160psi with new top and 35cc domes

nickt916

nickt916

did everything now, new wiseco pistons, 82mm with .005 clearance bore, 35cc domes and compression is at 160psi ... kinda weird? since the 35cc domes run at 190psi no? im a little disappointed, not sure why, maybe cuz its not broken in yet? not sure what it could be
 
sjetrider

sjetrider

615 Freeriders are addicted to T1 madness.
Location
in the 615 (Nashville)
If the cylender is ported high @ exhaust port it will greatly reduce your compression, if it is stock porting and every thing else .005 clearance is true replace valve in your comp. ga..
 
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yamaslut

Guest
nickt916 said:
did everything now, new wiseco pistons, 82mm with .005 clearance bore, 35cc domes and compression is at 160psi ... kinda weird? since the 35cc domes run at 190psi no? im a little disappointed, not sure why, maybe cuz its not broken in yet? not sure what it could be
Click to expand...

what's your squish?
what base gasket are you using?
any porting done?
how many hrs on the motor?
is the gage new?
 
nickt916

nickt916

i ran the engine for a minute or so, the new engine has about 2 minutes on it, its ported, the gauge is a few weeks old,
 
Watty

Watty

Random Performance
Location
Australia
I'd at least try to run it in first. Thats the whole point of running the engine in....so you have a good ring/bore matchup to hold compression.
 
Superjetjim

Superjetjim

X-
That compression is normal for a ported 753 - if its not ported (none raised exhaust ports) it will read 185 ish IIRC. Porting raises ports and this closes exhaust ports later = less to compress..
 
nickt916

nickt916

ill run it at the lake for the first time today, break in period is about 20-30 minutes after that ill ride it normal by the shore to make sure it doesnt break down on me in the middle of the lake or anything, when i get home ill check the compression again.
 
Waste Land

Waste Land

Non Multa Sed Multum
Location
Florence, AL
Big Kahuna said:
wrong Jessie, Most freestyle Porting does not touch the top of the exhaust port. only widens them, that being, there is no change in compression......
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Excuse me, widening. Witht hat being said is it not stille xhaust more air/fuel mixture then before needing more compression. When I had my cylinder done it needed new domes. to bring it up to the 180/190 range too
 
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yamaslut

Guest
fyi - pro-x piston / LPW freestyle porting / 35cc domes / 85mm bore / 185psi @ cyl
 
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yamaslut

Guest
Big Kahuna said:
wrong Jessie, Most freestyle Porting does not touch the top of the exhaust port. only widens them, that being, there is no change in compression......
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Paul told me it will effect the commpression
 
sjetrider

sjetrider

615 Freeriders are addicted to T1 madness.
Location
in the 615 (Nashville)
Stock 81mm ported cyl w/ 35cc domes and stock squish (aprox .060) should make 185psi, but I always thought when you go up in bore the domes would be totaly different. Unles Paul raised your exhaust ports slightly when porting????????? Which IMO but contrary to popular belief is not a problem so long as you run high enough compression to compensate.
 
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yamaslut

Guest
sjetrider said:
Stock 81mm ported cyl w/ 35cc domes and stock squish (aprox .060) should make 185psi, but I always thought when you go up in bore the domes would be totaly different. Unles Paul raised your exhaust ports slightly when porting????????? Which IMO but contrary to popular belief is not a problem so long as you run high enough compression to compensate.
Click to expand...

oops... it was decked and I was running a super thin base gasket...

sorry for the mis-information
 
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