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Discussion Starter · #1 ·
Would it be a good idea to install a set of compression releases in my 95" flat tops w/ 204 cams?
I don't know for sure what compression the 204s build, and the heads are off right now.
Or, is this totally unnecessary?
Thanks..
 

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If you have the heads off...do it. While not really needed for that build, comp. releases will most certainly extend the life of your starter and battery. Probably 50.00 to drill them and 80.00 for the releases. A starter is way more than that and also they are there if you decide to upgrade the compression someday.
 

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fatboy69 said:
If you have the heads off...do it. While not really needed for that build, comp. releases will most certainly extend the life of your starter and battery. Probably 50.00 to drill them and 80.00 for the releases. A starter is way more than that and also they are there if you decide to upgrade the compression someday.
I disagree with this logic. Compression releases are just one more thing to fail. The build is well below a compression ratio that would justify the use of compression releases. If you want to "upgrade" the compression later, you will be pulling the heads off to do that and you can then decide if they are warranted. I feel it is a waste of money at this point in time. It also takes away from the "sleeper" effect, compression releases are a dead give away that mods have been done. The starter and battery will see little or no difference in the build you described. My -2$en#e-
 

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I am with Springer here, currently running a tad short of 190psi ccp and no issues so far. Haven't had a really hot soaking start, but we'll see. One thing less, one thing less to break.
I love the sleeper argument.....
 

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Well to each his own I guess. As far as compression releases failing that is pretty far fetched I think. It's not a complex mechanical or electrical part. As far as "sleeper", who are you trying to impress, with about 4:1 crotch rockets to Harley's on the road, nobody's going home to tell their wife about the sleeper that took them till about 2000 RPM's. I appreciate the input though guys. Cheers.
 

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fatboy69 said:
Well to each his own I guess. As far as compression releases failing that is pretty far fetched I think. It's not a complex mechanical or electrical part. As far as "sleeper", who are you trying to impress, with about 4:1 crotch rockets to Harley's on the road, nobody's going home to tell their wife about the sleeper that took them till about 2000 RPM's. I appreciate the input though guys. Cheers.
I am more into not impressing the cops. Like not giving them a clue........
 

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True enough Vienna. Good point. I somehow overlooked that aspect.
 

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Discussion Starter · #9 ·
Thanks for the replies..
I was talking to a guy at the gym yesterday, and he said that a buddy of his was having starting issues with his Stage II.
Before this, I never heard of any compression related issues with this mild build. I think his bud may have battery problems instead.
If I don't need them, I don't want them.
 

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ViennaHog said:
I am with Springer here, currently running a tad short of 190psi ccp and no issues so far. Haven't had a really hot soaking start, but we'll see. One thing less, one thing less to break.
I love the sleeper argument.....
Same here.... I'm running just a tad under 10:1 (190+ psi cranking pressure) on my EVO and it starts fine without them. The starter doesn't seem to work any harder than it did when it was stock. Once you get close to 11:1 or so, then you might want to consider them. I like to follow the basic rule of mechanics: "the simpler something is, the more reliable it is". As springer said, it's just another thing to break. :)
 

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Fatboy69, sorry, no offence was intended. I agree the compression releases are a very simple item and not prone to breaking. But they do get dirty with carbon and may need to be removed and cleaned occassionally or the carbon can hold them open causing a loss in compression. They also add a threaded hole into the combustion chamber that needs to seal properly.

I consider 10.5:1 to be the threshold of needing them but many recommend them after 10:1.

As for the "sleeper" look I was talking about, it has nothing to do with crotch rockets, racing or trying to impress anyone, but merely keeping your bike stock looking for any number of various reasons.
 

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@gree:
Yes they do need to be removed and cleaned from time to time. And we all know the chance you take with a steel release screwed into an aluminum head.
 

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maybe off topic here and I certainly have no need form them myself, but has anyone tried those compression releases that screw in the spark plug hole then use a long reach spark plug specially made for them to reach into the cylinder? just curious how or if they work. Maybe usable in a case where you should have put them in during build but didnt and find out a little later due to hard cranking you need them?
 

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Those releases made by Spyke are for Evo's only no Twin cam...yet
 

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oh yea thats right, had only seen it in a magazine add once and forgot that it only mentioned evo's.

if anyone has used them I'm still curious to hear your thoughts on them.
 

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Compression releases

If I were to ever remove the heads, I would have them installed. {just to keep 'em guessing :265: }
 

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Well I need them at 10.5 and can tell you that if I forget to use them all HE$$ breaks loose. I can count on one hand the times I have forgot.

As springer said 10.5 and up you need them, period.

I have seen a lot of complaints on hard starting builds lately in the 9.8 and 10.0 range and am wondering if someone is making mistakes on the decking of the heads/cylinder's, or pistons, or gaskets or what. I know at dead nuts on 10.0 there is no need for them in the friends bike I have ridden and started.

They do need cleaned no two ways about it. That is a very small hole into the chamber and if you are carboning up it will show with weak or sticky function of the releases.

Chuck is right on, on this point. I have also messed one of the holes up and needed to use a helcoil. That was spinning it out with just a socket and my hand, the only way I put those or plugs in, ever. Still happened. Now when I break them or a plug loose I spin it out a few turns and then spin back in, then out, just to make sure it is spinning and I am not cutting the threads coming out. NEVER thought as careful as I am that it could happen, it did.

Follow the sage advice given by others here and spend that money on something else until you really need them.

On the stealth thing, yea right. Most people don't see them or even know what they are, and if the bike is running, what the he$$ is stealth^rolleyez^
 

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we install compression releases in all our heads, but keep in mind our clients wanna have the cool factor and be able to kick start.
spyke starters work well with the primo belt drice and cluth basket.
their comp releases are less than desirable.
i kicked a 120 inch pan today.
the very small releases we use are very hard to see.
you do have another weak link if you go this route.
to each his own, but i would not add compression release to my bike because i like a depenndable ride that i can ride everyday with as little maintenance and worry as possible.
trust springer-----------he is smarter than me, just not as handsome.
 

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SPRINGER...No offence taken. Just my 2 cents (canadian) worth . I'm just trying to help the feedback as I have used other's priceless feedback so often. Mine actually is hard starting with the 95" stage 2. Probably, as I have gathered, maybe a weak battery or starter. Although I do ride in fairly cold weather sometimes (-10 degress C) is my minimum. Do starters actually get "weak" or do they just die when they are spent?
 

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LAF said:
I have seen a lot of complaints on hard starting builds lately in the 9.8 and 10.0 range and am wondering if someone is making mistakes on the decking of the heads/cylinder's, or pistons, or gaskets or what. I know at dead nuts on 10.0 there is no need for them in the friends bike I have ridden and started.

It is not Static Compression that gives the starter hell or requires compression releases. It is Dynamic Compression Ratio, or rather, directly proportional, based on barometric pressure Cold Cranking Pressure (CCP). 10:1 static with a SE 211 at sea level is only about 183 psi CCP, but with a TW-21 it is a starter breaking, ping monster of 204 psi CCP.
 
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