Monoshock bonneville - Triumph Forum: Triumph Rat Motorcycle Forums
Air Cooled Twins Technical Talk Technical Talk for Hinckley Triumph Twins: Bonneville, Bobber, T100, Speedmaster, America, Thruxton, and Scrambler.


Sponsored by: Triumph Twin Power Ltd

 16Likes
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 16 (permalink) Old 11-26-2018, 04:54 AM Thread Starter
Formula Extreme
Main Motorcycle: 2004 T100 Black
Senior Member
 
sayonora's Avatar
 
Join Date: May 2012
Location: Europe
Posts: 795
Other Motorcycle: '55 royal enfield bullet
Extra Motorcycle: N/A
Garage
Monoshock bonneville

Hi

I'm currently modifying my bonneville for my RTW trip in 2020.
As I'm building parts for it, trying to keep it classic but functional I've stumbled upon a problem.

I'm using TOR's at the moment which I like for both looks and sound very much. This limits my water threshold by quite alot. None of the aftermarket high exhausts really please me aesthetically or functionally. All of them make the rear of the bike really wide and sound off.

I've made friends with a BMW afficionado who is helping me and advising me. This gave me the idea of building an exhaust system similar to his.

On his bmw's he has the BMW late 70s style single shock, where it sits on the right hand (shaft drive) side. This way he can mount an exhaust can where the other rear shock is supposed to go, making his bike very narrow.

I'm curious if anyone has an idea if a similar style setup can be done on the stock swingarm, using just one shock with a reinforced top and bottom mount, closer to the pivot point.



sayonora is offline  
Sponsored Links
Advertisement
 
post #2 of 16 (permalink) Old 11-26-2018, 08:06 AM
6t
SuperBike
Main Motorcycle: The one that I am on
Senior Member
 
6t's Avatar
 
Join Date: Apr 2007
Location: Eastern Canada
Posts: 1,569
Other Motorcycle: 2002 Bonneville America
Extra Motorcycle: Honda RC30
The stock swing arm will flex and twist if only supported on one side, not sure how you would brace it to prevent that happening. I have a 'bike with a single sided swing arm and it is pretty beefy.
rodburner and sayonora like this.

2002 T100 Anniversary. Lucifer Orange no more, "Scrambled"
Brakes and suspension, various Scrambler parts, speedo/tach in headlamp .
6t is offline  
post #3 of 16 (permalink) Old 11-26-2018, 01:53 PM
Team Owner
Main Motorcycle: None don't ride anymore
Senior Member
 
Join Date: Dec 2004
Location: Tacoma,WA
Posts: 4,837
As T mentioned,a huge amount of bracing would be needed,and with the swing arm pivot being the engine case,it would probably require the whole rear of the frame to be sub sectioned to relieve stress on the engine block. Next would be the length,strength and stiffness of a shock to literally support twice the normal load through the shock mounts. Also a factor,chains move up and down differing amounts at different points along their lengths,unlike shafts,which spin at a near constant length. When I mono shocked my bike,I already had stretched the swing arm,so just some reinforcements there and at the rear of the frame allowed for the single shock (cbr1000) to be mounted in line with the wheels. Very soft and smooth with 5 plus inches of travel. But 5” at the axle equated to more travel at the pivot than the countershaft sprocket was happy with,lol,eating the boxed section at the front of the arm. Would be easier to build a small,towable trailer for water and gear....
sayonora likes this.

Ruining a perfectly good Bonnie since 2004.
rodburner is offline  
 
post #4 of 16 (permalink) Old 11-26-2018, 09:05 PM
6t
SuperBike
Main Motorcycle: The one that I am on
Senior Member
 
6t's Avatar
 
Join Date: Apr 2007
Location: Eastern Canada
Posts: 1,569
Other Motorcycle: 2002 Bonneville America
Extra Motorcycle: Honda RC30
Quote:
Originally Posted by rodburner View Post
As T mentioned,a huge amount of bracing would be needed,and with the swing arm pivot being the engine case,it would probably require the whole rear of the frame to be sub sectioned to relieve stress on the engine block. Next would be the length,strength and stiffness of a shock to literally support twice the normal load through the shock mounts. Also a factor,chains move up and down differing amounts at different points along their lengths,unlike shafts,which spin at a near constant length. When I mono shocked my bike,I already had stretched the swing arm,so just some reinforcements there and at the rear of the frame allowed for the single shock (cbr1000) to be mounted in line with the wheels. Very soft and smooth with 5 plus inches of travel. But 5” at the axle equated to more travel at the pivot than the countershaft sprocket was happy with,lol,eating the boxed section at the front of the arm. Would be easier to build a small,towable trailer for water and gear....
I thought you had done things with your swing arm back in the day 'burner, just couldn't find the thread. Nice to see that you are still lurking around the forum. Take care.
HayMike likes this.

2002 T100 Anniversary. Lucifer Orange no more, "Scrambled"
Brakes and suspension, various Scrambler parts, speedo/tach in headlamp .
6t is offline  
post #5 of 16 (permalink) Old 11-27-2018, 01:03 AM
Team Owner
Main Motorcycle: None don't ride anymore
Senior Member
 
Join Date: Dec 2004
Location: Tacoma,WA
Posts: 4,837
Thanks T. Always here,just forget more than I know.lol
6t, HayMike and sayonora like this.

