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Discussion Starter · #1 ·
i have a 1981 yamha ss440 and i want to shave
th head on it to get more power, i want to know how much i can take off but at the same time not have a reliability problem
 

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Not sure on how much can be taken off because of casting processes and amount of material currently on there. But if you do have it shaved down you will need to start running higher octane fuel. How much higher depends on how much you raise the compression ratio (i.e. shave the head) Also you must remember the bearings on that crankshaft are 20+ years old unless they have been replaced, and that motors back in that era werent designed to handle lots of power. All i'm saying is be careful when you start modding some of the older engines. I'm sure that a sled shop would be able to tell you how much you could remove from the head before you got into the danger area.
 

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When I shaved the head on my Formula, the Skidoo shop said that I had to have at least 50 thou clearance left after. On my 470 that would be 20 thou I could shave, I however only went 10 thou, for that extra bit of compression. I would double check with a Yamaha Shop and see what they say.
 

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Well.. generaly you can shave as much off as ya want, so long as there is still a lil' bit left of where the Gasket goes. Leave juss enough of an "incline" on the head for the gasket, and ya should be good to go.
Matt
 

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jag
where do you come up with this stuff,
a lil' bit left.
To Funny
 

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Originally posted by 92hybrid
[br]i have a 1981 yamha ss440 and i want to shave
th head on it to get more power, i want to know how much i can take off but at the same time not have a reliability problem
I'm not sure exactly what can be cut off probley up to .020 and still be safe, but what you might want to think about is raising the port timing with this by putting in a thicker base gasket this will give you more power check a www.sledtech.net its a new mag that deals with some of the older sleds up to some of the newer ones they might be able to help you more...gabs
 

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I'm getting a little suspicious of this guy who mentions another sled forum in every one of his posts. I'm as open for new sources of information as anyone, but this just looks a little fishy to me.

What's the deal gabs, looking for members? It's cool if you are, but be open about it.
 

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Originally posted by Polaris XLTSP
[br]What's the deal gabs, looking for members? It's cool if you are, but be open about it.
I'm with ^. I looked in his profile, and his previous posts. I found ONE post where he didn't mention that website.... Fess up dude.
 

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well i wasn,t going to be the first,to mention it ,but gabs,i looked at your site,
you have a long way to go to ,to even compare to S.F.
do yourself a favor and drop the references to your site,theres nothing there.
 

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i would check compression now and freshen up the motor with rings pistons and rehash, in 1981 the fuel quality was a lot better than it is now so that engine might already be close to a 90-92 octane engine,,
 

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Is it just me, or is XC "special" a complete dick, or lack therof..?
I mean honestly..
Why do ya have to put down this dudes site, also?
Sled heads are the same damned heads as Mowers, and whatnot. I have suped up a Rider before, and I shaved just enough to leave a lil room for the gasket.. and that worked.. better yet, it hauled ass when thru w/ it!
Matt
 

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81 Jag, name calling is going against our site policy. Keep that in mind.

Nobody put the guy's site down, and I agree with ripperd and Polaris XLTSP. Gabs, STOP WITH THE ADVERTISING ON OUR SITE. Put the link in your favorites, but I visited that site you keep mentioning and I don't think you want my opinion on it. I also searched the site for this info u keep claiming it has, and if it does have it, it's very well hidden.

And sled heads are not the same as "damned heads as mowers"...
 

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Sorry Polaris Man.. but he doesn't have to be an ass about it..
From XC "special".. "do yourself a favor and drop the references to your site,theres nothing there."
I think that is a way of putting one down.. but that's just me..
How are "heads" not the same as another set of "heads"? I mean.. they are the same thing, doing the same thing(relizing by saying this there are diff. styles, etc..)
But how are sled heads diff.?
Matt
 

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the heads on sleds are basically a cap, on early mowers with the valves in the block theres heads were basically just caps. but you have the dome in the head that is built for you engine, the amount of squish is also different, it looks like a simple cap but on a two stroke there are a lot of engine dynamics that come from that little head. the problem with running high compression on todays trail sleds is the fact that you cant be garenteed fuel quality. how many people use 92 octane in there cars, it only take a few weeks for todays fuel to go bad, what about all those back woods bar,gasstations, some dont even carry high octane.
 

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^^^

What madcow said

about what XC Special said, good point, XC, try not to be so harsh from now on.

Excellent, everyone is happy now [:)]
 

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Polaris-Man says:

"but I visited that site you keep mentioning and I don't think you want my opinion on it."

well if you read between the lines,.
Thats my Point Also
 

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Originally posted by Xc Special
[br]Polaris-Man says:

"but I visited that site you keep mentioning and I don't think you want my opinion on it."

well if you read between the lines,.
Thats my Point Also
It's all in the wording [:D][8D]
 

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92hybrid
Sorry your topic got hyjacked,but seriously,i would leave it alone,it likely runs great as it is,cuting 10 or 20 thous will gain you a 2-3 maybe 4 hp.but looking for premimium fuel all the time is a pain in the a$$,.never mind the cost,
But Hey, myself, i look for any power gain,so go for it,
 

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Ok, I did not relize that 2-stroke engines were a lot diff. than 4-stroke.
You would have to "for-sure" use higher octane by shaving?
Matt
 

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for sure, you should go to the speed runs and vintage shows, i know your sled isnt a vintage, but some of those older srx 440's are just plain fast even compared to todays sleds. i bet them guys can help you out a lot.
 
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