How fast will it go?

[79t140]

I do not want a sport bike. I like the style of the older ones and classics, which is why I ride a 79. I do however, enjoy going fast and yes, a few wheelies now and then is fun for me. It's my preference and a risk I am willing to take.
I am really considering a new Bonnie but do ride with people and we have long flat, smooth roads in texas. Going 100 is not a big deal here. On the vintage, I can't even keep up with friends riding old 750 Nighhawks. Those bikes cruise at 95 to 100 easily. I was just hoping the new Bonnies had decent performance. It would be cool if they put the motor from one of their sport bikes in them.

 

[79t140]

I should also add that of course, the top speed isn't nearly as important as how well it rides at the normal range of speed. However, it is nice to know that you can go fast if you want to. Also, in Houston, it is common to ride at 85 every time you get on it.

 

[Speed3Chris]

I do not want a sport bike. I like the style of the older ones and classics, which is why I ride a 79. I do however, enjoy going fast and yes, a few wheelies now and then is fun for me. It's my preference and a risk I am willing to take.
I am really considering a new Bonnie but do ride with people and we have long flat, smooth roads in texas. Going 100 is not a big deal here. On the vintage, I can't even keep up with friends riding old 750 Nighhawks. Those bikes cruise at 95 to 100 easily. I was just hoping the new Bonnies had decent performance. It would be cool if they put the motor from one of their sport bikes in them.

I will say you are a bit unusual. You want a high speed bike with the style of a retro classic which is a naked std, not a high horsepower bike and not designed for high speed riding. A bonnie will not a do a wheelie by rolling on the throttle...even with big bore kit and cams. BIG bore and stroke perhaps yes but now you have a $16,000 bonnie.
If you hit the ton regularly, don't buy a bike like this. Will it hit the ton?..yes...but not comfortable riding there. This bike is OK at 70-80 but without wind protection there are much better bikes than this.
Bonnies do have decent power. In fact, if you actually use the power above what the bonnie offers with some basic tuning you will likely lose your license and why many who used to own sport bikes now own a bonnie...to slow down and enjoy the sport versus trying to prove something. This point in fact is why I haven't rushed to modify the motor and add performance. I believe in stock form I ride the bike too fast. This isn't the bike's fault but rather the bike exceeds the speed limit so effortlessly.
Why don't you pull out a roadtest of the old Nighthawk 750 and compare quarter mile times to a bonnie. A std bonnie with pipes and opened up airbox will run a 13 sec flat quarter. With a bit of compression and cams it will run in the 12's easily. I like the chances of a bonnie if racing.
See below:
http://hondanighthawks.net/750.htm
If you want to beat yourself up and ride near the ton on a naked std and want a retro bike, then perhaps choose a Ducati GT1000.
I will add for the price of a Duc GT1000 you can build a bonnie perhaps even faster for the same price but you have to know how to wrench. Insurance will still be cheaper on the bonnie. A Duc GT1000 has been correctly described as a sport bike cloked in retro garb which effectively what it is. Some guys don't even buy into the whole nostalgia thing and simply want the highest tech bike to get the job done. The wouldn't look twice at a bonnie or even a Duc GT1000 with 90 hp at the crank. The real question is...are the 100hp bikes overkill on the street. I would say yes but others would disagree.
Or if you want even a faster naked std and forgo a bit of nostalgia, a Speed triple maybe better.

 

[PieMan]

You can cruise all day at a ton, the engine can stand it. But as Chris says above, the wind blast on any un-faired bike is usually the limiting factor. How much can you take?

 

[mikenva]

Its alot more fun to have a bonnie that will run faster then you want to ride it then a star wars looking thing that you can ride as fast as it will go.Some of us like all the power we can get out of these bikes some dont but the reason everyone buys them is the look its what bikes use to be and the way a bike should look.Its allso the feel of a naked twin.Nothing like them.If you plan on rideing for hrs over 100 mph on any bike you may just as well shoot yourself and get it over with you will die soon anyway.

 

[Speed3Chris]

If you plan on rideing for hrs over 100 mph on any bike you may just as well shoot yourself and get it over with you will die soon anyway.

Yeah.

 

[79t140]

nah, not ride for over 100 at hours on end... However it's nice to be able to do once in a while when the opportunity arises. I completely agree on classic bikes. That's why my daily transportation is a 79 T 140 completely restored that I did myself and I also have a nice Norton in the garage. I do have a motocross background though and sometimes it's nice to have a little fun on your bike. I'm simply saying it would be fun to have a classic styled bike with the performance of a sport bike. For the record, I will never own a sport bike, I've ridden plenty but they are not for me.

 

[mikenva]

Well you can have what you want but it wont be cheap.My bike puts over 100 hp on the rear wheel but I could of bought another bike for what I have in the motor .Is it worth it? It is to me.It will run way faster top end then I ever want to ride it.It will pick the wheel up with just the throttle.It wont handle with a sport bike but in a stright line they dont dust you like they do with a stock bike.With 80ft/lbs of torque it is scary .Most sport bikes around the same hp make around 50ft/lbs they make there hp at 1200 rpm pluss mine is good to 9000 rpms.It will hurt you if you dont respect it.It pulls so hard from 4500 to red line that if you ride it hard your arms hurt.If thats what you are looking for call Carlos and tpusa he will fix you up.

