Bonneville America Forums Forums Technical Forums Performance Mods Big Bore Kit

Hey guys......Been thinking about a Big Bore modification on my America. Warranty just expired a few months back. Need some advice from those experienced with the mod. My biggest gripe with the America has always been lack of torque, especially in high gears. I'm use to years of riding vintage Indian Chiefs and Harleys which will pull right up a hill without ever down shifting (even with the little lady aboard). With the America, I have to sometimes go to 3rd to keep the motor from protesting. Does this 904 kit really boost the torque? How much? Don't care about how fast it goes (it's fast enough), just give me some good old fashion torque I can use. Not interested in changing too much, other than re-jetting, ect..The snorkle unit has already been removed. Thanks for any members help and knowledge on this.
Regards, Stan

Do a search for big bore with Dingua as the user name, he did it and documented his results really well! I seem to remember him bragging about the Torque...

From what I hear, the Wiseco bore kit is the way to go. And yes, it will give you a good bit more torque.

Benny,
When you come over in September I'll give you the, "See ya later - in my rear view mirror" and you can be the judge. Just don't Sally again.

Want a preview of what you'll see in the mirror?

I see today you're a Pooh Bah, must be some birthday designation?
I'll be nice to you, for today only though, don't get used to it.

Stan, that high quality Wiseco kit provides a double whammy to the Triumph twin.

One: you get the larger displacement, which you already know is a benefit.

Two: this greater displacement helps "tame down" your rather large stock cam. That is, feeding more cubes with the same cam helps pick up bottom end power - at the expense of some top end power, of course. But, you've said you're not looking for more top end, anyway.

Incidentally, have you considered dropping one tooth on your countershaft sprocket?

PapaDean,
Thanks for your imput. I recently switched to an 18" front sprocket in spite of knowing it would hurt my low end pulling power around town, but I do enjoy a more relaxed state at highway speeds. The torque thing with the America has bugged me from day one. As I told Dinqua, I think Triumph was really off the mark with the America's powerplant. They are fast enough in stock form, but if Triumph really wanted to take the cruiser market by storm, they should have made the motor at least 900-1000cc with more real usable torque. If they had done that, I'm fairly certain they would be enjoying a bigger slice of the market. Other than the torque thing, I think the America and SM models are a wonderful alternative to the Harley's and other heavy hitters out there. They are truly handsome machines and handle wonderful compared to other cruisers. At least Triumph remembered their heritage in that regard. Anyway, if I can get my America to pull like my old Indians and iron head Sportster, I'd be real happy with it. Have a great day.
Regards,
Stan