Screen for Triumph Bonneville T100.?

Question

What is the smallest screen I can fit that will still be effective in diverting some of the noise and windblast. Also the stock silencers are very quite when riding, such that I get very little feedback from the motor. Your advice appreciated.

Answer 1

Ms. Trix,,,try the old Bonneville mufflers from '70 or earlier.

They sound Great,,make more power and are Not stoopid Loud.
..................................
I just saw your previous question about gearing.
Sorry you didn't get any help on how to gear >Your bike >for You and >how/where you ride it.

That sense of wanting a "6th gear"....I doubt 1 tooth will satisfy that craving.
"Next Gear in High" should be about 15~20%---depends on lottsa variables.

As-Is ,,You should be running about 4000 rpm around 62mph/ 100kph.
( I may be wrong,,,just guessing,,,dont have enough details & specifics)

A 15~20% Drop from 4000RPM = 600rpm~800rpm

So in that example,,,,
4000 rpm @ 100kph would drop to
3200~3400 rpm.

Ride your bike at 3200~3400 and "Imagine" you are cruising at 100kph,,,,
Feel how it Pulls from that RPM(regardless what speed happens to be).
A Theoretical "6th gear" would feel approximately the same.
There's other considerations which demand a correction factor,,,
It's VooDoo,Not "Science"

But you can get a good idea of how a 15~20% Higher gear would Feel when accelerating from 100KPH.

Make sense??
"Ignore" the Speedo.
"Mind the Rev Counter"
Find an RPM in Hi Gear which YOU are satisfied with:
A)The way it Pulls from that RPM
B)The sound/feel of That RPM at steady cruise.

You may find 3200 rpm is what you'd like,,,or 3500,,,who Knows?
ONLY YOU,,,
Your weight,the amount of wind resistance of Your stature,,the way YOUR engine runs in YOUR climate and altitude,,etc.


ONE Tooth on countershaft/front sprkt ,(as bests as I can estimate w/o knowing specific)
..Is about 200 Rpm/3 Mph~3 kph

If You go ride your bike at 100Kph as-is,,,
And throttle back 200 rpm/3kph to 97kph......
That's the Effect of +1 Tooth on front sprkt.
If it's Enough for You,,,and you Like that---Great

If Not,,,you're going to hafta add more gear.

I half-looked,,,but could find No Info on '07 Bonney primary ratio or trans ratios,,,,could not even find final drive ratio or tooth count.

Old Twins ran a 2:1 Primary and Direct High,,,
so overall was simply Half of Final Drive ratio.

Best as I could imagine,,,arbitrarily assuming 2:1 Primary ,,,
a '07 has about a 4.60 Overall gear.

Torque Peak is published as 6000 rpm
HP peak ,,,,7200

I'm fairly well familiar with typical Brit philosophy of engine tuning,,,cams,airflow,etc and the resultant typical output graphs.

ROUGH,approx rule of thumb is that the useable Torque Begins at an RPM that is about Twice the spread of TQ to HP Peak.

An '07 T100 is advertising a 1200 Rpm spread between the 2 peaks,,,from 6000 to 7200.
Twice that is,,,2400 RPM.

Torque peak is 6000,,,less the 2400 theoretical RPM Band width(the word Theory sounds better than Wild Guess,,LOL)..
That's down to 3600 RPM.

Which IMPLIES that You Should be able to Cruise at 3600 Rpm vs 4000 and still have very good Pulling power when opening throttle from that speed.
Very little difference than current gearing.

Again,,not knowing the necessary details,,I cannot state a specific ratio to try.

But assuming you DO have a 4.60 overall,,,here's a comparison just as an example.
Using a 3000 rpm base,,, and 63MPH (100 KPH) Median,,and 6000 rpm Torque peak.
(all based on 2:1 Primary ,which is just a guess)
(and,,The Numbers are rounded haphazardly:)

4.6:1=18T x 42T (which I assumme is near Stock)
3000RPM =49 MPH
3900rpm=63mph/100kph
6000rpm= 97mph

4.4:1= 19T x 42T (+1 on Countershaft)
3000= 51mph
3700= 63mph >>>+1T = ( -)200Rpm
6000=100mph

4.2:1 = 18T x 38T (Stock Front? x -4T Rear)
3000=53Mph
3500=63mph>>>> -4T Rear = -400Rpm vs 4.60 stock gear
6000= 106mph

4.0:1 = 18T x 36T (Stock Front? x -6T rear)
3000=56Mph
3400=63mph>>-6T Rear = --500Rpm vs stock 4.60
6000=112mph

Ratio-wise,,,the difference between a 4.60 and a 4.0 is about 12%

Which is about the difference of what would be a 5th Gear to "6th" gear change.
(That's VERY subjective)---but it's about HALF of an average OVERDRIVE.
Most OD's are in 20% range

I Doubt you'd LIKE it,,,and depending of transmission spread,,,,but you Could gear it High enough to act as a pseudo 4spd w/5th OD.
That'd require a 3.80 or 3.60,,,,which is wayyyy Too High if bike has close-ratio gearbox.

Your 100kph cruise RPM would drop to 3200 & 3000 respectively
At your Current 4000rpm/100kph,,,,you'd be going
3.8@4000=78mph/125Kph
3.6@ 4000=83mph/134Kph

15~20Mph Faster,,or 800~1000 Rpm Lower compared to current gearing's 4000rpm/100kph cruise speed.

Anyway,,,Please forgive the rant,,I realize your question about Gearing has already been answered .
But there IS a more methodical approach to the matter,,,which Is calculable and will yield much closer to Desired results than simply buying what's available from a parts department.
You CAN determine what You WANT it to do,,,
and pre-test to get an idea of how it'll act BEFORE you spend your time & money.

........................................
Back to pipes,,,,
TRY to scmooze some Loaner Silencers from any '60's Unitized Twin....'65 to '70 era.
I think you may like the tone and the lil' extra power.
Sometimes a shoppe has a few laying around they might let You Try before you decide.

I think they Look better than those 60's BSA Gleaming Weiner-looking things that Triumph stuck on there lately

'67 Spitster,,,,mufflers look familiar?
http://www.vagn-jensen.dk/arkiv-solgte/image-arkiv/bsa-spitfire-mkIII-1967-1.jpg

One similar to yours
http://www.bikez.com/pictures/triumph/2004/20959_0_1_2_bonneville%20t100_Image%20credits%20-%20Triumph.jpg

Old School Bonney's..note the Tapered end,,short sound chamber,,and longer outlet pipe compared to your current type.

http://www.motos-anglaises.com/triumph/T120/T120j1.jpg

http://slipperyskip.com/Triumph/Triumph.jpg

Pipes are personal :)
You may hate 'em,,sooo,just a suggestion.
They do sound/run better though.


Take care.

Answer 2

There's a small range of screens Triumph offer - www.triumph.co.uk, with the 'fly screen' probably being the best solution for you. However there's also a very good forum at www.bonnevilleamerica.com which covers this kind of thing exactly. I'm buying a Bonneville variant, and found this the best site for asking specific questions - and I remember a question that dealt with recommended 3rd party screens and silencers.

Also, motorcycle clubs and most of the blokes working at Triumph dealerships seem to know how best to add bits to Bonnevilles - ask them

Answer 3

Get used to keeping an eye on the rev counter. Trust me you do not want nosier exhausts as these will attract unwanted attention from your neighbours and the local constabulary. Triumph Owners Club should be useful on zorts and fairings. http://www.tomcc.org/