or a short rod intended for high holed piston it will protrude above the deck and there is the 3mm, using rtv as gaskets once it cures shrinks to less then the normal gasket thickness and again posses more cylinder drop and clearance issues as heat cycles will reduce it again as re torque is required.
Bent crank ? How would a bent crank make the piston protrude, if the crank was bent it would not rotate smoothly but can not alter the stroke out ward if any thing it would reduce it and may cause piston to drag on a portion of the cylinder wall adding to the resistance in rotation of the crank.
 

Street Ryderz

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Oct 14, 2016
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Better to start fresh anyways than to keep piecing together a build I wasn't finished with. The 47mm piston have gapping oiler to the phantom having none. Here's even the same piston I was running won't work. What can you tell me about tthe burn pattern here I've look up some stuff. From what I know where the carbon and metal meet is supposed to be where the burn ends. Other than that idk
This piston wash pattern shows many things, excessive heat, alot of charge loss out the exhaust, improper turbulence in the chamber occurring horizontally rather than vertically.
 

Mossy

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Jan 7, 2022
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2,652
You're not making any sense, what do you mean by 40mm jug? The difference between a jug used for the 40mm stroke and the 38mm stroke is only around 1mm in height, as was mentioned above there are short and long rods in both strokes and high and low holed pistons and you can't just mix and match all willy nilly from one to another.
Generally short rods use low holed pistons and long use the high, not all ways but most commonly. If you put a low holed piston on a long rod or a short rod intended for high holed piston it will protrude above the deck and there is the 3mm, using rtv as gaskets once it cures shrinks to less then the normal gasket thickness and again posses more cylinder drop and clearance issues as heat cycles will reduce it again as re torque is required.
Bent crank ? How would a bent crank make the piston protrude, if the crank was bent it would not rotate smoothly but can not alter the stroke out ward if any thing it would reduce it and may cause piston to drag on a portion of the cylinder wall adding to the resistance in rotation of the crank.
The PK jugs measure up nice on the Zeda bottom with one gasket... that mm difference
 

Zingzing29

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Oct 26, 2021
Messages
284
So I have the triple 40 all done except for a. Few tweets. So once again I'm going to ask about plug color. Now from what I know they like 68-65 and. I have a 70. So I raised the clip one knotch because of this. Now I'm almost threw my gallon of gas and I checked the plug and had. Similar symptoms to running lean as before So I lowered the clip back to the middle slot. Now my guess is it's still lean with lots of oil at 18:1. Now that I'm more familiar and I know what the lean bogs is.
 

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Zak

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