I have a 98 banshee with FMF Fattys, k&n filter,
Ported and Polished, V-Force Reeds, Timing Adv.,
Boost Bottle,
I was wondering how my bike should compare to someone who has a 370 long rod. Thinking of doing some different mods to my bike and was thinking of a 370, but didn't know if it would be worth it for the $.
Thanks

 

hello. i think that if you have a very strong 350, a 370 long rod will be hard pressed to beat you. I have a Trinity Racing Stage 3 420 Long Rod. It is fast. The most amazing thing about bigger bores, is the torque. My banshee is torquier than I would have ever imagined. I have a friend that has a fast 350 bored a little over, probably about a 360, and over 150 yards I can pull him probably 8 bikes. That's alot, but gearing and traction play big parts. He was geared lower and on top-end he could very slowly gain on me. But I have mine geared a little higher to use the torque more, and make it fastest in 1-5 with my 21x12x10 paddles. 6th is too much.
Trinity has dyno charts in some of their ads. If you look closely, you can find one that has a stage 3 420 vs stage 3 350. It shows the 420 making 5 more peak hp, but lots more power all the way through. If you compare a stage 3 420 to a stage 4 350, it might be closer in a drag race, since the rpm's are all the way up.
It is hard to speculate about a 370. I think it'll be a close match, if everything else is the same between the two bikes. As far as the long rods, they don't make much power. See Trinity's website and look at their 420 regular rod page. The only advantage of long rods, is that they are supposed to be ease the sidewall pressure of the piston on the cylinder wall, and maybe they might let it rev an extra 100 rpm. Very little. The only reason that I went with that package is because I wanted my crank welded, and new crank bearings installed and I was having Trinity do all the labor anyway.
If you are going to invest in a bigger bore, I would consider spending the extra money and getting the 420. The 370 would be a 66 mm piston
and mine is a 70mm. But is a lot of money for not much more peak hp.

Daren420

 

Daren420,

Does it add so much torque that it would make trail riding easy without having to stay on the pipe all the time?

 

Let me describe my motor a bit. First of all, I went with dual carbs instead of a single for more top-end. Secondly, I have Paul Turner hi-rev pipes. It can be ridden easily in the woods, but you had better hang on. It is really smooth, instead of one hard hit, it has a smooth hit. When rolling along on hard packed dirt, I can roll on the throttle slowly and when it hits that certain rpm, it will lift the front wheels in 3rd gear. But, it is not a "point the front wheels at the sky wheelie," it is more of the "front wheels off the ground a foot, gaining speed really fast wheelie." It is a very controllable powerband. Actually when I first put it back together & got it jetted right, I went for a test ride. I was disappointed. It didn't seem like what I thought it should be. It pulled hard in the midrange, and top-end just felt flat. I thought something was wrong. Then when I took it to where I ride (sand), I was able to see first hand how it ran. It screamed. Don't get me wrong, I'm not saying that it's all that. But I will say this, I can beat almost everyone where I ride (drag racing) including a 250r with a cr500 motor on nitrous. I have raced one amatuer flattrack race this year, I won my heat, I won the dash, and I won the feature. I have trailridden my 'shee. It does it all better than I ever expected. It does run a bit warmer than a stocker, but I haven't had any problems. The reason why I built this particular engine: I didn't want a drag race only engine, but I wanted it to be competitive. I went for more cc's and less porting. My friends have ridden it, and can't believe it. I would have to say that as far as I know, it is the best all-around engine package available for the banshee. It's still not a four-stroke, but the most rideable banshee.
Another thing about my bike that helps is that I have a 15 tooth front sprocket on it (14 is stock). It spreads the gears a little and makes it more rideable. A friend that has a banshee w/pipes rode my quad. He was surprised. Although he knew how fast it was, he said it actually felt slower, just because it didn't have that big hit.

Daren420