790/865

[fergie]

What year did the regular bonnie (not the t-100) start getting the 865cc engine? Looking to buy a new(ish) bonnie and want to know what I'm getting. Also is 2005 the first year of the 865 in the t-100?

 

[Kirkus51]

pretty sure 07 was the 1st year of all 865. If it wasn't 07 then it was 06. My black is an 865 and it's an 07.

As near as I can tell absolutely no kind of difference in performance. the 790s had hotter cams.

 

[dschief]

Yep. 2006 was the last of the 790s.

 

[rodburner]

As near as I can tell absolutely no kind of difference in performance.

That doesn't say much for the high and might 865,does it?:lol3:

 

[Jimbon]

The extra 75cc of the standard 865 gives an extra 5hp and 5ft.lbs torque over the standard 790.

 

[dbacher06]

The 790 does have a different cam. No difference between the two. I have a 790, with tons of upgrades, and it makes more power then almost all the 865. Most people with Bonnie's are addicts and mod everything. Don't rule out the 790" if you can get a good deal on one.

 

[dschief]

To me, the 790 is a revvier engine, which equals more fun. The 865 has better low end torque, which equals smoother take offs from a dead stop.

 

[Sal Paradise]

I didn't want to waste a thread on this but - MY GOD IS MY BIKE RUNNING GREAT.... its a friggin dream, better than new. 2005 856 motor with minor mods,,,

 

[fergie]

I just missed a 2001 bonnie with 23000 km. for $2500 . It was on the local classified listings for all of a 1/2 hour. Owner said that he had not ridden it in two yrs. Just needed a tune up and cleaning

 

[GF]

I just missed a 2001 bonnie with 23000 km. for $2500 . It was on the local classified listings for all of a 1/2 hour. Owner said that he had not ridden it in two yrs. Just needed a tune up and cleaning

that sucks big. good luck w your search.

 

[msc66]

I just missed a 2001 bonnie with 23000 km. for $2500 . It was on the local classified listings for all of a 1/2 hour. Owner said that he had not ridden it in two yrs. Just needed a tune up and cleaning

Wow!

 

[Speed3Chris]

To me, the 790 is a revvier engine, which equals more fun. The 865 has better low end torque, which equals smoother take offs from a dead stop.

I guess it was inevitable that fans would come out of either engine size. Early 790's had good cams...or at least a better intake cam...exhaust cams are not far apart on any of the bonny motors...intake cams across the board can be better. Its the cams that give the early bonny its rev'y nature. All said, I prefer the 865 motor...replete with lousy cams. Simple reason is the added displacement is in bore and not stroke which doesn't detract from reviness...word . Its the cams that give the 790 its character...that and an ignitor with more timing advance. This is simply resolved with a Pieman ignitor with even more advance than the 790 stock box. Install either Thunderbike or TPUSA cams in a 865 motor and now you have the best of both worlds...hp and torque. If you think about it, the 865 is a bigger big bore kit to the 790 motor than the 904 is the 865 by a pretty large percentage so, that puts into perspective how important cams are to instilling the character and horsepower of a motor. Growing displacement most have said that have done it is more about torque than hp. Lack of displacement and torque is why 790 bikes came with a 17t front sprocket which made the gearing shorter in 5th for cruising as well. It did help fill the deficit of torque of the smaller motor however. Install the same sprocket on a 865 bike and now you have a revier bike. Extrapolating from the engine size comparison is why I am more a fan of high compression pistons for the 865 versus installing a big bore kit, though a big bore kit is more of bonus on the 790 engine size. The small increase in displacement for a BB kit with 865 motor isn't as much as a game changer as is the big jump in compression. Both motors need more cam, compression and ignition timing.
My thoughts.
PS: Sport bikes teach us that a lot of hp can be attained with smaller displacement. They get there by just what either bonnie motor needs...more cam, compression, ignition timing...and carb/TB size...budget permitting of course.