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Discussion Starter · #1 ·
I am not the mechanical type, but if anyone could explain to me the enormous difference in power output from these 2 engines I would appreciate it. Also I noticed a vast difference in dry weight. Can’t Triumph make The Bonneville lighter? My old 750 special was only 180 kg!
The 360o crank sequence, offers the best option for producing maximum torque and most importantly, the best possible exhaust note from a parallel twin.
Note that there is a 67cc difference between these two engines.


BMW F800
Water-cooled, 2-cylinder, 4-stroke engine, four valves, two overhead camshafts,
798 cc. 360o crank
62,5 kW (85 bhp) at 8.000 rpm. 86 Nm at 5.800 rpm
Electronic intake pipe injection/digital engine management (BMS-K)
Dry weight of less than 419 lbs (182 kg dry)
More than 200 km/h
At 120 km/h there is a claimed fuel consumption of 4.4 L/100 km

Bonneville
Air-cooled, DOHC, parallel-twin. 360 degree firing interval. 865cc
Twin carburetors
Weight 205kg (451lbs)
Max Power 67PS (66bhp) at 7,200 rpm
Max Torque 71Nm (52ft.lbf) at 6,000 rpm
 

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Engine is built in a Rotax plant and they worked with BMW to develope this engine. Bore/stroke 82.0 x 75.6 mm (3.2 x 3.0 inches). Nice bike, way high tech though comepared to the Bonnie.

Nice spec site F800 specs

Good review site F800 review

I would like one but there are very few motorcycles I would not like to have one or a few of.
 

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They're both parallel twins, the similarities end there.

Apples and Oranges.

If I was a rich man, I'd be having me one'a dem bad boy Beemers! I can only hope that they come out with the rumored about F800 'Sport' version.

I sat on yer basic F800 at the International Motorcycle Show, and the danm thing fit my shortass juuuuust fine. But I guess they have issues right now, shifting or some'n.

The Bonnie ignited in me an appreciation for inline twins again, and BMW made me an elitist for 60,000 miles aboard my 1150 Roadster. I would LOVE to make that Beemer F800 some kind of Hooligan Rat bike and park it in the middle of a bunch of stuck up RT snobs. :razz:

But..... go on a ride with them RT snobs? AH HELL NO, them mofo's know how to ride!!! Especially the quiet unassuming old guys with Orange reflective triangles on their backs......
:-D
 
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Discussion Starter · #5 ·
Thanks sweatmachine, I guess that makes sense but how about the weight issue, can they make it lighter?

Boneville; Bore/Stroke 90 x 68mm
BMW; Bore/Stroke 82 mm x 75,6 mm

I don't want to go off topic but I noticed in an issue of Classic Bike a 1942 250cc supercharged liquid cooled Benelli with an output of 52.5bhp @ 13,000 rpm!

My point is I would have thought we would have developed the combustion engine further by now, more efficient and lighter.
 

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I was looking at the F800 ST at the Javits cycle world show. Very nice bike, but same price as a Sprint ST ($11k) so I'd probably stick with Triumph if ever I was to get a sport-tourer.
Compared to the 865 twin...
Higher engine compression: 12.0:1
Bore x Stroke: 82 x 75 mm

here's more on the BMW

IMO the bonnies are way cooler for less money.
 

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Between the 12.0:1 compression, and fuel injection/ water cooling + having a longer stroke than the bonnie motor...pretty much explain's the performance difference.

Also, the bonnie is a modern classic. I dont believe their intention was to produce a 80hp motor when they had cosworth design it.


A 904 equipped bonnie such as mine is right along the #'s the beemer produces stock.
 

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Piston-I posted the same question about the weight of the Bonneville around January 1st. It was titled "A weighty problem for the new year" or something like that. (title result of maybe one too many rum egg nogs) Anyhow, there were some interesting responses ranging from irritation ("Why did you buy this beautiful bike if you thought it's too heavy!?") to major surgery ("I cut of everything past the shock mounts"). A suggestion by someone was to reduce the unsprung weight. Any modification along this line would reap the most benefit in performance and handling. I asked if aluminum wheels would be a good move, but got no direct response to that question. I discovered a manufacturer called Sun Rims, Inc. that make aluminum rims, even in colors (think black), but they are very pricey. It would be great to hear any weight reducing ideas that don't compromise the looks or personality of the bike.
 

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The problem with the weight is due to all the cast on the bike, remove your fuel tank and have a look at the huge square backbone, look at the large neck and how it is all 1 piece compared to part's from bonnevilles from the past.

The new bike's are definately larger than the bike's of old, which plays a part as well. Alum rim's would save you some weight and rotating mass, but wont affect the overall big picture alot.

If you really wanted to go nutz and reduce weight everywhere you could, I suppose you could do the following.

Cut off the rear footpeg brackets where they meet the frame and weld plates over the holes. Cut off the excess frame area behind the upper rear shock mounts.

Take a drill and a couple varying size's of drill bit's and strategically drill holes throughout the backbone from front to rear, perhaps from small to large or the oppisite per your taste and desired end result. You could possibly do this to the neck area as well.

Important note, I do not condone doing this.

