# high comp kit and cams for brute 650 , where to find?



## guimond47 (Oct 22, 2009)

hey guys, ive never done boring in my life but i have done top end motor work before and rebuilds, i just need help to find the right high comp kit for my brute and cam s for my needs. i would like to get at least a 700cc outta it, would be nice and a nice set of cams, all i do is go deep and mudding soo im looking for more bottom end-mid range power. 

okay now lets start. how do i bore out my cylinders? do i need a machine shop to do it? and what set of cams would be the greatest , where and what kind of high compression pistons should i get. do i need to rejet after this? i need to know a good step by step how to because i dont wanna cut the reliability of my brute. when i ride its always full trottle so im looking to get more out of it. what compression ratio do i need, i still want to run off 91-94 octane pump fuel as well. thanks, a few links or recomendations would be nice  

Steph


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## Waddaman (Oct 3, 2010)

For reliability and making it a lot easier on yourself you'd be better off buying a kit from a builder. All you have to do then is send your money, cams and cylinders to the builder. You will get back bored/honed cylinders, bigger cams, pistons etc etc, and all you need to do is put it back together. 

You should be alright going 12.5:1 compression with 94 octane, but be warned with more power means more broken stuff. You can't go wide open through mud with the extra power, you WILL break axles, diffs, tranny, and various other expensive things. With that much more power you must have thumb control or you'll regret it.

All you need to do is look at my signature to see which builder I recommend, couldn't be happier.


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## guimond47 (Oct 22, 2009)

yea, in mud i do control my trottle because ive had broke things before and now i have learnt and take it easy , i mostly go deep in ponds and lakes, not big fan of mud anyways


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## guimond47 (Oct 22, 2009)

having a hard time trying to find high comp pistons, any links?


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## Brute650i (Dec 17, 2008)

For 650 stock bore its gonna be hard to find any good pistons. 


Best bet will be find stock 750 cylinders and their are a lot more options


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## guimond47 (Oct 22, 2009)

ok well say i were to buy 750 jugs, does my bottom end need boring as well? and can i use the 650 cams/ heads? or can i use 650 heads / 750 cams, or does it have to be 750 heads and cams.. can i use my 650 carbs at least? and what about my dyna black box ? will that work with the 750 top end?


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## Brute650i (Dec 17, 2008)

On a 650i the cases shouldn't need bored to fit the cylinder only on 650sra if my memory is correct. 

The 650i everything else swaps over their are only minor differences between 650i and 750. It is a direct swap. 

When you go aftermarket their is no such thing as 650 cams and 750 cams as they are a direct replacement. 

It is as easy as replace 650i cylinder with 750 cylinder and reassemble with pistons and cams of your choice. . This will make it a 715cc. 

I would check with dsc he has a sale going on right now


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## guimond47 (Oct 22, 2009)

Oh really its that easy  wow perfert i was worried that i was gonna have to get new heads, carbs , black box chip lol oh and one more question . How bout the connecting rod? Is the 650 smaller then the 750 or?


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## rmax (Nov 21, 2009)

rember the 650i heads have smaller combustion chambers than the 750 ,= more compression ,so if you go with 11.5 to 1 750 pistons you will be around 12 to 1 , if you go 12.5 to 1 you will end up around 13 to 1 , that may not wok out with pump gas , i run a mix in mine 4 gal 93 non enithionel to 1 gal 116 vp race fuel an 1 step down cooler plug dpe8e works well with my set up ,also builder piston are for the most part a more true 11.5 to 1 than off the shelf pistons like say weisco, if you go with off the shelf you will be ok running pump gas


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## Brute650i (Dec 17, 2008)

Rod lengths are different between 650i and 750. 

You can put 750 crank and rods in 650 but you have to change both to make that work.


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## J2! (May 8, 2010)

My bike has the 650 motor in it and when I did the 840 I put a 700 crank and rods in it. With the stock crank it would have been an 801. I used AMR with his 12:1 and 2X cams. Diamond pistons and Web cams. Used my stock heads and stock carbs to save some money. It will run on 93. And if I remember right I think Glenn said he had to bore the cases for the 750 jugs to fit, not 100% on that.


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## guimond47 (Oct 22, 2009)

ok well then if i get stock wiesco pistons for a 750 with 750 cylinders, would it be okay to run pump gas super 91-94 on 12:1 compression ratio or can i get like a 13:1 and still be ok. im just trying to figuer out my number that will work great for my set up and wont be breaking the bank too much. and since the rods are shorter in a 650 then a 750 wont it have less of a stroke with 750 jugs and pistons witht the shorter 650 rods ...? ending with less compression?