 

[Speed3Chris]

Well you can have what you want but it wont be cheap.My bike puts over 100 hp on the rear wheel but I could of bought another bike for what I have in the motor .Is it worth it? It is to me.It will run way faster top end then I ever want to ride it.It will pick the wheel up with just the throttle.It wont handle with a sport bike but in a stright line they dont dust you like they do with a stock bike.With 80ft/lbs of torque it is scary .Most sport bikes around the same hp make around 50ft/lbs they make there hp at 1200 rpm pluss mine is good to 9000 rpms.It will hurt you if you dont respect it.It pulls so hard from 4500 to red line that if you ride it hard your arms hurt.If thats what you are looking for call Carlos and tpusa he will fix you up.

Mike knows more about these bikes than just about anybody and he walks the talk. Classics + very high performance don't go together unless you build it yourself which is big bucks. Where I differ I guess from you OP and Mike to a degree is I like sport bikes. I don't own one because I really don't want to ride that fast. I go 90 mph just about every time I ride my bonnie and I don't want to ride faster. No doubt Mike's bike is scary fast and most of all I respect his talent to have built the bike he wanted. Most can't say they built one of these motors up from scratch including me. I have built other motors up though and to me modding these bikes is a big part of the fun.
I won't build as fast of a bonnie as Mike likely ever but the motor will be apart for some go fast parts at some point.
OP...I say either build a faster bonnie or buy a faster bike if you have a need for speed.

 

[ivar]

That's why my daily transportation is a 79 T 140 completely restored that I did myself and I also have a nice Norton in the garage.

From your earlier posts, it sounds like a Bonnie will need to have some work done to provide what you're after, are you willing to do that or do you want to buy something box-stock?

With 2 classic brits in the garage, how about a Thunderbird Sport - or one of the big UJM's in addition? Like this 100HP XJR1300

 

[Jimbon]

Reading speeds at different revs in standard top gear on my 865 indicates a potential top speed in the neighbourhood of 120-125mph in top gear on the rev limiter. But of course the faster you go the harder the engine has to work against wind resistance to reach this potential top speed.

I have TORs that Triumph claim give an extra 8-10bhp and I've pulled the snorkel, which has had a noticeable effect of giving a more willing engine with greater pull. So if the standard Bonnie gives 66bhp + 9bhp for TORs and say an extra 5bhp for snorkel less freer breathing this gives a figure in the neighbourhood of 80bhp. (I wonder if this is so and what torque my bike now develops.)

As my Bonnie, when shod with factory fitted Metzler tyres, once reached 105-110 (on a track of course) before I pulled the snorkel, I suspect it's now capable of 120mph terminal velocity.

But the limiting factor to finding top speed is how the bike now handles with Avon Roadriders without a steering damper. In reality, my top speed after crossing a rut in the road (track) where I can control the resulting wobble/potential tank slapper (discovered with a wet bum) is 95mph.

 

[ivar]

I have TORs that Triumph claim give an extra 8-10bhp and I've pulled the snorkel, which has had a noticeable effect of giving a more willing engine with greater pull. So if the standard Bonnie gives 66bhp + 9bhp for TORs and say an extra 5bhp for snorkel less freer breathing this gives a figure in the neighbourhood of 80bhp. (I wonder if this is so and what torque my bike now develops.)

those figures sounds very optimistic

 

[sweatmachine]

those figures sounds very optimistic

Uh yeah. That setup will yield hp figures in the low 60s at the wheel. To get 80hp you need a 904cc plus free flowing exhaust and bi flatslide carbs. And some time on the dyno.

 

[Speed3Chris]

Reading speeds at different revs in standard top gear on my 865 indicates a potential top speed in the neighbourhood of 120-125mph in top gear on the rev limiter. But of course the faster you go the harder the engine has to work against wind resistance to reach this potential top speed.

I have TORs that Triumph claim give an extra 8-10bhp and I've pulled the snorkel, which has had a noticeable effect of giving a more willing engine with greater pull. So if the standard Bonnie gives 66bhp + 9bhp for TORs and say an extra 5bhp for snorkel less freer breathing this gives a figure in the neighbourhood of 80bhp. (I wonder if this is so and what torque my bike now develops.)

As my Bonnie, when shod with factory fitted Metzler tyres, once reached 105-110 (on a track of course) before I pulled the snorkel, I suspect it's now capable of 120mph terminal velocity.

But the limiting factor to finding top speed is how the bike now handles with Avon Roadriders without a steering damper. In reality, my top speed after crossing a rut in the road (track) where I can control the resulting wobble/potential tank slapper (discovered with a wet bum) is 95mph.

