Blue shadow
TY 4 Stroke Guru
Mine as a comp of 155 psi on all four with 10 to 1 low comp pistons and stock head gasket.
yamahaman1
Newbie
well i just dont understand how it can run so well...i mean my friend has a 700 mod f7 and this thing still out runs that easily.
wantboost
Expert
when i broke a ringland on #3 the sled ran great on and off the bottle but i had smoke out 1 pipe.did a compression test and had 90 psi.i was always told it takes about 70lbs of compression to fire a cylinder,so that cylinder will light just not make 100% power.you need to do a leakdown
yamahaman1
Newbie
I already did a leakdown...i dont think it was coming out of the valves so i think it was going into the crankcase...and where can i find those steel cylinders and for how much?
yamahaman1
Newbie
and another thing...this sled doesn't smoke
wantboost
Expert
what was the results from the leakdown
yamahaman1
Newbie
on 3 of the cylinders it definately lost a noticeable amount of pressure

kinger
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How much pressure, over 10% loss and you need a rebuild.
My question to the masses is do you need to hone when doing new rings? I get mixed awnsers that go something like this: To do it properly yes, otherwise its ok. LOL
My question to the masses is do you need to hone when doing new rings? I get mixed awnsers that go something like this: To do it properly yes, otherwise its ok. LOL
HURRICANE
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Honing niki cylinders will do nothing unless you use a diamond stone and very few guy's are equipt with that
yamahaman1
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Hurricane, where can i get those steel cylinders? so i take it you sleeve the block? would you have a block already done that you would sell? how much?


mulot30th
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wantboost said:just my thoughts but i think 85-90 lbs of compression is very low.my 03 came in at 210-220 with stock headgaskets,pistons and no shim
That is right with stock compression and gasket. right around 210#
140# is about right with 9-1
I don't remember exactly for the 10-1 pistons... I think its 160 or 165#
mbarryracing
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yamahaman1 said:on 3 of the cylinders it definately lost a noticeable amount of pressure
yamahaman1,
Hurricane's block is super strong and a great upgrade but it won't prevent or fix your leakdown problem if it's detonated piston related. If your block was truely distorted, it would blow oil by the rings and smoke bad as well. Chances are you have something other than the block that is causing your problem, but when you tear it all down and you have the block already out...
yamahaman1
Newbie
so are you thinking the rings are just probably bad? it doesnt smoke bad or miss
mbarryracing
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When doing a leakdown / pressurizing the cylinder you get excessive blow by coming out of the crankcase vent, it's piston / compression ring related.
If the valves were bad, it wouldn't come out the breather... If the bores were damaged, you'd have smoke.
When it runs, does it have excessive steam or oil mist blowing out of the breather?
I'd be willing to wager a cold beverage that you detonated a top ring land and stuck a compression ring or two but not enough to effect the oil control or wiper rings.
Fuel quality, fuel quality, fuel quality. After your rebuild on your stage 2, eat drink and sleep this...
If the valves were bad, it wouldn't come out the breather... If the bores were damaged, you'd have smoke.
When it runs, does it have excessive steam or oil mist blowing out of the breather?
I'd be willing to wager a cold beverage that you detonated a top ring land and stuck a compression ring or two but not enough to effect the oil control or wiper rings.
Fuel quality, fuel quality, fuel quality. After your rebuild on your stage 2, eat drink and sleep this...
givemeaboost
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Mines got 165# at 3300 ft elevation with Wiseco 10-1 pistons. At sea level it would be around 180#. Did you hold the slide up when checking or just hold the throttle open? This can make a difference but not as low as you are showing. The gauge can be off also. I've got one that reads 30# low.
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