I've been thinking about upgrading and going with a 686 kit. Basically what I want to know is how everybody likes their engines and how much upgrading has been done to them. I'm kinda stuck deciding if I want to put up the cash to go with porting in addition to a piston and cam. I know that this will really help but how much power are we talking about??

I still want to stick with the stock carbs even though I know I can get more out of FCR's. I might decide to go with them in the future but for now I'd like to stick with stock. Also if I go with a cam, I'll only be going with the stage one. Stage two sounds like too much of a jump and it looks like it will require some major port work to make it worth it.

So what's the story? How much good it it going to do bumping up the 26 extra cc's in addition to the higher compression?

If you could give me some sort of idea on the pricing that would be appreciated too. I have the pricing for the parts and boring but I'm curious about porting cost.

Thanks for the help in advance!

 

Black Widow- The craycraft 686's are a wicked ride. Play at the strip then hit the trails. Dollarbillz has run faster than 5.0 in 300 feet thru stock carbs and Crafty's 686 on race gas has run a 5.003 thru the stock carbs. He will break 5.0 the next trip out as he can improve his 60 foot times. Ryans 730 will rip below 5.0 when he decides to let her rip. (easier said than done by far) lol

Now your question on the 26cc's. Is it important?? I used to think not but now i do. I have been messing with a stock bore that has all the stuff the craycraft 686's have and it will most likely never break 5.0. I thought i could but the extra torque of the 686 is missing to get the great times. I thought that reving out of top would make up for it. So far it has not. After 2 trips to the strip a 5.3 is the best. The 60 foot times are slow (me) and not the quad. 2.05 on average. Lauching harder to get a 1.9 is reasonable expectation which will bring the time down to 5.1

Give Bob a call and get your own. [img]i/expressions/face-icon-small-smile.gif[/img] There basic 686 will make more power than most 727's that i have seen from other builders.

 

Porting with a valve job is like $400 and if your doing a cam and piston I think it would be worth it. On a 686 I don't think you'll see much if any more power with the FCRs over modding the stock ones but it will get rid of the slides bouncing from hitting jumps and that kind of thing.

 

I have never had any problems with my 686 Craycraft, pulls very hard.

 

FCR's are not bolt on HP. Only when you can not feed your motor with the stockers should you go to the larger FCR's.


But the throttle response is greater on the fcr's.

 

I have the 686 12:1 with Stage 2 and Craycraft's porting/coating. There is NO COMPARISON between a bolt on Raptor and one of Craycraft's 686 builds. My Raptor is like a wild mustang that you've already ridden one time, it knows you can hang on but it's been thinking of ways to hurt you the next time you get out the saddle:-)

I fought with the stock carbs for a while, gave up, and ordered FCRs. Now, Craycraft has replacement parts that can fix the problems with floats/needle valves and race gas at much less $$ than the FCRs. The FCRs give a big boost to low end performance but I'm not convinced they add anything to the top end. The FCRs are much more tunable than the stockers but without a dyno and gas analyzer, it's impossible to fully dial in all the adjustments.

I take meticulous care of all my machines but I don't hesitate to run the ***** off them and my Craycraft Raptor build is more reliable than I ever hoped. Mine is set up for MX but I can swap tires and go for a ride with my buddies in the woods without any worries of overheating or poor low rpm performance. When I was weighing the decision for porting, Bob said it was worth another 4-5 HP over the stock head. The high temp coatings are insurance if you run on the ragged edge of lean. Save a little longer and get the full blown 12:1 with Stage 2 and porting/coating, you won't be sorry.

 

I have the same setup as UBETRUN, and I am every bit as excited and proud of my THUMPER. I can't wait to compare it to the sparks engines supposed to be here Tuesday? We will see?

 

Dang!! I thought you were suppose to get that stuff last week,

 

Yeah, we all did about 6 months ago. We are usually guaranteed the engines about every two weeks. So after they don't show up on tuesday, it will probably be sometime in October, then November........

while I'm getting faster and faster

 

Raptor660fam- Which tuesday?? There are 52 of them in a year[img]i/expressions/face-icon-small-sad.gif[/img]