Big Bore ??????

Hey guys. Ive got a 11.1 JE piston(102mm) Mudbuster cam and raptor valve springs setting in my house for my 660 rhino. I wanted to ask some of yall that have done the bigbore kits..Is it worth it?

I wanted alitttle more power. I was going to port/polish also

Is it worth the money to pay someone to do the swap for me? Do you get anymore power that you can tell just by driving it? Ive got 1800 miles on my 07 660 with no problems so far. But just wanted to ask before i done the swap? Dont have money to waste..lol

info please!!!!

Nick , i already told you. it wont last as long as stock.
can you afford to do it. and do it again in a year or so....
big pistons in a small cylender are not the most
reliable. I am just telling you. go to RF.net and read.
them guys go through there motor once or twice a year.

Pay attention. i am only trying to help you.
you dont build a race car motor and drive it to work.
it dont work. Listen to me. its what i do......

Thanks for the info ol buddy..Ive talked to several that have 1000 miles on there bigbore kit but they may be just lucky IDK..lol

I've got a 686 kit sitting here, cylinder and all. Hot-Cam Stage 2, Kibblewhite valve spring kit with titanium retainers, 10.75 to 1 JE piston, rings and gaskets. I'll let ya know.............Braaaaappppppp And it ain't a race motor, it will last as long as the stocker.........

Thanks pate..Im going to need your help if i do it ol buddy :D

Pate, think your 686 Carb motor will beat Chris's 686 EFI motor?

ridepate wrote:

I've got a 686 kit sitting here, cylinder and all. Hot-Cam Stage 2, Kibblewhite valve spring kit with titanium retainers, 10.75 to 1 JE piston, rings and gaskets. I'll let ya know.............Braaaaappppppp And it ain't a race motor, it will last as long as the stocker.........

Never last as long as a stocker woods rideing. never happen.....
but it will be alot faster....

wvyankee2 wrote:

Pate, think your 686 Carb motor will beat Chris's 686 EFI motor?

Hell he is faster than me now....
i just like to woods ride....
Slow and rough..... :D

Wheelin wrote:

Thanks for the info ol buddy..Ive talked to several that have 1000 miles on there bigbore kit but they may be just lucky IDK..lol

there very lucky , alot more wont than will.
but you know i wish you the best.... :D

Jimbo has pointed this out weight, weitht, weigh to HP. The cam is the next step before 686! life. Go for it Nick. your competitive personality deserverses it. If you dont you will say...i wish i would have......................................................

I knew when I saw this thread that it would open a can of worms.......
But here is my applied !
Nick....weather it will last or not will depend on how you maintain and run it...bottom line!
Two examples: my Peterbilt has a Big Cam 3 400 Cummins...they are 400 horse @ the fly wheel. After I got done building it
I have 800 horse to the ground! People said that it won't last, but 318770 miles later......still ticking.
The other 2 blocks that were in the truck had 625 HP and the 2nd had 700 HP. Each went over 1,000,000 miles before they blew, and when they blew, it had nothing to do with the fact that they had way more horse then stock. #1 blew because the cam gear fell off of the cam shaft @ about 80mph....booooooom! And the 2nd blew because there was a leak in the after cooler,
taking coolant into #1 cylinder ...galled the sleeve, ceasing the piston in the cylinder and breaking the rist pin boss....rod came loose and BOOOOOOOOM 2 10" holes in the block! But the bottom line here is that this had
NOTHING to do with HORSE POWER!!!!!

In my drag boat.....502 ci....bout 750 horse....113 mph in the 1/8 mile....ran the boat all the time just ridin around in the lake....water skiing ....but every Thursday afternoon...out to the drags for 4 or 5 passes @ WOT or WFO...never broke.
Pulled it apart 1 time in 3 seasons to check things out......BEAUTIFUL!!

If the build is done right, run right, treated right, you'll have no issues.
One thing that I would look into on the Rhino is their inadequate cooling system....not trying to slam the Rhino here guys...
you wouldn't want to get the engine hot...

DO IT DUDE!!!!!!!!!!!!!!!!!!!!!!!

Foxfire wrote:

If the build is done right, run right, treated right, you'll have no issues.
One thing that I would look into on the Rhino is their inadequate cooling system....not trying to slam the Rhino here guys...
you wouldn't want to get the engine hot...

THIS PARAGRAPH SUMS UP MY ENTIRE THOUGHTS ON THIS ISSUE. Thanks FoxFire - now I dont have to type it.

well im just saving up to get the motor built i guess..everyone says i'll need a better cooling system though

pointless to spend the money on the engine if you cant cool it properly.

I agree with Chris but for different reasons. Why would bumping a 660 up to 686 cause it to fail, If you have a jug that is of the correct thickness and not one bored thin, then it just becomes the same as a stock 700. Now cam changes and compression ratios change things, if it has more compression than a stock 700 motor then it will require a higher octane fuel and the correct timing for the cam. If all these issues are addressed, then it will last as long as any stock motor. The only thing I think might be an issue is putting all this stuff on a 1800 mile motor, 1800 miles is a heck of a lot on a off road motor. Ive read many threads on stock rhino 660's being worn out and ready for a total rebuild at 2K. You might just blow the bottom end out. I would not hesitate to do this to a newer motor but would not on yours nick. I also built and drove dirt track race cars in my youth and built and blew many motors. :(lmao:

GunRunner wrote:

The only thing I think might be an issue is putting all this stuff on a 1800 mile motor, 1800 miles is a heck of a lot on a off road motor.

THIS IS A MAJOR CONCERN OF MINE AS WELL....

(thanks gunny for pointing it out - I missed it in my original read)

Personally I would save that piston and goodies for your next rhino...or sell it.... if you dont think it will work with your next vehicle.

I got to disagree with you guys. I think 1800 miles on one of these motors is just getting it broke in. These water cooled motors last well into 10,000 miles and beyond when taken care of. I work with a guy that has 19,000 miles on a Honda forman 450, and has done nothing to it.

I will agree with some of the other posts though. Increased cooling will be needed with a motor upgrade. Heat is the enemy of these motors and the cooler you keep them the better off they will be. I mentioned before about putting an automotive transmission cooler with an external oil tank on the oil side of these machines. Not only would it run cooler, but the extra oil would be good for it also. It would take a little engineering though, to make it work. I know larger aftermarket radiators for these machines are outragously priced.

Just use a oil cooler of a harley, cheap and easy to install. But i still say if you build a older motor you risk loosing the bottom end due to higher load on the rod bearings from the higher compression. What a honda foreman will go has nothing to due with what a yammy 660 will go being its pulling 3 times the weight. It has a lot to due with conditions and how its been maintained too.

Yes Gunny any time you build the top there is a concern with the bottom. I think a 686 is no issue though. If you go to a 727 or higher than yes it would concern me.

OK.....ya got the better part of the ENGINE apart........rip it the rest of the way and do the bottom end too!!
Now ya got a "New" motor!!!!
DO IT NICK!!!

Big diff in putting on a top end than spliting the cases to do the crank. Hell do it nick, all it can do is go fast or go boom! :(lmao: Shoot if I was going to build it Id go big as possible! Or just paint it up like pate, his looks fast sitting still

()

The only problem is , a Rhino piston is short.
and with higher compresion , i have read thay are wareing the ring lands
and the skerts out.

What the hell go for it. you already got it.
Shit its only Money. .......

i say go for it. i plan in doing mine in next winter. thats if i dont blow the motor sooner. :D

Add Nitrous and a blower, and a turbo, make that baby hump :(lmao: