I am seeing lots of fast quads, 673's, 686's, 720's,760's. After tearing mine down again the other day for a check up, update, i am begging to wonder if the boring has that much to do with it. I can see adding a 100cc or maybe even 50 will help some, but how much does 20 or 30 really do. We are going to build a stock bore soon so we shall find out. I was just wondering your thoughts.

 

I think the only advantge to a BIG bore machine is to improve the Torque curve. As you know, once you start going after that TOP END rush, you sacrafice the low end power, So going to a BIGGER bore brings along the Bottom and mid Ranges and makes a better more ridable machine.

I definatly believe that there is little to NO performance gain by just a FEW cc's. DSmike is proof, That a stock bore engine can compete with engines that are BIGGER in size.

So to make a long story short, I believe that the Motor packages like the 'PAMI 760' "IS" worth the money. Randy has DOne nothing but FLOGG the hell out of that motor since he has gotten it, SOo it is DEFINATLY reliable, And he has fended off ALL competitors(so far), and still stands on top. And all this, without turning a wrench, and still on pump gas.


Biggerisbetter. [img]i/expressions/face-icon-small-happy.gif[/img]It's not just a name, Its a fact!

 

I don't have many thoughts, all scattered, but am intrested in the stock bore build. There are a few DS guys that have acheived great numbers on a stock bore. I thought that the 686 was used more for the porting than the bore size.

 

Bigger- pump gas???? Only 93 around here. I thought he was 107 plus. anyway i know what you are saying

 

I dont think boring is the key to power. I have heard of some really fast ds's with stock bores. getting the bike breating is the key in my opinion. exhaust and intake mods, cams, high comp piston, dual carbs and I think some port work and maybe bigger valves and it should be up there with the top runners.

I have seen some stock bore banshees that rip it up real good. Actually some of the fastest banshees I have seen have been 350's.

I have decided to leave the Ds as is and buy a banshee.

I am going to try and see what I can get out of a stock bore banshee. It should be a fun experiment. And I will still have the ds and raptor to play with.

Later
Bat

 

Batoutahell,
I know people on this forum love to bash everything DirtWheels prints, but I thought I'd bring this up anyway. The August issue (the one with the now infamous shootout with the Z400, Cannibal, and 400EX) has an article about a stock displacement Banshee project. The Dyno run was not at the shop that performed the work, if that matters. They got almost 60HP out of the thing.

 

the size only makes a small amount of difference, it is mainly the flowing. if you heads and cam and exhaust won't flow than you arn't going to make power. i guess. mines to slow to base an opinion.[img]i/expressions/face-icon-small-sad.gif[/img]

 

raptorboy- How is she doing?

 

It really depends on # of things. If your valves are shrouded by the bore, then an overbore is going to help flow more so than one that isn't shrouded. As previosly mentioned if the cam, displacement, portwork, intake, carb, and exhaust are all matched and tuned well it will be one hell of a combo.

 

Big bore is cheap horsepower. I only upped my bore 50cc's but I also did a lot of other things as well. It made a night and day difference for me. I can hang with 400EX's, R's, and Raptors on the motocross track.