Does this compession sound right?

[FLY6584]

So after my cooling disaster today I figured I would take a look at the pistons/cylinder walls and check the compression.

The pistons/cylinder walls look perfect and the compression reads about 200. Not quite 200, but very close to it.

Does this sound right? I was under the impression that 35cc domes should produce about 185lbs on a stock unported motor.

The compression guage we were using wasn't that great. It was just a walmart guage so could this be the reason for the high readings?

I know I am supposed to be ok running 93 with my setup, but I have to admit the compression readings today have kind of worried me. :dunno:

 

[SJet]

What was the compression the last time you checked it?

 

[FLY6584]

What was the compression the last time you checked it?

This was the first time I checked it. I just installed the head. I dont even have two hours on the head.

 

[feartheride]

Have to start with a good guage

 

[SJet]

Oh,

I would check another ski with that guage, or try someone else's gauge. That way you aren't sorta guessing. If you are at a little under 200 lbs, I would run a little octane booster and 94 octane?

 

[FLY6584]

Oh,

I would check another ski with that guage, or try someone else's gauge. That way you aren't sorta guessing. If you are at a little under 200 lbs, I would run a little octane booster and 94 octane?

Yeah we checked my buddies ski at the same time with the same guage. He is running a riva head with 35cc domes and his was only reading about 165psi.

Thats whats scaring me.:bigeyes:

 

[DaUpJetSkier]

hmm so your head is reading high you think and his head is reading low unless its a ported motor but I would think 35cc's would make more than that. Try a different gauge, its the only way to really tell.

 

[SJet]

Is your motor stock, not ported? You might want to check the squish. This is always a good idea when changing heads and or domes.

 

[SJet]

I have a ported 61X cyl. with the ADA head and 35cc domes. It runs 170 lbs.

 

[FLY6584]

Is your motor stock, not ported? You might want to check the squish. This is always a good idea when changing heads and or domes.

No porting and I was told that there was no need to check the squish on an almost new stock motor with a new ADA Head.

Chucky out at Team Scream even said dont even bother checking the squish.

My guess is that it's the guage.

On a good note when the cooling lines aren't melting the ski runs awesome. It hits very hard.

I am very happy with my Freeride 12/17 Swirl. Tons of low end snap and absolutely no bottom end lag or bogg.

 

[Big Kahuna]

Oh,

I would check another ski with that guage, or try someone else's gauge. That way you aren't sorta guessing. If you are at a little under 200 lbs, I would run a little octane booster and 94 octane?

Do not run Octane Booster............ Ever..........

Also, what kind a head, 35cc domes on one head may not be the same on another........... believe the Compression values are a bit different from say a RIVA head vs. ADA

Typ ADA 35cc domes on 81mm bore is approx 180-185 lbs

at home, my 35cc domes gives be 180-185 lbs, but when I travel to the beach, the compression jumps to 190-195lbs.

 

[FLY6584]

Do not run Octane Booster............ Ever..........

Also, what kind a head, 35cc domes on one head may not be the same on another........... believe the Compression values are a bit different from say a RIVA head vs. ADA

Typ ADA 35cc domes on 81mm bore is approx 180-185 lbs

at home, my 35cc domes gives be 180-185 lbs, but when I travel to the beach, the compression jumps to 190-195lbs.

I'm running an ADA Head with 35cc domes and it's reading in the high 190's right at Sea Level and my buddy is running a Riva head with 35cc domes and it's reading about 165-170 right at Sea Level on the same guage.

His motor is a little older and he did say that it originally had been at about 200 when he first put the head on.

 

[SJet]

So, Octane booster = Not good?

Why?

 

[crammit442]

Do not run Octane Booster............ Ever..........

Also, what kind a head, 35cc domes on one head may not be the same on another........... believe the Compression values are a bit different from say a RIVA head vs. ADA

Typ ADA 35cc domes on 81mm bore is approx 180-185 lbs

at home, my 35cc domes gives be 180-185 lbs, but when I travel to the beach, the compression jumps to 190-195lbs.

I don't know where you get that. Octane booster will not make race gas out of pump gas, but it will make pump gas useable in a higher compression motor in a pinch.

Charles

 

[FLY6584]

I don't know where you get that. Octane booster will not make race gas out of pump gas, but it will make pump gas useable in a higher compression motor in a pinch.

Charles

So Charles what do you think about my high compression readings.

Should I just not worry about it and be happy that I've got high compression and the ski rips hard?

I know tons of people run 93 octane on 35cc domes so I should be fine.

 

[Shonuff]

I don't think it will boost it enough to be safe at 200psi.

He's looking at needing 105 for that.

 

[Shonuff]

105/93 mix

 

[FLY6584]

I don't think it will boost it enough to be safe at 200psi.

He's looking at needing 105 for that.

I just dont understand why my ski is the only ski with 35cc domes that reads 200psi. I'm guessing it has to be the guage, but then again why would my buddies ski with 35cc riva domes be reading 165-170? His ski rips pretty hard too.

 

[crammit442]

I don't think it will boost it enough to be safe at 200psi.

He's looking at needing 105 for that.

99 or 100 motor octane would be plenty for 200lbs cranking compression on an unported motor. I don't believe you really have that much compression. What brand starter do you have in your boat?

Charles

 

[Shonuff]

I just dont understand why my ski is the only ski with 35cc domes that reads 200psi. I'm guessing it has to be the guage, but then again why would my buddies ski with 35cc riva domes be reading 165-170? His ski rips pretty hard too.

Just like the cooling lines, you fools obviously have no idea what you're doing.