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Discussion Starter · #1 ·
I need to rebuild the topend on my 05 brute force 750 and i am in a dilema
I am a big time power junkie i love to have the fastest and most powerful machine in the huge group of folks i ride with.... My question is do you have to sacrifice power for reliability with these kits... I had my heart set on a FCP AMR or FST 840 kit but i am really worried about reliablity... do any of you have an 800 820 or 840 kit from any of the builders ive listed>
If so have you had any issues whatsoever...i do mean any issues from really big ones to very minute... I do alot of friendly drag races fast trail riding and mudbogging but i have 3 small children so on occassion i do some really slow long trail riding with them... Ive got the money in hand to get this show on the road i just dont know what route i should take... all comments and help is greatly appreciated!
also just a side not as far as reliablility goes i have an 03 prarie 650 with 12000 miles on her and all thats been done is routine maintanance and 3 cvt belts and thats it...
:D
 

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The vast majority of members on here have a kit from at least one of the three you mentioned, some have a kit from more than 1.
 

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Haven’t heard of any problems with the 840's on brute heads and cylinders. Only head gasket problems with the 700's going that big. If your spending the money to sleeve and bore you might as well go at least 840. Cost is the same if you do anything over standard bore 750. I'm sure going big bore will have its issues such as harder on everything including drive train, cooling issues this summer may occur but just speculating there. I might end up putting a high capacity Fundy water pump in for cooling. But that's the price that comes with double the power.
I've only had mine a couple weeks and its not fully broke in yet so everything is still working well. Knock on wood.
 

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My Brute just got finished up with the AMR 800 kit. Now mine is EFI and made 67.4x horsepower. If it was carb'ed John said it would probably make more. Plus No blow by and I still use the stock heads with stock valves. So there is more to be had in getting oversized valves and getting the heads ported by Glenn at AMR...
 

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Discussion Starter · #6 ·
800 820 and 840 kits

Like i said earlier i will be purchasing a kit from an engine builder by monday...
I just have a number of concerns and would really apreciate those of you that have these kits to chime in and let me know how you like your kit what kind of power increases you had over your stock bike is overheating an issue with any of these kits...I live in mississippi and the heat can get pretty extreme down here mid summer so this is a big concern for me...How many trouble free miles have you guys got on your kits...And last but not least and im not trying to start a builder bashing contest here but what is your take on the best kit for the best price for the most power... Also guys that have these kits for a while are you satisfied with the power of your kit or do u wish you went bigger....
one more thing does anyone on here know of someone that can build me some custom equal length header pipes...
Sorry i seem to be beating this to death but this is a big purchase for me and i want to make sure i make the right choice the first time...( No Regrets)
My family and i ride every weekend from early spring to early winter so i need reliability...
 

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Big Kev makes the custom pipes. I had a Fundy standard 750 bore that I sprayed in a few races but also know Big Kev sprays the crap out of his AMR 840 with no issues also. The 840 will be much faster I know that having both.

Comparisons of two approx. 1/4 mile or so distance was the same is what was impotant for comparision. 750-81 mph, 840-93 mph this is with speedo on pavement with 25" street tires and I went with a JH machine roller clutch that I'm sure attributed to some of the 840 gain along with the big race cams I'm now running.
 

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Mine is at AMR getting an 840 right now.. I done alot of research before having mine done too, for the same reasons, and decided that it was worth the 1500 mile round trip (X 2) !!! It should be done in a couple of weeks.. I took it to Glenn because he came VERY highly recommended.. Also he was a super nice fella, VERY helpful and don't mind taking time to explain ALL your options with you.. He'll get you all the motor he can for your money..Otherwise I wouldn't have taken it THAT far to get him to build it..From all the posts on here, Im sure I won't be dissapointed..:D
 

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Dam I wrote a long post and the browser crashed. But anyway in short I haven't had any problems with overheating with my FCP 840 kit in my 650i. I did have a problem with a head gasket but that was either from the machining of the head to fit the bigger pistons or from the nitrous. Flynt has excellent customer service and I didn't have to come out of pocket for anything when I had the head gasket leak. its been 300 miles since then and have been on a couple big rides with 29.5 laws and also it has had alot more nitrous through it and no problems whatsoever
 

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Discussion Starter · #11 ·
Hey guys

I really appreciate each and every post>>> I want to hear from everybody on here that runs a BBK reguardless of builder and if you had it dynoed i would love to know your RWHP stats, and or issues if any...Just doing my home work as much as possible before i go to spending my funds
Thanks in advance even though i dont know hardly any of yall and live a pretty good distance from most when it comes to My brute i consider all of yall my good friends
Thanks
BRad
owner of Alexander Atv Repair and Custom Parts:D
 

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Doing a quick search of this site will tell you all you need to know and much more.

You should call BigKev he can steer you in the right direction and give you an unbiased opinion.
 

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my 801 is also 67hp to the wheels
 

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My 785 is 68.28 to rear wheels with straight line to over 60 mph then drops to 68. This is on motor only, We will tune the NOS next week. Ran out of time. I'll post pic here and make a seperate post.
 

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Is that with the 418 cams?
 

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Yes it is. The CWR Mach 3's These are the very first cut cams that CWR sent me to test. We have been working on a new grind for about 6 months. Not bad for a small block??
 

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Not to bad from your sig
It sounds like you have a good bit of head work.

IMO mine is no slouch for having absolutely no head work with snorks and on 650 stroke.
 

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I wonder what my new build makes? I haven't see any actual 840 dyno sheets. Vforcemadness 800 FST made 73.7 on VFJ's dyno.
 

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I wonder what my new build makes? I haven't see any actual 840 dyno sheets. Vforcemadness 800 FST made 73.7 on VFJ's dyno.
Where did it reach 73 and how long did it stay there?
 
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