686 BIG BORE KIT-JE 10.75 COMPRESSION PISTON 102 MM BORE WITH GASKETS- ADDS OVER 6 HP.


First off is this true?

Second, with the 102 mm bore would i have to get machine work done or get a new sleeve. I am going to be getting some extra cash soon so i wanted to do something nice for the rappy.

 

Let me first explain that you arent buying a "686 kit" there, you're buying a piston and gaskets. A kit implies a package of modifications, that "kit" doesnt even include a camshaft. It will add probably 3-4 hp over a stock piston, but you need to get a cam in there to let it breathe. A 102mm piston is the largest that can fit in the oem sleeve, but you will have to get it bored out and honed. JE would not be my choice for pistons either, wiseco makes an 11:1 686 piston that runs on premium pump gas for about the same price you're looking at or cheaper. There are other alternatives but they dont provide any significant advantages and cost 200-300 dollars.

Also, get that degree key out of there, especially if you dont want to run race gas with the 11:1 or 10.5:1 piston

 

There is a WISECO 11:1 PISTON WITH COSMETIC UPPER GASKETS on Vitos for 149.95. Is that what you are talking about? I dont think its a big bore. So with that and a stage one cam would be better?

 

Maybe I'm not being clear. A 102mm piston is a 686, and IMO 686 is not a "big bore" although many marketing departments will try to convince you otherwise. You can get a 102mm size piston from any piston manufacturer that makes them for the raptor, and you can find wiseco and JE pistons literally thousands of places on the web. Most places will sell a number of sizes, ranging from 100mm which is stock size 660 to 102mm which is 686. JE also has a 105mm 727 piston but that requires quite a bit more effort.

Regardless of the piston you go with, it will produce a lot more power in conjuction with a cam than alone. THe camshaft you use is dependant on your budget and riding sytle/type. If you are on a budget or are a trail rider the stage 1 is a great cam. If you'd prefer more top end power and have an extra 140 for valve springs and install costs than a stage 2 will be a good upgrade.

 

Hey man I appreatiate you help. I will most likely get that wiseco 11:1 and a stage one hot cam.

 

Magicracing.com has great prices on wiseco and hotcams products.