Ruining a perfectly good Bonnie since 2004.
rodburner is offline  
post #6 of 16 (permalink) Old 11-27-2018, 03:02 AM
Formula Extreme
Main Motorcycle: 2010t100 67 ttspecial rep
Senior Member
 
mike-tt special's Avatar
 
Join Date: Apr 2012
Location: N wales uk
Posts: 908
Other Motorcycle: 91 zxr750(805cc)
Garage
i think sayonora means the bike wading capability when he says his "bikes water threshold".

And i have to agree with the others about the negatives of using a single shock on our swing-arms (the BMW gs have a great big strong cast shaft drive casing)
but should add there is another additional drawback about doing this on a world tour bike and that is the logistics of repairing/replacing what would have to be a one-off shock while halfway around the world (probably in the most remote part of it)

i think Triumph's own solution on a previous model off-road Tiger trail is a more practical solution https://uk.images.search.yahoo.com/i...ee&fr2=piv-web
sayonora likes this.

who wudda thought id wanna bonneville!
mike-tt special is offline  
post #7 of 16 (permalink) Old 11-27-2018, 06:31 AM Thread Starter
Formula Extreme
Main Motorcycle: 2004 T100 Black
Senior Member
 
sayonora's Avatar
 
Join Date: May 2012
Location: Europe
Posts: 795
Other Motorcycle: '55 royal enfield bullet
Extra Motorcycle: N/A
Garage
Hi Rod,

Thanks for the reply; I was thinking of your bike but I wasn't sure you were around anymore!

The reason I came up with this is because bmw pretty much just put a single shock on a twinshock swingarm at first. The bike you see above does not have the cast aluminium swingarm, but the steel one. In fact, Bas, the hyperpro technician and BMW guru who is helping me with my bike build and who owns and built the bikes above says that the alu swingarms and the modern swingarms are much less strong and are more prone to breaking than the steel ones.

He suggested me to either go with dualshocks or find a single sided swingarm that could fit. They are usually a bit of an eyesore though.

Is there any knowledge of drop-in swingarms from different bikes? I read KTM650 somewhere, but they are unicorns seemingly.

Having a shock malfunction is definitely not a very entertaining thought, but I'm sure we could find a sollution for that (possibly just fitting a GS type shock like his bikes use), but good point indeed. I have confidence in Bas and Hyperpro

I'd completely forgotten about the tiger trails bike. That could be an option aswel, though our bikes rear's are far more bootylicious than the tr7s was.

I know pretty much all of the parts on these bonnies are way overbuilt, hence the assumption this might work.
sayonora is offline  
post #8 of 16 (permalink) Old 11-27-2018, 12:15 PM
Formula Extreme
Main Motorcycle: 2010t100 67 ttspecial rep
Senior Member
 
mike-tt special's Avatar
 
Join Date: Apr 2012
Location: N wales uk
Posts: 908
Other Motorcycle: 91 zxr750(805cc)
Garage
sorry if i'm appearing to be so negative about this idea mate.

but another factor why i think this is ALOT! of hard work for very little gain is the difficulty modifying the chain run and brake assembly.
sayonora likes this.

who wudda thought id wanna bonneville!
mike-tt special is offline  
post #9 of 16 (permalink) Old 11-27-2018, 04:47 PM
Pole Position
Main Motorcycle: 2016 THRUXTON S/GREEN
Senior Member
 
Join Date: Jan 2009
Location: Daytona
Posts: 3,932
Other Motorcycle: FZ 09
Extra Motorcycle: 2016 FZ07
A whole lot of work to achieve something already in production in another bike. The Bonneville engine ( 790/865) is very heavy for it's output, has only 5 gears. If anything you could design or canabalize another frame entirely. While you can bump the engine up to a 904-1200 netting a 85-110 bhp. Good luck with your idea.
We currently build street trackers with monoshock frames but at a very high cost.
sayonora likes this.
vitesse is online now  
post #10 of 16 (permalink) Old 11-27-2018, 10:16 PM
Site Supporter
Supernova
Main Motorcycle: 2009 Bonneville SE
Lifetime Premium
 
Forchetto's Avatar
 
Join Date: Jun 2009
Location: Asturias, Spain
Posts: 20,619
Other Motorcycle: Yamaha XV1100
Extra Motorcycle: Qingqi QM200GY-BA
A few years ago member @kiwiraca did just that, a monoshock Bonnie, not that hard according to him. See thread linked, post 8 has photos:


https://www.triumphrat.net/air-coole...gone-wild.html
sayonora likes this.
Forchetto is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options
All posts must adhere to Forum Rules

Register Now



In order to be able to post messages on the Triumph Forum: Triumph Rat Motorcycle Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter your valid email address, that can receive an automated confirmation message. Otherwise, you won't be able to gain full access.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
Bonneville Newby Glanier89 The Welcome Center 2 09-17-2017 01:36 PM
Rebuild Master Cyllinder... nickolender Hinckley Classic Triples 4 07-03-2017 10:59 PM
Aftermarket Tach & Idiot Lights Wiring Bonneville roboo7 Air Cooled Twins Technical Talk 1 03-04-2017 04:45 AM
2016 Triumph Bonneville: Spy Shots Halfpint News Room - Homepage 37 05-19-2016 06:23 AM

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome