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what exactly does a higher compression get you how much of a difference does it make with both the stock bore and the 734?
 

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Each point in compression will net you 3-5% more overall power and theres no replacement for displacement 8)(except boost/N2O/rpm).
 

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I talked to Jason about the different pistons a few weeks ago, before the 13.1. He was saying there in only like a 1.5 hp difference between the 10.75.1 that runs pump gas to the 12.1 that requires race gas.
Not worth it in my book, unless you are building a drag bike.
 

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Am I lost??? Who's Jason???
 

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Say I wasn't worried about the $ of the race fuel. do you lose reliability??
 

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raptorDlux said:
Am I lost??? Who's Jason???
Jason is the guy that I believe owns rocket factory and has extentsive knowledge on the raptor 700.
 

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raptorDlux said:
Say I wasn't worried about the $ of the race fuel. do you lose reliability??

It is going to be less reliable as you start getting that high in compression. That is a HUGE jug in there to have at 13.1
I would say unless you are serious about racing, dont do it. If you are a trail/woods rider go with the 10.75. If you want a little more you could go to the 12.1 and I believe you can run a 50/50 mix with it...

All I know is 13.1 was high on my little 450. It really starts putting the wear and tear on things. Definately becomes less reliable, and the need to be "anal" becomes a must on how you warm it up, and when you change the oil, and with what kind your changing it with..and checking your internals.
It was more of a hastle then it was worth for me on the 450. The little extra power you get from running that high of compression just wasnt worth it to me....but then again, I am not racing. I ride woods/trails and such.
If you are a serious duner or racer, i can see doing this!
 

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As a serious duner, I would not run a 13.1 piston in my 700R. With as much torque as were getting out of these stump pullers I see no need to go over 10.75 unless you have over cammed it and killed bottom end.(I'd just make a cam change) I agree with Boom :eek: if all your going to do is drag and hillshoot and don't mind running straight race fuel then the 13.1 is fine but be prepared to do the added maintinence and way shorter intervals between rebuilds.
 

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i have a question that is somewhat on the same subject. If I get the rocket stroker crank and i am now running a 11:1 comp i understand that my compression will go up even more. do you guys know what it will go up to? will i need race gas, and how much reliability will i lose.
 

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i forgot one question. do you think it is more reliable to go with the big bore kit or stroke it .
 

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If not taken to the extreme both bore and stroking are plenty reliable. The 105.5mm bore 4mil stroke has proven to be a reliable combo. Now a sleeved 107 mm bore 8 mil stroke with 14.1 comp is a whole nother story.

With the 4mil stroker I believe that the actual comp ration when a 12.5.1 piston is used is right at 14.1 Someone correct me if I am wrong. I remember Jason from RF telling me that in a conversation at Dune Fest.
 

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You are correct Randy, I am @ 14:1 now, but I'm not sure where it will be here shortly

Mike
 

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Shredder770 said:
You are correct Randy, I am @ 14:1 now, but I'm not sure where it will be here shortly

Mike

Your a wild man ;) please keep me posted on your progress :thumbsup: How much time have you put on your 770 ?

Whats your take on the reliability factor with the high compression?
 

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Well I am fully prepared to pull my cylinder every summer to replace the piston/rings ect., And I dont think it will break so reliability is there but I believe performance will diminish. So with that said I dont expect to have much reliability problems. If reliability is the main focus then 10.75:1 un-stroked is the way to go (734) good power & good torque. I have only got about 7-10 hrs on the 770, with very minimal issues and those will be addressed next week

Mike
 

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Thanks for the info, that should be very usefull to those weighing their options on which direction to go on there builds :thumbsup:
 

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Shredder770 said:
Well I am fully prepared to pull my cylinder every summer to replace the piston/rings ect., And I dont think it will break so reliability is there but I believe performance will diminish. So with that said I dont expect to have much reliability problems. If reliability is the main focus then 10.75:1 un-stroked is the way to go (734) good power & good torque. I have only got about 7-10 hrs on the 770, with very minimal issues and those will be addressed next week

Mike
:beer: Thats my plan with a Stage 1 cam!
 

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thanks guys that answers a lot>
 

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one other thing. kind of off topic but still relates to the high comp pistons. when you talk about rebuilds, what do you see a rebuild as?
Is it rings, bore, bearings, and piston, or is there more.
I'm pretty handy, I've built car engines before, just never opened up a quad motor.
last one. I have quite the collection of tools, but do you need any large shop tools like a press etc..?
Hey thanks again.
 
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