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## guimond47 (Oct 22, 2009)

I ran into a guy in town that specializes in kawi and does the same clutch work as vforce John on the lathe... Back to topic he told me that 650 rods are 3mm longer then 750 rods. So if i were to throw 750 cylinders and stock 750 pistons it would make it high comp because my rods are 3mm longer then the 750 rods. Correct.? Now if i were to cam it. How much more clearance would be tolerated ? He told me that i wouldnt be able to clear a big cam without cp pistons that have big cam indents in it... Or i may be lucky with a small mild cam... Chim in please guys thanks


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## Waddaman (Oct 3, 2010)

A 650i's stroke is 3mm less than a 750i - You can just google each models Stroke.

But the 650i and 750i have different crank and rod part #s and Brute650i already stated the rods are different so.. if there longer or not i do not know.

Stock 750 pistons are not going to make it high compression unless you consider 8.8 high compression.. lol. (different cyl heads on 650i so it will be a tiny bit higher than that but not much.)

Yes you will need some real pistons with decent sized valve reliefs to run a real camshaft or anything bigger than a basic hot cam.

I still stand by my original post made 2 years ago..... If you want these parts/power you need cams/pistons.. which is what all builders sell and you know they will work, simply drop it in. Why buy all the seperate parts and go through all that work for really nothing??


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## guimond47 (Oct 22, 2009)

Higher comp pistons are slightly longer then stock pistons and thats what makes them high comp because there's less clearance between the piston and head at combustion point. Now like i was saying sapossibily the rods are longer on a 650. Meanin i wouldnt need these high comp pistons. The rods increase the stroke. I know for a fact the cranks are the same . Thats false info u just told me. The difference start at the rod bushings (colors) and up. Anyone else wanna chim on this.? U cant buy a 750 "kit" that high comp from a 650 hence why i have to do this lol


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## Brute 840 (Feb 9, 2012)

wrong wrong
the 750 crank is different than the 650 crank,the rods are longer on the 650 crank do to the shorter stroke on a 650 crank and if you were to put 650 rods on a 750 crank the pistons will not have the clearance needed to run the motor
if you go with a 750 crank you will Need 750 Rods,if you use a 650 crank you will need 650 rods,
a 840 piston on a 650 crank and rod is 801 and on a 750 crank is a 840 if you just put 750 jugs on your 650I bottom end you will have a 715,do your home work talk to builders before doing anything!


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## guimond47 (Oct 22, 2009)

I'm talking to a builder but he only knows 750i injected. Not carbs ... Soo see this info that u guys are giving me is big help!

---------- Post added at 02:00 PM ---------- Previous post was at 01:40 PM ----------

Ok . With that being said. With my 650 crank and rods. Going to an 840 big bore.. Will i clear an aftermarket cam. I'm looking at the 11.1 cp kit 840 big bore


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## Brute 840 (Feb 9, 2012)

if it is shelf CP pistons I am sure the valve reliefs aren't deep enough,you are better off getting a builder piston and cam


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## chevzr2 (Nov 25, 2009)

guimond47 said:


> I'm talking to a builder but he only knows 750i injected. Not carbs ... Soo see this info that u guys are giving me is big help!
> 
> ---------- Post added at 02:00 PM ---------- Previous post was at 01:40 PM ----------
> 
> Ok . With that being said. With my 650 crank and rods. Going to an 840 big bore.. Will i clear an aftermarket cam. I'm looking at the 11.1 cp kit 840 big bore


I went threw this last summer building a 650/801 kit, I used a dsc 840 bbk on a 650i carbed bottom end, stock 650 heads will not work, the crown on the high comp pistons will hit the combustion chamber, you have to clear the heads, basicly griding them down which I would say not to do, or use 750 heads, which I did because I had a few parts bikes kicking around.

I put 750 fuel injection on it with a msd, I custom tuned a tune I got from a member, that bike friken rips hard (fak and I built it for ths g/f too) it kills my 2012 750 brute with digitune and muzzy pros, basicly like I am standing still when she pulls away on me when i'm flat out at 66 mph on the hwy....I have 28" s/w ol2's she has 28" s/w mega mayham's....
I had he 801 up to 86 mph on gps, before its final tune/clutching, its nuts, makes can am 800 cry and 1000's scratch their head....lol


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## 2010Bruterider (Jun 20, 2010)

chevzr2 said:


> I had he 801 up to 86 mph on gps, before its final tune/clutching, its nuts, makes can am 800 cry and 1000's scratch their head....lol



Sweet! What cams did you use? It sounds like you created a monster.


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## chevzr2 (Nov 25, 2009)

2010Bruterider said:


> Sweet! What cams did you use? It sounds like you created a monster.


I used the stage 2 cams from dale a dsc, its part of his kit, going to take it out to its first mud bog in the morning, see how this beast does in the pit against all the canned hams around here in Manitoba Canada!


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