:)
 

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BMW F800S is $9,900.00 and compares more favorably IMO to the pre-07 Tiger.F800S
Beemer is getting about the same power as a Scrambler from their single, and not much short of the Bonnies at that with F650GS. $7200.00
F650GS
Don't even look at the Country & Moto Spec
Country
Moto
I think the singles are built in Italy by Aprilia. Nice stuff. Only problem is you can't find a dealer because BMW terms for dealerships make Triumphs look downright benevolent. Makes you kinda wonder when the 675 Triple Tiger Cub is coming, don't it?


[ This message was edited by: Brooksie on 2007-02-02 19:22 ]
 

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The easiest way for most of us to reduce bonnie's weight is to reduce the weight that sits on the seat. :-D

Larry
 
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Discussion Starter · #13 ·
I was looking at Mecatwin's Bonneville TT and their weight comes to 189 kg. I guess there is room to improve.
Only 790 cc ( 86 x 68 mm=75 hp @ 7400 rpm)
 

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On 2007-02-02 18:36, SCCTrim wrote:
The problem with the weight is due to all the cast on the bike, remove your fuel tank and have a look at the huge square backbone, look at the large neck and how it is all 1 piece compared to part's from bonnevilles from the past.

The new bike's are definately larger than the bike's of old, which plays a part as well. Alum rim's would save you some weight and rotating mass, but wont affect the overall big picture alot.

If you really wanted to go nutz and reduce weight everywhere you could, I suppose you could do the following.

Cut off the rear footpeg brackets where they meet the frame and weld plates over the holes. Cut off the excess frame area behind the upper rear shock mounts.

Take a drill and a couple varying size's of drill bit's and strategically drill holes throughout the backbone from front to rear, perhaps from small to large or the oppisite per your taste and desired end result. You could possibly do this to the neck area as well.

Important note, I do not condone doing this.

:)
You could acid dip the frame, swiss cheese the thing and go to titainium fasteners. Take off the fenders and seat , go to aluminum bars , drill all the covers out, go to aluminum wheels, put a whizzzer gas tank on, etc., etc., etc., and what would you have?? Certainly not a Triumph. These bikes were built to a certain spec and I love mine with just the few mods I have made. Lightness is a virtue but not at the expense of cool in this case-IMHO. Cost/benefit analysis comes in here.
These are not racing machines in the pure sense so I can take the extra weight as part of the package. I am looking at aluminm rims though.
 

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:roflmoa2:

Can anybody explain why the Honda 800 Interceptor that I like to borrow from a buddy is faster than my Bonneville 800??

Let's see ... what do they have in common other than engine displacement ... hmmmmm ... got it! Two wheels! :-D
 

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Can anybody explain to me why I couldn't run the mile any faster after losing 60 pounds?

You is what you is,
it is what it is,
and try as you may,
a Bonneville remains a Bonneville.

Don't get hung up on spec's, get the bike that stirs yer soul.

All said though, as much as I like the F800S.....
an R1200R with a complete Remus system (resulting in 109 hp) would be in MY garage!
 

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Right on! Spec is nice when reading magazines to try and get an idea what a bike performs like for your needs. After that, I'm not a good enough rider to care is a Honda CBR can't trail brake as well as a Yamaha R1. I just like riding.
 

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Is a case of old tech-vs-new tech. Try home maintenance on a BMW. The main reason I changed from BMW to Triumph was that my R1100RT cost more to service than my Audi.
 

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Open that engine up, skim the head to give it a bit more compression (10.4:1) and give it the fuel/air mixture it deserves and it will give that beemer a run for its money believe me!

My bonnie now has 70 rwhp @ 7000 rpm and 61 rw lb ft of torque @ 5000 rpm, and that is after the loss through the drive train.

It is my opinion that the bonnie is only so unimpressive performance wise stock because carbs = high emissions & totally with the old school theme of the bike.

Performance had to be reduced to get the thing through the strict emissions tests. I saw that restrictor plate in the airbox when I cut it up and I couldnt believe the size of it. Of course it will never be a rocket ship but she is sure strangled after coming out of that showroom.

Just my opinion though.
 

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I'm looking forward to a possible test ride of the new F800 this weekend; open house at BMW dealerships here locally. I sat on the F800S at the bike show, and it FIT.... nicely! The Bonneville's parallel twin has made me quite the fan of it's power delivery. However the advantages BMW's twin offers over the Bonnie would be to include mag wheels (lighter & durability), tubeless tires (plug & play babieee!), belt drive (no mo' stretched and/or dirty chains), lighter curb weight, MUCH better suspension, 80 hp vs 54 hp....... however, all at a price tag more than a fully equipped Thruxton. Oh..... and I'm assuming an ABS feature may be offered.

Don't get me wrong, I love my Bonnie and it's retro appeal. But I've had to pour money into it to get not even ten horsepower, sunk MORE money into suspension components that work, have experienced not only flat (tube) tires, but broken spokes as well. In a perfect world I'd like to keep it as my retro Bonnie bar hopper poser bike, AND do my 500 mile weekends on the new Beemer. In a perfect world I'd be rich.......
 
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