A stock bonnie motor with opened up airbox and free flowing pipes will create a max. of 62-64 hp at the wheel which translates to low to mid 70 hp at the crank. Those that have hotrodded the bonnie with 904 BB and + 813 cams with some tuning and relatively stock head and carbs get mid 70 hp at the wheel. With freer flowing head and carbs and 80-82 hp at the wheel = 90 hp or a bit above at the crank....which probably brings it up to the performance of the Duc GT1000 for about the same money. To create the latter count on about $3K or a bit more. A good bang for buck improvement and what I will likely go for is are TPUSA's HC pistons + 813 cams. I believe Carlos quotes a 8-10 hp pop for this kit all else being left alone which for 1 large is a pretty good deal and arguably best value for increasing performance. For another $2K you get another 7 hp or so with BB kit and flowed head and maybe not even that without carbs which makes things even more expensive. Each has to do the math to see if its worth it to them.
PS: pulling the snorkel maybe worth 1hp on a good day.

 

[mikenva]

yea you dont have as much as you think .Maybe low 60hp it takes more then that to hit 8000 in 5th gear.In real world you might see 115 or less on the speedo you can take about 6 mph off that for the speedo being off.I can tell you a stock 790 setup rev limit gear ,tires and so on will only do about 117 mph it will show around 121 on the speedo.I set up like that when I had the 988 motor just to see what it felt like.At that speed its like cruse control when you hit the rev limit.790 box only goes 7400 rpm 865 box will go around 8000 rpm .I have seen the speedo go over 130 once its no fun to ride that fast on a naked bike.A face shield on a open face helment touches your nose at that speed,wind is bad news.I give alot of respect to the guys that can hang on to these bikes over 150 mph on the flats there crazy lol.Got to say it is like a high though when you get to the point wind over rides engine you hardly know its running.

 

[Jimbon]

Obviously Triumph's figures are given as measurements at the crank. They are either lying about increased output with TORs or this is about 75bhp for my 865cc at the crank.

Suck it and see first hand experience clearly shows that any calculation that comes up with a 1bhp increase for pulling the snorkel is a gross underestimate.

Pulling the snorkel has made a much bigger difference to my bike's performance which, clearly due to a much improved airflow and therefore burn efficiency and power increase, revs and pulls noticeably and satisfyingly stronger than a 1bhp increase, which would not even be felt when accelerating.

My original point was that all this is irrelevant to top speed if you crash before getting there.

 

[Speed3Chris]

Obviously Triumph's figures are given as measurements at the crank. They are either lying about increased output with TORs or this is about 75bhp for my 865cc at the crank.

Suck it and see first hand experience clearly shows that any calculation that comes up with a 1bhp increase for pulling the snorkel is a gross underestimate.

Pulling the snorkel has made a much bigger difference to my bike's performance which, clearly due to a much improved airflow and therefore burn efficiency and power increase, revs and pulls noticeably and satisfyingly stronger than a 1bhp increase, which would not even be felt when accelerating.

My original point was that all this is irrelevant to top speed if you crash before getting there.

This isn't higher math. 67 hp at the crank for stock motor + 8 hp for Tors = 75 hp at the crank = 63 hp at the rear tire. This is if everything is right. Introduction of Tors is probably closer to 5-7 hp increase...same as Norman Hyde reports with his Togas.

Removing the snorkel doesn't do much. You can disagree all want but that is the reality. If you want increase...btw the airbox is more restrictive than the pipes...gut the airbox. Middle ground is remove the restrictor plate. Pulling the snorkel and then opening up the airbox wall to the ID of filter will improve flow...maybe 2 hp...lol.

Sucking on the snorkel only makes you sick but not as bad as crashing at top speed. :sheep:

 

[Jimbon]

Removing the snorkel doesn't do much. You can disagree all want but that is the reality. If you want increase...btw the airbox is more restrictive than the pipes...gut the airbox. Middle ground is remove the restrictor plate. Pulling the snorkel and then opening up the airbox wall to the ID of filter will improve flow...maybe 2 hp...lol.

Where's the solid evidence for this?

 

[Speed3Chris]

Where's the solid evidence for this?

How about for your remarks that removing the snorkel offers a substantive boost in performance?
Btw...at what rpm are you speaking of? Up to 4500 rpm with stock motor aka airpump, there is virtually no difference in performance between stock airbox and pods aka no airbox. Pods versus gutting the box manifests only a slight improvement "above" redline for those that have raised their redline. Pulling the snorkel adds noise more than hp. If you want any quantifiable improvement, then at least pull the restictor plate. Gutting the box will yield improvement approaching redline.

 

[Jimbon]

How about for your remarks that removing the snorkel offers a substantive boost in performance?

I've already said: first hand experience:

If it has wings, feathers, webbed feet and quacks, it's a duck; if I can hear the increased howl of air rushing through the airbox and my bike revs and pulls substantially harder so that it puts a bigger smile on my face, the bike's developing much more than an extra 1 or 2 bhp.