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Discussion Starter #1
Ok just got off the phone with rocket factory for the stroker crank with all my mods all I need is to buy the crank $999.00, I can use a my stuff even my piston but would have to send them the piston so they can shave a hair off it. They say it a better crank then the stock so depenabillity will be go. Its a 4mm bigger strok. Now do you think it worth it. This will make my bike a 770. :eek:
 

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the 770 is the same motor the Rocket factory won king of the dunes with........I'll have mine in 3 weeks and I'm betting the reliability will be fine. Just run good gas........105 or better keep your maintenance intervals correct, your water temp in check and it should run a long time.

Mike

Getting Stoked for Sand Mountain.............30 days and counting.
 

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Shredder770 said:
You mean your getting "stroked" for sand mt. :thumbsup: :thumbsup:

Why would you have to run higher octane gas if you are not changing the comp? Its my understanding that if you use the 10.75.1 piston that you can run 92 oct just fine!
 

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The Rocket factory bike that won King of the dunes was running close to 14.1 comp and VP C-12 race gas
if I heard Jason right.

So if you running the 10.75 to 1 piston then you won't be exactly the same as theirs.
 

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If youre running the high compression 105.5 piston you will be close also. Yes they were running the good stuff but, they also had a 140lb rider.....that we wont be able to duplicate.....most of us anyway.

Mike
 

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Boom, I am running the 12.00:1 compression and with the stroke it adds a bit more dont know what the final # is yet but it wont be the 14.00:1 the Rockets are running. and if it is........damn the luck!!! :thumbsup: :grin_nod: :eek:

mike
 

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Just Called Jason at the Rocket Factory for clarification, the high compression piston is between 12-12.5:1 and when you Stroke it with the 4 mil it bumps it up to right at 14.0:1 +/- a small amount.

Mike
 

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ahhhh.....but is 700rider? And if he is only running the 10.75.1, then will doing the stroke increase his compression enough to require race gas?
 

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ok....so he will have to run race gas! Even with the 10.75.1 piston!
 

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With Raw math it should put him @ 12.25:1 and depending where he is.....Florida I believe.... which is at sea level I would reccommend at least 100 octane or so. Remember that a stock yfz is 11.5:1 and it runs fine on 92. my current 734 is the high compression piston and I run @ 4500 ft above sea level and run a 75/25 Mix 75 being 92 octane and 25 being 113 and I have had absolutely no problems. I went to Coos Bay oregon the week before dunefest and ran 50/50...........perfect. its a small insurance against ruining a expensive motor. So it may cost 20.00 more over the weekend to run race gas........the rush is worth every dime!

Mike
 

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You cant compare what a 450's comp ratio and octane needs are to the 700's. Its totally different. 450 has a lot less weight, drag, and is a much smaller motor. take the yz450 for example. they use to run 12.5.1 and now run 12.3.1. Same motor as the yfz, and the yfz gets the 11.4.1. Thats because if you use a 12.5.1 piston in the quad (twice the drag and half again the weight) it will ping like mad.
Same thing for the 450 -700. 700 is a completely different motor and chassy, and the cutoff point for race gas is MUCH lower than the 450. :thumbsup:
 

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I will be porting 3 raptor 700 heads this weekend. So come on guys order up some 770 kits with the ported head. LOL Actualy I will be porting mine, Jason, and Matts heads. I will also try and post some pictures of the Sand Shark with the new drag look (cut plastic, +6 swinger, and aluminum axle)
 

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Compression is all relative whether youre running a YZ, YFZ or anything else with high compression you need to compensate with octane above 12+:1. in my Turbo sleds it would detonate and ping all over the place(Not that I allowed this to happen) put in good full burn is much better.

Mike
 

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Hey Sparky, That axle is awsome......checked it out today. couldnt believe how light it was. Better get Ryan to get my Engine out of my bike so you can have the head off of it for Jasons 804

Mike
 

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Discussion Starter #15
135boom said:
ahhhh.....but is 700rider? And if he is only running the 10.75.1, then will doing the stroke increase his compression enough to require race gas?
I'm runing the 12-1 comp. and I'm useing 110 gas right now which I know is a little to high but haven't had the time to play with it. Oh and jason said with the big bore it makes it the 770, with the stock bore it only makes it a 720. But my ? still is it worth a $1000 for that small of a stroke.
 

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700rider, make sure you replace your rod when you do the stroke!
Its allready tore down, and it will be your weekest link.
 

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Shredder770 said:
Compression is all relative whether youre running a YZ, YFZ or anything else with high compression you need to compensate with octane above 12+:1. in my Turbo sleds it would detonate and ping all over the place(Not that I allowed this to happen) put in good full burn is much better.

Mike
Not necessarily Mike. a yz450 does not require race gas. it runs 12.3 now, and use to run 12.5. The yfz HAS to have race gas running those compression numbers.

yz250f's are high compression, above 12 and they dont require race gas.

my point is, you cant say, well my yfz can run 11.9.1 or 12.1 without racegas, so that means my 700 will be cool too. Where in reality, much more than the 10.75.1 and you HAVE to run race gas on the 700. This is why the 700 is stock with 9.2.1....it cant take much more. That is a big piston, and a lot of internally moving parts, with a lot of resistance and drag. Not to mention the weight of the machine.

The bigger the cylinder and piston, the lower the compression will have to be before running into HAVING to run high octane fuel.

I think we might be saying the same thing, just differently :3question: :thumbsup:
 

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smithZ said:
700rider, make sure you replace your rod when you do the stroke!
Its allready tore down, and it will be your weekest link.
All the stroker cranks come with a VERY good rod. And no its not a hotrod. Its custom built for our stroker cranks

[attachment deleted by admin to free up space]
 

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135boom said:
Shredder770 said:
Compression is all relative whether youre running a YZ, YFZ or anything else with high compression you need to compensate with octane above 12+:1. in my Turbo sleds it would detonate and ping all over the place(Not that I allowed this to happen) put in good full burn is much better.

Mike

I think we might be saying the same thing, just differently :3question: :thumbsup:
You Might be on to something Boom. I feel at Sea level a 12.0:1 on a 700 or bigger must run more octane and where I am at 4500 you can get away witth not. Is really all I was saying. and to answer 700rider the only advise i will give is simple

"The speed in which you seek to achive is directly related to the velocity of your wallet".

I've never seen a U-Haul behind a Hearse........so go for it you cant take it with you!

Mike
 

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Discussion Starter #20
All the stroker cranks come with a VERY good rod. And no its not a hotrod. Its custom built for our stroker cranks
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Why do I have to buy a whole new crank, can't I send my crank in and have you guys put a new rod in it, would that be cheaper. I mean why throw away a good crank. Just trying to learn something here. From the looks of it you guys are takeing the cranks apart put in the new rods then welding them together. Also why do you weld them when they come pressed in.
 
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