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I got a few PM's about doing a build up on a V twin motor
this is what I have learned while doing mine.
the arctic cat 650 v2 is the same motor as the prairie 650, the same basic motor as the prairie 700, twin peaks 700, and the v-force 700.

Bottom End:
if you want to add some cc's you can change to a 700 crank and rods I think it adds about 35cc's
while the engine is apart all 3 timing chains, the oil chain, all crank bearings, and gaskets should be changed. the left side case half has a crankshaft bearing that cannot be changed if it is worn the case is junk.
with a dynatek cdi and high compression pistions you need to use an oil catch can. the one that works best is the one from a YZF450 (about $12). You will need to drill and tap the case for the return oil line.
A 4 degree timing keyway is avalible for this motor. the only special tools needed are a clutch puller and a flywheel puller
bottom end parts can be found at any cat or kawie dealer or on Ebay

Big Bore Kits:
700 cylinders will bolt right on but you must change pistons.
for High compression pistons you will need 3 layer head gaskets. single layer head gaskets will not last long.
mine is an FST 765 kit. (the 700 crank and rods make it 800cc's)
the old sleeves were pressed out the jugs were bored and the new sleeves were pressed in. I did loose some cooling volume around the cylinder. cylinder base gaskets are stock but the head gaskets come with the kit. the pistons are both the same but are directional (each is marked for front). all ring gaps and clearances are stock specs. all bolt torks are stock
Fundy PowerSports, FourStrokeTech, and AMR all make big bore kits

Heads:
the 04 rocker arms need to be modified if you are going to run an aftermarket cam (kawasaski fixed the problem in 05).
better cams will need stiffer valve springs.
Oversized valves can be machined into the heads (Fundy PowerSports, FourStrokeTech, and AMR are companies that do head work and make cams)

Exhaust:
the only full exhaust system for the V2 is made by speedwerx. it comes with a much larger diameter header pipes.
other options are slip on silencers or the exhaust mod.

Intake:
there are 2 options with intakes, first is intakes with the tube between the them or intakes for larger carbs. I'm still using the stockers.
the air intake will have to be modified (my airbox has 7-1.25" holes in it).
also a high flow air filter should be used ( I use a K&N)
carb jetting is going to increase (mine went from size 122 to 200)
intakes are normally for sale on ebay

Electrical
Dyna tek , Moose power Module, High lifter module, and cooperhead are all available for the V2
the copper head is programable, but I would recomend the Dyna tek
after market coils are available.
CDI modules are cheapest on Ebay

Cooling System:
with the loss of coolent volume around the cylinders your motor will run hotter than stock you will need a temp gauge
I use an additive in my coolent and also I added an oil cooler in front of the radiator
I also removed the winch to let more air to the radiator but it is not nessary with the oil cooler
oil cooler is from Highlifter

Clutching:
I have tried everything with clutching and belts
the only belt to get is the stock brute force belt.
any clutch machining should be done by a guy called VforceJohn (kawieriders.com)
I use a Maroon primary and a stock brute force secondary springs
for weights I use 58 gram for trail riding and 54 gram for racing and mud riding
I got my springs and weights from EPI

Drivetrain:
replace all u joints
the mounting bolts on the diff need to be replaced with larger bolts to remove any play or movement in the mounting or the mounts will get ripped off. (had my mounts reinforced)
if you run outlaw or silverback tires then you will need better axels ( I run 28" mud lites and have never broke an axel).
I don't think 4.0 gears are nessary

I think that is it woot
the motor will pull hard and wheelies will be a problem if you are trying to work with the quad
I run mine in high most of the time and am pleased with the way it performs
 
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STICKY!!!!!
 

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<div class='quotetop'>QUOTE (mitchell87 @ Sep 16 2009, 10:59 PM) <{POST_SNAPBACK}></div>
STICKY!!!!![/b]
X2 Awesome write up, I am one who recently asked about this, my buddy has an early 05 V-2 that has really noisy timing chains so while he is in there he wants to do your BBK. Thanks for all the info, GREAT information to have.
 

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Interesting, thanks Wayne.

I picked up a 650 brute force motor, what is the difference between that motor and the praire 650. I'm burning oil right now and was thinking of swapping it in and building the current motor up over the winter.
 

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Great Yooper!! post definitly should be pinned! Just what I was looking for
Thanks
 

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Discussion Starter · #7 ·
<div class='quotetop'>QUOTE (FirecatV2 @ Sep 17 2009, 09:35 AM) <{POST_SNAPBACK}></div>
Interesting, thanks Wayne.

I picked up a 650 brute force motor, what is the difference between that motor and the praire 650. I'm burning oil right now and was thinking of swapping it in and building the current motor up over the winter.[/b]
I think the heads and intakes are different. sell the brute motor and we will wake your motor up :D
 

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There are two different 650 V-twin motors. One is used on the sra B.F. and the other one is found in the i.r.s brute, I belive the i.r.s makes more power. And yes, I think you should pin this.
 

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Nice stuff, i heard the brute force straight axle is same thing and the only difference with the 650i (indepented) was the timing , which if you bough a dynatech got fixed anyway
?
 

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So the motor I have is from a 08 Brute IRS. Would it be better? ie. more power?


I do want to sell it but I need to know if it runs, so I want to swap it in. Got the clutches too. My research on Kawie riders suggest the primary clutches are different. I got the motor and a pile of Brute parts so if I can sell them it will be time for more CC's, cam, high comp pistons, oil cooler ...
 

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Discussion Starter · #11 ·
the brute motor is a good motor but you may have to make your own intake system and air box
 

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Thanks Yooper. I wasn't thinking the about the intakes and box being different.
 

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the left side case half has a crankshaft bearing that cannot be changed if it is worn the case is junk.
There is someone on Ebay that now makes/sells these...$100 and that's a lot cheaper than getting new/replacement cases!
I have tried everything with clutching and belts
the only belt to get is the stock brute force belt.
I can attest to this...he went through tons of belts until he got it dialed in. Follow his lead on this.

One thing I'd like to add is that Yooper went through a ton of timing chains initially after the BBK was installed. It was later determined that the tensioners were to blame, not the chains. He replaced the tensioners and all has been well since.

Great writeup Yooper!
 

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is anyone still monitoring this thread, i have a BKP kit for my 650v2 and have some play in my front rod and seeing what all i need to replace once i break into it before putting it back together. thanks
its a 06 650 v2 with the 730 kit from big kev performance with valve job and and all just seeing what i need to upgrade in the bottom half of engine.
 

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Is anyone still on this thread? I blew the engine on my 06' 650 V2 and want to upgrade for the rebuild. I'm looking for leads on a good crate engine or at least some complete rebuild kits. I looked at Big Kev's and it looks like its just the hardware - no gaskets, timing chains, etc. that you need for a complete rebuild. I'd really prefer to just buy a crate and swap it in, but I'm finding way too much with Google. Any advice on where I can find an upgraded bolt in replacement?
 

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I am also wondering if this thread is still being followed. I am wanting to beef up my 04 I bought last year and was wondering what years that set up would work on
 
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