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Discussion Starter · #1 ·
Just wondering if you guys could help me out with my next project which will be an 11:1 piston (686) stage 2 hotcam,springs etc etc AND I WAS LOOKING FOR INFO ON upgrading the stock carbs....I did a search and couldnt find out anything. Which ones to go with? :3question: Also would it be better off just doing a bigger stroke and running say a 719 piston etc? RELIABILITY is what I'm looking for and atleast a minimum of 60rwhp...... :grin_nod:

Any help would be greatly appreciated!
 

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Upgrading or replacing?

A few of the shops, Craycraft used to but I haven't kept up with it, can modify the stockers for a couple/few hundred. For 600-900 (plus intake for 39's) you can get a set of dual FCRs in 35 or 39mm sizes. Most people will tell you to go with the 39's, but if you want to save a few bucks the 35's work very well for most builds. Skip the edelbrock, but there are Mikuni TM and Lectron singles out there that work well. I'd stick with the FCR though.

If you're looking for reliability AND 60rwhp you're better off going with the +4mm stroke and +2mm piston (719cc). A good 686 can make that kind of power, but you'd want a new rod. And if you're already replacing the rod, you might as well get more displacement out of it.
 

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Discussion Starter · #3 ·
I was looking to see if I'd gain HP by swapping the stock carbs out with an upgraded or better designed pair. FCR is the brand? The 719 kit is what I was looking at beside the 686...... out of all the piston brands/rods/etc etc which would you go with maddog? You seem to know quite a bit! I'm new to all of this only owning it just over a month but this setup which felt so good before now feels very weak..... also found a dragstrip in about 45 mins from me tha ta guy built with a true tree and everything that people here in texas go to. Sounds like fun but my stock displacement doesnt belong there and my truck doesnt hook on dirt :grin_nod:
 

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it gets expensive to be fast. 60HP ain't gonna get the job done on a drag strip, you can certainly have fun with it, but it won't be a top tier bike.

To be fully done with a motor to include 39fcrs,dual exhaust and all the motor internals, you need to set aside 2500-3500 depending on what internal components you choose.
 

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03Rappy660 said:
I was looking to see if I'd gain HP by swapping the stock carbs out with an upgraded or better designed pair. FCR is the brand? The 719 kit is what I was looking at beside the 686...... out of all the piston brands/rods/etc etc which would you go with maddog? You seem to know quite a bit! I'm new to all of this only owning it just over a month but this setup which felt so good before now feels very weak..... also found a dragstrip in about 45 mins from me tha ta guy built with a true tree and everything that people here in texas go to. Sounds like fun but my stock displacement doesnt belong there and my truck doesnt hook on dirt :grin_nod:
Keihin is the brand, FCR is the model, and the raptor carbs are duals in either 35 or 39mm sizes. 39mm will make more power, and are best used on a bike with a strong top end. The 35's are more for the mx/gncc type of riding offering a little better throttle response. If you're building it for the strip, definately go with the 39's. But if you plan on spending more time in the trails and can find a set for a few hundred less, look into the 35's. For the same or similar price, stick with 39mm.

There are 2 common options for the displacement, a hotrods crank/rod assembly and custom CP piston or a Barker/Vito's crank/rod assembly and any off the shelf piston. They are similarly priced if you use a wiseco or JE piston for the Barker/Vito's crank. Personally I'd go with the Barker/Vito setup with a 101 or 102mm 11:1 wiseco for reliability. If you're building for the drag strip, you can be sure to drastically reduce reliability and increase service intervals.

Porting and cam choice will have a LOT to do with power output, reliability, and rideability.

From this point what you really need to do is decide exactly what you want the bike to do, and how much money you want to spend to make it do that.
 

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Discussion Starter · #6 ·
CoalShedRacing said:
it gets expensive to be fast. 60HP ain't gonna get the job done on a drag strip, you can certainly have fun with it, but it won't be a top tier bike.

To be fully done with a motor to include 39fcrs,dual exhaust and all the motor internals, you need to set aside 2500-3500 depending on what internal components you choose.

That sounds about what I was looking at spending....guess its time to go shopping!
 

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If that's the route you want to go CSR can get you going with a very good build. There are a couple other good places out there too, you may want to consider if one is close enough to go visit and save some shipping costs.
 

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Discussion Starter · #8 ·
Theres a shop here called Rage Performance. Pretty much eveyrone here goes to them going to give them a call tomorrow and see what the deal is.....

Thank you again everyone for the advice!!
 

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03Rappy660 said:
Theres a shop here called Rage Performance. Pretty much eveyrone here goes to them going to give them a call tomorrow and see what the deal is.....

Thank you again everyone for the advice!!
Just make sure you know what you're paying for. Asking for some dyno sheets to back claimed power levels would be a good thing to ask for. As for the carbs and pipes, no one beats my prices on those. I'll be happy to answer any questions you might have, there are lots of very knowledgeable folks on this site who offer free advice.
 

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When I said others, I meant Kenz, Craycraft, B&M, and sparks. Heck even CT, Trinity, LRD, Powroll, and Duncan would be a better shot than most local "shops".

I just meant that maybe one of these would be local to you and be worth a gander.
 
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