how wild can a 686 be built?

i am really wanting to build my motor in my 07 660. i was wanting to do a 720 stroker. i was looking on weller racing site to gauge prices and about fell outta my chair. $1,900.00 for just the kit  .. and i would still have labor ontop of everything else that i need besides the kit. my motor is bone stock right now. are 686 kits all the same power gains or it all depends on how you build it and who builds it? this is my first motor build so forgive me for the stubid newbie questions. i want bottom and mid range power i dont need to do 70 mph i really dont care about top end. i dont use top end. i ride mud , rocks , trails , hills , creeks. the only place my rhino get to see speeds over 30 mph are on the coal roads cruisin. can i build a 686 that will put a smile on my face and get it done for 1500.00? i dont wanna build a motor only to be disapointed in the power gains!

I have not done it yet but from when i talked to James he told me for about $700 in parts i could do a 686 with a cam and that would really wake it up.  Sorry i cant give you any real world feedback but from what i saw it shows like you should gain about 15 hp with that build (stock hp is supposed to be 22-25).  So if you look at percentages that QUITE a large jump.  Anyone who has done it PLEASE feel free to correct me if my research is wrong!  I still fully plan on doing this to mine but right now im looking into another endeavor (kinda non rhino related) that will take my tinkering time so i see no point in ordering parts just to have them sitting in my garage.  But this other endeavor looks like i may have to wait for a while for it so if thats the case i will do the Rhino's engine in the mean time.

good questions guys i'm in the same boat if i'm keeping the old girl then the motor mods in my near future just don't know 686 or stroker some real world prices and facts are what i'm looking for also

as much as I would like to do the stroker I think the best bet for me money wise is going to be a 686. I don't have 2000 - 3000 to dump into a motor. hell a grand is gonna be tough for a 686 but I gotta do something my rhino is a dog and that's giving it credit. but I will say it still gets the job done everytime!

Just a cam , will give you a VERY noticeable seat of the pants increase...pipes , not so much , until you do the cam.

by doing the work your self you can build one fairly reasonable , had not been for having to replace my head (1800.00) could have done the stroker and piston (102mm) for 1,000-1,200, my crank was 400.00
piston & rings were 180.00 an another 100.00 for boring , but then I kept seeing more things to make it more reliable, billet middle gear support I think was 200.00, you can start getting parts a little along till you get it all helps not be a chuck out of pocket all at once , but get a good manual an study up on what you want out of your motor  ,  by the way I love my stroker

I would have to agree I love my stroker to. I did mine in steps some what I guess I did the the cam & throttle body first then piston then I guess I said the hell with it stroke it and glad I did haven't stopped smiling since.

Teddy, aka "Mr. HP"...lol...aka "Mr cc".. must be nice... 

Ok JP I said sorry about the redneck family comfort ride comment. Lol

mike734 wrote:

i want bottom and mid range power i dont need to do 70 mph i really dont care about top end. i dont use top end. i ride mud , rocks , trails , hills , creeks. the only place my rhino get to see speeds over 30 mph are on the coal roads cruisin. can i build a 686 that will put a smile on my face and get it done for 1500.00? i dont wanna build a motor only to be disapointed in the power gains!

 just take it to James  for a weekend

as much as I would like too he is 8 - 9 hours away. that's alot of driving. drive down drop it off drive home then back down to pick it up then back home. hell I`ll have more in gas then the build of the motor.

I did the 686 from Alba and got the MSD programmable at the same time, let them know about forum and they may help you on price. Either get a mudblaster cam or get Alba to make you one. Then either JBS or machined sheave and you will be amazed. Oh yea don't take a shortcut like me. Get a good middle drive plate!!

doughjk wrote:

I did the 686 from Alba and got the MSD programmable at the same time, let them know about forum and they may help you on price. Either get a mudblaster cam or get Alba to make you one. Then either JBS or machined sheave and you will be amazed. Oh yea don't take a shortcut like me. Get a good middle drive plate!!

then you gotta open the case and that's when it starts costing you.  but your right middle drive plate does need to be upgraded

I really should do the support I am running heavy ass 28s now and going to 30" mudlites soon.

If you change middle drive plate while everything's in good shape I don't think there would be any additional cost except maybe a couple of shims. If you have top end out for bore, your almost there, $150.00 bucks and your worry free.  I'd hate to guess how much I've spent so far, busted both cases, oil pump and relief valve, gears, bearings  etc...

p.s. while engine is out check nut in front u-joint mine was very loose, may have contributed to failure

Loctite every bolt and nut you can,billet middle drive is a direct replacement with oem shims....how hard can a 686 be made to run....a bunch....a stock 660 on a chassis dyno I used made 20rear wheel HP....A built stock bore 660 I built for a buddy with a killer topend and stock bore and stroke with a good piston made 50 rear wheel hp....we figured a loss of 20rwhp through the drivetrain based on factories engine HP assumption of 40 crank HP...the overbore by 2mm really doesn't amount to anything more....save the bore, go the next size over from what you have...the power is in the upgrades not the overbore...that built motor had a nice duners cam and duners clutch in it, it wasn't a x11 race cam or a super lightened high rpm clutch to clarify, which will show more power....he dunes it all season...

hey Nate, any special pricing on the 734 kits for us 700 guys?

I built a 720 stroker and disappointed the power isn't there for bottom end. I may get slammed for this but about to sell it and put a sportsman 800 and trans in this thing.

Maddox wrote:

I built a 720 stroker and disappointed the power isn't there for bottom end.    I may get slammed for this but about to sell it and put a sportsman 800 and trans in this thing.  

then shoot me a price. I`ll buy it , fix it and tear shit up with it.

What you think it's worth? I believe this build is a haul ass top speed not a mud toy build.

ah then im not interested. I ride mud , hills and creek beds. I want bottom and mid I could care less about doing 60mph.

That's me I built thinking it would be a torque monster. I'm running ol2s and could care less about anything over 30

yeah I jus put 28" mega mayhems on mine.

I'm going to get a wide band and try some tuning cause you would think this thing would have more bottom end. I first had 12oz weights in my jbs sheave and a 1mm shim but it would run way to many Rpms. I jumped up to 14s it mellowed out some and also removed shim cause belt was touching the box. Just frustrates me after spending thousands of dollars and when we ride in a group I'm always getting pulled out by stock bikes with 31s and bigger tires. I actually had more fun when my rhino had the 450 motor it seemed to crawl better

Maddox what cam are you running , look at my set-up mine is great bottom end an pulls good through top end my 720 stroker is a great set-up may want to talk to James but I think you got the wrong cam for your riding style