The first 10 HP cost you about $500 the next 10 HP will cost you another $1000 easy on top of that and the next 10 HP will cost you another $2000 on top of that. HP=dollars squared.

 

Hey Capt, going from 660cc's to 686 is only a 4% increase in displacment. If the engine had the same volumetric efficiency this would only give you a 1.6hp increase (based on 40hp) that's what a good stk with pipe Rap makes on my dyno.
The big change is with porting, compression, cam, carbs and so on.
Our trail Rap 686's make about 60 rwhp and yes it is night and day differnt over a stk piped rap.
Hope this helps,
Ray

 

It is a little surprising that more people dont worry about torque as much as horsepower because it can be as big a factor in performance as overall horsepower.My 686 with just a piston and air filter with a pipe and header is probably not putting out too much horsepower but the low end pipe that i use combined with my fat main jets performs very well.

 

Well i'm having everything done. 686 bore, Higher comp piston (can't decide on 11:1 or, 12:1 JE but, need to soon it is going in shortly) stage 2 cam, port polish head, bigger/better valves, carillo rod, HD Clutch and, springs.

From what i'm gathering I "Roughly" w3ent from stock 35 Hp to maybe 45 with my pipe&jetting, proflow and, K&N. Now i'm having the rest of the stuff done and, it is a little over 5 more HP for 2k (low to mid 50's). I think I made a big mistake!

I did this hole thing to try to compete w/ my buddies Banshees and, YFZ 450s who have a bit of work done (450's just pipes). We ride all types of terrain from the dunes, to trails, to MX Jumping. Wanted a reliable as possible but faster enigine and, i'll be gfetting a slightly faster time bomb for all that dough? )@!$%!@#(@_)(@!$_(&!W@#)*@&R#_)~@($_)@~%$_(*!!!!!!

 

You should have closer to 55-60 HP if you get your carbs dialed in. You won't think it's a waste of money when you ride it. A Banshee is cheap to mod, if you don't have more money that your Banshee riding buddies, you won't beat them on a Raptor. Start thinking about suspension improvements, you will have much more motor than the stock suspension can handle when your 686 is done. You're not getting a time bomb, that's a good reliable build. If you can get race gas local, go for the high compression motor.

I agree with sixsixT's analogy that it's $$ squared but my experience has been a little more expensive when you add in the other stuff needed to feed/control a bigger motor. $500 for a pipe and filter for 10 HP. $1600 for a high compression Craycraft 686 and another $800 in carbs for 10 HP. $5000+ for a ***** to the wall Ti 730 and all the parts to feed/control it for 10 HP (?). Without running funny fuel, NOS, turbo, etc., I don't think it's possible to get another 10HP (80 HP) at any price.

 

"Race Gas"???? I can get 100 octane and, 103 octane which is Race Gas in my view at quite a few local gas stations. I can get 110 at the dunes (4 hours away) and, 1 place near my house (not as easy). Can 12:5:1 run well on 100- 103 octane? If 11:1 will run on the high grade 93 and, any pump?

 

You could have traded it in and used the money you spent for the difference and got a piped YFZ and been a better all around machine, although maybe not as comfortable.

 

Thomez - Wow, that helped my desion. Seeing the 450 came out 2 months after i bought my Raptor and, no one knew anything about it at the time. Buying that wasn't even an option. So know, instead fo deciding on compression with my motor apart on a bench somewhere in AZ i'll tell them to take my motor and, trade it in a their local dealer. Brilliant!

Speaking of the 450.... It has 11:1 or so compression right? and, you run premium pump gas (92-3 octane here) in that right?

 

2004LEBanshee - a craycraft 686 w/o carbs or rod runs around 1600 + shipping. Every build can be different, so call him to find out for sure.

Capt bags - the yfz is a 11.9:1 comp ratio and runs on premium from the factory. Since the stock pistons are questionable at best, many people have been opting for the 13:1 gtyr piston and just running 104.

 

I think a 686 like mine with the FCR's, oversized vavles, and all that good stuff will put out 60-65hp. I like to think that anyways, and it certainly feels that way when you open her up.