I got my bike back this week and got to test it out Friday night. Trinity installed their new 440 kit, port and polished the head, added an FCR 41mm carb and a K&N filter. This thing flat out hauls a$$. You thought you hit the rev limiter fast before, try this kit out. They are going to have Web Cams create a new grind to optimize the power output this motor now has. My bike is going in to Dyna to have a new ignition box made that will have more spark energy and a higher rev limit. With cams and a new box this thing is going to be unstoppable. It seems to like rpms very well, with enough bottom to pull hard out of berms. With stock cams and ignition this thing is putting out 45 hp. We are looking at the +50 mark after cams and ignition. I posted the dyno sheet for this along with some updated pictures of my bike. The dyno sheet is the 440 kit verses the piped 400 not stock. That is how much of an improvement this kit is. It has a much stronger powerband with a 13 hp increase and 8 ftlb of torque more than the piped version. Dynos are not the same as the next guys, but CT claims 46 hp with a 453 kit and cams, while Yosh claims 46 hp with a stroker and ignition box. Hopefully the chance to compare will come soon.

 

WP-I rode at Pismo last weekend with a guy from Stanton. I can give you his e-mail address if you are looking for people to ride with????

 

is that 440 kit a stroker, big bore, or both?

 

Whats the difference between a stroker and a big bore?

 

Yes I want his info. The more people to ride with the better. I will be practicing at Comp Park on saturday and monday if you are interested. The Trinity kit is a big bore. The difference is a big bore increases the piston diameter while the stroker is a longer travel of the crank by changing its mounting position. With a stroker you need to change the rod or piston to accomodate the longer stroke or add a spacer plate.

 

<< Whats the difference between a stroker and a big bore? >>


Stroker: Same piston diameter, but piston travel distance is increased by changing to a stroker crankshaft. Typically gives more torque at any specific rpm, but motor does not want/need to rev any higher than stock, to make peak power.

Big Bore: Same crank, but piston diameter increased. Depending on what is done to the compression ratio, motor may benefit from higher revs than stock.

 

So wouldn't the stroker kit be more desirable than the big bore kit? Is it alot more money? How about reliability, which would last longer?

 

<< So wouldn't the stroker kit be more desirable than the big bore kit? Is it alot more money? How about reliability, which would last longer? >>


For most people a stroker would not be more desirable &amp; yes it's much more expensive because it requires a new or reworked crank &amp; rod, special pistons, cylinder spacers, ETC &amp; you have to split the cases.

You want an oversquare engine in a quad (larger bore than stroke) These engines rev much higher &amp; quicker than longer strokes &amp; thats better for 90% of quad riding.

With strokers you also get into rod angle &amp; piston speed issues.

So a big bore is more reliable, Cheaper &amp; for most people it's the better choice.